ALBERT

Description: 1. A survey was carried out on dairy farms in the south of Scotland during the period 1958–59 to obtain information on: (a) the mineral element composition of spring pastures associated with grass tetany or staggers and hypomagnesaemia, and (b) the influence of magnesium supplements on the incidence of these conditions and on serum magnesium levels.2. Pastures associated with grass tetany had a significantly lower average magnesium and sodium content and a higher potassium content than those which were classed as normal. These differences were magnified in the values of the ratios K/(Ca + Mg) and (K + Ca + P)/(Mg + Na) which were considerably higher in tetany pastures. The incidence of tetany was positively correlated with the value of the former ratio. These results are similar to those obtained in Holland.3. The analytical results for pastures associated with hypomagnesaemia in clinically normal cows were not significantly different from those for normal pastures and there was no evidence of any association between the composition of the pasture and the incidence or severity of the hypomagnesaemia or the serum magnesium levels.4. The magnesium and sodium contents of the majority of the pastures examined would be judged as inadequate in the light of available information on the requirement of these elements.5. There was no evidence of any correlation between the magnesium content of the pasture and that of any of the other elements studied.6. Cases of grass tetany occurred in 25% of the 108 herds studied, the mean incidence in affected herds being 4·5 ± 0·65%. The overall incidence was 1·1 ± 0·25% and was significantly lower when a magnesium supplement was given as a prophylactic measure.7. Hypomagnesaemia was detected in clinically normal cows after turning out in 41·2% of the herds, the overall incidence being 8·7 ± 1·0%. On tetany free farms the feeding of calcined magnesite or magnesium-rich mineral mixtures did not appear to reduce the incidence of hypomagnesaemia or the fall in serum magnesium levels which occurred after turning out.8. These results emphasize the wide individual variation in the susceptibility of different cows to the factors causing hypomagnesaemia and grass tetany and also the differences between the two conditions in their dietary relationships. It is suggested that dietary factors may be responsible for producing the clinical signs of grass tetany in hypo-magnesaemic cows.

Description: 1. The amounts of N, P and K recovered by five arable crops and by permanent grass from soil alone, and from fertilizer and farmyard manure (FYM) dressings were measured. All the crops responded well to P and K fertilizers and all except clover responded to N. Uptakes from soil alone are therefore the maximum amounts of each nutrient that each crop could remove when supplied with other fertilizer nutrients (the exchangeable Ca and Mg in the soil were adequate).2. Permanent grass (free from legumes) obtained about 114 lb. N/acre each year from soil and other natural sources; winter wheat obtained 1001b. N, kale and potatoes about 80 lb. N and spring barley only 57 lb. A 1 year ley of clover and grass fixed at least 1 cwt. N/aere/year. Permanent grass removed most P from soil (17 lb./acre a year), potatoes removed least (6 lb. of P) and other crops intermediate amounts. Most K was taken from soil by kale (70 lb. K/acre/year) and least (20 lb.) by potatoes. Annual variations in the amounts of nutrients recovered from soil by any one crop were much greater with K than with N or P.3. Most fertilizer N was recovered by kale and least by potatoes; with these crops two-thirds and one-third respectively of the light dressing was recovered, percentage recovery from the higher rate of N tested was less. Kale and the 1 year ley recovered nearly one-quarter of the P applied, permanent grass recovered little more than one-tenth. Clover-grass ley recovered most fertilizer K, apparently taking up four-fifths of that applied. Potatoes, kale and permanent grass all recovered more than half of the fertilizer K given, cereals were least efficient although both responded well to K dressings.4. Farmyard manure supplied large amounts of nutrients to all crops. Similar amounts of N, P and K appeared to be recovered from FYM whether or not NPK fertilizer was also used. A rough estimate was that crops like kale, potatoes and permanent grass, which received FYM each year, recovered about 30 lb. of N, 4 lb. of P and 75 lb. of K from a 10 tons/acre dressing.

Description: 1. An experiment, lasting 3 years, was carried out to investigate the control of hypomagnesaemia on a medium-heavy loam soil in Northern Ireland, using as criteria herbage analysis and analysis of blood sera of grazing dairy cows.2. Applications of calcined magnesite and magnesian limestone as soil treatments raised the magnesium contents of herbage slightly but not to levels judged to be safe. Low blood sorum magnesium levels were recorded for cows grazing this herbage although no cases of tetany occurred.3. Magnesium sulphate, appliedas a spray, temporarily raised the ‘apparent’ magnesium content of the herbage but was easily washed off by rain.4. Finely powdered calcined magnesite applied as a dust to the herbage immediately before grazing appeared to be a promising method of control under Northern Ireland conditions.

Description: The errors of 454 cereal experiments organized by the National Institute for Agricultural Botany between 1956 and 1960 are examined in relation to block size. All the experiments used long, narrow plots and were harvested by combine. The most important conclusion is that the gain in efficiency by using small blocks in cereal experiments is as great now as it was before combine-harvesting and long, narrow plots were introduced. An empirical rule is that the variance per plot is roughly proportional to n½, where n is the number of plots per block.

Description: 1. 4 g. of Mg per day given as either magnesium oxide or magnesium nitrate failed to increase plasma magnesium levels of fourteen lactating ewes which had initial values of about 1·0 mg. Mg/100 ml.2. Increases which were recorded 4 hr. after drenching were not sustained for the full 24 hr. period between drenches.

Description: The L-threonine requirement of the weanling pig is 0·45% of the air-dry food. This level supports as good growth and economy of food conversion and promotes as good retention of nitrogen as higher amounts.It is unlikely, when pigs are fed normal rations, that L-threonine will be the limiting essential amino acid.A comparison in the period 120–180 lb. live weight between diets supplying 0·47 and 0·87% L-lysine, respectively, showed no benefit from feeding the higher amount. It seems uneconomic to feed animal-protein to supply lysine after 1201b. live weight. The requirement can be met at less cost from vegetable sources.In conclusion, the author desires to express his indebtedness to Messrs V. Thurlbourn and R. D. Willis for taking charge of the experimental animals during the N-balance trial. Also to Mr E. A. Porter for his care of the pigs during the growth trial.

Description: 1. A small-scale plot experiment which had been conducted from 1947 to 1952 to study the effect of massive dressings of fertilizer nitrogen, with and without phosphate and potash, on the yield and quality of a rye-grass dominant sward was continued from 1953 to 1958 with two changes in the mineral treatments in 1953. A 4 × 4 Graeco-Latin square was used.The nitrogen treatments applied each year were: (1) no nitrogenous fertilizer, (2) 260 lb. nitrogen, (3) 520 lb. nitrogen and (4) 416 lb. nitrogen per acre per year.The mineral treatments were: (A) no mineral fertilizer, (B) 336–504 lb. K2O per acre per year depending on nitrogen treatment, (C) 101–202 lb. K2O and 81–101 lb. P2O5 per acre per year depending on nitrogen treatment, and (D) no mineral fertilizer after 1953, although K2O and P2O5 had been applied during the previous 6-year period.All the fertilizers were applied in four or five equal dressings each year, one for each cut.Treatments 1 and 4 were cut four times and treatments 2 and 3 five times per year.2. Applications of phosphate did not affect the yields of herbage dry matter or crude protein, but yields were severely depressed in the absence of potash. With adequate potash the yields under all nitrogen treatments were maintained for the 6-year period and were at the same level as in the previous 6-year period. The mean yields of dry matter for the 6-year period when potash was applied were 5200, 8420, 10,180 and 9700 lb. per acre per year for treatments, 1, 2, 3 and 4. Without potash the corresponding mean yields were 5460, 6410, 6210 and 6880 lb. Average crude protein yields were 760, 1360, 1940 and 1660 lb. per acre per year with potash and 780, 1100, 1220 and 13201b. without potash.3. The weighted mean contents of crude protein for the 6-year period averaged over all the mineral treatments were 14·4, 16·7, 19·4 and 18·2% for nitrogen treatments 1, 2, 3 and 4. The mean crudeprotein contents of treatments with and without potash were 16·7 and 17·6%, respectively.4. The average response to nitrogen was 15·0, 10·9 and 12·4 lb. dry matter per 1 lb. of nitrogen applied on treatments 2, 3 and 4, respectively, compared with a no-clover sward, and 7·8, 7·3 and 7·9 lb. compared with a grass + clover sward. The recovery of nitrogen in terms of crude protein was 45, 40 and 40% for treatments 2, 3 and 4, respectively, when compared with a no-clover sward.5. The botanical composition of the plots continued to be determined by the nitrogen and potash treatments. On plots receiving ‘Nitro-Chalk’ clover was virtually non-existent, whereas on plots which received potash and no nitrogen, clover was present. With a combination of potash and nitrogen vigorous swards of timothy were found but if only nitrogen and no potash was applied, poorer grasses, such as Festuca rubra, were dominant.6. Soil analyses showed increased pH values and decreased contents of Mg with increasing applications of ‘Nitro-Chalk’. P2O5 values were low except where phosphate was being applied. The most marked change was in the K2O values which varied from 4 units on treatments A and D which received no minerals to 40 units on treatment B which received the heavy dressings of potash.7. Mineral analyses of the herbage for 1953 and 1958 are given. High K contents were found on treatments where potash was applied and this was associated with decreased Mg and Na contents.8. Some details are given of a field-scale trial on the Institute farm where high levels of nitrogen and potash have been applied for 11 and 12 years with successful results.

Description: 1. Ten experiments were carried out on grassland in various parts of England and Scotland to compare ammonium nitrate, ammonium sulphate, urea with less than 1% biuret and urea with about 4% biuret. The grass was cut a number of times during the season and each nitrogen fertilizer was applied at rates supplying 30 and 60 lb. per acre of nitrogen in spring and after each cut except the last.2. Total yield and yields at most individual cuts of both dry matter and nitrogen in the herbage were increased by each increment of applied nitrogen.3. Ammonium nitrate and ammonium sulphate gave similar dry-matter yields at all cuts in six experiments, while in four on calcareous soils ammonium sulphate gave lower yields than ammonium nitrate at one or more cuts. Ammonium sulphate gave lower yields at the second or third cuts in more experiments than at the first cut.4. Urea with 〈 1% biuret gave lower dry-matter yields than ammonium nitrate at one or more cuts in eight of the ten experiments. Urea became less efficient relative to ammonium nitrate as the season advanced.5. The efficiency of urea with 〈 1% biuret relative to ammonium nitrate in each experiment was positively correlated with the ammonia absorption potential of the soil.6. Urea with 〈 1% biuret and urea with about 4% biuret gave similar yields.

Description: 1. A comparison was made between the pulse rate of shorn and unshorn sheep maintained in the shade and direct sunlight during the various seasons of the year.2. The variability of the pulse rate during the day generally agreed with the daily changes in body temperature and presumed level of metabolism. Fluctuations were greater in unshorn sheep.3. Pulse rate was lower during summer (60–100 for unshorn and 63–100 for shorn sheep) than in winter (90–130 for unshorn and 90–115 for shorn sheep). It tended to increase with a rise in ambient temperature, especially during winter and spring. A lower pulse rate accompanied a rise in environmental temperature, during summer. The slowest pulse rate of 42 per minute was observed during summer in the hot dry area.4. The pulse rate of both groups increased with a rise in rectal temperature, particularly at low ambient temperatures. At comparable rectal temperatures, a higher average pulse rate was observed in shorn sheep during winter and spring. With elevated summer temperatures, equal pulse rates were noted in both groups of equal rectal temperatures. Since the rectal temperatures of the shorn exceeded that of unshorn sheep, in high environmental temperatures, and in the sun, their pulse rate under these conditions was also higher.5. The differences in pulse rate between the two groups appeared to reflect the combined effects of metabolic rate, body temperature and the vasomotor activity, all of which vary with season and environmental temperatures.

Description: 1. A balanced factorial experiment was carried out with forty-eight Merino ewes. There were two levels of each of the four factors: environmental temperature, thyroxine status, vitamin A intake and progesterone status. Each ewe was killed at 25 days' pregnancy. The embryos and their membranes were weighed and examined histologically.2. There appeared to be no treatment effects on the embryonic length/weight ratio. The ratio between embryonic weight and ‘conceptus minus fluid’ weight may have been affected. There was no evidence of treatment effects on the degree of differentiation of either the embryo or the chorioallantois.3. Surviving embryos tended to be large where thyroxine was supplied, i.e. where viability was good, and vice versa. Dead embryos fell into two groups: those less than 3 mm. long and those 6 mm. or more which had probably died shortly before the ewes were killed.4. There were no significant correlations between the weights of live embryos and mean rectal temperature, plasma vitamin A concentration or any of the histological indices measured in the endometrium. In the hot-room live embryo weight was correlated with the height of the ewe's bladder epithelium (P 〈 0·01).5. It is suggested that in the absence of adequate maternal thyroid hormone (i) the trophoblast may enlarge too slowly to stimulate adequately some response in the endometrium essential for maintenance of the embryo, or (ii) disproportionate growth in different parts of the conceptus may result directly in embryonic failure.

Description: 1. A balanced factorial experiment was carried out with 48 Merino ewes. There were two levels of each of the four factors: environmental temperature, thyroxine status, vitamin A intake and progesterone status. Each ewe was killed at 25 days' pregnancy. The ovaries were removed, weighed and examined histologically.2. There were no significant treatment effects on ovarian weight, corpus luteum diameter, lutein cell frequency, lutein cell nuclear diameter, the number of Graafian follicles exceeding 0·9 or 1·9 mm. diameter, or mean follicle diameter. The results suggest that with more animals heat might prove to depress ovarian weight and vitamin A to increase ovarian weight, corpus luteum diameter and the number of large follicles.3. There were no significant differences between the mean values for those ewes with live embryos and those with dead ones with respect to any of the above indices.4. The results support the conclusion that variations in embryonic viability due to the experimental treatments were not mediated primarily through variations in ovarian hormone secretion.

Description: Albumen quality, shell thickness and incidence of blood and meat spots in eggs from the progeny of indigenous poultry of Uganda crossed with four imported breeds were compared with results from the pure imported Rhode Island Red breed and discussed relative to figures previously obtained from indigenous poultry. The measurements were taken for a 5-day period during the 12th month of age of the birds when maintained under a high environmental temperature in Uganda.The albumen quality of all four cross-breeds, as measured by Haugh units, was significantly higher than that of the Rhode Island Red breed.All four cross-breeds produced eggs with shells significantly thicker than the Rhode Island Red, only slightly below the generally accepted figure of 0·013 in.The incidence of both blood and meat spots was lower in all four cross-breeds than in the Rhode Island Red, in the case of blood spots significantly lower in one cross-breed and in the case of meat spots significantly lower in three cross-breeds.

Description: … In short, he used many learned arguments to persuade his audience out of their senses; and from stench made a transition to filth, which he affirmed was also a mistaken idea, in as much as objects so called, were no other than certain modifications of matter, consisting of the same principles that enter into the composition of all created essences, whatever they may be: that in the filthiest production of nature a philosopher considered nothing but the earth, water, salt and air of which it was compounded.…

Description: Four hundred and twenty-two ewes, of a number of different breeds and ages (flocks 1–9) were used in experiments with hormones in the normal breeding season. Two main trials were conducted, the first making use of 377 animals, the second involving 45.Trial 1Three hundred and seventy-seven ewes were observed, in eight farm flocks, in a study of response to different treatments involving the administration of progesterone (in oil solution) and p.m.s. The trial sought to determine the effect of various dosage levels of progesterone and intervals of injection on the normal breeding performance of the ewe. Hormone treatment was applied at such time in the breeding season as to make it most improbable that conception would be limited by adverse animal or environmental factors. The aim was to determine the effect of the hormone technique per se on both immediate and long-term reproductive performance. Injection procedures and methods of flock management were arranged so that they might later be repeated in applications during the period of anoestrus.Two hundred and thirty-three ewes were injected intramuscularly with doses of progesterone in oil solution over a 7-day period. For eighty-nine ewes, four doses of 40 mg. were administered at 2-day intervals; for 144, 3 doses of 50 mg. were given at 3-day intervals. A single injection of 750 i.u. of p.m.s. was given subcutaneously to each ewe 2 days after the final dose of progesterone. One hundred and forty-four ewes remained untreated and served as a control.Progesterone therapy was effective in inhibiting oestrus and ovulation in the majority of ewes. Most injected animals came in oestrus 1–5 days following the injection of p.m.s.; 10% showed evidence of ‘silent heat’. 70% of ewes receiving progesterone at 2-day intervals and 68·2% of those receiving it at 3-day intervals conceived at the ‘controlled’ oestrus. 75% of the controls conceived at first mating. Treatment did not adversely affect the conception percentage to any appreciable extent.In animals conceiving at first oestrus, the average number of lambs born per ewe was 1·78 for injected and 1·44 for controls. In each flock there was an increase in lamb-crop, which would seem to be the result of the p.m.s. injection. Information on the effect of therapy on subsequent ewe fertility shows that 6·4% of ewes failed to conceive; this figure was the same for both treated and control animals. An attempt to use A.I. in conjunction with progesterone- p.m.s. therapy gave a conception percentage of 24, as compared with 68 in normally bred sheep.The results are discussed in relation to factors such as breed and age of ewe, and according to the particular mating procedure employed. There is no evidence that the forms of progesterone-p.m.s. therapy employed in this work would constitute a limiting factor to conception in out-of-season breeding.Trial 2The forty-five mature Welsh Mountain ewes used were in one flock. Each animal was injected on the 13th day of the oestrous cycle with a single dose of either 50 or 100 mg. of a micro-crystal suspension of progesterone. Two forms of suspension were used, the difference between the two being in the size of the individual crystals. Ewes came in oestrus 7–13 days following injection, the range for 50 mg. dosage being 7–13, and for 100 mg. 10–13 days. 25% of animals showed ‘silent heat’. Results suggest that injection of suspension adversely affects the normal expression of oestrus.

Description: 1. When Merinos of varying wool lengths were exposed at constant air temperature of 36° C. (c. 97° F.) to infra-red radiation of energy equivalent to that which they might receive from the sun, the following responses were noted:(a) A very highly significant (P 〈 0·001) inverse relationship between respiration rate and wool length.(b) A non-significant inverse relationship between rectal temperature and wool length.(c) A very highly significant (P 〈 0·001) quadratic relationship between back wool-tip temperature and wool length.(d) A very highly significant (P 〈 0·001) inverse relationship between back-skin temperature and wool length.Thus, the length of wool determines to a large extent the degree of protection given to the sheep against radiant heat.2. The rate of conduction of heat per unit area through the back wool in different sheep was hyperbolically related to wool length. Below 1 cm. woollength heat was taken up very rapidly; beyond 4 cm., increasing wool length afforded negligible additional protection.

Description: 1. The value of ‘worm-free’ sheep in the assessment of pasture is illustrated by an experiment in which the effect of internal parasites could only be distinguished by the use of ‘worm-free’ controls.2. The effect of augmenting the initial pasture infestation (with nematodes parasitic in the sheep) was slight.3. In an experiment with ewes and lambs at three lambing percentages and over a range of stocking rates:

Description: An objective appraisal system for intact lamb and mutton carcasses utilizing a fleshing index to relate carcass weight and length is presented. Gross fleshing index is defined as the number of pounds by which any carcass is heavier or lighter than the average carcass of its particular length. Penalty for overfatness is made when necessary by an estimation technique involving measurement of fat status at the level of the first lumbar vertebra on the intact carcass with the aid of a steel probe. The net fleshing index, a simple numerical expression of carcass fleshing, is arrived at by deducting the penalty for overfatness (when necessary) from the gross fleshing index. The greater the net fleshing index the greater the relative merit of the carcass.

Description: Correlations between various characteristics at each weight indicate that (i) a good percentage of lean is associated with increased bone, a larger eyemuscle area and, in particular, less backfat; (ii) the carcass conformation score for 260 lb. hogs has a high negative association with average backfat and this may be because the extreme amounts of fat on some these hogs adversely affected the balance of the carcass.Visual scores or assessments made on the shoulder, ham, streak and on the carcass conformation bear no relationship to the proportionate weights or to the leanness of the respective parts of the carcass. They reflect only the requirements of the trade which are based on shape and are not substantiated by dissection. In nearly all cases, gilts achieve better scores than hogs. The back rasher score assessed on a good fat to lean ratio and a good eye muscle is much higher for gilts than for hogs and decreases as the slaughter weight increases. There is a positive association between back rasher score and the leanness of the back.

Description: 1. Three trials are reported in which the grazing behaviour of separate groups of cows, one receiving supplementary food, either as conserved roughage, concentrate or fodder crop, was observed over 24 hr. periods. A fourth trial, assessing the effect of summer temperatures on unshaded milking cows, is briefly described.2. In trials 1 and 2 the stall feeding of either conserved roughage or concentrate reduced grazing as compared with unsupplemented cows by approximately 10%.3. Allowing access to a fresh ‘strip’ of a fodder crop at a set time each day, whilst not altering total grazing time, very markedly altered periodicity of grazing. Cows delayed grazing up to 3 hr. whilst awaiting a fresh ‘strip’.4. Environmental temperatures up to 87° F. did not alter total grazing time as compared with grazing time when temperature reached a maximum of only 70° F.5. The value of supplementary feeding of dairy cattle at pasture, at least where the intake of pasture is sufficient for maintenance and a low level of production, appears to be open to question.

Description: An insignificant short-term increase in the natural dose of ionizing radiation during the embryogenesis period is beneficial not only for the embryonic development of the chicks, but also for their postembryonic growth and development as well as the egg production of the pullets.Irradiation of incubated eggs with microdoses of radioactive radiations is another possibility for the utilization of atomic energy bringing about an improvement in the economically useful properties of poultry.

Description: An artificial rumen is described which has been shown to simulate closely conditions in the bovine rumen. Criteria of its validity include quantitative and qualitative bacteriological data, V.F.A. production, pH levels and digestion rates; these were examined with a variety of diets using cows on similar diets as controls. An important feature of the apparatus is the high degree of control which can be exercised over the progress of the in vitro ruminal fermentation, permitting experiments of considerable duration.

Description: 1. The potency of balancing interactions between the protein of herring press-cake (dried) and solubles (condensed) on one side, and certain vegetable feeds on the other, has been examined on 2- to 4-week-old chicks:(a) Initially by comparing the co-effect of a series of different combinations of the herring products when ingested together with certain cereals plus extracted ground-nut meal, to that estimated earlier when the same combinations of herring products formed the sole dietary protein.(b) Thereafter by studying whether the co-effect of the herring products was influenced or not by substituting extracted soya-bean meal for the ground-nut meal.(c) Further by tentative trials to show that registered interactions were caused by some keystone amino acids.2. A special dietary system was devised for the purpose (a basal diet of actual feeds + a synthetic, practically protein-free basal diet + the tested feed, eventually + adjustments), the results being recorded as combinative protein value = c.p.v.3. Interactions between dietary constituents not only were shown under the circumstances, but proved to be an easily acting factor of great power. Herring solubles in proportions of 15–45% were formerly found to bring about a statistically significant improvement of the meal when fed together with this as the only protein of the diet. But: (a) the introduction of certain cereals and ground-nut readily converted the beneficial effect of the solubles into a significantly negative one. (b) Whereas soya-beans instead of ground-nut evidently reversed the situation again. In this third grouping solubles at moderate levels appeared neutral, meaning that herring solubles combined significantly better with soya-bean than with ground-nut when fed to young chicks in presence of a set of cereals and herring meal, (c) Responses to supplemental, crystalline amino acids showed that the interactions between the protein sources could be attributed to their constituent amino acids. Thus the little efficient combination of solubles and ground-nut plus certain cereals could be greatly improved by small quantities of all ten essential amino acids together, and equally much by lysine plus threonine only. Contrarily, the diet appeared weakened when lysine, threonine or isoloucine were omitted singly or together from the whole ten. The same was the case with single addition of leucine.4. The discussion stresses the pre-eminent importance of the diet in biological estimations of protein value. It also points out the practical significance of skilful combination of different protein sources.

Description: 1. In the seeding year the total dry-matter yield in swards sown without a cover crop was increased by infrequent defoliation, but the yield of crude protein was decreased. The highest production of starch equivalent was obtained when a cover crop was used.2. In the absence of a cover crop, the yield of red clover was higher under infrequent defoliation, but the yield of white clover was higher under frequent grazing.3. Frequent grazing, and the use of a cover crop, reduced the ingress of weeds more than infrequent defoliation. Nitrogen applied to the cover crop also reduced the growth of weeds.4. Nitro-chalk increased the total yield of herbage except when under a cover crop; it reduced the growth of red and white clovers, but this was not so marked under frequent grazing.5. Nitro-chalk increased the annual yield of crude protein under frequent grazing, but decreased it in all herbage mixtures under infrequent defoliation; nitrogen had no effect when a cover crop was used. The increase in yield of starch equivalent due to the application of nitrogen and its apparent recovery was greater under frequent grazing than under the other two managements. Under infrequent defoliation, in the absence of a cover crop, the recovery of nitrogen was particularly low.6. The ryegrass mixture and ryegrass-dominant general-purpose mixture made more growth, and suppressed clover and weeds to a greater extent than did the timothy and cocksfoot mixtures. This was modified by management in that ryegrass was particularly aggressive under frequent grazing (management 1) but not under managements 2 and 3.7. In the autumn of the seeding year the yield of total herbage was highest under infrequent defoliation, particularly in the cocksfoot, and general-purpose swards. All undersown mixtures gave lower yields than when no cover crop was used.8. Nitrogen increased the yield of herbage in May and June under frequent grazing, and in the August cut under infrequent defoliation, but in the autumn particularly it was reduced where a cover crop was used.9. The application of nitrogen decreased the protein content in all herbage mixtures when a cover crop was used or when defoliation was infrequent. Under frequent grazing the nitrogen increased the percentage of crude protein in the first two grazings, but decreased it in the September grazing.10. The production from the various mixtures was modified by management: under frequent grazing in May the ryegrass-dominant mixtures were higher yielding than the others, but in July the general-purpose and cocksfoot swards were the most productive. Under infrequent defoliation in August the timothy mixture had the highest yield and cocksfoot the lowest, and under this management cocksfoot and timothy swards had the highest yield in the autumn of the seeding year.

Description: 1. A feeding trial involving sixty-four individually fed pigs was carried out to assess the effect of reducing the protein content of the diet at different live weights. The effect was examined at two planes of protein intake, 19 % falling to 14 % in the finishing stages, and 16 % falling to 12 %.2. High protein levels improved growth rate and food conversion efficiency during the growing phase, and also improved carcass quality in terms of the lean content of the carcass, eye muscle area and length.

Description: Thirty-two ewes (of which 22 were P.M.S.- treated) were individually mated, each one either to two different rams or to four different rams successively, at predetermined intervals of time during a single oestrus period. The onset of heat was determined by a raddled vasectomized ram with free access to the ewe flock. Since each ram used was of a different breed the genotypes of the resulting lambs denoted which of the matings on each ewe had been effective.

Description: 1. A study was made of the effects of diet on the growth of the internal organs, and in particular the four stomachs of lambs.2. A total of twenty-three lambs was reared from birth on various diets ranging from all milk to small amounts of milk and roughage ad lib. The lambs were slaughtered at various ages and the fresh wet weights of the parts of the alimentary tract and the other internal organs were recorded.3. The growth rates of the four stomachs were influenced by the plane of nutrition, however, the type rather than the plane of nutrition was more important in determining the weights of the stomachs relative to each other and to live weight.4. Lambs fed solely milk from birth had the development of their fore-stomachs retarded at about the level found in the 3-week-old grazing lamb. The abomasums of these lambs were abnormally heavy.5. The rumens and reticulums, which were retarded in their growth by milk feeding, reached normal proportions very quickly once roughage was fed.

Description: The present work extends the information on the skin thickness of cattle and shows that generalizations made in previous work were only partly correct, for there are significant differences only between the skin thickness of the Zebu ‘races’ of tropical cattle and Bos taurus.Again there appeared to be no significant difference between animals of different ages within breeds.The work confirmed that cattle of eleven tropical breeds comprising four of the major ‘races’ of African indigenous cattle have a significantly thinner papillary layer than temperate breeds, and this was very strongly correlated with their superior heat toleration.Further support based on wider premises was therefore given to suggestions made by Dowling regarding the importance of the histology of the skin in heat toleration.

Description: Two early weaning experiments are reported. When grazing young, high protein pastures, lambs weaned at 7, 10, 13 and 18 weeks of age grew equally well and there were no significant differences between their carcass weights, grades, and dressing percentages.However, when grazing pastures in the preflowering and flowering stages of growth, lambs weaned at 8 weeks of age did not grow as well as unweaned controls. Their carcass weights, grades, and dressing percentages were also inferior. It is suggested that these differences were primarily due to an inadequate protein intake.No difference in wool production was found either between the ewes of early weaned and control lambs, or between the lambs themselves.

Description: 1. Ten manurial treatments were applied annually to cattle cabbage grown in a six-course rotation for 7 years. Samples were taken in the early winter each year, and from five harvests taken at fortnightly intervals in the last year.2. The dry-matter yields each year closely followed the weather conditions during the growing season. There was no significant fall in the dry-matter yield during the last season. The treatments supplying phosphorus or phosphorus and potassium substantially increased yield, but the application of nitrogen did not.3. The application of nitrogen, potassium or phosphorus increased the levels of these constituents in the crop in practically all cases. The application of phosphorus produced hearted plants which contained significantly less dry matter than the openleavod plants produced in its absence. The levels of ether extract, crude fibre, ash, silica and magnesium wore not significantly affected by the manorial treatments.4. There was little variation in composition as the season advanced except for significant increases in the crude-fibre levels and decreases in the nitrogen-free extractives levels.5. The distribution of the chemical components was investigated in the outer leaves, heart leaves and stem of the plant. This was compared with that in the marrow-stem kales.6. The chemical composition of the cattle cabbage compares fairly closely with that found for the marrow-stem kales grown under similar conditions. It is, however, lower in dry matter, crude fibre, magnesium and chlorine. It may be considered as a replacement for marrow-stem kale as a source of crude protein and all the major minerals except chlorine and possibly magnesium.

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 shoulder and belly areas of these calves was measured by the capsule method. Density of the sweat glands in the shoulder and belly areas of these calves was measured, using a biopsy punch. Density was estimated by counting the hair follicles.(1) The Zebu cross sweats more than the Shorthorn, at least from the shoulder area, and this is related to its higher sweat gland density as compared with that of the Shorthorn.(2) In the Zebu cross cutaneous evaporation from the shoulder area is greater than that of the belly and this is associated with the differences in the number of sweat glands.(3) In the Shorthorn cutaneous evaporation is the same from both shoulder and belly areas and the number of sweat glands in these regions is also the same.

Description: 1. The digestibilities of the protein, oil and carbohydrate by chick in mash and pellets made from this mash have been determined at weekly intervals from 0 to 9 weeks.2. There was no difference in the chemical composition of the food due to pelleting, not were there any differences in the digestibilities due either to pelleting or the age of the chick.

Description: 1. The excretion of 144Ce in the faeces, urine and milk has been followed in two dairy cows receiving twice daily doses of 120 μc. with the feed over a 10-day experimental period. During the terminal 3 days, recoveries from the faeces amounted to 93–119% of the daily dose. From the urine and milk, respectively, 0·23 and 0·17% and 0010 and 0·016% of the total amount fed was recovered from the two animals.2. The concentration of 144Ce in various parts of the gut was estimated after equilibrium conditions had been attained. The highest concentrations were found in the contents of the omasum and hind-gut.3. The possible use of 144Ce as a marker in digestibility and similar trials is discussed.

Description: 1. The normal level of blood ammonia in the sheep seems to be somewhat higher than in nonruminants.2. The toxicity of ammonium acetate, ammonium chloride or urea placed in the rumen follows different metabolic pathways. In the case of the chloride there is an uncomplicated metabolic acidosis which is not, however, adequate to account for the toxic symptoms. When the acetate is administered there is also a respiratory alkalosis and in the presence of urea the changes in the acid-base status, though interesting, do not account for the toxicity.3. The toxicity is almost certainly due finally to a direct effect of the circulating ammonium ion level though in the case of urea, there is an earlier effect that may be of a pharmacological type and is less severe.4. The organisms within the rumen rapidly reach a maximum level of adaptation (7 days) to handle large quantities of ammonia by a synthetic pathway.5. The intravenous administration of L-arginine did not markedly ameliorate the ammonia toxicity.

Description: 1. The oxygen consumption of young pigs from 1 to 37 days of age has been measured in a closed circuit respiratory metabolism chamber, over the environmental temperature range 4–37° C.2. The values obtained for single pigs alone in the chamber have been compared with the results of measurements on groups of pigs 3–6 days of age taken together.3. It has been found that as environmental temperature falls below 30° C. and the grouped pigs huddle together, oxygen consumption per kg. for the group becomes smaller than values for single pigs of the same individual weight, and corresponds more with results from the larger single pig.4. Rectal temperature is maintained in pigs of the group at a lower energy cost than that required for the single pig, the saving in energy expenditure becoming proportionately greater as ambient temperature falls.5. These results are discussed in relation to body size and skin temperature.

Description: 1. Three levels of a nitrogenous fertilizer, supplying 0,104 and 208 lb. N per acre were applied in 1955 and 1956 to a rye-grass/white clover sward in its fourth and fifth harvest years on a loam soil overlying chalk.2. Levels of animal production were measured using fattening cattle maintained on the plots at a stocking rate of 1⅓ per acre: excess herbage was conserved and fed back to them later.3. Low rainfall in 1955 seriously affected yields of herbage and response to fertilizer, and severely reduced the clover content in all treatments.4. Rate of live-weight gain per head was not reduced by the application of fertilizer at either level. Vigour of the sward was maintained by fertilizer application in a dry spring period in 1956, whereas, in the control treatment, which was low in clover, gains per head were markedly reduced because of inadequate dry-matter production.5. By applying two-thirds of the fertilizer in late summer, a considerable extension of grazing time was obtained, particularly when rainfall was adequate. At the highest level of fertilizer application in 1956 the grazing season was extended from 6 months to 7½, and the cattle continued on conserved feed to a total of 8½ months. Response to the medium and high levels of application on grazed herbage only was 12 and 15 bullock-days per acre, respectively, in 1955. In 1956 the response was 46, and 67/59 (the two high nitrogen treatments). In terms of total live-weight gain per acre the response in 1955 to medium and high levels was 23 and 32% above control, up to 427 lb. per acre: in 1956 it rose to 51 and 52/55% with the highest treatment reaching 657 lb. per acre. Greater financial returns than are indicated by live-weight gain should result from the rising price per pound of carcass as the supply of fresh beef dwindles in early winter.6. Carcass data indicated that both greater rate of gain and the extra time spent on fertilized herbage and conserved feed increased carcass weight and maturity in the normal pattern of development, fat most rapidly, muscle next and bone least. No significant differences in conformation due to treatment was detected by analysis of grouped joints.

Description: 1. A simple inexpensive anemometer is described; the instrument is intended for general husbandry use.2. The essential part of the apparatus is a 1 in. diameter electrically heated duralumin sphere capping a mercury-in-glass thermometer.3. Charts are given relating wind-speed to sphere temperature, ambient temperature and heat input to the sphere. No further calibration is required.

Description: Natural infection by Verticillium albo-atrum occurred in two experiments, one comparing test crosses of inbred parents, the other a complete set of crosses between non-inbred parents. Although the uncontrolled variation was rather large, significant differences between progenies were detected in both cases. The differences were mainly accounted for by differences in general combining ability among the parents but not entirely so in the second experiment.

Description: 1. A male-sterile winter bean, inherited as a simple Mendelian recessive, is described.2. The sterility gene was shown to be expressed in the cytoplasm of eleven inbred lines of English winter beans, two varieties of English spring beans, six varieties of foreign spring beans and three varieties of broad beans (Vicia faba major). It is concluded that these varieties are unlikely to provide a fertility-inducing cytoplasm which would allow the development of a non-restoring pollinator.3. Evidence of linkage between three chlorophyll-deficient mutants and the male sterility locus is given and circumstances are outlined by which a suitable marker gene could be employed to assist in large-scale production of hybrid seed.

Description: A population of 1549 Welsh Mountain sheep, typed for haemoglobin and blood potassium concentration, were examined for correlations with production traits.The statistical analysis was carried out within years, to avoid seasonal effects, and constants were fitted for sire, parity of birth and sex, as well as for haemoglobin and potassium type.Few of the associations dependent on haemoglobin and potassium level reached significance at generally accepted levels of probability but an underlying consistency existed in mean values. Generally, animals of LK phenotypes showed marginally better neo-natal growth than HK phenotypes and animals possessing haemoglobin A had greater fleece-weights than those which did not.

Description: 1. The literature on the early weaning of lambs has been reviewed.2. Four experiments were carried out at the Grassland Research Institute, Hurley, during 1959, 1960 and 1961 on the early weaning of Suffolk x Half-Bred lambs. The technique used involved weaning one of a pair of twin lambs at ages varying from 15 to 28 days.3. In 1959 oneof each of apair of six twin lambs was weaned on to grass alone at 15–20 days. No losses occurred, but the weaned lambs grew very slowly. The unweaned twin lambs remaining with the ewes (i.e. reared as singles) grew at rates comparable to those of single lambs.

Description: 1.Within a flock of 55 Welsh Mountain ewes maintained under lowland conditions the first ewe came into oestrus on the 14th October. The mean cycle length of 44 normal cycles was 16 days 3 hr.2. The onset of oestrus as assessed by the time of mounting of the ram does not appear to be evenly distributed throughout the day (24 hr.).

Description: 1. The metabolizable energies and net energies for fattening and for maintenance of the organic matter of sixteen dried grasses have been related to their apparent digestibilities and to their chemical compositions.

Description: Ammonium nitrate and ammonium sulphate wore compared as top-dressing applications in thirty-six field experiments on winter wheat and eighty-nine on grassland in various parts of Great Britain in 1956-62. The rates of application were 35-60 lb./acre of nitrogen for winter wheat and 30-100 lb./acre for grassland in one application only.

Description: 1. A feeding trial involving 128 individually fed Large White pigs was carried out using four levels of dietary energy in combination with four levels of crude protein in the ‘growers’ rations of bacon pigs. Growth rate, food conversion efficiency, carcass quality and nitrogen balance were the parameters measured.

Description: 1. Twenty-two experiments on main-crop potatoes in 1955–7 compared calcium nitrate and ammonium sulphate applied to the seedbeds before planting. Urea was also tested in fifteen of the experiments in 1956–7. The three fertilizers were compared at rates that supplied 0·5, 1·Oand 1·5 cwt. N/acre.2. Seven experiments on kale in 1955–8 compared seedbed dressings of calcium nitrate and ammonium sulphate. Urea “was also tested in. five of the experiments in 1956–8. The rates used were 0·6, 1·2 and 1·8 cwt. N/acre in 1955 and 1·0 and 2·0 cwt. N/acre subsequently. Single dressings applied to the seedbed were also compared with divided dressings applied partly to the seedbed and partly in mid-season.3. Generally the potatoes gave only small responses to N; there was no worthwhile gain from applying more than 1·0 cwt. N/acre in 1955 and 0·5 cwt. N in 1956 and 1957. Nitrogen gave much larger proportionate increases in yields of kale, at several of the centres crops continued to respond up to dressings of 2·0 cwt. N/acre.4. Calcium nitrate generally gave lower yields of potatoes than ammonium sulphate and the superiority of ammonium sulphate was greater with the higher dressings. Losses in yield with the nitrate were usually associated with a severe check to early growth occurring in dry springs and with dressings concentrated close to the seed, but lower yields were also obtained at some centres where early growth was not damaged. Calcium nitrate and ammonium sulphate were roughly equivalent for kale when the nitrate did not damage germination; heavy seedbed dressings of the nitrate reduced kale plant numbers severely unless there was adequate rain after sowing.5. Granulated urea tested in 1956 contained 4·5% of biuret, it delayed emergence and reduced plant establishment seriously in several of the potato experiments; damage increased with the level of manuring and was accentuated when dressings were broadcast over furrows before hand-planting. Yields given by this batch of urea were less than with other N fertilizers and when 1·5 cwt. N/acre was applied they were less than with no nitrogen at all. Purer crystalline urea (having less than 1% of biuret) used in the 1957 experiments caused no damage to emergence of potatoes and gave yields similar to those obtained with ammonium sulphate. There were similar effects in the kale experiments; granulated urea containing much biuret damaged germination severely in 1956; the purer products containing little biuret used in later years reduced plant numbers at one centre in 1957 and at the single 1958 centre. Where there was no damage to the establishment of kale, urea and ammonium sulphate gave similar yields.6. Dressings applied partly to the seedbed and partly in mid-season gave slightly higher average yields of kale than an equivalent total amount of nitrogen all applied before sowing.

Description: 1. There were many distinct, consistent, individual differences in the thyroid activity of several of the animals used in this study. Graphic indications of breed differences were present at several high temperatures, and statistical analyses supported differences between the Jerseys raised at each temperature and the other two corresponding breeds. The Jerseys displayed higher rates. In no instances were there thyroid 131I release rate differences between Holsteins and Brown Swiss.2. There was a negative correlation between thyroid 131I release rate and temperature for each breed raised at each temperature. Correlations for the 50° F. animals were statistically significant below the 0·05 level of probability and for the 80° F. animals they were significant below the 0·01 level. As the environmental temperature increased from 35° to 80° F. there was a gradual decrease in thyroid 131I release rate. Above 80° F. there was a sharp decline in thyroid 131I activity.3. Within the range of environmental temperatures from 35° to 70° F. the animals raised at 80° F. displayed thyroid release rates higher than those of the animals raised at 50° F. At 80° and 90° F. the 50° F. Jerseys exhibited higher activity. The Jersey differences approached statistical significance. At the lower temperatures graphic differences between the Brown Swiss and the Holsteins raised at the two temperatures appeared to be present, but they were not generally supported by statistical analysis.4. At temperatures of 80° F. and above, when regulatory mechanisms could not control body temperature, both groups showed considerable rises in body temperature concomitant with decreases in thyroid 131I activity and TDN consumption. The 80° F. group showed a rise less sharp than that of the 50° F. group.

Description: The average yields of irrigated long-staple cotton in the three-course rotations: dura, fallow, cotton, D-F-C; lubia, fallow, cotton, L-F-C; and fallow, fallow, cotton, F-F-C, were studied over 12 years in an experiment in the Sudan Gezira; the fallows (resting land) were either hoed or were left uncultivated during the rainy season, so that the effects of the operation of hoeing on the subsequent cotton yields could be measured.Where the fallows were unhoed L-F-C yielded more cotton than F-F-C, which gave at first higher yields than D-F-C, although this difference had disappeared by the end of the period. Fallow hoeing increased yields in all rotations; this response was maintained in D-F-C and L-F-C. In F-F-C the response to hoeing either fallow diminished steadily in time and whilst the higher response to hoeing both fallows also decreased, its rate of decrease was no greater than when only one fallow was hoed. The response to hoeing fluctuated considerably from year to year. In all rotations these fluctuations were associated with rainfall and the relationships have been expressed in the form of regression equations; separate equations were necessary for each rotation as the relationships were quite distinct.The variety X1730 A out-yielded Domains Sakel. There were interactions between the varieties and the other treatments, but these interactions were such that the varieties differed more at higher levels of yield and did not modify the above conclusions appreciably.

Description: 1. The percentage of intramuscular fat (and its iodine number), of moisture (fat-free), and of total, myofibrillar, sarcoplasmic, stroma and non-protein nitrogens in lumbar 1. dorsi muscles, and their ultimate pH, fibre diameter, cross-sectional area and weight (both absolutely and as a percentage of the total musculature) were determined at bacon weight in two male and two female litter-mate pigs from each of four pure-bred sows mated with one boar of the same breed. Such data were obtained for pigs of Large White, Landrace and Welsh breeds.

Description: 1. The results are reported of three experiments in which metabolism trials were carried out with milking cows given artificial diets low in magnesium with or without supplementary magnesium.2. In Exps. 1 and 2, the basal diets provided cither about 13 or about 9 g. of magnesium/day, that is an intake of magnesium similar to that found previously with cut-grass diets (Rook & Balch, 1958) which produced hypomagnesaemia. The ‘availability’ of the magnesium of the artificial diets was, however, of the order of 25–35 % and higher than that of cut-grass diets, and for all cows the artificial diets provided magnesium in excess of requirements, as indicated by the excretion of measurable amounts of magnesium in the urine and the maintenance of normal concentrations of magnesium in the blood serum.

Description: The difficulties in the semi-arid regions of East Africa where cattle exist during the dry season on forage with a very low nitrogen content is discussed

Description: 1.Two experiments were carried out to investigate the possibility of sustaining good growth rates and high feed conversion efficiency on restricted levels of feed under conditions of high temperature and humidity.2. Large White pigs were used over the weight ranges 50-90 lb. and 90-160 lb. live weight.3. In Exp. 1, three groups each of eight pigs were fed on three planes, high, medium and low, the aim being to restrict energy intake while providing adequate protein intake for good growth. In Exp. 2, two groups each of eight pigs were fed on the medium plane from 50-90 lb. live weight and thereafter one group remained on the medium plane, while the other was fed a very low plane. The very low plane consisted of a daily feed allowance of 31b. 4oz. from 90 to 1601b. live weight. All the pigs were individually fed.

Description: 1. The free amino acid content of seeds Aberystwyth S. 143 cocksfoot (Dactylis glomerata L.), S.321 perennial ryegrass (Lolium perenne L.), S. 48 and S. 352 timothy varieties (Phleum pratense L.) was studied during ripening.

Description: The skin is thin at birth. Seasonal variations and changes in the plane of nutrition affect the skin thickness. The differences in skin thickness between breeds of both B. taurus and B. indicus species, are highly significant. Both thin and relatively thick hides may be associated with any combination of milk and beef, early and late maturity, temperate and tropical type cattle.

Description: 1. Heat tolerance in nine hair-coated wethers on a maintenance diet was studied during the hottest period of the year near Salisbury, Southern Rhodesia.

Description: 1. An experiment was conducted in 1959 and 1960 on a rye-grass-white clover sward under a ventilated Dutch light structure to study the influence of the following treatments in all combinations. Cutting to within 1 in. or within 3 in. of ground level, cutting six times per year as for grazing or four times a year as for silage, applying water to restore the soil to field capacity (a) when the soil moisture tension at 1 ft. depth reached 10 cm. Hg, or (6) when the soil moisture tension at 1 ft. reached 50 cm, Hg, or (c) once only in the growing season. Observations were made on the effect of the treatments on the yield and seasonal distribution of herbage dry matter, the clover content, the crude-protein and crude-fibre content, and the root weights.

Description: It has been shown that lucerne/grass mixtures, especially those containing a high proportion of cocksfoot, can make a valuable contribution to the winter feeding of livestock when the autumn growth is allowed to stand in the field until the winter. For instance, Hughes (1954) showed that it was possible to carry store cattle right through the winter on such herbage with little supplementary feeding. Other experimental work (Barker, Hanley & Ridgman, 1955) has shown that mowing or grazing this autumn growth in September may lead to poorer production in subsequent years than October defoliation. It therefore seemed desirable to determine the effect of date of grazing in the winter on the subsequent yield of a lucerne/grass ley and two experiments for this purpose were carried out at Cambridge from 1953 to 1957.

Description: 1. Over 3 years, different levels of first winter nutrition were imposed on groups of North and South Country Cheviot ewe hoggs (lambs). In 1956–57, three levels, high, mid and low, were fed indoors. In 1957-58, only two levels, high and mid, were fed indoors, with the low level being represented by hill wintering. In 1958–59, two levels were represented by away wintering and hill wintering.2. Low-plane feeding was designed to simulate average hill wintering, creating a 10% loss in live weight. Mid-plane feeding was designed to maintain live weight at approximately the same level throughout the winter. High-plane feeding was designed to produce a live-weight gain of 15–20% in 1956–57 and the maximum gain possible in 1957–58.

Description: 1. Fourteen muscles from a normal 46-week-old Friesian heifer and from its 40-week-old half-sister, which showed the pronounced muscle hypertrophy of ‘doppelender’ cattle, were analysed for moisture, hydroxyproline, sodium, potassium, total nitrogen, and intramuscular fat: the iodine number of the latter was determined. In four of the muscles sarcoplasmic, myofibrillar and stroma nitrogens were also estimated.2. Hypertrophy was associated with a mean increase in the percentage of total nitrogen, with markedly lower percentages of hydroxyproline and of intramuscular fat, and with a decreased K/Na ratio.

Description: 1. In grass seed crops accurate assessment of the optimum harvest date is made difficult by the lack of knowledge of seed ripeness. In order to define ripeness in physiological terms studies have been initiated the first of which is described in this paper.2. Samples of Aberystwyth S. 321 perennial ryegrass (Lolium perenne L.), S. 143 cocksfoot (Dactylis glomerata L.), S. 48 and S. 352 timothy varieties (Phleum pratense L.) were taken at 3-day intervals from inflorescence emergence to seed harvest. These were analysed for total 80 % ethanol soluble carbohydrates (TSC) reducing sugars, sucrose and starch, whilst duplicate samples were air-dried for determination of thousand seed weight and percentage germination.

Description: 1. The data used in this study were the estimated 210-day weights of 2351 calves born on eight farms in the years 1958–61. In each year data were only used from herds which recorded at least five calves of each sex in that year. One hundred such herd years were included in the study.2. The mean 210-day difference in weight between male and female calves was 27 lb. 1202 male calves had a mean weight of 380 lb. and 1149 female calves had a mean weight of 353 lb.3. The response of calf weight to age of dam was different in the two sexes. The weight of the female calf was found to increase with dam age in a linear fashion, whereas the response of male calves was best described by a quadratic relationship with the maximum response at a dam age of 8 years.

Description: 1. The age of 210 days was selected for calf weight standardization. In general this is a preweaning weight under prevailing Jamaican conditions, and it represents a compromise between a very early age (90–120 days) which would reflect closely the milking ability of the dam, and the actual weaning age (approximately 260 days) when the grazing management of the herd would constitute a major unpredictable variable.2. Either one or two weighings taken between the fourth and the ninth months of life was used to standardize calf weights to 210 days of age. In either instance for groups of calves, a mean estimate was derived which was very close to the actual mean 210-day weight, and which was suitable for data relating to groups of animals.

Description: A descriptive background is given to a group of beef farms in Jamaica on which a series of grass and animal production studies were carried out using technical and economical data derived from those farms over a 5-year period. During this time the farms co-operated in keeping standardized costaccounts and recording detailed outputs from farms and from improved and unimproved lands within those farms. Studies were made of the economics of pasture improvement and also of improvement in husbandry and breeding programmes. The possible value of the results to the small farms in the area is discussed.

Description: 1. The penises of five bull calves were examined during the first year of life, using epidural anaesthesia or sedation with chlorpromazine hydrochloride.2. The process of separation between penis and sheath is described and data on age and weight of the calves are given.3. There was considerable variation in times and rates of development, but in general terms the penis began to separate from the sheath at about 4 months of age, and the process was completed at about 10 months.4. From the second to the sixth or seventh month of life the penises of these calves were short, and not manually protrusible.

Description: Phosphate responses of wheat in a number of soil types have been correlated with the amounts of phosphate extracted by ten different methods. Of these only total organic phosphorus, and inorganic phosphorus extracted with hot 0·1N caustic soda, were significantly related to phosphate response, the former at the 1% level and the latter at the 5% level. The amount of organic phosphorus in the soil was also found to be significantly related, in each instance at the 5% level, to phosphate responses of grass and the percentage phosphate in the grass. When the amount of organic phosphorus was considered together with the phosphate retention capacity of the soil, to give a measure of available mineralized phosphate, the relationships to response (and uptake of phosphorus by grasses) was more significant than with organic phosphorus alone.The organic phosphorus fraction accounted for about 86% of the total soil phosphorus. Measurable amounts of water-soluble organic phosphorus were found with all the soils. The amounts were, however, not significantly related to phosphate response. Moreover, it was found that while the soil extract containing organic phosphorus decomposed, it did so without the production of mineral phosphate. From this, and further evidence in the literature, it is considered that the organic complex in the soil, rather than the water soluble phosphorus, is the main source for the plant.

Description: 1. The crude protein requirement of goats for maintenance has been determined from balance studies. The requirement per kg., as found by three different methods of treatments of the balance data, is practically the same, viz. 2·63 g. crude protein.2. The digestible crude protein requirement also has been calculated, again by two different methods, and is estimated at 1·12 lb./1000 lb. body weight. This value is undoubtedly very much higher than the value (0·65 lb./1000 lb.) obtained previously from the endogenous urinary nitrogen determinations alone.3. The dry-matter requirement of goat per 100 lb. live weight has been determined. Calculated on the basis of live weight raised to the power 0·734, the requirement was found to be 2·6 lb./100 lb.

Description: 1. EUN and MFN excretions have been determined in goats on a N-low ration and also on a N-free ration. The values obtained were,EUN = 0·052 g./kg. live weight andMFN = 0·41 g./100 g. dry-matter feed intake.2. The values so determined with the two feeding regimens, for both the EUN and MFN agreed very closely.3. The minimum protein requirement of goats for maintenance, as calculated from the EUN value, is 0·65 lb./1000 lb. live weight.4. The formula for calculating the utilizable protein requirement for this species is found to be P = 0·89. W0.734, and is almost identical with the one given by Mitchell.5. The usefulness of the above formula in predicting the EUN of immature goats is discussed.

Description: Records of fertility and birth weights were examined in eight breeds of goat, indigenous to, or imported into, the subtropical environment of Israel. These included the local Syrian Mountain, Negev and Damascus breeds, and the imported Malta, Appenzeller, Saanen, Fawn German and Anglo- Nubian.All breeds of goat, local or imported, kidded at the end of winter and in early spring, and all, save the late-maturing Damascus and part of the Anglo- Nubian, kidded for the first time at the age of 1 year.In imported breeds of goat which acclimatized well in the subtropical environment fertility was not impaired.

Description: In a cross-breeding experiment involving all types of matings among Friesian, Ayrshire and Jersey cattle, the effect of maternal size has been investigated, based on various comparisons of reciprocal crosses, using data on weight and body size from birth to 2 years of age. Among the thirteen characters analysed, there was a close relationship at I month old between the relative maturity of the characters and the relative extent of their maternal effects. This relationship showed that the more mature characters were the least affected by the maternal environment. Cross-bred calves out of a mother of the larger breed were larger at birth than the reciprocal crosses but in all cases this difference disappeared during the first year's growth.The early expression of the offspring's genotype for body size depended on whether prenatal growth had been favoured or restricted by the maternal environment within limits. Maternal retardation of growth resulted in neonatal phenotypes closely related to their genetic ranking for mature body size, whereas early expression of the genotype is obscured by lavish prenatal conditions.A mammalian growth model is presented and the results are interpreted in terms of this model. The explanation assumes that temporary advantage is taken, during growth, of variations in the environment, when the latter exceeds a minimal level demanded by the genotype for stable development to normal mature size. This supply and demand hypothesis of growth is discussed in terms of its implications for genetic selection of different types of body characters. The main conclusion is that an understanding of the early environment, particularly the maternal one, may permit selection for some adult characteristics to be carried out at an early age.

Description: 1. Statistics of several measured parameters are reported. They show that fermentation rates of rumen contents from zebu and European-type cattle in East Africa differ due to time of feeding, to individual animals, and to differences between zebu and grade.2. The fermentation products were determined as acid, CO2 and methane. The proportion of methane showed an inverse correlation with the rate of fermentation.3. The mean fermentation rate showed a trend in the direction expected from the weight gains of the animals.

Description: 1. Two series of simple nitrogen manuring trials, one on level of sulphate of ammonia applied to the seedbed at twenty-two centres and the other on the time of top dressing with ‘Nitro-Chalk’ at nineteen centres, were conducted on commercial farms in south-east Scotland during 1954 to 1957.2. The optimum level of sulphate of ammonia varied with season and farm type. The optimum dressing was at least 0·9 cwt. N/acre in the dry season of 1955, and in the other years was estimated to be 0·9 cwt. N/acre on arable farms and about 0·-25–0·4 cwt. on ley rotation farms when the barley did not follow sheeped turnips. In the latter event no fertilizer was best.3. The nitrogen content of the grain increased little until after the 1 cwt. sulphate of ammonia level, although the optimum yield was not obtained in many experiments without some rise in the grain nitrogen content.

Description: 1. A factorial experiment on wether hoggs was carried out to examine the effects on bone growth and composition and on blood composition of four dietary factors. The factors were extra calcium, phosphorus, vitamin D, and energy in the form of starch, and each was fed in all possible combinations, so that there were sixteen dietary treatment groups in all. Each group consisted of three animals.2. Serum calcium and blood inorganic phosphorus concentrations were determined monthly, and radiographs of most parts of the skeleton were taken at the beginning and end of the experiment. After about 6 months on the experimental diets the animals were killed and the ash weights and percentage of ash of different parts of the skeleton and of the whole skeleton were determined. Live-weight changes and food intakes were also measured.

Description: 1. The mean velocity ῡ and the velocity frequency distribution f(υ) of bull spermatozoa with normal motility have been determined in standardized eggyolk—citrate buffers at different pH values, ranging frompH 5·70 to 8·35.Under assumed approximately anaerobic conditions at37·0 ± 0·1° C. the mean velocity was found to show a straight-line relationship -with pH in the physiological region pH 5·70–7·50, according to the general equationStatistically, k was shown to be a linear function of a, namely,Consequently, the dependence of the mean velocity of the spermatozoa from any ejaculate can be characterized by the one parameter a = dῡ/dpH. (dimension μ/sec./pH), determining the slope of the ῡ υs. pH curve.The mean velocity of all individual spermatozoa (measurements of all ejaculates at the same pH value pooled together) could be described accurately by the equation:For some ejaculates the linear relationship was found to hold up to pH 8·00.2. The velocity frequency distribution curves were found to change with pH. At pH 5·70 the curves are skew with a relatively high top value. At increasing pH values both the top value and skewness decrease. The mean standard deviation of the velocity distribution f(υ) was found to be proportional to pH and could be described by the equationThis means that the variability in swimming speeds of the individual spermatozoa of any ejaculate increases proportionally with pH, indicating a strain effect of increasing alkalinity on the population, irrespective of the general stimulation of motility in the region up to pH 7·50.3. At each pH value the mean velocity decreases with time. Under assumed approximately anaerobic conditions at 37° C. the speed of velocity decrease as a function of pH was found to differ so much between different ejaculates that no generalization could be derived from the available material. The same holds for the effect of pH on the number of normally moving spermatozoa in the diluted ejaculate.4. The total number of spermatozoa moving normally depends on pH, but the optimum varies with the individual ejaculates.

Description: The beneficial effect on the nutritive value of bread and similar cereals of adding small amounts of lysine and other essential amino acids has recently aroused considerable interest both in Great Britain and in America. Tests carried out with rats have shown considerably improved growth rates accompanied by increased efficiency of food conversion.

Description: Swarm preparations are leas frequent (at least during July and August in southern England) among colonies with queens reared in the current year than among those with queens of the previous year (Simpson, 1957). Queens which had survived one and two winters are now considered; they are described as 1- and 2-year-old, respectively.

Description: A field experiment was carried out to study the effect on spring oats of undersowing with broad red clover, Italian rye-grass and a mixture of both. Two levels of nitrogen were used, namely, no nitrogen and 3 cwt. per acre of ‘Nitro-Chalk’.1. Oat shoot weight was reduced by undersowing, Italian rye-grass having a greater effect than red clover, particularly where nitrogen was applied.2. In the absence of nitrogenous fertilizer undersowing did not reduce oat plant height, but where nitrogen had been given, Italian rye-grass either alone or in a mixture with the clover, reduced the height; the legume alone had no effect.3. Undersowing generally reduced the number of oat panicles. Italian rye-grass had no effect when nitrogen was not applied, but a marked reduction was observed when nitrogen was applied. The legume had the greater influence where nitrogen was not applied.4. Red clover increased the number of whorls, and the number of single-grained spikelets per panicle. Grass sown alone or with clover reduced the number of single-grained spikelets per head.5. The total number of grains per panicle, 1000 grain weight, percentage husk and the percentage of saleable grain were not influenced by undersowing.6. No lodging occurred but there was an indication that resistance to bending of the straw was affected by undersowing with Italian rye-grass.7. Seeding herbage under the oats had a bigger influence on the yield of straw than grain. Italian rye-grass sown alone or with clover reduced the yield of straw where nitrogen had been applied. The legume alone had no effect. Grain yields showed a similar trend.8. Yield and percentage crude protein in the straw were reduced by Italian rye-grass alone or in a mixture with clover when nitrogen was applied, but there was no effect where nitrogen was withheld. The grass had a greater effect than red clover while a mixture of both was intermediate to the legume and grass sown separately. Italian rye-grass greatly reduced the recovery of applied nitrogen by the cereal.9. The percentage moisture in the oat sheaves was increased by undersown herbage and red clover had a bigger influence than the grass. The application of nitrogen reduced the bulk of clover under the cereal and its adverse influence on the harvesting of the oats. In the absence of undersowing, nitrogen had no effect on the percentage moisture in the sheaves.

Description: 1. The ratios of water drunk:hay eaten were studied for groups of Zebu and grade Hereford steers.2. In all comparable conditions the ratio was significantly smaller for the Zebus.3. Restricting water availability to about half significantly reduced the ratios for both types of steers.4. The decrease in hay eaten resulting from restriction of water was less for the Zebus.5. Restricting the hay intake to approximately half significantly increased the ratios for both groups.6. The Zebus drank significantly less water than did the grades in relation to body weight.7. It is concluded that the results of water restriction may not be as disastrous as would have appeared likely from the constant ratio relationship of water and food intakes previously suggested, particularly in the case of the Zebu steers who have been shown to be better adapted to dry conditions.

Description: Studies have been made on calcium and inorganic phosphorus in pasture grass and their relationship to blood levels in Zebu cattle.Excitement, adrenaline injections and fatigue were investigated as possible causes of variations in the inorganic-phosphorus levels of the blood of Zebu cattle.Sudden rainfall appeared to cause alterations in the inorganic phosphorus levels of blood. This hypothesis, when tested on two separate batches of cattle on two occasions, showed that there was a highly significant relationship between water intake and the level of inorganic phosphorus of Zebu cattle blood.Water starvation caused a steady increase in the level of inorganic phosphorus and when water was available for the cattle to drink the inorganic phosphorus level fell rapidly to a subnormal level before returning to normal. These results are discussed in the light of the available literature.

Description: 1. The live-weight gains and food consumption of groups of chickens subjected to two different patterns, (A) and (B), of allocation of a restricted quantity of food, were compared with the live-weight gains and food consumption of a control group (C), fed ad lib. throughout the experiment.2. Group B (compensatory growth regime), showed a greater relative growth rate after re-alimentation than group A (mild restriction followed by ad lib. feeding). The growth rate of group B was shown to be significantly greater than that of the control group at equivalent live weights. In addition, it was shown that the increased growth rate, induced by periods of restriction of similar severity and duration, was very similar for birds within the ranges of 200–300 g. live weight and 750–1100 g. live weight.3. The differences, due to treatment, in the growth rate after re-alimentation were in part caused by a concurrent increase in appetite. The severity and duration of the undernutrition immediately prior to re-alimentation would appear to affect appetite during re-alimentation more than the total restriction imposed. Measured in terms of food consumed, the restriction imposed upon groups A and B was the same, but in terms of live weight gain group B was very slightly more retarded than group A.

Description: An experiment on the use of wheat straw (ploughed in or composted at the rate of 53⅓ cwt./acre every second year) and NPK fertilizers in the maintenance of fertility was carried out at Rothamsted between 1933 and 1958. The effects of these treatments on the yields of the crops of the rotation used in the experiment—barley, sugar beet, potatoes—are discussed in the present paper.The treatments appear to have had no effect on crop yields through improvements to the soil caused by better structure or increased organic matter content. All the effects obtained can be attributed to changes in the supplies of available nutrients. The most important of these changes appear to have been: (1) nitrogen deficiencies due to the immobilization of soil nitrogen or nitrogen fertilizer by the straw: there is some evidence that this added to the store of slowly available nitrogen; (2) additions to potassium supplies from potassium in the straw. Factor (1) affected all three crops. Factor (2) affected potatoes, the only crop of the three to give good responses to potassium.It was found that when the straw was ploughed in directly about 0·08 ewt. N fertilizer applied to the crops for each ton of straw was sufficient to overcome losses in yield due to nitrogen deficiencies. The straw improved the yields of potatoes in the first and second years after application. Provided that allowance was made for losses of available nitrogen the yields of potatoes from ploughed-in straw were about the same as the yields obtained by adding K fertilizer to the crop, equal in amount to the potassium in the straw. When part of the fertilizers was ploughed in with the straw instead of being given directly to the crop the yields of potatoes were reduced.Compost made with NT fertilizers and straw and ploughed in with K fertilizer gave much poorer yields than were obtained by ploughing the straw in directly and applying the fertilizers to the crops. Losses of available nitrogen were severe, all the N fertilizer used in making the compost (0·15 cwt. N for each ton of straw) being either lost through drainage or immobilized by the straw. In addition, more than one half of the potassium in the straw was lost in composting.There was no evidence that any of the nitrogen immobilized in the decomposition of the straw became available in the first or second years after application. Residues from repeated applications of straw every second year over 18 years increased the yields of potatoes and sugar beet in the last 6 years of the experiment. The increases may have been due to the release of previously immobilized nitrogen.

Description: 1. Thirty-two single lambs were grazed together on pasture. At weekly intervals, from birth to 112 days of age, two lambs were slaughtered and various organs weighed immediately after death. Also the alimentary tracts of seven adult sheep were obtained immediately after death.2. The rumen had the fastest growth rate of the four stomachs, followed by the reticulum, omasum, and abomasum, in that order.3. Immediately after birth the four stomachs altered rapidly in their relative proportions, but by about 66 days of age they had reached approximately adult proportions.4. The weights of the liver, heart and kidneys, relative to live weight, decreased during the first few weeks of life, and thereafter remained constant.5. The weight of the spleen, relative to live weight, increased during the first week of life and thereafter remained constant.

Description: Three experiments were carried out to obtain more information upon the effects of varying the plane of feeding for bacon pigs.Exps. 1 and 2 followed the same 3 × 2 factorial design in which (a) diets were fed with or without procaine penicillin and (b) a comparison was made between very high (VH-VH), high (H-H) and low (L-L) planes of feeding for pigs from about 8 weeks old to slaughter at about 200 lb. live weight. The planes of feeding were defined according to the amount of t.d.n. offered to each pig daily.For each of these two experiments eight lots of six litter mates were used. One pig from each litter was allocated to each of the six treatments, and although litter mates were housed as a group, all pigs were fed individually in separate compartments.Exp. 3 was a 2 × 3 × 2 factorial to compare two breeds and three planes of feeding during 2 years. During each year three lots of pure-bred Landrace and three lots of Wessex Saddleback × Large White litter mates were used. Each lot consisted of three gilts and three barrows and one pig of each sex was allocated to each of the three feeding treatments. From the start of the experiment, when the pigs were about 8 weeks old, to about 100 lb. weight, all animals were kept to a very high (VH) plane of feeding. From then to slaughter at about 200 lb. live weight the following planes of feeding were compared: (1) very high plane (VH), (2) increasingly restricted plane (R) and (3) low plane (L). As in Exps. 1 and 2 these planes were denned in terms of t.d.n., and litter mates were housed together but fed individually in separate compartments.In both Exps. 1 and 2 pigs with procaine penicillin in their feed grew very slightly faster and more efficiently than those not fed antibiotic, but the differences did not reach the 5% level of statistical significance. The feeding of antibiotio did not affect the response of the pigs to variations in the plane of feeding.In comparison with pigs kept to the VH-VH plane of feeding, pigs kept to the H-H and L-L planes grew 13 and 22% more slowly in Exp. 1, and 11 and 26% more slowly in Exp. 2, but plane of feeding had no effect upon food conversion efficiency in either experiment. These results are for the total experimental period.In both Exps. 1 and 2 reductions in plane of feeding had no significant effect upon length of carcass or thickness of streak, but they caused increases in killing-out percentage and decreases in all measurements of fat thickness. They also caused increases in the area of ‘eye’ muscle (statistically significant in Exp. 2, but not in Exp. 1) and a lengthening in the shape of the ‘eye’ muscle in the bacon rasher (statistically significant in Exp. 1, but not in Exp. 2).In Exp. 3 the Wessex crosses grew faster and more efficiently than the Landrace, but these differences were considerably larger during one year than during the other. In comparison to the Landrace, the Wessex-cross carcasses had a tendency to be shorter (P 〈 0·10) and to have thicker shoulder fats. They also had 1% more ‘fore’ and 1% less ‘ham’.Compared with pigs kept to the VH-VH plane of feeding, those kept to the VH-R and VH-L planes grew 18 and 36% more slowly, respectively, during the finishing period. Over the total experimental period there was no difference in food conversion efficiency between pigs kept to the VH-VH and VH-R planes, but efficiency was poorer by 4–5% with the VH-L plane. There was no breed × feeding interaction in the data for growth rates or food conversion efficiencies.In Exp. 3 plane of feeding had no significant effect upon killing-out percentage, shape index of ‘eye’ muscle or thickness of streak. The two lower planes of feeding caused reductions in the average rump fat, fat (1) over the ‘eye’ muscle and in the proportion of ‘middle’ in the carcasses; they also caused increases in the proportion of ‘ham’ in the carcasses.Other carcass quality data contained significant interactions which complicated their interpretation. The effects of plane of feeding were inconsistent between:(A) years, for length of carcass, maximum shoulder fat, area of eye muscle and iodine values of the back fat;(B) breeds, for minimum back fat and percentage ‘fore’;(C) sexes, for dressing percentage and fat (2) over ‘eye’ muscle;(D) breeds and years, for dressing percentage;(E) breeds and sexes, for maximum shoulder fat.The results of the three experiments have been compared with other data on planes of feeding from Rowett Research Institute. A table has been given showing the probable average effects of using different planes of feeding in preference to a VH-VH plane for pigs to be slaughtered at about 200 lb. live weight. The variability in these effects under different circumstances has been discussed and a note has been made of the relative improvements in carcass quality which can be affected through feeding and through breeding.

Description: 1. A survey of the reasons for disposal of 1000 sows from farms in a selected area of East Anglia showed that the most important causes of sow wastage were ‘failure to breed’, ‘piglet mortality’, ‘old age’ and ‘low fertility’ which together accounted for 64·3% of the sows.2. The average length of breeding life was 3·75 litters per sow and the modal number of litters was only two. This expectation of life is very short but is in agreement with an earlier estimate based on Breed Society records.3. Failure to breed was the most important cause of sow wastage and accounted for 21·4% of the sows. The incidence of reproductive failure was greatest in young sows and of all the sows discarded as sterile 30·3% were discarded after having had only one litter. Cases of failure to breed were divisible into two broad groups.

Description: 1. An analysis of pre-weaning mortality in inbred Large White pigs showed that the over-all mortality in ten generations of sows was 47·3%. During the first four generations mortality fluctuated between 30 and 45%; from the 5th to the 9th it fluctuated between 50 and 68% and in the 10th rose to 88%.2. 70·2% of all deaths occurred in the first 3 days post-parturition and the average birth weight of pigs which died within 3 days was only 1003·5 g. compared with 1258·5 g. for those which survived. 83·0% of pigs weighing less than 900 g. at birth died within 3 days, whereas only 18·5% of pigs weighing more than 1400 g. died within the same period.3. There were marked seasonal variations in mortality, this being highest during the winter months. Mortality was highest in litters of under 5 and over 15, but between 5 and 15 there was no increase in mortality with litter size. There was no difference in mortality between males and females.4. Foetal growth was studied in 80 outbred sows of various breeds. Foetal weight was affected not only by age but also by litter size. The withinlitter variation in foetal weight increased with litter size but no increase in between-litter variation with litter size could be demonstrated statistically. Male foetuses were slightly heavier than females at all stages of pregnancy investigated.5. The growth of the inbred Large White foetus was also studied at an early and late stage of inbreeding, and the reduced birth weight in the latter was shown to be reflected in slower growth of the foetus from mid-pregnancy onwards.6. The anatomical composition of inbred Large White foetuses at a late stage of inbreeding has been compared with that of similar foetuses at an earlier stage and also with normal outbred Essex foetuses, at 51, 74, 97 and 108 days of pregnancy. The chemical composition of inbred Large White foetuses of a later stage of inbreeding was compared with that of outbred Essex foetuses at 51, 74, 97 and 108 days. The differences in anatomical composition between the smallest and largest foetuses within litters are comparable with those found postnatally in pigs fed on a high or low plane of nutrition, but this was not reflected in a very definite way in the chemical composition. X-ray photographs showed that ossification was more advanced in the largest foetus within a litter than in the smallest but the appearance of the ossification centres was not delayed in the latter.7. Attempts to make reciprocal ovum transfers between inbred Large White and outbred Essex sows met with little success, probably due to the low fertility of the Large Whites, the prolonged exposure of the ovum during transference and the necessity of effecting the transfer of the ova at the 2-cell stage. The latter was conditioned by the rate of passage of the ova through the tube and the fact that they enter the uterus in the 4-cell stage.

Description: 1. In a population of Hereford crossbred steers carcass conformation was measured by weighing wholesale joints cut in London and Home Counties fashion and dissecting a single rib sample joint. Correlations were calculated between weight of joints and certain linear carcass measurements.2. Weights of individual joints in a group of good cuts were studied in relation to carcass composition estimated from sample joint dissection. Carcass fatness at constant carcass weight was correlated positively with some joints and negatively with others. A thigh width measurement was related to the weight of these joints in a similar fashion. This accounted for the low value of thigh width as an index of the proportion of good cuts.3. The weights of joints, and many of the measurements, were highly correlated with carcass weight. When carcass weight was allowed for, partial correlations were too low to support the use of linear measurements to predict weight of joints in individual carcasses.

Description: 1. A study on the effects of the type of diet on the histological development of the fore-stomachs of the lamb is presented.2. The rumen papillae were well developed in a 7-week-old lamb that had been fed solely on milk from birth, but compared to a lamb of the same age that had access to lucerne chaff from birth, they were smaller in size and more conical in shape. There was no difference in the appearance of the rumen mucosal surfaces of two lambs of 13 weeks of age, one of which had access to lucerne chaff from birth and the other access to lucerne chaff for only 4 weeks prior to slaughter.3. The type of diet appeared to have little effect on the appearance of the reticulum mucosal surface.4. The appearance of the omasum mucosal surface was only normal when lucerne chaff was fed to lambs.5. The histology of the rumen wall was normal in the milk-fed lamb. However, compared to the lamb of the same age that had been fed on lucerne chaff, the papillary body formation, stratum granulosum and stratum corneum were less well developed.6. Apart from a thinner stratum granulosum and stratum corneum, the histology of the reticulum wall of the milk-fed lamb was little different from that of the lamb of the same age that had been fed on lucerne chaff.7. The histology of the omasum wall of the 7-week-old milk-fed lamb was very similar to that found in the lamb at birth.

Description: 1. Fourteen experiments with winter wheat on heavy-land farms from 1958–60 compared autumn dressings of sulphate of ammonia with equivalent early (March) or late (May) spring top-dressings. Dressings applied on two or all three dates of application were also compared.2. Consistent and significant gains in yield from low (0·5 or 0·6 cwt. N/acre) and high (1·0 or 1·2 cwt. N/acre) levels were obtained at most centres, which were on fields under arable rotation.3. With the low level of N, gains in yield were greatest from a single May top-dressing. There was no gain from dividing the dressing.4. With the high level of N, dressings divided between autumn-May or March-May were best. March-May was the most consistently satisfactory treatment and gave the highest mean increases in yield in 1959 and 1960, but in 1958 autumn-May was better. Single May dressings gave slightly lower yields. There was no advantage from dividing N between all three dates of application.5. Single applications of N in autumn gave lower yields than single applications in spring; supplementing autumn N with a late spring top-dressing gave almost the same yield as giving all the N in spring. Dividing the dressing in this way may be convenient on many heavy-land farms.6. The percentage of N in the grain was highest with a late top-dressing of fertilizer-N, lowest with autumn N and intermediate with March top-dressings.

Description: 1. A general survey of the histological changes of the fore-stomachs of the lambs from 46 days of foetal life to 77 days of post-natal life is presented.2. In all the rumen foetal specimens the mucosal surface was smooth. At birth small, conical papillae were visible and from this age onwards these papillae increased rapidly in size and tended to be long and tongue-shaped in appearance. Little change occurred in the appearance of the rumen papillae after 56 days of age.3. The outlines of the reticulum reticular ribs were visible in the 100-day-old foetal specimen. At birth the normal honeycomb-like structure of the reticulum was well developed, but the papillae on and between the reticular ribs were small and had rounded tips. From 20 days of age onwards the reticulum features increased in size and the papillae became pointed in shape.4. At 46 days of foetal life the omasum wall was folded to form developing laminae and by 70 days of foetal life laminae of four orders were present. The main age changes in the appearance of the mucosal surface from this age onward was an increase in the length of the laminae, the formation of small conical papillae on the laminae, and an increase in the inter-laminae spaces.5. All three fore-stomachs showed the same general histological changes with age. The epithelium changed from a stratified cuboidal type in the foetal specimens to a keratinized, stratified, squamous epithelium in the post-natal specimens. The basal layer of the epithelium became folded to form papillae, reticular ribs and laminae, and in the rumen and reticulum further folding of this layer took place to form papillary bodies.

Description: 1. On cropping Agdell Experiment topsoils to exhaustion with perennial rye-grass in the glasshouse the total K uptakes were directly proportional to the initial exchangeable K contents of the soils.2. The ability of the Agdell topsoils to release non-exchangeable K under glasshouse conditions decreased in the order: PK-rotation with fallow 〈 NPK rotation with fallow 〈 PK-rotation with clover 〈 NPK-rotation with clover 〈 no-fertilizerrotation with fallow = no-fertilizer rotation with clover.3. Releases of non-exchangeable K were at least 2·5 times larger than the falls in the exchangeable K for all the Agdell soils.4. In a ‘take-down’ experiment in the glasshouse on a soil receiving K fertilizer each year in the Saxmundham Rotation I Experiment, loosely held non-exchangeable K was released at a near-linear rate. At least a part of the loosely held non-exchangeable K in the Agdell soils was also released at a near-linear rate.

Description: 1. Continuous cropping with perennial ryegrass in the glasshouse was used to measure the release of non-exchangeable potassium from twenty soils representative of a wide variety of soil series.2. Releases of non-exchangeable potassium ranged from almost none to 〉 2000 lb. K/acre.3. The main reason for the variations in the potassium-releasing powers of the soils was traced to differences in the amount and potassium content of the finer clay fractions. Small potassiumcontents in the fine clay and small contents of fine clay were associated with small releases of nonexchangeable potassium.4. Accumulated potash fertilizer residues or the presence of such minerals as glauconite can be responsible for the good potassium-releasing powers of some soils.5. Some of the limitations of glasshouse work for assessing the potash status of soils are discussed.6. Evidence was obtained for the existence in many soils of at least two categories of useful nonexchangeable potassium.

Description: Part of the variation among butterfat yields in dairy cows arises from genetic differences among the animals. The proportion which this bears to the total variance is known as heritability. In the ‘narrow’ sense it is defined (Lush, 1940), as the proportion of the total variance that is due to additive gene effects; the ‘broad’ sense definition includes genetic variation arising from non-additive gene effects as well as that due to additive effects. Since related animals have a proportion of their genes in common the covariance among their production records can be used for estimating genetic variation and hence heritability. This paper discusses three groups of related animals most frequently used for this purpose, twins, daughter-dam pairs and paternal half-sibs, and presents the results of analysing production records of artificially bred heifers in New Zealand, including evidence of the magnitude of the sampling errors of the heritability estimates.

Description: 1. The study of the photoperiodic responses of varieties and forms of the genus Avena has revealed considerable diversity within the group.2. The investigation of a number of forms differing in geographical distribution confirms the close relationship between photoperiodism and region of origin. There appears to exist a definite relationship between the geographic origin of a given form and the limits of its tolerance to short day. The forms from the more southerly latitudes suffered less from short day than those of northern origin.3. Panicle exsertion was entirely suppressed under photoperiods of 12 hr. and less in A. sativa varieties Victory, S. 84 and Black Supreme, which have been selected for high yielding ability in more northerly latitudes.4. Plants which failed to produce exserted panicles in varietal tests were dissected, and it was found that floral differentiation had not been inhibited by the shortened photoperiods, but that the full elongation of the internodes, especially the upper internodes, had been suppressed.5. Selection experiments with progenies of the cross Wintok × A.fatna form Cc 3872 grown under different photoperiods confirmed a highly selective response to daylength, thus indicating that this response is under genetic control.

Description: 1. A cross-bred sheep was fed successively with supplements of dried skim-milk or lactose. The effect of the supplements on the lactase activity of the rumen liquid was followed.2. Lactase activity was expressed as mg. lactose hydrolysed per ml. rumen liquid, or per mg. protein nitrogen. The enzymic activity fluctuated considerably after a change in the diet, and did not become constant even when the ration remained the same for 7 weeks.

Description: 1. A co-ordinated trial has been carried out at twenty-two centres to compare the value of wheat, crushed or ground, with that of fine wheat offal (weatings) when fed in equal amounts in the rations of growing pigs.2. Pigs fed the wheat rations grew faster (8·7% improvement for crushed wheat, 6·3% for ground), had. more efficient food conversion (9·0 and 6·5%) and yielded heavier carcasses for a given final live weight (1·4 and 1·3%) than pigs fed weatings but were fatter at the shoulder (5·6 and 7·5%) and the loin (11·2 and 13·1%); all these effects were highly significant. Differences in length of carcass were not significant.3. Improvements in growth rate and food conversion were significantly greater with crushed wheat than with ground wheat. None of the other differences between crushed wheat and ground wheat was significant.4. An economic appraisal has been made which shows that, on the basis of certain assumptions, the feeding of wheat would have resulted in higher profit per year than the feeding of weatings under the price structure and system of grading prevailing during the period of the experiment.5. Changes in the price structure (average price of bacon pigs, differentials between grades and cost of wheat and weatings), in the average quality of the carcasses (length of the carcass and fat at the shoulder and loin) and in the size of treatment effects on food conversion, all have a substantial effect on relative profits. The appraisal suggests, however, that feeding wheat would be more profitable than feeding weatings when the above changes were extremely severe.

Description: A laboratory and pot-culture investigation to seek reasons for the variable response of grass and other crops to top-dressings of urea, and to the occasional phytotoxicity to seedlings of urea either mixed in the soil or drilled in contact with the seeds is described.The part played by biuret, the chief impurity in commercial urea, has been examined. It can be phytotoxic to germinating seedlings when in contact, but in the quantities likely to be applied in agriculture in top-dressings, e.g. 150 lb. of urea with up to 2·5% of biuret, its effect is negligible. Up to at least 5% of biuret can be present in urea without affecting its ammonification or nitrification in soil.It has been shown that loss of nitrogen to the atmosphere can account for the poorer responses of grassland to top-dressings of urea as compared with ‘Nitro-Chalk’ or ammonium sulphate.The phytotoxic behaviour of pure urea to germinating seeds seems to be due to rapid production of ammonia. This gas is also evolved from topdressings of urea. Both the phytotoxicity and the loss to the atmosphere can be reduced by mixing urea with acid salts to neutralize the ammonia.

Description: 1. An experiment was conducted at Jealott's Hill from 1945 to 1956 to study yield trends of cereals grown continuously and in four-course rotations including 1-year ‘renovation’ treatments in the form of (a) grazed ley, (b) ley cut for hay and grazed, (c) rape grazed, (d) mustard for green manure, (e) fallow.Winter wheat, spring oats and spring barley were successive test crops common to all rotations and followed the ‘renovations’ or spring barley in the corresponding phase of the continuous cereals system. Main plot (rotation) comparisons were confounded with two levels of nitrogen fertilizer (0·2 and 0·4 cwt. N/acre) and three straw treatments (straw removed, burned or ploughed in) which were applied to all three cereal test crops.All plots except those in fallow received 0·3 cwt. P2O5 and 0·3 cwt. K2O/acre every year. From 1945–48, leys, rape and mustard received 0·2cwt. fertilizer N/acre; from 1949 this dressing was doubled.Grazing of leys and rape was by sheep.2. In the earlier years the highest yields of wheat were obtained in the rotations containing rape, mustard or fallow, but in the later years yields after leys were superior to those in all other rotations. Wheat yields in the continuous cereals rotation soon declined and remained at the lowest level throughout, due largely to severe incidence of ‘take-all’ disease.In the later years yields of barley and oats following 1-year ley were also superior to those in all other rotations.3. In the six cropping rotations compared, all three cereal crops showed very marked responses to applied fertilizer nitrogen, particularly in the later years as the natural fertility of the site declined.

Description: 1. The potential herbage yield of Hyparrhenia veld under mowing and fertilizer managements was measured, as a part of the work to study the utilization of the natural grassland for the feeding of cattle in the dry season.2. The uninterrupted seasonal pattern of herbage growth results in a relatively large yield of stemmy, low-quality fodder at the end of the growing season.3. Cutting at simulated ‘silage’ and ‘hay’ stages of growth reduced herbage yields compared with one, end-of-season harvest, but because of increased leanness, the regrowth herbage had a higher crude-protein content.4. The seasonal crude-protein yield was unaffected by mowing treatments, and a reduction in herbage yield was counterbalanced by an increase in percentage crude protein.5. The use of nitrogenous fertilizers resulted in a large increase in both herbage yield and percentage crude protein. The calculated nitrogen recovery was approximately 40%.6. There were no harmful effects on either veld vigour or botanical composition after 4 years of mowing and fertilizer treatments. The nitrogen fertilizer treatments alone showed a transient residual effect.7. The practical bearing of the results is discussed briefly. Only a low-quality fodder can, in practice, be harvested from the natural grassland, unless nitrogen fertilizers are used.

Description: A score card is suggested for the judging of lamb and mutton carcasses. To apply the score card, measurements have to be recorded on length of leg (F), circumference of buttock (D), width (A) and depth (B) of ‘eye muscle’ (m. longissimus dorsi) and depth of back fat (C) and rib fat (J). In addition, visual judgement is required of fat covering on leg (E), marbling (G) and texture and colour of eye muscle (H). Points are deducted beyond an optimum weight which differs for lamb and mutton carcasses respectively.

Description: The results of the grassland experiments show that as a straight nitrogen fertilizer urea was, on average, slightly less effective than the conventional materials. In the majority of individual experiments there was no significant difference between the yields from urea and those from ‘Nitro-Chalk’; on the other hand, in a very few experiments the urea yields were much lower. The arithmetic means of the averages in each series of grassland experiments indicate that urea gave total yields about 93% of those from ‘Nitro-Chalk’ and the average response (i.e. difference from control) from urea was about 85% of that from ‘Nitro-Chalk’.The available data for cereals are considerably less than for grassland but here again there is an indication of the infrequent slightly lower efficiency of urea.On kale the results are confusing. At times urea was safe but in one experiment heavy dressings incorporated in the seed-bed caused serious damage.