ALBERT

Description: The results show that liquid fertilizers generally gave lower yields of dry matter than conventional solid fertilizers in four experiments on grassland. In seven trials, on autumn wheat, spring wheat, sugar beet and kale, the efficiencies of the two forms of fertilizer were similar.Liquid fertilizers containing ammonia must be injected into the soil and this needs special equipment, more complicated, particularly where anhydrous ammonia is to be used, than the distributors used for solid fertilizers. Running the injector over established grassland sometimes resulted in considerable damage to the sward. When used to top-dress winter wheat across the line of drilling some plants were killed.

Description: 1. The problem of inbreeding and the fixation of apparent heterosis in the cultivated tomato and in inbreeding crop species generally is discussed. The case is argued that ‘heterosis’ as normally understood in out-breeders is not likely to exist as a general phenomenon in inbreeding species.2. Selections were made among segregating progenies of two successful, commercial F1 hybrids, and the performance of the selected lines, up to the F4 generation, shows that the superiority of the hybrids over their parents can be fixed in purebreeding lines.3. Owing to selection effects in inbreeding species of crops the best parents will differ in respect of fewer quantitative loci than is to be expected from general experiments on quantitative inheritance. In the present material, desirable recombinants were isolated at a frequency of 1 in every 1000–1500 F2 individuals.4. The utility of F1 hybrids in the tomato thus depends on the economy of effort involved in their development as compared with the isolation of pure lines. It is concluded that the production of hybrids is to be favoured only when reliable methods of prediction of their performance are available, and then as an interim measure while pure-line forms become available.

Description: 1. The availability of iron in five species of legumes has been investigated, using the rat as the experimental animal.2. Two procedures were employed, namely, the increase in blood haemoglobin concentration, and the gain in total grams of haemoglobin, by nutritionally anaemic rats.3. Inorganic iron, as ferric chloride, was shown to be significantly more available than the iron contained in the five legumes.4. A significant difference in iron availability between alsike and wild white clover was obtained with both methods of expressing the results. Differences between other species were not significant.5. The data are compared with those obtained for three species of grass in an identical experiment reported previously.

Description: An account is given of the considerations which have been found in practice to govern the design of a small cabinet for growing plants under closely controlled conditions of atmospheric environment. Starting with questions of size, shape and material, the connexion between size of chamber and type of illumination is considered, followed by general policy on air supply. The main outlines of design having been laid down in this way, the various environmental factors to be controlled are reviewed. These include: (a) composition of the air, with particular reference to carbon dioxide; (b) light intensity. Various possible sources are reviewed, and the difficulties of imitating natural conditions of illumination are discussed, together with methods of measuring the illumination and checking for stability; (c) temperature. The degree of control needed for various purposes is considered, particularly in connexion with control of humidity, followed by systems of control, and the most advantageous arrangements for them. The cycle of operations of a control system is considered in some detail, and division of the system into a small relay-operated heater and a background heating or cooling system is advocated; (d) humidity. A similar division between background and relay-operated humidifiers is also advisable, and methods of achieving this are outlined. Dew-point control is shown to be most suitable for the background humidity, while a hot wick of low thermal capacity suffices for the relay-operated device. Finally, the principal uses of such cabinets are dealt with: (a) as adjuncts to field experimentation; (b) for work on plant pathology; (c) for producing standard plant material at any time of year; and rough estimates of running costs are given.

Description: 1. In a field experiment all plants of S. 48 timothy produced ears after being sown on or before 24 April; more than 90% of the plants still flowered if sown up to 19 May but fertility declined after later sowings, until only vegetative growth resulted in plants sown on or after 30 June.2. In a pot experiment, during which the performance of individual tillers was recorded, all tillers arising after 23 July were found to remain vegetative. Ear-bearing capacity declined towards this date but was still high in tillers appearing as late as 2 July in plants sown in the middle of May.3. Tillers on the main stem were more fertile and produced heavier ears than other tillers of the same age and order of succession on the plant.4. Many plants sown late in the field produced ears which formed vegetative proliferations after the end of the summer.5. The results are discussed in relation to the response of timothy to the changing environment, notably the length of day. It is suggested that timothy does not react to favourable photoperiods immediately upon germination and that failure to flower in plants sown after the middle of May does not necessarily imply any inadequacy of the environment to cause floral initiation, since it was possible for tillers appearing up to 2 July to produce ears, with few exceptions. Factors inherent in the organization of the plant are considered to be responsible for a decline of ear-boaring capacity from tiller to tiller, which occurred irrespective of changing environmental conditions.

Description: 1. Four varieties of marrow stem kale, three of thousand headed kale, Hungry Gap Kale, Rape-Kale and five other rape varieties were sampled at two centres in mid-Wales and separate leaf and stem samples analysed for manganese, molybdenum and boron. Similar samples of four varieties of marrow stem kale, two of thousand headed kale, Hungry Gap Kale, Rape-Kale and two other varieties of rape were taken from two further centres and prepared with the most stringent precautions to prevent contamination. Iron, copper, zinc and lead were determined in these samples.

Description: 1. A theoretical feeding scale, designed to supply the full nutritional requirements of the lactating sow and prevent weight loss (allowing approximately 8 lb. meal per sow and 0·8 lb. per piglet), was tested against a much lower but commonly recommended level (2 lb. meal per sow and 1 lb. per piglet). The meal (barley meal, 40%; ground oats 25%; middlings, 20%; white fish meal, 7·5%;, groundnut meal, 2·5%; dried grass meal, 3·8%; ground limestone, 0·3%; common salt, 0·3%; vitamins A, D and B2 supplement, 0·6%) contained approximately 16·25% crude protein and had a digestible energy value of approximately 1300 Cal./lb. During pregnancies all sows were fed equal amounts of a meal containing approximately 13·0% crude protein.2. Four pairs of Wessex Saddleback litter sisters were divided between the two treatments and records taken over three lactations of food consumptions, sow body weights, milk yields, milk compositions, litter growth rates, creep-feed consumptions and reproductive performances. Litter sizes were standardized between pairs of sows within the first 10 days after farrowing.

Description: 1. Each of three litter sister sows was fed one of three levels of crude protein in the diet during two 8-day periods in the fourth and seventh weeks of lactation. The three protein levels were 11, 15 and 19% of the diet on an air-dry basis. The scale of feeding was varied to maintain each sow at constant weight throughout the 8-week lactation period.2. During two 3-day collection periods following 5-day preliminary periods, intake of nitrogen from the diet and outputs of nitrogen in faeces, urine and milk were measured.3. The sow receiving the medium level of protein in the diet was in positive nitrogen balance during both collection periods.4. The major effect of increasing the protein level of the diet was an increase in the output of urinary nitrogen. Neither milk yield nor output of protein in the milk appeared to be affected over the limited period studied.5. Apparent digestibility of dietary protein was 75% on the low level and 85% on the medium and high levels of intake.

Description: In recent investigations at this Institute, attempts have been made to devise for dairy cows a ration extremely low in magnesium to be used in fundamental studies of magnesium metabolism. All common farm roughages are moderately rich in magnesium, and wood pulp, which is low in this element, has been tested as a roughage for use in these experimental rations. American workers (Titus, 1926; Mead & Goss, 1935; Byers, Stanbus, Nelson, Brown, Davis & Gardiner, 1955; Matrone, Ramsey & Wise, 1957; Smith, McLaren, Anderson, Welch & Campbell, 1957; Ellis & Pfander, 1958; Williams, Musgrave, Schul & MacVicar, 1958) have previously used wood pulp as a substitute for roughage in the development of purified rations for cattle and sheep, and it was fed extensively as a substitute farm feedingstuff in Norway during the war years (1940–44)(Edin, Helleday & Nordfelt, 1941; Hvidsten, 1946). This note records some observations on the feeding of wood pulp, often as the sole roughage, to both dry and milking cows.

Description: 1. A 3-year experiment is described in which perennial rye-grass/white clover swards were cut to within either 1 in. of 2–2½ in. of ground level when the herbage had reached either the ‘grazing’ or the ‘silage’ stage of growth. Superimposed on the cutting treatments were several fertilizer treatments which involved application of varying amounts of nitrogen at different dates over the season.2. Throughout the experiment cutting to within 1 in. of ground level gave greater dry-matter and crude-protein yields of mixed herbage and of clover than cutting to within 2–2½ in. of ground level, the increase in dry-matter yield ranging from 39 to 49%.3. The response of clover to these ‘height of cutting’ treatments developed more slowly than the response of the sward as a whole, and was modified in the later stages by the particular fertilizer nitrogen treatment applied.4. It is suggested that the greater herbage yields obtained from close- than from lax-cut swards resulted from the differential effects of the two cutting treatments on stem and leaf formation in the grasses, but the need for further investigation is stressed.5. Discrepancies between the effects of the ‘height of cutting’ treatments in this experiment and those reported by other workers are indicated, and it is shown that these discrepancies probably result from the varying cutting frequencies adopted.6. Cutting the sward at varying stages of growth and increasing the rate of fertilizer nitrogen application had very similar effects on mixed herbage and clover yields in this experiment to those reported previously by other workers.7. Where the total amount of fertilizer nitrogen applied over the season was small (4 cwt. ‘Nitro-Chalk’/acre) delaying the first dressing until after the first or second cut reduced the dry-matter and crude-protein yields of mixed herbage, and had little effect on those of clover. A similar delay where greater total amounts of fertilizer nitrogen were used (8–12 cwt. ‘Nitro-Chalk’/acre) reduced the dry-matter yields of mixed herbage, and slightly increased the dry-matter and crude-protein yields of clover. Under these heavy nitrogen treatments the crude-protein yields of mixed herbage decreased only where the delay involved a reduction in the total amount of fertilizer nitrogen applied over the season.8. Although delaying the first dressing of the season reduced mixed herbage yields at all fertilizer nitrogen levels, it resulted in a more uniform distribution of production over the season. The practical significance of this is discussed.

Description: Thirty-six Hereford dwarfs, ‘comprest’, dwarf-like, and eight controls were available. Body and skin measurements were taken and the types of head abnormalities and cardiovascular activities were recorded. Haematological tests and chemical analysis of blood and hair were carried out.Typical dwarfs showed characteristic head abnormalities with varying degrees either at birth or later in life, possibly as a result of different stages of development at which the defective gene(s) comes into operation. There were progressive changes (qualitative and quantitative) in the expression of dwarf characteristics. Typical dwarfs were chronic bloaters, with pot-shaped belly or with normal belly. Atypical dwarfs were either stunted, showing (miscellaneous) deleterious genes or ‘comprest’ types. The daily live-weight gain of typical dwarfs ranged from 0·71 to 1·69 with an average of 1·26 lb. (controls 1·72 lb.). Body, head, and limb indices in typical dwarfs are similar to those of the ‘comprest’ and the control animals at comparable weights. Volume index was higher in the control than in the typical dwarfs. In the bloater dwarfs the width of the body at the shoulder region was considerably narrower. Skins of the typical dwarfs were thinner. The bloater dwarfs showed a diurnal bloat cycle (in relation to feeding time) as judged by body circumference. The severity of bloat was irregular.There was no significant difference between typical dwarfs and control animals in rectal temperature, pulse rate, blood, specific gravity, prothrombin time, sedimentation rate, red cell count, electrophoretic pattern of serum proteins, serum creatine and creatinine and calcium/phosphorus ratio in hair samples. Typical dwarfs had slower respiration rate, lower blood haemoglobin, haematocrit, and white blood count than did the controls. Post-mortem examination of dwarfs did not show similar causes of death in each case. The heart of the dwarfs was spheroid, showing severe dilation in most cases.

Description: Two procedures were followed to train boars to mount a dummy sow for semen collections. Of thirty-nine boars which were introduced to the dummy sow with no previous training twelve were trained successfully. Of eight boars which were first allowed daily mating with an oestrous sow in the pen housing the dummy sow, seven were trained successfully.Measurements of semen characteristics were made on twenty-five fertile boars including nine boars (morphological characteristics only) in use at commercial insemination centres.The mean ejaculate volume of thirty-four ‘first’ ejaculates was 173·7 ml. (range 85–275 ml.). The mean volume of the fluid fraction was 109·3 ml. (range 15·220 ml.). For second ejaculates these values were 156·9 ml. (range 80·220 ml.) and 93·2 ml. (range 25·165 ml.).The mean sperm concentration in thirty-five ‘first’ ejaculates was 284·5 x 106/ml. (range 11 × 106/ml. to 925 × 106/ml.). The mean concentration for ten second ejaculates was 224·4 × 106/ml. (range 18 × 106 to 295 × 106/ml.).In samples collected in successive 20 ml. fractions the highest concentration was found in the first 20–40 ml. In some boars the spermatozoa were distributed more uniformly throughout the ejaculate than in others.The mean number of spermatozoa per first ejaculate was 28·26 × 109 (range 0·77 × 109 to 80·0 × 109). The mean for second ejaculates was 15·88 × 109 (range 0·76 × 109 to 44·17 × 109). The mean initial pH of thirty-four first ejaculates was 7·22 (range 6·85–7·9); for second ejaculates it was 7·54 (range 7·22–8·0).There was a marked increase of pH with time after collection when semen was stored in open vessels; this did not occur when semen was stored in filled stoppered vessels.The mean pH of the sperm fraction in six ejaculates was 7·06 (range 6·8–7·4); the mean pH for post-sperm fractions of the same ejaculates was 7·36 (range 7·0–7·6).The freezing points of three ejaculates were –0·54, –0·55 and –0·56° C.The mean methylene blue reduction time for seven ejaculates was 5·0 min. (range 2·5–6·5 min.). The reducing power of boar semen was virtually unaffected when all the spermatozoa were killed by freezing.Motility of boar semen was lost rapidly when it was examined under a cover-glass; motility was restored by aeration (removal and replacement of the cover-glass).The mean percentages of nine morphological classes of spermatozoa in ejaculated semen of fertile boars were as follows: Malformed heads, 3·0; malformed middle-pieces, 2·7; bent tails, 4·5; coiled tails, 0·9; headless, 0·3; tailless, 0·3; broken necks, 0·1; neck beads, 11·8; middle-piece beads, 17·18.The decline in the concentration of spermatozoa in successive fractions of an ejaculate was associated with a decline in the frequency of middle-piece beads.The semen of one sterile boar showed a mean frquency of 77% malformed middle-pieces.The mean percentages of the above classes in samples from the vasa deferentia of nineteen fertile boars were: malformed heads, 5·7; malformed middle-pieces, 5·1; bent tails, 3·6; coiled tails, 0·06; headless, 0·6; tailless, 0·3; broken necks, 0·1; neck beads, 17·4; middle-piece beads, 59·2.The average percentages in samples from vasa deferentia of four sterile boars were: malformed heads, 11·9; malformed middle-pieces, 30·7; bent tails, 9·1; coiled tails, 0·5; headless, 0·4; tailless, 0·5; fractured necks, 0·9; neck beads, 24·2; middlepiece beads, 30·0.The mean testis and epididymis weights were 359·2 and 84·7 g. Expressed as percentages of body weight the weights were 0·285 and 0·068. The mean within pair differences in weights were 48·9 g. (between testes) and 8·5 g. (between epididymides).The macroscopic and microscopic histological features of the testes are described. Tubular atrophy associated with impaction was found to be a common feature of this sample of boar testes. There was no clear relationship of the histological features of the testes either to semen characteristics or to fertility. It is shown that fertile boars may show grossly pathological testes characteristics. The cause of the observed pathological changes was not identified. The findings are discussed.

Description: 1. Digestibility trials, using sheep, were carried out on five batches of oat hay grown during 2 years; nitrogen balance experiments were made simultaneously.2. The oat hay was not readily consumed by the sheep; this necessitated calculating the digestibility data on an ‘as consumed’ and on an ‘as offered’ basis; it also prevented a majority of the sheep from obtaining their maintenance requirements of energy or from maintaining nitrogen equilibrium.3. Statistical analysis of the data revealed a downward drift in digestibility in the succeeding periods of the 1955 trial.4. While stage of maturity had little consistent effect on digestibility or on the amounts of digestible nutrients present, the percentage digestible crude protein did increase with advance in maturity.5. The amounts of digestible nutrients present in oat hay indicated that it had a nutritive value between those of oat straw and medium-quality meadow hay.6. The data suggest that the maximum yield of digestible nutrients is obtained when the oat hay is cut at the ‘late cheesy’ stage of maturity.

Description: An experiment on irrigated wheat was laid out in a split-plot design in which six levels of N, three dates of sowing and two times and methods of application were tried. The data were subjected to pooled analysis and it was noticed that years, dates of sowing, manures and the interaction of manures and dates of sowing were highly significant, while the time and method of application of the fertilizer and all other interactions were non-significant. Graphs have been presented depicting the law of diminishing returns. Optimum levels of N have also been given. Application of the fertilizer by placement to normal and late sown crops is much better than its application by broadcasting.

Description: 1. An experimental test of the effects of 15, 30 and 60 mg. of hexoestrol (ear implants) on growth (over a period of 95 to 98 days) has been carried out in Argentina, using 172 Hereford steers (all 4–5 years old).2. On pasture where the growth rate was only about 0·4 kg. a day, the optimum dose was 30 mg., which gave an extra 0·14 kg. per day.3. The carcasses from the 30 mg. group were significantly heavier by 8 kg., those from the 15 mg. group by 7 kg., but those from the 60 mg. group were only 3 kg. heavier than those from the control group.4. It is suggested that both the poorer response and the lower optimum dose were due to the poorer pastures on which this experiment was carried out.5. Evidence for the carcasses of the treated animals being significantly leaner than the controls was given by the 60 nag. group—the grading was poorer, the excess kidney fat was less, and the subcutaneous fat was thinner.6. Carcass measurements showed differences in the treated groups, but these in general followed the differences in carcass weight.7. Measurements of width of thigh and thorax provided evidence that the depth of carcass had been increased by hexoestrol.8. The incidence of ‘tail raising’ had been increased from 10% in the control group, to 50% and more in the 15, 30 and 60 mg. groups. Carcasses from such animals had a slightly greater width at the thigh.9. The existence of an optimum dose is not thought to be due to restlessness, as indicated by ‘tail raising’, but to a depressant action of hexoestrol on growth. In this connexion, data on the weights of the kidneys show that the 60 mg. dose decreases kidney weight (and implicitly the level of protein metabolism) to the value of the control.10. Evidence was obtained of a rapid change in live weight when the steers were without food. During a single morning this was, on the average, about 13 kg. per animal, followed by a further 25 kg. during the subsequent 24 hr. (see Appendix II).

Description: 1. Observations were made on the behaviour of young spring- and autumn-bom calves reared at pasture.2. Bucket-fed calves rapidly learnt to graze, whereas single-suckled animals running with their dams made no serious attempt to graze until they were 6 weeks old.3. The time spent in grazing was modified by the presence of hay and probably by that of concentrates, and it was influenced also by the quality and quantity of herbage on offer.

Description: 1. Twelve lambs varying in age from 5 to 35 days in age were slaughtered and their carbohydrate-digesting enzymes studied for any change in activity with increase in age.2. Results are given for the changes in weight of different parts of the digestive organs and their contents, and for the content of NaCl and of total acidity in the abomasum contents.3. Pancreatic and small intestine amylase showed only a slight increase in activity up to 5 weeks of age.4. Lactase and maltase activity in the small intestine were almost constant from 1 week to 5 weeks of age.5. No sucrase activity was measurable in any of the lambs slaughtered in either the small intestine wall or its contents.6. A comparison was made between the carbohydrase activity of the young pig and the lamb.7. Calculations based on the enzyme activities of the tissues showed the theoretical amounts of different carbohydrates which can be digested by lambs and young pigs of varying age groups.8. The results suggest that the young lamb is dependent on the early development of its rumen fauna and flora for the utilization of all other carbohydrates except lactose and glucose.

Description: The metabolism of nitrogen during incubation, at 28° C. for 184 days, of a soil treated with 1% by weight of five different bulky organic manures and 0·5% calcium carbonate was studied.1. Ammonia and nitrite could not be detected at any sampling date with any treatment, hence nitrate levels in treated soils compared with that in the control soil indicated the extent of mineralization or fixation of nitrogen.2. A good straw compost (carbon/nitrogen ratio, C/N, 20·6) was the only material which showed mineralization of nitrogen over practically the whole of the incubation period.3. Rotted farmyard manure (C/N 15–6) caused a small, whilst fresh grass (C/N 22·6), caused a fair amount of nitrogen fixation in the early stages, but there was a small overall mineralization of nitrogen by the final sampling.4. A poor straw compost (C/N 42·5) and straw (C/N 147·0) both caused considerable fixation of nitrogen in the early stages. With continuing incubation the bulk of the nitrogen fixed by the poor compost, but only a small portion of that fixed by the straw, was released.

Description: The relationship between cortical area and fibre area has been examined in the N/N, N/ +, + / +, + /nr and nr/nr genotypes of the New Zealand Romney, using skin biopsies taken at birth, 1, 3 and 16 months of age. The presence of the nr gene was shown to reduce significantly the relative cortical area. Within the genotypes there was an increase in relative cortical area with increasing age and in two-tooth ewes of N/N and N/ + there was an increase in relative cortical area in winter compared to summer.Fibre growth rates in length for primaries and for prenatal and post-natal secondaries were found for lambs between 1 and 3 months and for 16-monthold ewes. In N/N, N/+ and nr/nr primary fibre growth tended to be increased and post-natal secondary fibre growth tended to be decreased relative to + / + values.In both cortical area and fibre growth rate the greatest genotypic effect was shown by the primary fibres.Some estimates of cortical volume have been made by combining the information on cortical area and fibre growth rate and the relationship of these factors to follicle density and mean fibre area has been discussed. Finally, an indication has been given of how the associations of all these four factors might be usefully examined in some British breeds.

Description: 1. Controlled self- and cross-pollinations were performed on field bean plants. It was found that while manipulation of the flower stimulated seed setting, both self- and cross-pollination were equally effective.2. Estimations of pollen germination on artificial medium, to which had been added extracts of styles or ovaries from the same or a different plant, gave some slight evidence of a specific inhibition by ‘self’ extracts. No analogous effect was detected on pollen tube growth.3. Experiments in which the style was cut at varying intervals after pollination detected no difference between self- and foreign pollen in rate of growth through the style. Pollen placed on stigmas of immature flowers began growth at once although the fertility achieved was less than when mature flowers were used.4. The composition of seed from mixed self- and cross-pollination was examined. Early application of foreign pollen increased the proportion of crossfertilization but the results were similar in hybrids and inbreds.5. Flower manipulation was more effective in stimulating seed setting than shaking the plants. Spraying with hormone solution was ineffective.6. It was found that plants varied in their capacity to set seed without flower manipulation (autofertility). Hybrid plants were more autofertile than plants from inbred lines.7. X-ray pictures of unopened flowers suggested that the pollen may be more abundant and less diffuse in hybrids than in inbreds.8. The expression of autofertility was affected by many genetic factors.9. Seed produced by open pollination of F1 hybrids contained a much higher proportion derived from self-pollination than did seed from inbred plants grown in the same plot. Possible explanations for this difference, and some consequences for the population genetics of the species, are discussed.

Description: An investigation of the estimation of the fertility of bulls' semen was carried out using the Impedance Bridge. A significant relationship between fertility and Impedance Change Frequency was confirmed, and this relationship extended to a within-bull significance.

Description: 1. An experiment was carried out to determine the effect of L-thyroxine implantation upon the wool production and live-weight change of Corriedale and Suffolk × Border Leicester-Merino sheep.2. Groups fed hay in restricted amounts gave approximately 12% more wool when treated with thyroxine. Since there was no change in fibre diameter, this was presumably due to an increase in staple length.3. Groups fed hay ad lib. gave no significant increase in wool production when treated with thyroxine, nor did their rate of food consumption alter. Their level of wool production over the 5-month period was approximately the same as that of the thyroxine treated, restricted fed, sheep.4. All thyroxine-treated groups lost approximately 10% of their live weight. This was in the nature of a steady decrease from the second to the seventh week after treatment. Live weights then remained at about the same level for a further 8–10 weeks when they commenced to return gradually to their original weights.

Description: The experiment with two trials was carried out to determine the effect of low and high germination and three seed rates of lucerne on the establishment, mortality, and yield of fodder on heavy soil at Cambridge during 1955–8.Highly significant differences were obtained between seed rates and germinations in the number of plants established in the year of sowing. The highest number of plants with thin and short tap roots were in a dense crop at 15 lb./acre and 83% of them were unable to survive the first winter. The highest mortality occurred between sowing and the first harvest year, and the heaviest loss of plants was in the lucerne drilled at 15 lb./acre and lowest at 5 lb./acre. Interaction between germination and seed rates was significant at 1% level in the first and at 5% level in the second count only.The highest differences in yield results were in the first harvest year, when a significantly lower yield was obtained at 5 lb./acre than at 10 or 15 lb./acre, but there was no significant difference in yield between 10 and 15 lb./acre. Lucerne with a high germination at all seed rates gave significantly higher yields than lucerne with a low germination in both trials.

Description: 1. The digestive organs and contents of twelve lambs, varying in age from 1 to 5 weeks, have been examined for their proteolytic enzyme activity at pH 1·8, 3·5 and 8·5.2. Enzyme activity at 1·8 was present only in the abomasum and its contents.3. All tissues and contents examined were active on haemoglobin at pH 3·5.4. Small intestine contents and pancreas alone were active on azocasein at pH 8·5.5. The majority of tissues and contents increased their proteolytic activity with increase in age. The abomasum wall, however, increased in activity up to 21 days and thereafter decreased, both at pH 1·8 and 3·5.6. Milk-clotting action was measured on abomasum wall and contents. There was an absence of milk clots in the abomasum after 21 days, by which time rumen function had commenced.

Description: A split-sample experiment involving 14,319 first inseminations was carried out at sixteen artificial insemination centres to compare the fertility of semen diluted with skim-milk and skim-milk containing 10% glycerol when used on the first, second, third and fourth days after the day of collections.The addition of glycerol to the heat-treated skimmilk diluent significantly reduced the decline in fertility with increasing age. However, there were indications that glycerolization also reduced initial fertility.

Description: Maize stomata are shown to be markedly affected by severe drought lasting about a week or more, in that they do not recover their apparent pattern of normal behaviour after the water supply to the plant is restored, although the leaves regain their turgidity and seem normal. On the other hand, sorghum stomata recover well from severe drought lasting 14 days and their recovery follows fairly closely behind the restoration of turgidity to the leaves. It is suggested that this difference in ability of stomata to recover from severe drought in some measure accounts for the superiority of sorghum as a grain crop in dry regions.Severe drought in maize is shown to be less damaging to the young plant than to the old, because the stomata of the unopened leaves behave normally when unfolded after the drought is broken.

Description: It was shown in previous work (Evans, 1958) that a cereal diet supplemented with 7% of white-fish meal supplied around 0·76% of lysine and 0·5% of methionine plus cystine. The addition of more pure l-lysine monochloride or dl -methionine to this animal-protein diet failed to bring about any significant improvement in the rate of growth, efficiency of food conversion or in the nitrogen retention of the pig, in the critical period between weaning and 80 lb. live weight. When the same cereal diet was supplemented by as much as 20% of ex. dec. ground-nut meal, however, the lysine content amounted to only 0·62% but the methionine plus cystine was 0·53%. On adding 0·2% l-lysine plus 0·2% dl-methionine to the 20% ground-nut diet the utilization of the nitrogen in the food was improved and the excretion of nitrogen in the urine was reduced. This finding was confirmed by means of a statistically designed growth trial, the daily rate of live-weight gain, improving from a mean value of 0·86 to 0·98 lb. following the addition of 0·2% of lysine and methionine, respectively, to the diet, the corresponding saving in meal consumption, between 35 and 80 lb. live weight, amounting to 16 lb. One group of ten pigs received a supplement of 0·2% of methionine only, and since it failed to show any improvement in performance over the control group it was concluded that 0·5% of methionine plus cystine must suffice to support satisfactory growth.

Description: An experiment to investigate the differential response of lambs of various breeds and crosses to different planes of nutrition is described.Two groups of twin lambs were used comprising Blackfaces and their crosses ( x Lincoln, Wiltshire and Border Leicester rams) and Welsh and their osses ( x Suffolk and Wiltshire rams).From October to January, each cross was divided between high and low planes of nutrition. Approximately half of the twin pairs were split and the remaining pairs distributed between the environments. Significant differences were found between the crosses and twin pairs of the same cross for body weight, body measurements and wool production but not for various blood characters. For almost all characters studied, plane differences were found. There was, however, only one significant (P 〈 1%) cross-plane interaction—for non-protein nitrogen concentration in the blood.At the end of January, each plane was subdivided to produce high-high, high-low, low-high and low-low groups. The lambs remained in these groups until May. As before, differences between crosses were found for body weights and measurements, and wool characters but not for most blood characters. The majority of characters were affected by plane of nutrition. Cross-plane interactions were not found except in antibody response to Erisipelothrix rhusiopathia vaccine (P 〈 5%).At the end of May the high-high group were slaughtered and the remaining three groups fattened on grass until each reached the same average weight as the high-high group. Carcass measurements showed that all the crosses shared a striking ability to recover from previous poor nutritional treatments. One significant (P 〈 5%) interaction of cross and plane was found in weight of cannon bone.The most characteristic feature of the results has been the similarity of response of the different genotypes to the different nutritional environments. The few interactions found to be statistically significant by conventional methods are difficult to interpret because of the many tests of significance carried out in the analyses.

Description: It has been established that the mineral deficiencies can be rectified on both the fescue dominant and Molinia dominant swards of mid-Wales without recourse to ploughing and reseeding (Milton & Davies, 1947). The processes adopted consisted either of liming the native swards in the absence of fertilizers or else fertilizing the sward either in the presence or absence of lime. The grazing animal played an important part in the changes that took place. Some of the treatments resulted in the partial or complete extinction of the native hill herbage and its replacement by grasses and clovers of high productivity and mineral content.

Description: 1. Field studies on Impatient parviflora DC. in shaded situations indicated the need for experimental investigation of the effects on growth of varying single factors of the aerial environment in otherwise constant conditions.2. The use of cabinets which allow accurate control of the aerial environment for studies in physiology, morphogenesis, pathology and plant selection is discussed.3. By comparison of the development and assimilatory ability of the leaves of I. parviflora, it is shown that plants may be grown in wholly artificial conditions which are substantially identical with those grown under comparable conditions out of doors.

Description: 1. Three winter feeding experiments (1954–57) were carried out using small flocks of Border Leicester x Cheviot ewes tupped by a Suffolk ram.2. The feeds used were various combinations of (a) silage, (b) hay, (c) ‘winter grass’, and (d)concentrates. Their value in late pregnancy was compared in terms of performance of the ewe and the birth weight of the lambs.3. In addition, in one year (1956–57) the effect of level of nutrition in early pregnancy and during the first 28 days of lactation was studied.4. It was found that ‘winter grass’ could replace silage and hay where a concentrate ration was being fed.5. Satisfactory results were obtained with a concentrate ration of ⅜ lb. per head per day rising to ¾ lb. per head per day by lambing time.6. In the mild winter of 1956–57 a group of ewes produced normal healthy lambs when fed entirely on ‘winter grass’ during the latter half of pregnancy.7. The intensity of grazing of the ewes in early pregnancy affected their live-weight gain, but this seemed to have little effect on lamb production.8. A high plane of nutrition during early lactation resulted in a significantly greater live-weight gain of lambs over this period. The difference had been reduced to a non-significant level by mid-June.9. None of the treatments imposed had any very marked effect on the nematode egg-output of the ewes.

Description: The experiment involved nine litters, each containing four male and female pairs of pigs. At about 10 days of age the four pairs within each litter were randomized one to each of the following treatments. (1) Pigs left with their dams, weaned at 56 days old and then fed ad lib. until they each weighed 50 lb. (2) Pigs weaned at 10 days old and fed ad lib. until they each weighed 50 lb. (3) Pigs weaned at 10 days old, given restricted feed allowances so that they weighed 30 lb. at 56 days old, then fed ad lib. until they each weighed 50 lb. (4) Pigs weaned at 10 days old and given restricted feed allowances so that they weighed 30 lb. at 56 days old and 50 lb. at 90 days old. Between 50 lb. and slaughter at 205 lb. all pigs were kept to the same very high plane of feeding, which was based on live weight. All pigs were individually fed from weaning onwards.

Description: 1. Dry-meal diets for pigs weaned at 6–7 lb. mean live weight and 6·9 days mean age were supplemented with antibiotic, pepsin and an α-amylase preparation according to a factorial design involving sixty-four pigs on eight treatments. Antibiotic was included in the respective diets from weaning to 40 lb. live weight and the enzymes from weaning to 25 lb. live weight.2. Antibiotic supplementation gave a 12·5% increase in rate of growth from weaning to 40 lb. P 〈 0·001) by reducing the incidence of scour and increasing food consumption from weaning to 25 lb. Antibiotic exerted no effect upon efficiency of food conversion.3. Pepsin supplementation increased the incidence of scour and reduced rate of growth by 3·7% whilst being fed (P 〈 0·1) and by 8·6% after it was omitted at 25 lb. live weight (P 〈 0·01). Efficiency of food conversion was reduced by 5·5% when pepsin was fed (P 〈 0·05) and by 4·6% after it was omitted at 25 lb. live weight (P 〈 0·1).4. α-Amylase appeared to exert little influence upon either growth rate or efficiency of food conversion except in the presence of pepsin. It appeared to counteract the harmful effects of pepsin on growth rate from weaning to 25 lb. and on food conversion efficiency from 25 to 40 lb. This resulted in a 5·5% increase in growth rate during the first period (P 〈 0·01) and 5·7% improvement in food conversion efficiency during the second period (P 〈 0·05).5. The overall effects of antibiotic, pepsin and α-amylase supplementation upon time taken to reach 40 lb. live weight were a reduction of 5·6 days, an increase of 3·8 days and a reduction of 3·9 days, respectively.

Description: 1. The red cells of sheep's blood containing a high concentration of potassium were found to have a higher dry-matter content and specific gravity than the red cells of sheep's blood with a low potassium content.2. While the diet and age of the animal affected the dry-matter content and specific gravity of the plasma, they did not have a noticeable effect on the results obtained for the red blood cells.3. Breed influenced the measurements for both the red blood cell and plasma.4. In the three breeds of sheep examined an inverse relationship existed between the dry matter content of the red blood cells and of the plasma.5. There is evidence that a correlation exists between the haemoglobin type of animal and the dry-matter content and specific gravity of the red blood cells.

Description: In Exp. 1 groups of piglets weaned at about 9 lb. live weight were fed one of three 29% protein diets up to 26 lb. live weight. These diets A, B and C contained 42, 20 and 0% dried skim milk, 15, 25 and 32% white fish meal and 22, 34 and 47% rolled oat groats, respectively. At 26 lb. all pigs were changed over to a standard 17% protein diet.The replacement of about one-half of the dried skim milk in diet A with white fish meal and rolled oat groats caused 4% faster growth from 9 to 26 lb. live weight, but the replacement of all the dried skim milk caused growth over the same weight range to be slower by 6%. The quadratic component of these treatment effects was significant at P 〈 0·0·25. The slower growth with the diet containing no dried skim milk was associated with a lower daily consumption of feed, and the improved growth rate with the intermediate skim milk level was probably associated with an improvement in food conversion efficiency. Treatment differences in food conversion efficiency before 26 lb. live weight, however, were not statistically significant. There were no significant carry-over effects of treatments upon performance from 26 to 50 lb. live weight.In Exp. 2 piglets weaned at about 9 lb. live weight were fed individually up to 40 lb. live weight. From 9 to 26 lb. antibiotic levels of 22, 45, 67 and 90 mg./lb. feed were compared, but from 26 to 40 lb. all pigs were fed a standard diet containing 18 mg. antibiotic/lb. In diets fed before 26 lb. the antibiotic was a mixture of 3 parts by weight chlortetracycline: 1 part by weight procaine penicillin. From 26 to 40 lb. live weight the antibiotic fed was chlortetracycline.Before 26 lb. live weight increases in antibiotic level caused average increases of up to 5% in growth rate and 4% in food conversion efficiency. Taken in conjunction with previous results the improvement in growth rate in favour of the highest antibiotic level was significant at P 〈 0·05.There were no carry-over effects of antibiotic level on growth rate from 26 to 40 lb., but there was the suggestion of a linear trend whereby each increase in antibiotic level fed before 26 lb. caused a decrease in food conversion efficiency between 26 and 401b. (P = 0·10).The results are discussed in relation to financial economies which may be made in diets for early weaned pigs.

Description: The results of about ninety field experiments carried out over three years to test dicalcium phosphate, nitrophosphate, ammoniated fertilizer and Gafsa rock phosphate are summarized and discussed. Soils with pH values of 6·5 and below are listed as ‘acid’, those with higher pH values as ‘neutral’. All comparisons were made in terms of fertilizers supplying the same total amounts of phosphorus.Dicalcium phosphate dihydrate gave approximately the same yields as superphosphate for potatoes (both on acid and on neutral soils) and for grass, kale and barley. In one group of swede experiments mostly carried out in the north-east of the country dicalcium phosphate was inferior to superphosphate, but it was equal to superphosphate in another group of swede experiments, most of which were on acid soils in wetter areas.A nitrophosphate made in England on pilot-plant scale was consistently inferior to superphosphate for barley, potatoes and swedes.

Description: 1. Acid-base changes were observed in the blood of some sheep after turning them out to lush spring grass.2. These changes were observed in animals previously fed a diet of hay plus concentrates. No changes were found in animals previously fed hay alone.3. Reasons are given for believing the acidosis observed was a consequence of feeding on lush pasture, and not a consequence of the exercise and excitement involved in rounding up sheep for sampling.

Description: 1. A crossing experiment was carried out between two breeds of sheep: the Wiltshire Horn—a breed with a short-stapled fleece which is normally shed both in lambs and adults, and the Scottish Blackface—which has a long-stapled carpet type of fleece. Animals of F1, F2 and both backcross generations were studied for gross characteristics of the fleece.2. The influence of the Wiltshire genotype caused a high incidence of fleece-shedding animals amongst all the crosses. Three separate components of the shedding process were distinguished: (a) the ability to shed, (b) the extent of shedding—or proportion of the body area denuded, (c) the time of onset of shedding. Attributes (a) and (b) were determined genetically; control was probably on a multifactorial basis, although there may have been fewer genes involved than for the other characters studied. Given the genetically determined existence of (a) and (b), (c) was apparently controlled by the environment. Seasonal change in day length was postulated as a major operative factor.3. The mid-side staple length of Wiltshire crosses was less than that of the Blackface parents. The decrease resulted partly from shedding and partly also from a reduction in the average growth rate of some fibres. When corrected for shedding the mean staple lengths of the crosses were about equal to the values theoretically expected on the basis of multifactorial inheritance without directional dominance.4. The mean fleece weight of the Wiltshire crosses was less than that of the Blackface parents, due, about equally, to: (a) loss of wool by fleece shedding, (b) reduced wool production—probably caused, at least partly, by the decreased average growth rate of some of the component fibres of the fleece. Differences in wool production appeared to be inherited multifaetorially.

Description: 1. Changes are observed in the concentrations of a wide range of substances found in blood and rumen contents when sheep are first turned out to lush spring grass.2. With some metabolites (e.g. rumen α-amino nitrogen, blood VFA) the increase is only temporary, and the animal (or its rumen microbial population) quickly adapts to the changed conditions. With other metabolites (e.g. rumen VFA) there is a sustained increase over a period of at least three weeks on grass.3. It is possible that the nature of the previous diet may determine the magnitude of the metabolic changes occurring.4. The overall nature of these changes should be taken into account in assessing the aetiology of the metabolic diseases occurring in ruminants under similar conditions.

Description: 1. Both sides of sixty-eight carcasses of Aberdeen-Angus cross steers and heifers were broken down into wholesale joints by the same butcher using a modification of the London and Home Counties style of cutting. Thirty-four of the cattle were fattened on grass in the summer of 1955 and the other thirty-four in yards during the following winter.2. Sides of steer carcasses averaged some 50–60 lb. heavier than those of heifers both in summer and winter, and the yard-fattened cattle gave sides averaging 10–20 lb. heavier than those from grassfattened cattle.3. The cuts along the underline of the animals (brisket and flanks) were increasing in weight at proportionally the greatest rate and the shin and hind-leg cuts at about half this rate, with those along the top of the back intermediate.4. At a side weight of 300 lb., steers were significantly lighter than heifers in the weight of kidney knob, cod fat, thin flank, forequarter flank, loin and rump, whereas they were significantly heavier than heifers in weight of leg, shin, topside, top rump and the neck cuts (clod and sticking). These differences suggested that at this weight of side, heifers were at a more advanced stage of development than steers.

Description: 1. An in vitro apparatus is described for measuring the percentage dry-matter digestibility of roughages.2. Samples of hay, dried herbage, oat hay and oat straw were tested in vitro and the values obtained compared with in vivo results obtained with sheep.

Description: 1. The sources of calves for rearing for beef are discussed and the dependence of the beef industry upon the dairy industry demonstrated.2. An experiment designed to compare the effects of four levels of feeding on the growth rate, conformation, economy of food conversion and type of carcase produced, of three breeds of spring-born steers, Hereford, Dairy Shorthorn and Friesian, is described. The levels of feeding are high or moderate in the calf stage, each followed by high or moderate feeding in subsequent winters.3. The results on growth and time of fattening are given and discussed.4. The calves fed on a high level were almost twice the weight of those fed on a moderate level at 8 months old.5. The well-reared calf had an advantage over the moderately reared calf for the rest of its life.6. Although calves which had been reared moderately showed a marked improvement in growth rate when subsequently fed on a higher level they did not reach the weight of calves fed well throughout at 2 years old.7. The level of feeding in the calf stage had little effect upon the time of fattening provided that the level of feeding in the winter periods of subsequent life was on a high level.8. When subsequent feeding was on a moderate level in the winter months, the calf reared well initially fattened on grass a year earlier than the moderately reared animal.9. The high-moderate treatment is shown to be the most satisfactory from many points of view. On this treatment a minimum of concentrates is used in the production of beef.10. The moderate-moderate cattle may be too heavy for present-day requirements when finished off grass at 3½ years old.11. Cattle which were fed on a high level in winter from 8 to 14 months put on less live weight in the following summer than those fed moderately. A live-weight gain of about 1 lb. a day in winter would appear to be satisfactory if the cattle are to make good use of grass in the following summer.12. These main feeding treatment effects applied to the three breeds used.13. The Friesians were heavier than Dairy Shorthorns or Herefords as calves, and the live weight at most ages was in descending order Friesians, Dairy Shorthorns, Herefords.14. The growth rate of Friesian steers was higher than that of the other two breeds at most stages of life, but the difference between Dairy Shorthorns and Herefords was negligible.15. The Herefords finished earlier than the Dairy Shorthorns and Friesians when fattened in yards or on grass.16. There was some indication (Brookes, 1954) that husk and ringworm caused less trouble with cattle which had been well reared than with those moderately reared.

Description: 1. Twelve experiments were carried out in Bedfordshire and Hertfordshire in 1955–57 to compare combine-drilling and broadcasting muriate of potash for barley. Ordinary mineral soils were used and only one contained more than 25% of calcium carbonate.2. On average of all the experiments in each year 0·25 cwt. K2O/acre drilled with the seed gave higher yields than 0·5 cwt. K2O/acre broadcast and worked into the seedbed. The average extra yields of barley from combine-drilling, as compared with broadcasting, were 1·2 cwt./acre when 0·25 cwt. K2O/acre was applied and 2·0 cwt./acre of grain when twice as much K2O was given. In twenty-one of the total of twenty-four comparisons drilling gave higher yields than broadcasting and in onethird of these comparisons the effects were significant. Combine-drilling gave higher average yields of straw than broadcasting.3. The average level of response was not great, the low and high rates of combine-drilled muriate of potash increasing yields by 13 and 16%, respectively. Only a small proportion of the applied potassium was taken up by the crops; apparent recoveries by grain plus straw averaged 11% of the light-drilled dressing and 8% of the heavy dressing.4. The level of response to potassium varied from year to year, but was much greater on average in the 1955 experiments than in 1956 and 1957. There was no close relationship between the degree of response and values for dilute hydrochloric-acidsoluble potassium or exchangeable potassium in the soils used.

Description: 1. Symptoms of zinc deficiency and toxicity have been studied in guar, brinjal, maize, tobacco and Mosambi (Mozambique) using a sand-culture technique.2. In zinc-deficient guar plants, depressed vegetative growth and smaller leaves than normal ones were found. Only few flower buds were seen, and there was abscission of leaves at the time of flowering.3. Chlorosis followed by necrosis and finally the drying up of leaves was the most characteristic deficiency symptom in the case of brinjal; growth was stunted and flowers failed to set fruits.4. In the newer leaves of maize, intermittent light yellow bands were formed just parallel to the midrib.5. In the lower leaves of tobacco, chlorosis followed by necrosis was observed; growth was stunted and leaves were small in size.6. In Mosambi (Mozambique), whitish yellow patches in between the veins were observed; leaves were small, pointed and quite unhealthy.7. There was an increase in zinc uptake with increased rates of application of zinc.8. Crude protein increased with increasing zinc supply up to levels beyond the optimum for growth.

Description: 1. Groups of colonies have been moved to crops requiring pollination: group A, before any blossom appeared; group B, when 5–15% of the crop was in flower; and group C, when the crop was in full flower, and the amount which the colonies of the different groups visited the crop was determined. The results tend to show that colonies of group B visited the experimental crop more than colonies of group A, thus supporting recommendations that colonies should not be moved to a crop requiring pollination until it has started to flower, so that the bees will not have previously become conditioned to visiting other flower species in the locality.2. When a colony is moved to a new site its foragers tend to visit species they have visited previously, and the amount of a particular pollen that a colony collects at a new site is sometimes related to the amount of it the colony collected before it was moved.3. The conclusion of previous workers that different colonies utilize the local flora in different ways have been confirmed. Different colonies vary greatly both in the number and kind of species they visit and in the extent to which they visit the same species. Although the extent to which colonies visit certain species tends to be related to the extent they have visited them previously, exceptions often occur.

Description: Eighty-three fertilized sheep ova were stored at 0–8° C. for 6–72 hr. in sterile sheep serum or Ringer's solution and subsequently transferred to suitable recipient ewes in order to determine their viability following storage.In Exp. 1, nine out of twelve ova stored in sheep serum, but none out of five ova stored in Ringer's solution, continued development after subjection to storage at 5–8° C. for 6–9 hr. Seven out of fifteen, none of nineteen, and none of nine ova were found developing in recipients after subjection to 5–8° C. in serum for 24, 48 and 72 hr., respectively.In Exp. 2, lambs were born to recipients of four out of six ova stored for 24 hr. at 4·5–7° C, and of two out of five ova stored for 72 hr. at these temperatures. None of the recipients of twelve ova stored for 24, 48 and 72 hr. (four ova of each duration) at 0·4° C. produced live lambs.In Exp. 3, none of thirty-four ova developed after subjection to freezing to −79° C. in 12·5% glycerol in serum.

Description: 1. The influence of frequency of cutting on the yield and chemical composition of Pennisetum purpureum Schum under the environmental conditions obtaining in south-western Nigeria was studied in 1953–54. The cutting frequencies adopted being seventeen, eight, six and four times sampling a year, which permitted the plants to grow for intervals of 3, 6, 8 and 12 weeks, respectively, before cutting.2. When elephant grass was sampled four times a year, at an interval of 12 weeks, a yield of 52·9 tons of green fodder per acre was obtained for the 11-month period (24 June 1953 to 27 May 1954). This yield was 1·8 times more than the green fodder produced from plots sampled seventeen times a year, at 3-weekly intervals, and 1-4 times more than that obtained from each of those sampled six times a year (intervals of 8-weeks) and eight times a year (6-weekly intervals), respectively. These yields, which are probably the highest ever recorded for any grass species grown in unfertilized soils in Nigeria, are also higher than the yields reported under similar conditions and treatments in other tropical countries.3. The percentage dry matter similarly increased with the length of cutting intervals. Differences in yields of dry matter between the various treatments are more pronounced than similar differences for green fodder yields. The dry-matter yields obtained from either the 6-weekly or the 8-weekly cutting intervals were significantly higher than those obtained from the 3-weekly cut samples, while those from the 12-weekly cut samples were significantly superior to each of the other cutting treatments. The difference in yield between the 8- and the 6-weekly cut samples, however, was not statistically significant.4. A progressive reduction in yields of dry matter and of green fodder was shown with successive cuttings, particularly in the case of the more frequently cut grasses; the yields obtained during the 1964 seasons were lower than those of 1953. It is possible that the application of fertilizers might arrest this diminution in growth and yield.5. It was shown that when the grass was allowed to grow for a period longer than 3 weeks, the stems of Pennisetum purpureum Schum tend to mature more rapidly than the leaves. This fact might be responsible for the rapid deterioration in nutrient content, so characteristic of tropical fodders.6. The percentage crude protein and of silicafree ash fell as cutting intervals increased; the percentage dry matter, crude fibre and nitrogenfree extract rose directly with length of cutting intervals. It was shown that it is best to cut elephant grass every 3 weeks of growth in order to obtain the highest yield of protein and of silicafree ash per acre; this grass should, however, be cut every 12 weeks to obtain the maximum yield of total nutrients and carbohydrates. It does not appear profitable to cut or graze elephant grass at 6- or 8-weekly intervals for either of the above purposes.7. While green fodder yields were directly, drymatter yields were inversely, related to the degree of monthly precipitation. Generally, periods of high rainfall were followed by high yields of green fodder and low yields of dry matter, those of low rainfall by low green fodder and high dry-matter yields. The percentage crude protein and of silicafree ash of dry matter, fluctuated directly with rainfall; the percentage nitrogen-free extract and of crude fibre showed an inverse relationship with rainfall fluctuations.It is these latter constituents rather than the former which thus reflect the dry-matter content of the herbage.

Description: The evidence from these combined variety × plant density experiments, together with the additional data on varieties previously reported (Bunting & Willey, 1958), suggests that, for fodder or ensilage production in Britain, the varieties we have designated as ‘medium’ (i.e. within the range represented by the hybrids Wis. 275 and Wis. 341 A), sown to give a final density of 9–12 plants/sq.yd. would be most suitable. Higher plant populations probably give slightly higher yields, but the differences will rarely be of practical importance and are likely to be offset by the greater incidence of lodging and the consequent increase in harvesting difficulties.

Description: 1. Eight experienced judges used a 20-point scoring scale in different ways when assessing the ‘proportion of lean to fat’ from the same photographs of cut bacon sides presented in the same arrangements. The average score for the 220 judgements made during the experiment by a single judge, which represents his over-all level of scoring or ‘standard of judging’, ranged from 13·7 to 12·0. The standard deviation, a measure of the degree of discrimination attempted by the judge, ranged from 3·26 to 4·74.2. The judges varied in their consistency of assessment or ‘repeatability’. The standard error for a single judge, measuring the extent of the variation of his scores within photographs, ranged from 0·89 to 1·99. The judges who attempted to discriminate most between photographs tended to be the least consistent in their judgements, although one judge was a notable exception to this trend.3. The consistency of judgement tended to decrease from the good (high-scoring) rashers to the poor (low-scoring) rashers, but this effect was more marked for some judges than for others.4. Some of the variation in the scores awarded to each photograph was due to alterations in the standard of judging from batch to batch. When this was allowed for, the standard errors were all reduced and ranged from 0·61 to 1·31. The judges tended to adjust their standards according to the average quality of the batch being assessed. This led to the variation among the average scores for the batches being less than it would have been had their standards remained constant.5. Alterations in the standard of judging during the experiment affected the scores awarded to good (high-scoring) rashers rather less than those awarded to poor (low-scoring) ones.6. The correlations between the individual judge's mean scores for the forty-four photographs and the over-all mean scores were very high. For seven judges, they ranged from 0·962 to 0·984, whereas for the eighth judge the correlation was 0·918. The lower correlation for this judge was due to two rashers with very thin fat being heavily marked down.7. The correlations between the over-all mean scores and two different combinations of three objective measurements were both about 0·92; these measurements were therefore slightly less closely related to the over-all scores than were an individual judge's mean scores.8. The possibility of making the experimental technique more realistic and of improving the precision of such visual judgements by providing photographic scales of reference are discussed.

Description: During the 12 months from September 1955 to August 1956, the reproductive tracts and ovaries of 4094 adult Merino ewes, recovered from the municipal abattoir at Pietermaritzburg, were examined. The great majority of the ewes had been consigned to the abattoir from one of three regions, between which differences in the nutritional value of the natural vegetation at different times of the year are recognized. From observations of the occurrence in the ovaries of active corpora lutea, it appeared that in some areas, mating Merino ewes during autumn and early winter is likely to result in the greatest percentage of ewes conceiving and in the highest lambing percentages. There was a suggestion, however, that in the more arid karoo areas, the percentage of ewes ovulating, as well as the mean ovulation rate per ewe, may remain relatively constant throughout the year. It seems likely that the low fertility of ewes of this breed may be due partly to the practice of introducing the rams into the flock at a time of year (spring and summer) in which many of the ewes are anoestrous, a practice which is often adopted in South Africa in order to avoid the poor growth rates which are known to occur among young lambs as a result of the high temperatures and the internal parasite infestations that are comcommon in the summer months. A need, in different areas, for extensive experimental evidence of the most suitable season for mating, is indicated.No evidence of nutritional effects on fertility, either within or between areas, was obtained, but it is suggested that a higher proportion of ewes in certain areas may be capable of lambing in autumn as a result of more effective selection for this trait in these areas. There is also evidence that lack of fertilization of ova and early embryonic death may contribute significantly to the breed's low fertility.Corpora lutea were observed more frequently in the right ovary than in the left. In gravid uteri, a greater proportion of foetuses were found in the right horn and, in addition, significantly more ova apparently migrated from the left ovary to the right horn than from the right ovary to the left horn. The numbers are given of large (diameter 〉 4 mm.) and medium (diameter 2–4 mm.) follicles observed in the ovaries both of non-pregnant ewes and of ewes in different stages of pregnancy, these stages having been estimated from measurements of foetal crownrump lengths.

Description: 1. Pure swards of S. 48 timothy and S. 215 meadow fescue were cut (a) after ear emergence, (b) before ear emergence and in the aftermath to prevent flowering, and (c) every 4 weeks. The number and weight of tillers and leaves were determined.2. Tiller numbers declined considerably from early spring to the middle of summer. This fall was reduced by a system of frequent defoliation in the wet summer of 1956, especially in timothy.3. Leaf weight per unit area of sward increased rapidly from early spring until about the time of ear emergence; no further significant gains were recorded after ears had appeared, when the plots were cut for hay.4. The weight per leaf also increased in the spring and was similar in both species. In the regrowth following a cut meadow fescue produced considerably heavier leaves than timothy.5. As both grasses approached the flowering stage, their leaf canopy was increasingly raised above ground level. Variable proportions of foliage were thus removed by cutting according to the developmental stage of the plant. Crop growth rates following a cut appeared to be related to the amount of leaf material remaining in the sward.6. Relative growth rates during uninterrupted growth were greatest around the time of ear emergence.

Description: Eleven winter wheat experiments were carried out from 1955–57, to compare the effects of nitrogen on three stiff-strawed varieties of winter wheat, Heine 7, Hybrid 46 and Minister. In 1955 the experiments tested ‘Nitro-Chalk’ top-dressings at rates supplying 0·45, 0·90 and 1·35 cwt. N/acre. In addition, drilled dressings supplying 0·15 cwt. N/acre were supplemented with either 0·30 or 0·75 cwt. N/acre as a top-dressing.In the 1956 and 1957 experiments ‘Nitro-Chalk’ top-dressings were applied at 0·60 and 1·20 cwt. N/acre. In addition, divided dressings were compared by supplementing 0·15 cwt. N/acre by combine-drill with 0·45 cwt. N top-dressing.Significant increases in yield were obtained from the first increment of nitrogen in twenty-three of the thirty-three available comparisons. There were significant additional gains from the second increment of nitrogen in only seven of the same comparisons. Responses to nitrogen varied considerably between seasons. Large and consistent responses were obtained at all centres in 1955 and dressings supplying 0·9 cwt. N/acre were well worthwhile. In 1956 responses were generally smaller and dressings in excess of 0·6 cwt. N/acre could only be justified at two centres. Mean responses in 1957 were lower than those obtained in either of the previous season and 0·6 cwt. N/acre was sufficient for maximum yields at three of the four centres.There was little advantage in dividing dressings of nitrogen between autumn and spring in any of the experiments and none of the differences reached significance. On average, higher yields were obtained by retaining the whole of the nitrogen until the spring, than by applying part of the dressing in autumn by combine-drill.Comparisons between the varieties show that Hybrid 46 was the only variety which was able to take consistent advantage of the heaviest rates of manuring. In each year Hybrid 46 produced the highest percentage increase in yield and Minister the lowest. In addition Hybrid 46 contained the highest percentage of nitrogen in the grain when averaged over each level of manuring. The percentage recovery of nitrogen was calculated for each year and each variety. Comparisons of this data show that Hybrid 46 converted more of the fertilizer nitrogen into grain or crude protein than either of the other two varieties. The experiments provide evidence that there are considerable variations in the efficiency with which present-day winter wheat varieties can utilize nitrogen, and that varieties with both high fertilizer efficiency and high unmanured yields are likely to increase the level of crop production.

Description: 1. Three calves were individually exposed in a climatic room to an environment of 45° C. dry-bulb and 28° C. wet-bulb temperature for 21 successive days up to 5 hr. each day.2. In the 21-day period, mostly during the first half of it, the following changes in the physiological reactions of the animals were observed: progressive reductions in rectal temperature, in heart rate and in respiratory rate with a change of breathing from a laboured to a less laboured type.3. It was suggested that a decrease in metabolic heat production might play a part in the observed acclimatization.

Description: 1. Attempts to investigate the physical properties of bran, and other feedingstuffs, with regard to their ability to absorb and retain water, have been outlined.2. Two experiments have been described in which pigs were fed bran, fibrous cellulose, or different levels of powdered cellulose, added to normal pig rations. These experiments involved 24 hr. faecal collections, and ultimate slaughter of the animals, together with analysis of faecal material and gut contents.3. The addition of bran or fibrous cellulose to a ration causes a reduction in the average percentage of dry matter in the faeces, but tends to emphasize fluctuations in faecal dry-matter percentage, which are attributed to fluctuations in rate of passage through the large intestine.4. The behaviour of the powdered cellulose was anomalous, giving rise to hard stools. It appeared to be almost inert in relation to water.

Description: Since this paper was completed, Reith & Inkson (1958) have presented results for a further series of factorial experiments with f.y.m. and fertilizers in north-east Scotland, 1947–54. The authors claimed that for N their results confirmed those of Crowther & Yates; however, their Table 3 gives results very similar to those presented here: i.e. in the absence of f.y.m., PK basal greatly increased the response to N, but was ineffective where f.y.m. was also applied. The authors appear to have appreciated that these results, based on individual plot yields, were inconsistent with their main conclusions drawn from main effects and first-order interactions only, but do not seem to have realized their significance.

Description: 1. Three calves were exposed in a climatic room to an environment of 40° C. dry-bulb and 38° C. wet-bulb temperature for up to 110 min. each day for 1-2 weeks.2. These exposures produced progressive changes in the physiological reactions of the animals to heat:(a) Rectal temperature and skin temperature (for a given time of exposure) declined. In consequence there was a marked increase in the tolerance time, i.e. in the time for which the animals could withstand the hot environment before reaching a rectal temperature of 42° C.(b) Respiratory rate rose earlier and assumed higher levels (for given levels of body temperature).(c) Heart rate decreased markedly.3. These changes are discussed in relation to heat loss and heat production and have been interpreted as reflecting chiefly a reduction in the metabolic heat production of the animals.

Description: Ten calves were exposed for 3 hr. to an atmosphere in which the dry-bulb temperature was 40° C. and the wet-bulb temperature 33° C, (a) with their normal coats, and (b) after their coats had been clipped.When clipped the calves tolerated the same hot environment better than they did before they were clipped, as evidenced by significant reductions in skin temperature, rectal temperature, respiratory rate and heart rate, as well as by a lessening of various manifestations of distress.This effect of clipping was thought to be due mainly to an improvement in skin, evaporative cooling.

Description: 1. The efficiency of food conversion by pullets and yearlings fed on high- and low-energy diets has been determined.2. Egg production was slightly higher by birds fed the low-energy diet for both pullets and yearling hens; pullets laid more eggs than yearling hens.3. For each age, the gross food intake was greater for birds fed the low-energy diet; the consumptions of digestible protein, non-protein digestible energy and metabolizable energy were the same for both diets and both ages of bird.4. The food cost per dozen eggs was slightly greater in the yearling year when the cost of rearing the pullets was ignored, and about the same when it was included.5. The efficiency of utilization of digestible energy and protein showed only a slight decrease from the pullet to the yearling year.6. The variation in the composition and digestibility of eighteen consecutive mixes of the highenergy diet and twenty-five of the low-energy diet was: crude protein 2%, non-protein digestible energy 5% and metabolizable energy 0·4 kg. cal./g. The digestibility of the crude protein and oil was 87%, for both diets; carbohydrates were 81% digestible in the high-energy diet and 59% in the low-energy diet.

Description: In the communication: ‘Studies of the skeleton of the sheep. III. The relationship between phosphorus intake and resorption and repair of the skeleton in pregnancy and lactation’, D. Benzie, A. W. Boyne, A. C. Dalgarno, J. Duckworth & R. Hill, J. Agric. Sci. (1959), 52, 1–12, Plates 3 a and 3 b have been interchanged.

Description: 1. The structure of the muzzle of the cow, its blood supply and the histochemistry of its glands have been studied.2. The nasolabial glands are multilobular compound tubulo-acinar glands similar in structure to salivary glands. They secrete a watery mucincontaining fluid. It is suggested that they may be sweat gland homologues.3. Arterio-venous anastomoses are present in the muzzle. Their possible function is discussed.4. Although this investigation has shown how much the muzzle differs from the rest of the integument no particular function can be ascribed to it on the basis of the findings described.

Description: 1. The normal pattern of grazing behaviour of free-range indigenous cattle under conditions of lenient stocking and overstocking has been studied throughout the year.2. There was a fairly fixed daily pattern of herd behaviour. The cattle usually started day grazing round sunrise and ceased approximately 1 hr. after sunset. There was a morning and afternoon peak of intense grazing activity separated by a rest period and watering about midday. There was usually one peak of night grazing.3. The average daily grazing times varied from 8 hr. during the rains period of relative feed abundance, to about 13 hr. during the dry season period of malnutrition.4. During the dry season there were no major differences in grazing times between the leniently stooked and overstocked groups. Both herds were losing weight.5. The relatively greater weight gains of the overstocked herd compared with the leniently stooked group during the rains resulted from the increased grazing times of the overstocked herd.6. The night grazing remained fairly constant at approximately 20% of the total daily grazing time.7. There were no seasonal effects on the pattern of grazing behaviour. High daytime temperatures did not cause an increase in the proportion of night grazing of indigenous cattle.

Description: Farmyard manure affected the response of the potato crop to fertilizers similarly in seven series of experiments (sixty-two in all) at Rothamsted, and in the West Midlands and north of England.In the absence of f.y.m. there were large interactions between each of the fertilizer nutrients, but with f.y.m. the interactions were small. These interactions appear to have been ignored by previous workers, who claimed that N responses ar unaffected by dressings of f.y.m. In fact, f.y.m. increased the response to N applied alone, but decreased the N response where basal P and K fertilizers were also applied. For P the results were similar to those for N.Most of the experimental sites were low in K, and K responses were very large, especially in the presence of basal NP fertilizer. Farmyard manure greatly reduced the response to K, particularly in presence of basal NP fertilizer.A few Rothamsted experiments with f.y.m. and fertilizers and several times of planting showed that the large responses to f.y.m. alone and to fertilizers used in combination (but without f.y.m.) were not reduced by late planting. The result conflicts with previous reports of these data, in which interactions between nutrients were ignored. The combined effect of f.y.m. and fertilizers at late planting was little more than their separate effects, presumably due to delayed maturity, the influence of which would be exaggerated by the early burning-off of haulm in this series of experiments.Most of the experiments were limited to testing fertilizers at two levels (presence and absence), so the effective quantities of nutrients provided by f.y.m. for the crop to which it was applied could only be estimated approximately; the average amounts suggested for normal f.y.m. are 0·3 cwt. N, 0·4 cwt. P2O5 and 0·75 cwt. K2O in 10 tons f.y.m.These results lead to the practical conclusion that, in manuring potato crops on average land, much the same plant food ratios will be appropriate whether or not F.Y.M. is given, and the amount of fertilizer applied can be decreased to allow for the nutrients contained in the f.y.m.

Description: 1. An experiment has been described in which pigs were fed rations containing four different levels of cellulose, each ration being fed successively at three different levels of water intake. The cellulose levels were superimposed on a highly digestible basal ration.2. It appears that altering the level of water intake, while keeping the ration constant, has only a very limited effect on the level of faecal dry-matter percentage, and on the pattern of variation therein.3. Further evidence is cited in support of the theories, advanced in a previous paper, relating to the influence of fibrous cellulose on water relationships in the digesta and faeces.

Description: 1. Two experiments have been described in which pigs were fed different levels of fibrous cellulose superimposed on a highly digestible purified basal ration. These experiments involved 24 hr. faecal collections and ultimate slaughter of the animals, together with analysis of faecal material and gut contents.2. The results of these experiments, together with those from experiments described in the previous paper in this series, have provided the basis for a discussion of the effects of adding bran and cellulose to pig rations, and of the influence of the progress of the residues of feeds through the digestive tract, on the pattern of excretion and the dry matter content of the faeces.

Description: 1. Six methods of diluting chicken's blood prior to counting erythrocytes and leucocytes in haemacytometers have been studied. No difficulty is found in recognizing erythrocytes. The most satisfactory method of counting leucocytes was the method described by Natt & Herrick (1952) in which the diluent contains methyl violet. Formulae are given which enable standard errors of estimates to be calculated.2. Three methods of staining blood smears for the differentiation of the various leucocytes have been studied. The method using Leishman's stain appeared to result in good differentiation and was simple to use. However, an experiment to study sampling errors has shown that there may be considerable differences between observers in the percentages of lymphocytes and heterophils when the latter are high, showing that the estimates of these quantities may be biassed. These differences may have been caused by a tendency for heterophils to concentrate to the edges of the smears and for the observers to select different fields for their counts.3. Although blood counts varied only slightly during the day, there were considerable differences from day to day. The average erythrocyte count for ten chickens fluctuated between about 2·9 and 3·5 millions per mm.3 during the first 3 weeks after hatching and was more steady for the next 4 weeks at about 2·9 millions per mm.3. The average leucocyte count rose from about 10,000 to 35,000 per mm.3 during the first 7 weeks of life, the rate of increase being greatest when the chickens were youngest; the rise was mainly due to a rise in the number of lymphocytes.4. There were also considerable differences in blood counts between chickens even though environmental and genetic conditions were standardized as far as possible.

Description: 1. Seven experiments on spring barley and five on spring wheat carried out in 1955–7 compared dressings of ammonium sulphate and calcium nitrate applied to the seedbeds at 0·3 and 0·6 cwt. N/acre. The fertilizers were tested both when broadcast and when drilled with the seed.2. Consistently higher yields of barley were produced by drilling than by broadcasting ammonium sulphate. Drilling calcium nitrate at 0·3 cwt. N/acre was superior to broadcasting for barley but when applied with the seed at 0·6 cwt. N/acre this fertilizer retarded germination and early growth and gave smaller yields than were obtained by broadcasting. Broadcast dressings of both fertilizers gave higher yields of wheat than combine-drilled dressings. There is a considerable risk of fertilizer ‘scorch’ when compound fertilizers containing all their nitrogen in nitrate form are combine-drilled at rates sufficient for maximum yield. This risk may be discounted when adequate rain follows drilling but the check to germination may be sufficient to reduce yields in dry springs, on light soils, and on badly prepared seedbeds. Fertilizers containing all their nitrogen in ammonium form appear to be quite safe at the rates of dressing tested in this work.3. Calcium nitrate and ammonium sulphate gave similar yields and nitrogen contents of both crops when the fertilizers were broadcast on the seedbed. Nitrates applied at sowing-time to cereals grown in the drier parts of the country do not appear to be leached out of the root-zone before they can be taken up by crops.

Description: Quantitative and qualitative bacteriological comparisons were made between complementary samples of cud and rumen contents using five fistulated cows receiving various diets; no marked differences were observed between samples taken from the same animal at the same time. This, with the method of collecting cud described, simplifies bacteriological evaluation of the rumen contents of intactanimals.

Description: 1. The availability of iron in three species of grass has been investigated using the rat as the experimental animal.2. Two procedures, namely, the increase in blood haemoglobin concentration, and the gain in total gramme of haemoglobin by nutritionally anaemic rats were employed.3. Inorganic iron, as ferric chloride, was shown to be significantly more available than the iron contained in the three grasses.4. The iron in the grass timothy was found to be significantly more available than that in ryegrass or cocksfoot.5. Possible reasons for the differences in iron availability were discussed.

Description: Field experiments are described comparing the yield of herbage on a series of grass-clover plots which were irrigated after various deficits had developed. In addition to the irrigation treatments, different rates of nitrogen were applied.The maximum yields were obtained when only small deficits were allowed (maximum pF 3·3). This applied particularly to grass-clover swards to which no nitrogen fertilizer was applied.There was not much reduction in yield on predominantly perennial ryegrass swards liberally supplied with nitrogen when larger deficits were allowed to develop (pF c. 4·0).Estimates of soil water deficit from meteorological data using Penman's method agreed very well with direct measurements.

Description: Subacute oxalic acid poisoning was reproduced by the administration of varying doses of oxalic acid. The amount needed varied according to the nutritional status of the animal immediately prior to the experimental period. If lucerne was present in the diet or if calcium or strontium was added much larger doses were tolerated. Such an animal excreted large amounts of oxalic acid as oxalate in the faeces, and as carbonate and oxalate in the urine. In animals which failed to survive the blood urea rose, while the amount of carbonate in the urine did not. In many such animals there was a decrease in blood calcium. It is considered that the major portion of the oxalate is decomposed by bacterial action in the rumen and that the primary factor in subacute oxalic acid poisoning in sheep is rumen dysfunction due to its effect on the pH of the rumen.

Description: 1. Three varieties of giant rape, two broad leaved Essex rapes, Hungry Gap Kale and Rape-Kale, were grown at two centres in mid-Wales. They were sampled in the early winter period and the samples divided into separate leaf and stem samples. These samples were used to calculate leaf to stem ratios on a green and dry-matter basis.2. The levels of the proximate constituents, silica, calcium, magnesium, phosphorus, sodium, potassium, chlorine, total sulphur, sulphate sulphur and ‘organic’ sulphur were determined in the dried samples. Whole plant values were calculated from the leaf and stem values with the appropriate leaf to stem ratios.3. The leaf values for ether extract, crude protein, silica-free ash, silica, calcium, phosphorus, magnesium, chlorine, total sulphur and ‘organic’ sulphur are higher than the corresponding stem values. For dry matter, crude fibre, nitrogen-free extractives and sodium the reverse is found, whilst for sulphate sulphur there is no definite distribution.4. There are no significant differences in composition between the main groups of varieties, and the rape-type kales are very similar to the other rapes in this respect.

Description: Small doses of oxalic acid were given to sheep and typical results in sheep receiving 3 and 6 g. per day are given in detail. Little was excreted in the faeces, although sufficient calcium was present in the faeces to combine with 12 times the amount of oxalate present. The blood urea value rose, the blood calcium fell and there was an increase in the CO2 combining power. Only very small amounts of oxalic acid were found in the tissues after death. Sheep receiving the larger dose showed typical acute changes in the kidneys with deposition of crystals. Nevertheless, little evidence of renal failure or actual obstruction was obtained, the volume of the urine being maintained and the urea concentration remaining normal.

Description: 1. Four varieties of marrow stem kale, three of thousand headed kales, Hungry Gap Kale and Rape-Kale were grown at three centres in mid-Wales. They were sampled in the early winter period and separate leaf and stem samples analysed for the proximate constituents and minerals.2. Leaf to stem ratios were measured on both a green and dry matter basis and the latter values used to calculate whole plant values for the chemical constituents.3. The leaves of the marrow stem kales were higher in dry matter than the stems, except in the case of the Purple Stem Kale. This variety resembled the thousand headed and rape-type kales in having a higher dry matter in the stems. On a dry matter basis, the leaves of all the varieties were richer than the stems in ether extract, crude protein, total ash and all the minerals except potassium and sodium. These elements occurred to a greater extent in the stems of the fleshy stemmed marrow stem kales than in the leaves. The stems were higher in crude fibre and nitrogen-free extractives.4. The leaves of the rape-type kales were higher than those of the other varieties in silica, phosphorus and potassium. They were the best source of phosphorus on a whole plant basis. The marrow stem kales had considerably higher leaf and stem values for sodium and were markedly superior to the other varieties as a source of the element.

Description: 1. Results are reported of an experiment carried out under commercial conditions to obtain information on the effect of four different levels of allmeal feeding on the performance and carcass grading results of fattening pigs.2. There were four treatments. All pigs were given the same meal mixtures and were fed dry and ad lib. up to four different daily maximums, namely, 6½, 6, 5½ and 5 lb. meal/pig/day. There were five pens of nine group-fed pigs on each treatment, involving a total of 180 pigs. The pigs were on experiment from approximately 8 weeks of age to bacon weight. Comprehensive carcass measurements were made on all pigs.3. The results showed that as the level of feeding was decreased, the growth rate of the pigs, back fat thickness and belly thickness were reduced, and the depth and breadth of eye muscle were increased, while the efficiency of food utilization, carcass dressing percentage and carcass length were not markedly affected. Commercial grading results similarly improved as the level of feeding was reduced.4. It was concluded that under the conditions prevailing, the maximum daily meal allowance should be of the order of 5½ lb./pig in order to obtain relatively satisfactory carcass grading.5. Subdivision of the carcass measurement and commercial grading data according to sex of pig showed that in general at each level of feeding the carcasses of the female pigs were superior to those of the male animals.The possibilities of segregating pigs according to sex during fattening as a means whereby undue retardation in the growth rate of the females might be prevented without adversely affecting their carcass grading, was discussed.

Description: The effect of environment on the production and size of eggs, feed efficiency and mortality of New Hampshire hens in individual cages was studied simultaneously in five areas of Guatemala having temperatures covering a range of 0°–45° C. with variable humidities.While birds housed in the tropical lowlands did show visible signs of thermo-stress, there were no significant differences in egg size, production, feed consumption, mortality and body weight between areas or between groups within areas. The inconsistency of these data with other published reports is explained on the basis of the observed extremely wide diurnal range for temperatures and humidities. An attempt is made to present accepted physiological phenomena in the form of a working hypothesis wherein the diurnal temperature range is related to the fowl's tolerance to thermo-stress.

Description: 1. The desirability of employing the genetic variation present in diploid and tetraploid wild species for the improvement of the cultivated hexaploid species stimulated an investigation into the synthesis of various amphiploid forms in Avena.2. Five amphiploids at the hexaploid level have been produced, but the present investigation is limited to the amphiploids developed from the cross A. barbata (2n = 28)×.A. strigosa subsp. hirtula (2n= 14), their hybrids with the natural hexaploid species and with other amphiploid types.3. These amphiploids, like their parents, possessed black paleae, with hairs and a fairly strong geniculate awn on both the lower and upper grains. The bases of both the lower and upper grains possessed the articulation surfaces characteristic of A. fatua. Their hybrids with A. fatua were similar in spikelet morphology, but the A. sterilis type of spikelet was dominant in both the amphiploid 6x × A. sterilis and amphiploid 6x × A. byzantina. Partial dominance of the cultivated type base over the shedding type was evident in crosses with A. sativa and A. nuda but the naked caryopsis and multiflorous spikelet were recessive in the latter cross. In crosses between the A. barbata/A. hirtula 6x amphiploid and the A. abyssinica/A. strigosa 6x amphiploid (Cc 4387) the hybrid exhibited a reversal of dominance relationships, with the cultivated base type of Cc4387 being completely recessive to the shedding base.

Description: An experiment is described in which sixty-four individually-fed pigs were used to investigate the effects of dietary protein status and administration of aureomycin on growth, efficiency of feed utilization and carcass conformation.The main features of the results obtained were:1. Pigs fed a ‘standard’ protein diet showed superior performance in terms of growth and economy of feed utilization in comparison with a ‘substandard’ ration. Appreciable differences in carcass quality including reduction in backfat and total body fat, concomitant with an increase in the lean meat content also resulted from variation in ration protein content. These results have been discussed in terms of the possible significance of both dietary crude protein status and amino acid content.2. The administration of aureomycin at a ‘nutritional’ level had no apparent effect on any of the indices of pig productivity subject to analysis.3. The high killing percentages noted over-all, have been discussed in relation to dietary energy and fibre levels.

Description: 1. A total of forty pigs (four litters) were slaughtered at weekly intervals from birth to 5 weeks of age.2. Results are given for the changes in weight of different parts of the digestive organs and their contents with increasing age, and for the content of NaCl and of total acidity in the stomach contents.3. Stomach pH was on average more alkaline than pH 3.4 at all ages up to 5 weeks; the average pH of the duodenum was 6.5 and of the small intestine 6.4.4. Total NaCl and total acidity in stomach contents remained roughly constant from birth up to 5 weeks of age. No free HCl was detected in any of the stomach contents of the pigs.5. The consistency of the stomach contents varied with the age of the pig; the hard milk clot which was characteristic of the contents at 2–3 weeks of age appeared softer and more broken in older pigs.

Description: 1. Forty Large White pigs varying in age from birth to 5 weeks were slaughtered and their carbohydrate digesting enzymes studied for any change in activity with increase in age.2. Pancreatic amylase, sucrase and maltase increased from low levels at birth to high levels at 5 weeks of age.3. The total amount of lactase present at birth and of small intestine amylase at 1-week-old was maintained at a constant level up to 5 weeks of age. The increased weight of the intestine with the growth of the pig made the quantity of these enzymes appear to decrease with age when the values were expressed per kg. body weight or per g. dry tissue.4. Anaemia had no marked effect on the activity of the enzymes though the rate of enzyme development appeared to be retarded in the case of maltase.5. The quantity of pancreatic amylase present in the pancreas was sufficient at all ages to digest the amounts of starch likely to be included in a synthetic diet. Maltase, on the other hand, appeared to be limiting in early life.

Description: The response of S. 123 extra-late-flowering red clover in the year of sowing to three sprayings of gibberellic acid (GA) given at 28-day intervals is described. Plants in both soil and vermiculite cultures were used.1. The first effects, noticeable in the basal rosette, were an increase in petiole length and a parallel increase in leaf area.2. Fewer stems were formed on the treated plants but their thickness and the number and length of the internodes were increased.3. Secondary branching was not significantly increased but the GA-treated plants produced a large number of tertiary branches from axillary buds on the secondary branches. Tertiary branching was not frequent in the control plants.4. Cauline leaves showed an increased length/breadth ratio at each node with treatment, elongation tending to be most marked at those nodes where leaf formation coincided with GA sprayings. Leaf thickness was also increased by GA treatment.5. Treated plants produced nearly 80% more heads, and flowering after GA treatment was up to 14 days earlier than the control.

Description: An American Brahman calf of about 7–8 months age was placed in a hot chamber with a temperature of 108° F. dry bulb and 92° F. wet bulb. Sweat droplets were detected by preparing sweat prints on tannic acid papers applied closely to shaved skin areas smeared with ferric chloride solutions. The distribution of sweat spots on the sweat prints is similar to that of sweat glands.

Description: 1. An experiment was carried out from 1 August 1953 to 31 July 1955 to compare strip grazing with rotational grazing on the basis of the total animal production obtained from dairy cattle on irrigated pasture.2. The same overall stocking rate was used for both treatments. Herbage surplus to grazing requirements at any time was conserved as hay and fed back to the appropriate group of cows at the end of the grazing season.3. The aim was to manage the area under each technique as efficiently as the technique permitted.4. The average production from the rotationally grazed group during the main pasture season of 260 days was 8740 lb. milk per acre (including 354 lb. of butterfatand 766 lb. of solids-not-fat) and from the strip-grazed group 8867 lb. milk per acre (including 358 lb. of butterfat and 766 lb. of solidsnotfat).The average weight of pasture nutrients utilized per annum by the rotationally grazed group was 5887 lb. starch equivalent per acre and by the stripgrazed group 5896 lb. starch equivalent per acre.None of the treatment differences in animal production was significant.5. The differences between the results of this experiment and those obtained by other workers are discussed.

Description: 1. The effect of treating mineral soils with hydrofluoric acid to decompose clay minerals on the extraction of soil organic matter by alkaline and neutral reagents has been investigated.2. It was found that treatment of soil with hydrofluoric acid had little effect on the extraction of organic matter by alkaline or neutral reagents, but that it released considerable amounts of ammonium and organic matter. More than 90% of the nitrogen in Rothamsted soils was dissolved by repeated treatments with dilute solutions of hydrofluoric acid and sodium hydroxide.3. It is shown that treatment of clay minerals with n-HF:n-HCl solution at room temperature for 24 hr. effects quantitative release of fixed ammonium from clay minerals and that similar treatment of soil is not likely to cause significant decomposition of organic nitrogen compounds to ammonium. It is suggested that a method based on this treatment may prove useful for the determination of fixed ammonium in soil. Results obtained by this method indicated that 4–8% of the nitrogen in surface soils and 19–45% of the nitrogen in subsoils examined was in the form of fixed ammonium.4. It is concluded that some mineral soils contain a significant quantity of ammonium and organic matter intimately associated with clay minerals and that this clay-bound material is not dissolved by neutral and alkaline reagents used for the extraction of soil organic matter, but is released by hydrofluoric acid.

Description: 1. Thirty-four lambs varying from 1 week old up to 22 weeks have been treated with: (a) p.m.s. alone; (b) Progesterone + p.m.s.; (c) p.m.s. + chorionic gonadotrophin (c.g.).2. At 1 week old the lamb's ovaries were unresponsive to treatment (a).3. At 4 weeks follicular growth was obtained in groups treated with both (a) and (b).4. At 8 weeks of age follicular stimulation was obtained from treatment (a), follicle luteinization from (b), and ovulation from (c).5. At 10 weeks luteinization was observed in (b) and ovulation in (c).6. At 12 weeks luteinization occurred following treatment (a) and ovulation followed treatments (b) and (c).

Description: 1. The peripheral metabolism of thyroxine in sheep in pregnancy was investigated by measuring the rate of disappearance from blood of injected 131I-thyroxine. Only limited changes in thyroid metabolism during pregnancy were observed. The rate of turnover of thyroxine slightly increased, but this was not accompanied by increased levels of plasma protein-bound iodine (PBI), or thyroxinebinding protein.2. In a 3·5-month foetus, the thyroid was active, and a marked concentration of iodide by the foetus was observed. The significance of this activity could not be assessed in the absence of knowledge on the placental passage of iodide or thyroxine in the sheep.3. Knowledge of thyroid metabolism is inadequate at present to explain any correlation between animal productivity and either hormone supplementation, or PBI concentration.

Description: 1. The volume of rumen liquor in milk-fed calves at different ages up to 32 weeks was estimated by injecting polyethylene glycol into the rumen and subsequently determining its concentration in the rumen liquor. This volume increased progressively with age in relation to unit body weight. The increase xswas approximately fourfold between 4–8 weeks on the one hand and 28–32 weeks on the other.2. The amount of milk entering the rumen during a feed was estimated at different ages up to 32 weeks by the subsequent determination of the volume and fat content of the rumen liquor. In the majority of cases less than 5% of the milk fed entered the rumen. There did not appear to be any increase in the quantities of milk entering the rumen as the calves got older.3. An estimate of the rate of flow of fluid into and out of the rumen (other than milk at feeding) was made by measuring the rate of disappearance of polyethylene glycol from the rumen. A mean figure of 255 ml./hr./100 kg. body weight s.d. ± 50 was obtained in this way. It is suggested that this value probably represents the rate of flow of saliva.4. Magnesium, in a concentration up to about 8 mg./100 ml. in the rumen liquor, did not appear to be absorbed to more than a small extent through the rumen wall.

Description: 1. Fractionation experiments have been described in which powdered bone materials were extracted with dilute acids using three different techniques. Ethylene diamine tetracetic acid (EDTA) was also used in one series of experiments.2. The results suggested that the magnesium of bone is present in two main forms, one relatively soluble and the other relatively insoluble in dilute acids.3. It appeared that a large proportion (at least 70%) of the total bone magnesium was located on the surfaces of the bone crystals either as Mg2+ or MgOH+ ions adsorbed at the primary cation adsorbing centres (the surface phosphate ions of the apatite crystals) or as Mg2+ ions replacing surface Ca2+ ions of the crystal lattice.4. Evidence that magnesium carbonate does not occur in significant amounts in bone salt was obtained.5. These results were discussed in relation to the hypomagnesaemia of lactating cows.6. The carbon dioxide of bone also appeared to be present in two main forms, one relatively soluble and the other relatively insoluble in dilute acids.

Description: Two calves (Zebu × Australian Illawara Shorthorn and Shorthorn) of about 7–8 months of age were exposed to controlled atmospheric conditions. Cutaneous evaporation from the belly area of these calves was measured by the capsule method. Records of the temperature of the skin under test and that of the air passed over the skin was also maintained.The amount of water passing through the cattle skin was proportional to the difference between the saturated water-vapour pressure at skin temperature and the water-vapour pressure in the air. Tests were made for the water-vapour pressure difference varying from 9 to 25 mm. Hg.

Description: Data concerning a random sample of flocks in Yorkshire and Lancashire were collected, in the form of answers to a questionnaire. Information was received from 88% of the 272 farms approached.The present survey, a more detailed repetition of one performed in 1952–53, has extended the information already collected and enabled deductions to be made regarding the relationship between disease losses, breed and husbandry methods. The advantages and disadvantages of this type of survey are discussed.

Description: 1. The technique for assessing rejection and acceptance thresholds for gustatory sense in goats is described.2. Quinine dihydrochloride is rejected at a level of 125 mg./100 ml. and accepted at 12·5 mg./100 ml.3. Sodium chloride has a rejected threshold of 5·0 g./100 ml. and an acceptance threshold of 1·25 g./100 ml.4. Acetic acid is rejected at 5 ml/100 ml. but is accepted at 1·25 ml./100 ml.5. Glucose does not provide data for the assessment of thresholds, since all the goats consume solutions containing the highest concentration of glucose offered, viz. 40 g./100 ml.

Description: 1. A method of determining fixed ammonium in soil based on estimation of the difference in the amounts of ammonium released on treatment with N-HF:N-HC1 and with N-KCI has been investigated and compared with the hydrofluoric acid method of Rodrigues and the alkaline distillation method of Barshad.2. Results obtained by the N-HF:N-HCl procedure with profile samples of various soils indicated that 3–8% (average, 5·6%) of the nitrogen in the surface soils and 9–44% (average, 21·5%) of the nitrogen in the subsoils examined was in the form of fixed ammonium. Rodrigues's method gave much higher values and Barshad's method gave much lower values.3. Studies on the forms of nitrogen in soil profiles showed that the proportion of soil nitrogen released by acid hydrolysis as total-N and α-amino-N decreased with depth in the profile, whereas the proportion liberated as ammonium by acid hydrolysis increased with depth. They also showed that a considerable amount of the ammonium released by acid hydrolysis was derived from fixed ammonium in clay minerals.4. It was found that the proportion of soil nitrogen dissolved by N-HF:N-HCl increased with depth in the profile, whereas the proportion dissolved by neutral and alkaline reagents used to extract soil organic matter decreased with depth. On the average, 23·2% of the nitrogen in the surface soils and 47·4% of the nitrogen in the subsoils was dissolved by a single treatment with N-HF:N-HCl at room temperature for 24 hr.5. The reliability and significance of the results obtained by the N-HF:N-HCl method are discussed.

Description: Since the introduction of silos and associated techniques of ensilage production in the late 1870's, maize has been the principal silage crop in the United States. Many British authorities agree that maize is a ‘splendid silage crop, highly nutritious, heavy yielding and easy to cut and handle’ (Bond, 1948, see also Watson & Smith, 1956; Woodman & Amos, 1944) but, nevertheless, it is very rarely grown in Britain for silage. In this country, as in most countries of Western Europe, the predominant aim of maize cultivation has been to produce succulent green fodder for direct feeding to animals during time of drought and consequent grass shortage. The acreage grown in England is small, but in Western Germany in 1955 there were about 100,000 acres of fodder maize (Becker, 1956), while in France, in 1954, the acreage exceeded 500,000 (Desroches, 1955). Recently in Western Europe considerable interest has been shown in the possibilities of maize as a silage crop, and within the past few years preliminary results have been reported from Holland (Becker, 1956; Anon. 1954, 1955); Denmark (Bagge & Hansen, 1956); Belgium (Lacroix, 1955; Ledent, 1955); Germany (Jungehulsing, 1955; Schell, 1954); France (Desroches, 1955), and Switzerland (Bachmann, 1952).

Description: 1. The ash content of the skeleton of Cheviot ewes fed a daily ration containing about 4·5 g. of phosphorus fell by 18·8% between mid-gestation and mid-lactation, and 2 months after the end of lactation the loss was fully replaced.2. In ewes fed a daily ration containing about 1·5 g. of phosphorus the loss of skeletal ash was 39·9% at mid-lactation, and this was not replaced 2 months after the end of lactation. When the phosphorus intake was raised in mid-lactation from 1·5 to 4·5 g. repair was greater but was still not complete.3. Resorption was greater in bones rich in cancellous tissue, such as the cervical vertebrae, than in those rich in compact tissue, such as the shafts of long bones, but when severe resorption took place significant losses were found in the shafts of long bones as well as in other bones.4. Whole blood inorganic phosphorus values were very low, particularly during lactation, in ewes fed on the low-phosphorus ration. When extra phosphorus was fed from mid-lactation onwards blood phosphorus values rose to normal in less than four weeks, a much more rapid recovery than that which took place in the skeleton.5. Resorption of the skeletons of ewes on both moderate and low-phosphorus rations could be detected using radiographs taken of the radius in the living animal at mid-lactation, and severe resorption found in ewes fed on the low-phosphorus ration could be distinguished readily from the milder resorption found in ewes fed on the moderate-phosphorus ration.

Description: 1. Three female calves (Shorthorn, Zebux Australian Illawara Shorthorn, and American Brahman) of about 7–8 months old were exposed to different combinations of wet- and dry-bulb temperatures in the psychrometric chamber at the Physiology Department of the University of Queensland.2. A capsule method has been developed for measurement of cutaneous evaporation from limited areas. This method has been described in detail.3. Cutaneous evaporation from the shoulder area of the Zebu cross was significantly higher than that of the Shorthorn. There was, however, no difference between the two animals in their cutaneous evaporation from the belly area.4. In the Zebu cross the cutaneous water losses from the shoulder area, on the average, increased linearly with increase in skin temperature. In the Shorthorn, there was no important increase in the cutaneous evaporation from the shoulder area, although the skin temperature increased by about 2–3/ F.5. The Zebu cross had lower skin temperatures of the shoulder area when compared with that of the Shorthorn. These lower skin temperatures were associated with higher cutaneous evaporation.6. Increase in rectal temperature was not accompanied by increase in cutaneous evaporation in all the three animals studied.7. In all the three calves the cutaneous evaporation increased with increase in air temperature.

Description: 1. The energy exchange of two sheep closely clipped at weekly intervals was determined at three feeding levels and seven environmental temperatures, using a respiration apparatus in which radiant temperature was equal to ambient temperature. All measurements were made under conditions in which the animal was in equilibrium with its environment and heat storage was zero.2. Body weight and fleece growth were both markedly reduced at the lowest feeding level. Weight losses were most marked at the lowest temperatures.3. The energy lost in faeces decreased slightly as environmental temperature increased from 8 to 38° C. Urine energy losses also fell. Losses of energy as methane were maximal in the temperature range 23–28° C. As a result of these changes, the metabolizable energy of food increased with environmental temperature by 7 Cal./24 hr./° C.4. The environmental temperature of the sheep at which their heat production was minimal, i.e. the ‘critical’ temperature was 39–40° C. for the lowest feeding level, 33° C. for the medium feeding level and 24–27° C. for the highest feeding level.

Description: 1. The heat emission of two closely clipped sheep was studied in forty experiments in which three feeding levels were employed and in which environmental temperatures ranged from 8 to 38° C.2. The sheep shivered at temperatures below 23° C., but the first reaction to cold was a corrugation of the skin referable to contraction of the fascial muscles.3. As environmental temperature increased voluntary water consumption and urinary volume increased markedly. Only a small degree of cooling resulted from this warming of large quantities of water through a relatively small temperature gradient.4. The basal loss of heat by vaporization of water was 316 Cal./m.2/24 hr. in one sheep (3) and 307 Cal./ m.2/24 hr. in the other (23). Increased vaporization occurred at environmental temperatures of 31° C. for the experiments at the low-feeding level, 27° C. at the medium level and 26° C. at the high level. The water-vapour loss increased subsequently by 87 Cal./m.2/24 hr./° C. change in environmental temperature in sheep 3 and by 88 Cal./m.2/24 hr./° C. in sheep 23. Respiratory frequencies increased with increasing heat loss by vaporization. Some evidence suggests that when the water-vapour loss was high the excretion of potassium through the skin was increased.