ALBERT

Notes: SYNOPSIS. Miamiensis avidus n. g., n. sp., a marine facultative parasite, is described. Morphological studies were made on specimens treated with the Chatton-Lwoff silver impregnation technique and living material was examined with phase microscopy. Particular attention was given the infraciliature of the buccal apparatus and its importance to generic assignment in the order Hymenostomatida.

Notes: SYNOPSIS. A comparison of the effects upon trypsin-dispersed chick liver cell cultures of a virulent (Jones' Barn) and a non-pathogenic (Lahore) strain of Trichomonas gallinae revealed significant differences in behavior of the parasites in cell cultures and in the response of such cultures. The virulent strain multiplies faster in nutrient medium in the presence of cell cultures; stimulates great activity of the macrophages; is not handled effectively by these phagocytes in which it can multiply causing their ultimate destruction; is found significantly more often within the cytoplasm of the liver epithelial and fibroblast-like cells; causes very much more profound degenerative changes in all the cells, both invaded and non-invaded; and suppresses effectively the division rate of the fibroblast-like cells. On the other hand, the nonpathogenic strain multiplies at a lower rate in the presence of cell cultures; stimulates less activity of the macrophages; is handled readily by these phagocytes in which it multiplies only very rarely, if ever; is found seldom within the liver epithelial and fibroblast-like cells; causes far less degeneration of all the cell culture elements; and suppresses significantly less the dlvision rate of the fibroblast-like cells.At the end of a 20–24 hour period typically only a few living cells are left in cultures exposed even to attenuated isolates of the virulent strain, whereas those inoculated with the mild one do not show much degeneration even after 28 hours. The effects upon the cell cultures of cell-free filtrates of actively growing trichomonad cultures are relatively minor, but the changes caused by the filtrates of cultures of Jones' Barn strain appear to be more extensive than those caused by similar filtrates of Lahore strain.

Notes: SYNOPSIS. An iron deficiency was noted for Tetrahymena grown in a proteose-peptone-yeast extract medium. Thus, the addition of an iron chelate and glucose was found to give consistent and luxuriant growth, whereas a number of other additives, including sodium acetate, an inorganic salt mixture lacking iron, and vitamins were found to be without influence on growth rate or cellular yield.Iron-deficient cells showed a marked reduction of oxidative capacity when suspended in a non-nutrient medium as well as when supplied with oxidizable substrates. A 1 hour incubation of iron-deficient Tetrahymena with iron chelate restored oxidative capacity only when the cells were suspended in a nutrient (peptone) medium. Growth of Tetrahymena in media autoclaved with salts resulted in cells with a larger volume but with no increase in oxidative capacity.The addition of 2,4-dinitrophenol elevated respiration of cells suspended in a non-nutrient medium, and of iron deficient cells suspended in the growth medium, suggesting that this compound increases the availability of iron or iron containing compounds, or by-passes the limiting steps.Respiratory quotients were lowered by an iron deficiency and elevated when the cells were grown in the presence of iron and glucose. This suggests more complete utilization of the carbohydrate, possibly due to the activity of a number of enzymes known to be iron-containing metalloproteins that are required for oxidative glucose dissimilation.

Notes: SYNOPSIS. Small amebas are difficult to describe because of the lack of permanent morphological criteria. Investigations from the nuclear division and physiological points of view may be useful, but the study of motion and behaviour under natural conditions gives better results in order to show the natural relationship. Descriptions of four new forms of small marine amebas are given. These species belong to the genera Rugipes, Acanthamoeba, Flabellula and Vahlkampfia.

Notes: SYNOPSIS. The development of the macronuclear Anlagen of Paramecium aurelia was studied by means of electron, light and ultra-violet microscopy of timed stages following conjugation. In the youngest Anlagen, no differentiated structures could be made out, and staining reactions gave little or no indications of the presence of DNA or RNA. As development proceeds, a number of conspicuous “sponge-like” RNA-containing bodies surrounded by a “matrix” containing DNA can be seen. Eventually these RNA bodies develop DNA centres and apparently disintegrate, yielding the “large bodies” characteristic of the mature macronucleus, and the “small bodies” then also appear. The relation of these observations to interpretations of the structural elements in the macronucleus is discussed.

Notes: SYNOPSIS. Two new species of Isospora are described from the feces of an eastern spotted skunk Spilogale putorius ambarvalis imported into Montana from Florida. The oocysts of I. spilogales n. sp. are 29 to 38 by 22 to 28 μ and contain 2 sporocysts measuring 17 to 22 by 13 to 16 μ; a few Caryospora-like oocysts containing a single sporocyst were considered abnormal I. spilogales oocysts. The oocysts of I. sengeri n. sp. are 16 to 23 by 12 to 18 μ and contain 2 sporocysts measuring 10 to 14 by 8 to 12 μ.

Notes: SYNOPSIS. The Tulahuen and Peruvian strains of Trypanosoma cruzi have been compared as to their ability to metabolize C14-glucose uniformly labeled, or labeled in carbons 1, 2, or 6. Most of the radioactivity from uniformly labeled glucose is incorporated into organic acids in both strains, but significant radioactivity is also recovered in CO2. The Tulahuen strain has a slightly higher rate of glucose consumption, and the rate of incorporation of uniformly labeled glucose-C14 into CO2 is also higher. More radioactivity is incorporated into proteins from uniformly labeled glucose-C14 in the Tulahuen strain, but the radioactivity recovered in total organic acids is fairly similar in both cases. On the basis of the rates of C14O2 production from C14-glucose specifically labeled in carbons 1, 2, or 6, as well as the rates of incorporation into glycerol from uniformly labeled C14-glucose and glucose-6-C14, it is considered that the reactions of the pentose phosphate pathway play a more important role in the Tulahuen strain. The pentose phosphate pathway accounts for 41.4% of the glucose catabolized by the Tulahuen strain compared to only 27.9% in the Peruvian strain. It is suggested that differences in the participation of alternative pathways of carbohydrate metabolism may have some relationship to pathogenicity.

Notes: SYNOPSIS. Dactylosoma is a genus of blood protozoa which undergo schizogony, without producing pigment, in the red cells of the lower vertebrates, especially amphibia. The best known species is D. ranarum, but even for this species the life cycle, except as it occurs in the erythrocyte, and the vector remain unknown. Study of slides from the blood of two species of Formosan frogs, Rana guentheri and R. limnocharis, revealed Dactylosoma ranarum in the former, and what appeared to be a new species, for which the name Dactylosoma taiwanensis is proposed, in the latter. Rana limnocharis has not previously been known to be a host of Dactylosoma, nor has this genus of parasite been reported from Formosa. Dactylosoma ranarum, though not known from many species of frogs and toads, occurs in Asia, Africa, Europe, and in Central and South America. This suggests that it must have been a parasite of Anura for a very long time. Since frogs and toads are incapable of long migrations and are very intolerant of salt water, so wide a distribution may also have palaeogeographic significance.

Notes: SYNOPSIS. The formation of chains was induced both in exponentially growing and in synchronized cultures of Tetrahymena Pyriformis GL, by application of one or two hr 34°C shocks. An arrest in constriction along the division furrow is brought about as a result of prolonged exposure to 34° during an early phase of cell division.After return to optimal temperatures, the chains remain in their original tandem configuration. They possess two sets of cortical structures, and generally also two macronuclei.Subsequently, two new oral primordia appear, one in each component. These primordia develop in synchrony with each other. The later development of the chains is correlated with the placement of the oral primordia. In some situations, these primordia form immediately posterior to the pre-existing oral areas and replace them; in these cases, the original division furrow is obliterated, and irregular and probably unstable homopolar doublets form. More frequently, one or both of the oral primordia are normal division primordia. In these cases, the original oral area of the anterior component persists, while that of the posterior component is resorbed. The original fission line persists, and two new fission lines are formed anterior to each of the new oral primordia. When constriction takes place along the new fission lines, the original arrested fission line is occasionally reactivated, and the chain then divides into four cells. More often, the original furrow is not reactivated (or only incompletely reactivated), and the chain divides into two or three cells, depending on how close the two new division furrows are to each other.The chains ultimately give rise to normal clones of singlet cells. No clones of doublets were observed.In the Discussion, the synchronization of developmental events in the two components of the chain is emphasized. The cases of reactivation of the original fission line in synchrony with constriction along the newly formed fission lines seem to indicate that furrowing results from an interaction of a preformed cortical site (fission line) with a pervasive substance which acts to trigger constriction.

Notes: SYNOPSIS. Studies were carried out on the introduction of labeled precursors into the DNA of Paramecium aurelia (syngen 4, stock 51) by way of the bacteria that are used for food. A thymine-requiring strain of Escherichia coli (15 T−) was labeled by growth in either H3-methyl thymidine or 2-C14 bromouracil, washed free of the exogenous label, and fed to the paramecia. The tritium label from the bacteria was incorporated almost exclusively into the DNA of the paramecia, whereas it was much less specifically incorporated when introduced directly from the medium. The Cu label from bromouracil was also incorporated mainly into the DNA of the paramecia although a small amount appeared in RNA. The formation of labeled food vacuoles was followed. Food vacuoles were formed at a nearly constant rate, with the total number of vacuoles increasing throughout the cycle. The lifetime of the vacuoles was about 2.5 hours. Incorporation of the label into the DXA of the paramecia begins within a few minutes of the formation of the first labeled vacuole. DNA synthesis begins about 1.5 hr after the previous fission (total cell cycle about 5.8 hr) and progresses at a nearly constant rate throughout the remainder of the cycle.

Notes: SYNOPSIS. Ca45 addition to cultures of Hymenomonas, a coccolithophorid chrysomonad, cultivated axenically, led to the autoradiographic confirmation of the intracellular nature of coccolithogenesis. Quantitative studies with isotopically enriched Ca+2 indicate the greatest activity resides in the intracellular fraction. Age of the cultures at the time of isotope addition did not appear to affect the specific activity of the coccoliths. Exchange between cell-free isotopically enriched coccoliths and the environment was also demonstrated. The findings are discussed especially from the viewpoint that the initial intracellular deposition of CaCO3 onto a preformed organic matrix is considered to be an animal rather than a plant characteristic.

Notes: SYNOPSIS. Xenon applied at sufficient pressures ranging from 30 pounds per square inch to 225 p.s.i. caused reduction in contractile vacuole activity, increase in cellular volume, expansion of the surface region, cessation of forward movement, and cytolysis of paramecia. Krypton at 915 p.s.i. prevented contractile vacuole activity, but forward movement continued for at least 30 min. When subjected to 115 p.s.i. of N2O, paramecia moved in slow oscillations, and contractile vacuoles failed to empty. At 265 p.s.i. of N2O movement ceased and cytolysis resulted. The pressure required to terminate movement in the same time interval following application of the pressure was less for N2O than for xenon. The expansion of the surface of the cells suggests that inert gases produce narcosis by dissolving into this region.

Notes: SYNOPSIS. The isolation of a culture of Leptomonas mirabilis from the fly Cynomyopsis cadaverina from Guatemala shows that this flagellate is not a stage of Herpetomonas muscarum. It is characterized by giant forms that reach 200 μ in length.All records of giant leptomonads from flies are reviewed. This species was established in culture only by the addition of mosquito extract to the medium. Division of the giant flagellates appears to occur by equal binary fission.

Notes: SYNOPSIS. The peritrich Pyxidiella curvicaula (Penard) was observed in the activated sludge of an English sewage works and was successfully cultured in the laboratory.A number of observations were made upon clonal cultures of P. curvicaula which indicated that this species is colonial at one stage in the asexual life cycle. The branching of the colonial adult is more complex than originally described, and a maximum of 17 individuals has been observed upon one stalk.Since P. curvicaula is in reality a colonial peritrich, it should therefore be transferred to the genus Opercularia Stein, with the name of the species changed to Opercularia curvicaula.

Notes: SYNOPSIS. A method for the in vitro culture of O. purkynei was developed which permitted the continuous culture of this protozoon in clone culture for a. period of 32 months. The shortest division time was 24 hr. The concentration of cells varied between 700 and 1000/ml in the routine procedure. Variations in spination which occurred in the clone culture suggested that this characteristic was of doubtful taxonomic importance.Ground wheat and alfalfa served as substrates but soluble sugars did not. Green plant material appeared to be necessary for continued growth of the protozoa. Ingestion of a large streptococcus was demonstrated by vital staining of a mixed population of bacteria with tetrazolium prior to incubation with the protozoan suspension in the presence of wheat. O. purkynei can tolerate exposure to variations in osmotic pressure, temperature, and oxygen which are consonant with its transfer in nature by grooming or ingestion of contaminated food or drink.

Notes: SYNOPSIS. After several years of field work devoted primarily to determining the incidence of infection of the common milkweed Asclepias syriaca with the trypanosomatid Phytomonas elmassiani, the life cycle of this parasite was determined under controlled conditions. Upon ingestion of phytomonads by the bug Oncopeltus fasciatus, reproduction apparently ceases but growth of individual phytomonads continues until they assume relatively giant proportions. Ten days after ingestion, giant forms are found in the hemocoel of the bug and by 12 days similar forms are present in the salivary glands. In this latter organ, unequal fission takes place with the ultimate formation of numerous forms similar to those found in the plant. Within 2 weeks after these infected bugs had fed on milkweeds, parasites were detected in the latex of formerly non-parasitized plants. The lack of reproduction in the alimentary tract, the formation of giant forms, and the migration through the hemocoel to the salivary glands contrast markedly with the development of Leptomonas oncoptlti in the same bug. In the latter organism, budding leads to the formation of leishmaniform organisms which pass out with feces and are presumably the infective stage of the leptomonad.

Notes: SYNOPSIS. The division delay responses of Tetrahymena (“set-back” curves) which result from heat shocks of the type used in synchronizing studies have been examined in logarithmic and synchronized T. pyriformis GL. The curves indicate an increasing sensitivity to heat shocks with increasing cell age, a sudden sharp increase just prior to the “transition point” and a loss of sensitivity at the transition point. A correlated study of morphogenesis in the synchronous generation suggests that the sudden increase in thermal sensitivity before the transition point is due to a dedifferentiation and redifferentiation of the developing oral primordium which can be induced at this time. The results also suggest that the “stabilization” of the primordium which follows the transition point may occur at more than one developmental stage, i.e., is not stage-specific. It is suggested that stabilization may therefore be due to conditions lying outside the primordium.

Notes: SYNOPSIS. Cytoplasmic stippling, intensification of the cell margin, and alterations in color, which have been reported in erythrocytes parasitized by Plasmodium falciparum in man, have been seen also in bovine erythrocytes parasitized by either Babesia bigemina or B. argentina. These changes appear to be identical in the human and bovine infections.Tests with each component of Giemsa stain in simple aqueous solutions alone and in various combinations with eosin, together with tests with Giemsa stains containing one azure component, showed that demonstration of the changes depends on the presence of azure A and eosin and on prolonged staining times at pH 7.2 to 7.4. Specific tests suggested that the changes represent catabolic by-products of the parasites.

Notes: SYNOPSIS. Studies on the composition of commercial Giemsa stain and its effect upon staining quality are reported. These studies were supplemented by observations on the preparation of the components of Giemsa stain and their staining properties in aqueous solution, in Nocht's solution, and in laboratory prepared Giemsa stains containing one azure component. Five groups of commercial batches were differentiated on the basis of their staining reactions on thick and thin films of bovine blood containing Babesia bigemina and B. argentina. Spectrophotometric and chromatographic analysis showed that four groups differed in the proportions of the thiazine components present, while the fifth-group did not appear to be Giemsa stain. Comparison of their staining effects with those obtained with each component in laboratory prepared stains indicated that the major effects of commercial batches on both blood cells and parasites were due to the thiazine component or components in highest proportions, with satisfactory staining of protozoa associated with those batches containing high proportions of methylene blue and azure B and low proportions of the remaining thiazine components.The function of each component of Giemsa stain is defined and the need for the proper balancing of thiazine eosinates with free azure is shown. Close correlation was obtained between analysis by spectrophotometry and chromatography and direct staining tests when samples initially with low MX values were re-examined spectrophotometrically after removal of their methylene violet content. The existence of a leuco form of eosin is reported and its possible significance to the Romanowsky effect is discussed.

Notes: Two groups of ewes, each containing single and twin lambs, were folded over a ‘worm-free’ pasture, with a creep provided for the lambs, allowing them to graze ahead of the ewes. The lambs of one group received supplementary feeding. Higher growth rates of the Iambs were recorded than those previously reported by other workers. The growth rates of twin lambs were improved more than those of singles and the lambs receiving supplementary feeding gained at a significantly faster rate than those on pasture only. Faecal egg counts indicated that worm infestation in the lambs was maintained at a very low level.

Notes: Data from an experiment already reported (2) are used to examine a statistical method proposed by Walker et al. (8) for apportioning the nitrogen harvested in grass in a grass/ legume sward to legume, fertilizer and soil. Multiple regressions of the yield of N in the grass (Gn) upon N harvested in the associated legume (Cn) and N applied in fertilizer (Fn) were highly significant; but they were very variable, mainly because of the strong (negative) correlation between Cn and Fn. In some cases the coefficient for clover N was negative, in some cases the coefficient for fertilizer N exceeded unity; and the residual constant varied widely among 4 sets of plots on the same soil. The interpretation of such equations in physical terms is criticized on these grounds. The use of pure grass swards in conjunction with mixed swards gave estimates of the recovery of fertilizer N, and of the transfer of N from clover to grass, which agreed better with other published data than did the coefficients in a multiple regression. A simple regression of the estimate of transferred N in the grass upon the N harvested in the clover yielded a second constant. This constant, which varied considerably from one series of plots to another, is thought to indicate interactions between the various sources of N, which would be attributed to a direct effect of soil N if the multiple regressions were interpreted as Walker et al. suggest.

Notes: Pure swards of S22 Italian ryegrass, H.1 hybrid ryegrass, S170 tall fescue, S48 timothy, S215 meadow fescue and Germinal cocksfoot were each harvested at several stages of maturity during first growth in the spring, and in the subsequent regrowths. Each batch of herbage was fed to sheep in a digestion trial under conditions of voluntary intake. Results from the first growth herbages showed the expected fall in digestibility with increasing maturity. However, the digestibility of S22, H.1, S170 and S48 began to fall well before ear emergence, whereas the digestibility of Germinal fell only slowly up to the time of ear emergence, as had been found previously with S24 and S23 ryegrass and S37 cocksfoot. The rate of fall of digestibility in H.1 and S48 (0.4 units/day) also appeared to be lower than with the perennial ryegrasses and cocksfoot (0.5 units/day). The monthly regrowths within each herbage were of similar digestibility, but the mean digestibility of regrowths differed between herbages, being highest for S215 and lowest for Germinal and S170. The grasses with highest digestibility in the early Spring, in particular S22 ryegrass, were not, however, always the most digestible in the subsequent regrowths. The numbers of sheep fed on each herbage were insufficient to show whether there were significant differences in voluntary intake between different herbage species of the same digestibility. It is suggested that an intake/digestibility relationship, based on data from more animals, should be developed for each herbage species. Only if different relationships are found can it be concluded that factors other than level of digestibility have an effect on intake.

Notes: The productivity and persistence of 27 varieties of herbage plants were compared, following sowing on a blanket peat after ploughing. Yields were estimated from 3–5 cuts per year for 5 growing seasons. The top yields in each year ranged from 2510 lb/ac. in the 5th year when no nitrogenous fertilizer was applied up to 4700 lb/ac. in the 3rd year when given 174 lb N/ac. Such levels are slightly less than half the level expected on lowland, but livestock output on hill land is far lower than on lowland. Varietal differences were significant, with red fescues, especially S59 smooth-stalked meadow grass, S170 tall fescue, S143 cocksfoot, Yorkshire fog and S53 meadow fescue giving top yields and persistence. Aberystwyth varieties were in all cases superior to other varieties. S50 timothy and S23 perennial ryegrass were persistent but production was low. The conclusions are compared with those of other investigators.

Notes: The traditional method of calculating field output by the utilized-starch-equivalent (U.S.E.) system is compared with a recommended simpler and quicker method. The concept of calculating a U.S.E. factor is introduced and forms the basis for the new method. A monthly U.S.E. factor is used, in conjunction with monthly cow-day (CD.) records to calculate U.S.E. Savings of at least 50% may be expected. Agreement between the two methods is very close and the more seasonal nature of the calculation for sheep and non-milking cattle under the new method may be preferable.

Notes: In 1960 spring-born calves were reared indoors or at pasture on 3 dairy farms near Hurley. In the following year the experiment was repeated on 3 farms in the nortli-east and on 2 in the south-west of England.Several calves died, and this may have been because of inadequate milk feeding. Generally, however, the growth of calves reared at pasture was comparable with that of animals reared indoors. Tfie use of grass enabled substantial savings to be made in the amount of concentrate feedingstuffs and hay fed.

Notes: Digestibility data are presented on the following; Andropogon gayanus hay and bush foggage, Arachis hypogoea (groundnut) haulms, Glycine max (soya-bean) hay. Sorghum vulgare (sorghum) leaves and hay, Stizolobium sp. (velvet bean) hay, Vigna sinensis (cowpea) hay and haulms, and S. vnlgare/Stizolobium sp. mixture. The results are discussed from the agronomic aspect.

Notes: Two systems of recording the output of grass fields—by cow-days (CD.) and by utilized starch equivalent (U.S.E.)—were compared with field measurements of the dry matter and digestible matter consumed over a period of two years.On one farm, each recording system was positively correlated with both the amount of dry matter and the amount of digestible matter consumed from individual fields by grazing cows. Consequently, the two systems reflected equally well the total quantity of utilized herbage and its quality. This was explained by a highly significant correlation between the two recording systems. The same correlation between the two recording systems existed on 20 other farms.It was concluded that the C.D. and the U.S.E. systems gave equally reliable results when assessing field output within dairy farms. Because C.D. can be determined with greater ease they should be used instead of the U.S.E. system. However, the U.S.E. system is still advocated for assessing grass utilization for animal production on a farm basis, since it indicates the level of efficiency which farmers achieve in using their grass.

Notes: An investigation into the merits of intensive rotational grazing or paddock grazing was started in 1960. The experiment covered 40 acres, half of which was divided into 20 single-acre paddocks and the other half into 2 fields of 9 and 11 acres, respectively. Two groups of carefully paired cows were used to measure the output of milk per acre. Surplus grass was used for drystock and for conservation. The final output was expressed in terms of U.S.E. per acre, which was computed from the records of milk production, livestock maintenance and fattening and grass cut for conservation. The following conclusions seem reasonable: (a) Where the stocking rate is the same under both systems and the grass supply exceeds the animals' appetites, very little difference in terms of milk yield per acre will be found between intensive rotational grazing and lax rotational grazing over the grazing season; (b) Where, because of heavier stocking or a poorer growth of grass, the animals' appetites begin to exceed the grass supply, the intensive system of rotational grazing will be able to carry the stock for a longer period and consequently will give a greater output of milk per acre; (c) Intensive rotational grazing gives greater opportunity for taking off surplus grass for dryslock or for conservation.

Notes: A comparison of non-mat and mat ecotypes of three reseeded hill swards showed that mat pasture soil was characterized by relatively high C/N ratios, low available nutrient status, low burrowing earthworm biomass, and low soil microbial activity (determined as CO2 evolution).A replicated trial was laid out on a uniform mat area of one of these swards (Ciderhouse Hill) and lime and fertilizer treatments were applied in two successive seasons. Lime treatment reduced mat weight, increased the proportion of ‘sown’ grasses in the sward and stimulated soil microbial activity, Initially, burrowing earthworm biomass was inhibited by lime; but, after an interval of four years, a positive response was noted at the lower treatment level. Sodium nitrate interacted with lime to increase soil microbial activity. Soil cellulolytic activity was increased by nitrate and phosphate treatments. The level of soil moisture in the field at the time of soil sampling appeared to influence soil microbial activity measured under standard conditions in the laboratory: high rainfall tended to reduce microbial activity. The significance of these findings and the infiuence of nutritional and climatic factors on sward reversion and mat formation are discussed.

Notes: The sheep grazing intensity and herbage intake on 3 high-level grasslands above 2250 ft were investigated. The seasonal intake, which varied from 450 to 700 lb dry matter/acre, was obtained by the yield-difference method, using cages moved monthly.

Notes: Leaf-area index was increased by nitrogen application, but the increase was restricted by frequent cutting, which limited the incidence of high leaf-area indices. Timothy swards had higher leaf-area indices than meadow-fescue swards between April and mid-July, the period in which maximum values were recorded. N significantly increased the leaf area per g of leaf (leaf-area/leaf-weight ratio) at the beginning of the experiment, but not thereafter; the effect of cutting on this ratio varied with the date of cutting. Leaf areas per g of leaf were similar for the 2 species at the beginning and end of the experiment, but in mid-summer values for timothy increased whilst those for meadow fescue decreased. The relationship between leaf-area index and yield of dry matter is discussed.

Notes: Book reviewed in this article:CUNNINGHAM LABORATORY, C.S.I.R.O., AUSTRALIA. Some concepts and methods in sub–tropical pasture researchEDWARDS, C. A., HEATH, G. W. The principles of agricultural entomology.MINISTRY OF AGRICULTURE, FISHERIES AND FOOD, ENGLAND AND WALES. Hay: quality and feeding.

Notes: Studies on height/weight relationship of the key grass species of Western Rajasthan ranges, India, were undertaken so as to form concepts which will guide the assessnient of the extent of their utilization by the livestock. Regression studies of the data obtained indicated that the relationship between the percentage of height clipped and the percentage of weight removed is quadratic. A graph has been drawn for each of the 5 species to relate the percentage of height removed with the percentage of weight utilized. The studies have shown that the weight distribution in respect of height is different in different species.

Notes: The dry-matter intake of silage was increased when the silage had a higher dry-matter content and when the time of access to the silage was increased from 3 to 24 h. Concentrate supplementation had a greater influence in depressing the intake of hay than that of silage. Only a small difference was observed in the replacement of hay by concentrates when the concentrates were given with two hays of different dry-matter digestibility. Concentrates with a relatively high protein content depressed roughage intake to a lesser extent than concentrates with a low protein content.

Notes: Book reviewed in this article:McILROY, R. J. An introduction to tropical grassland husbandry.MINISTRY OF AGRICULTURE FISHERIES AND FOOD. Bulletin 195: Fertilizers for the farm

Notes: An experiment on the prevention of hypomagnesaemic tetany by foliar application of calcined magnesite was carried out with the dairy herd of Greenmount Agricultural College. Hypomagnesaemia and tetany were prevented by‘dusting’ pasture with calcined magnesite at the rate of 28 lb per acre just before grazing, whereas hypomagnesaemia and cases of tetany (including one death) occurred when the animals were grazing pasture which had not been dusted.

Notes: Populations of Lolium spp., Dacrylis spp., and Phleum, each based on two or more cultivars, were subjected to three managements and iwo nitrogen levels. Rapid changes i n population structure occurred in response lo agronomic selection pressures and some cultivars were eliminated from the swards in less than four years, even though they were able to persist for longer periods when sown separately. The frequency and method of defoliation, time of nitrogen application, and edaphic factors produced changes i n the proportion of the cultivar subgroups in the populations, and there were indications of differential survival within cultivars. The results are discussed in relation to the utilization of cultivars in mixtures and the selective action of biotic and edaphic factors.

Notes: The release of the plant-cell juices is a prerequisite for a lactic-acid fermentation in silage. Investigations with plant material at different moisture contents have indicated that above about 2 g water per g dry matter sufficient juice is released from properly ensiled material to permit the onset of fermentation; below this moisture content lactic-acid production is delayed, if not prevented.When material of suitable moisture content is ensiled at a temperature of 25°C, the onset of fermentation is somewhat slower than at 40°C. However, within these limits, the temperature is not critical, provided that the silage is completely sealed to exclude air. The infiltration of even small amounts of fresh air delays the release of the juices and, especially at the lower temperatures, often results in an undesirable fermentation.A number of miscellaneous treatments, designed to hasten the release of the juices, failed to show any advantages in small-scale tests.

Notes: The two years' experiments described compared the growth of suckling lambs on ‘long’ and ‘short’ ryegrass swards. The animals were carried at a moderate stocking rate. Differences in sward height were established before grazing began and were maintained throughout each season. There were no significant differences in lamb growth between treatments. The structures of the swards are discussed in relation to the results, and the possible effect of differences in parasitic infestation on ‘long’ and ‘short’ swards is considered.

Notes: Using ryegrass and lucerne silages, investigations were made into the relationship between plant-cell breakdown, as evidenced by a collapse of the silage mass and by an increase in its electrical conductivity, and the initiation of lactic-acid production. Changes in the water activity of the juices available as a medium for the silage bacteria were also examined. It has been shown that cell breakdown and the resultant release of the plant juices Is a necessary pre-requisite for the production of significant amounts of lactic acid during ensilage. The investigation also confirms that the complete exclusion of fresh air from the silage mass can usually be expected to result in cell breakdown within a few hours.

Notes: There was a significant reduction in the seed yield of S26 cocksfoot in the first harvest year following undersowing in oats. Yields were markedly improved, however, by the application of extra nitro-chalk in spring, by using a partial cover crop and by cutting the oats for silage.Over three harvest years the financial returns were very similar for all treatments studied.

Notes: Book reviews in this article:CLARKE, H. G. Commercial sheep management.VOISIN, A. Grass tetany.WALSH, A. Profitable meat production.

Notes: Determinations of the in vitro digestibilities of leaf-blade, leaf-sheath and stem fractions of the grasses cocksfoot, perennial ryegrass, timothy and tall fescue and of the leaves and stems of lucerne and sainfoin have shown that all parts of the plant have a high digestibility at early stages of growth. With increasing maturity, however, the digestibility of the stem falls off at a much faster rate than that of the leaf; in grasses, leaf-sheath digestibility declines at an intermediate rate. The decline of digestibility is associated with a reduction in the content of water-soluble and protein constituents in the plant, and with a reduction in the digestibility of fibre. This may provide a biochemical basis for the selection of forage plants of high digestibility in plant-breeding studies.

Notes: The effects of (2–chloroethyl) trimethyIammonium chloride (CCC) on inflorescence production and culm length in seedlings of Aberystwyth S51 timothy (Phleum pratense L.) are described. Concentrations of CCC ranging from molar to 0.01 molar were applied as a soil drench at a rate of 75 ml/sq. ft to plants at the 3rd, 6th or 8th leaf stage. All treatments reduced the culm length at heading, maximum effect being obtained from those given at the earliest growth stages. The number of heads per plant and the total head-length per plant increased with treatment, showing a maximum after molar treatments at the 6th or 8th leaf stages. Mean head-length remained relatively constant. The results are discussed in relation to seed production problems and the questions to be answered prior to field-scale treatment are outlined.

Notes: Leaf and tiller development along the main shoot of cocksfoot, ryegrass, timothy, Hordeum bulbosum, meadow fescue, S170 tall fescue and an Algerian tall fescue are described. Comparisons between plants grown at two levels of applied nitrogen, and in a heated and an unheated glasshouse, from January to April, 1961, showed that timothy, cocksfoot and, to a lesser extent, H. bulbosum and ryegrass, generally developed leaves faster than the fescues. Numbers of live leaves per shoot, and numbers of actively-elongating leaves per shoot declined in a similar varietal order. Despite this, the large leaves of the fescues resulted in their having a leaf area per main shoot equal to, or exceeding that of, the other grasses for most of the experiment. In general, rate of leaf appearance, number of live leaves, number of actively-elongating leaves and leaf length were increased by a high level of N and high temperature, but high tesnperature reduced leaf width and, in some instances, tiller numbers.

Notes: Extensive replicated plot experiments were carried out at Henley Manor Farm from 1956–1961 to obtain accurate measurements of herbage production and response to nitrogenous fertilizers under West of England conditions. 356 plots were used; use of the herbage by both cutting and grazing was studied. The principal results are: Grass/ clover swards (containing approx. 35% clover) grown without nitrogenous fertilizer averaged 75 cwt dry matter per acre per annum. Application of nitro-chalk to initially grass/clover swards reduced the clover content of the herbage. About 133 lb N/annum was required by an all-grass sward to equal the production of a grass/clover sward without N. Attempts to increase production of grass/clover swards by using N for early growth and relying on clover for mid-season growth were unsuccessful in 2 out of 3 years. Swards (initially grass/clover) gave significant increases in total dry-matter production from regular use of the lowest level of N (26.0 or 34.7 lb N/acre/cut or graze) in 44 out of 49 cases. Extremely high yields were obtained from the heaviest use of N (104.2 lb N/acre/silage cut). 52.1 lb N/acre/cut or graze was the optimum rate of application on ail-grass and grass/clover swards. Up to about 350 lb N/acre/annum the dosage-response curve was very nearly straight for all-grass and grass/clover swards. On the grazed plots herbage left ungrazed amounted on average to only 6% of the total. The health of all stock on the high nitrogen plots (as well as all others) was excellent.

Notes: Assessments of animal preference (measured as mean % herbage removed) were made on varieties of cocksfoot in Yorkshire and in Scotland, and parallel chemical analyses were carried out. A similar range of varieties were examined at progressive stages of spring growth at Cambridge. In vitro digestibility tests were made also. In the Yorkshire trials, a significant positive relationship was established between soluble carbohydrates and animal preference and a negative correlation between fibre and animal preference. In Scotland, the relationship between soluble carbohydrate and animal preference was less pronounced. Animal preference in the spring was for the early varieties which have thick and succulent stems up to the stage of ear emergence. In the aftermath animal preferences were less marked.In trials at Cambridge, the early varieties, notably Scotia, were higher than the late varieties both in digestibility and in soluble carbohydrates. This tendency was also present in Scotland but was less pronounced.

Notes: Details are given of the system of grassland management used on the farm of the Hannah Dairy Research Institute in the 5-year period 1958–62, when the aim was to inerease production economically by achieving a balance between the use of grass, grassland conservation products, home-grown cereals and the minimum amount of purchased feeds.Over the period the number of cows and lst-calf heifers increased from 50 to 53, while the total annual milk production increased from 41,000 to 50,000 gal. The yield of milk increased from 820 to 945 gal. per cow, and from 300 to 380 gal. per acre. Concentrate usage declined from 2.5 to 1.8 lb per gal.The margin of milk sales less purchased feed rose from £111 to £129 per cow in the 5 years and the net output averaged £59 per acre. The health of the stock was excellent.

Notes: When light dressings of 0·75, 1·50 and 2·25 cwt muriate of potash per acre (60% K2O) were applied in autumn and spring to swards receiving two levels of sulphate of ammonia, 30 or 60 lb N/acre, and kieserite (29% MgO) at 0, 4 or 12 cwt/acre, magnesium content was reduced as the level of muriate of potash increased. Autumn application resulted in a higher magnesium content, at the expense of the amount of the potash absorbed in the spring herbage. The effects at the lowest levels of application of muriate of potash were slight and became insignificant in later herbage samples.

Notes: During 1959–62 a study was nmdc of the effect or the density of plant population, photoperiod, temperature and light intensity on stolon rornialion, floral induetion, bud expansion and inflorescence development in S184 white clover.The density of the plant population alfected not only stolon and inflorescence formation, but also the root system. The‘open’ sward with about 60 plants per sq. yd gave the highest number of inflorescences per unit area, and al the same time contained few plants with tap roots.White clover had a long-day photoperiodjc requirement, but there was variation between the individual plants in their requirements of daylength, temperature and light intensity.Overwintering did not appear to be essential for floral induction and primordia development. Too low or too high temperatures during the overwintering period appeared, respectively, to delay or stimulate vegetative growth, while both extremes of temperature seemed to delay floral induction and reduce inflorescence formation. A medium range of temperature (40°–55°F) followed by an increasing temperature, daylength and light intensity, appeared to be most satisfactory for primordia initiation and flowering.There is some inter-relation between temperature and light intensity, but light intensity stimulates vegetative growth and development of the primordia, as well as being essential for the formation of numerous inflorescences.

Notes: The mean yields of 4 varieties of lucerne were compared under 5 methods of growing: broadcast with and without grass; drills 2 ft apart; alternate lucerne/grass drills 1 ft apart; spaced plants. One cut was harvested in the sowing year and 3 cuts a year for the next 3 years.The alternate lucerne/grass drills yielded 20% less dry matter than the comparable broadcast plots. Broadcasting and sowing in alternate drills had the same effect on the pattern of lucerne/grass competition. The meadow fescue companion produced its highest yield at the first cut and there was a marked drop during each year and from year to year. There was little evidence of nitrogen transfer from the lucerne to the grass.

Notes: Perennial ryegrass and meadow fescue were grown alone and in association in field plots, to gain an idea of the nature and importance of the competitive interactions between them, and their relative contributions to the yield of the newly-established sward.Experiments over 10 weeks and 9 months both showed that the contribution by fescue to the overall dry-matter yield was severely restricted by perennial ryegrass. There were no deaths of fescue plants during the experimental period (which included an overwintered treatment). The depression in yield was rather a result of a marked decrease in size and weight of the individual plants, brought about by competition for light and nutrients from the faster-growing ryegrass.

Notes: Two levels of nitrogen application (70 and 180 lb per acre per annum) were compared on 6 long-duration leys. The treatments were repeated for periods of up to 4 years on tiie same swards. The higher N dressing produced 2230 lb more dry matter per acre than the low rate, an increase of 28%, and the yield was also more evenly spread throughout the season. There was virtually no clover on the high-N swards. The proportion of clover varied under low N but tended to increase as the season progressed. The sown grasses remained the dominant sward constituents throughout the experiment, and there was no sign of loss of vigour on the high-N swards. Utilized-starch-equivalent outputs were calculated from 3 different swards for 1956–8 and there was a significant positive correlation between the dry-matter yields and utilized-starch-equivalent output of swards.

Notes: Cocksfoot sown late in summer or early in autumn to provide a seed crop the following year generally produces a disappointing yield. The experiments described were set up to study this problem. Seeds of four varieties, American, Danish and two British cocksfoots, were sown at fortnightly intervals during the spring and summer of 1956. The sowings were repeated in 1957 with the addition of Potomac, a bred variety from USA, and an ecotype from Israel.Plants sown after mid-May showed a diminishing capacity to produce panicles the following summer. The last sowing in 1957 caused the weight of green hay per plant in 1958 to be at least 50% below that of the spring-sown plants, and panicle number to drop 60–80%. Sowing after mid-May affected panicle development in the autumn and in the following hay crop. Date of sowing had no effect on mean date of panicle emergence in the following summer. In the populations as a whole, neither the presence nor the number of panicles in the first autumn was related to productivity in the hay stand.

Notes: The effects of sowing from 10 to 50 lb/acre of tall-fescue seed on plant establishment and on the annual and seasonal distribution of DM yield of tall fescue and its companion grasses were measured through two growing seasons. Increasing the seed rate increased plant numbers per unit area and decreased per cent establishment. Adding Scots timothy as a companion grass depressed both plant number and per cent establishment. S37 cocksfoot and New Zealand perennial ryegrass reduced both still further. Total annual dry-matter production was relatively unaffected by varying either the seed rate or the companion grass. The contribution of tall fescue to total production was highest when sown alone and was successively reduced by timothy, perennial ryegrass and cocksfoot. When sown alone there were only slight differences in contribution of tall fescue due to seed rate. With any companion grass the contribution from tall fescue increased with increasing seed rate. Early growth was not reduced by modifying seed rate but was reduced by all the companion grasses. It is concluded that increasing the seed rate of tall fescue above 30 lb is not justified, that Scots timothy can be sown at 3 lb/acre with tall fescue without affecting total production or early growth of the mixture, with the advantages of control of unsown species and improved palatability of the herbage.

Notes: Differences resulting from previous cropping were shown in the yields of the first test crop of rape and also in the second test crop of oats which followed. Rape yields were highly correlated with the yield of the legume crop harvested earlier in the season, the highest residual effect being observed after lucerne, followed by lucerne/grass, red clover/ grass and grass alone, in descending order. The application of nitrogen to the legume and grass swards reduced the yield of oats, the second test crop. Here again, lucerne gave better residual yields than grass.

Notes: Eight lots of seed of S23 perennial ryegrass which had been artificially dried to different moisture levels and stored for 20 years were tested for germinating capacity, and the effects of long-term storage on subsequent plant development were studied. The results of the germination tests indicated a continuation of the downward trend in viability previously reported. Observations on the derived mature plants revealed no difference between lots in general growth habit; a few seedlings showed symptoms of some retardation in growth but most plants manifested the high tillering and prostrate growth typical of S23 perennial ryegrass. Pollen fertility was markedly reduced in 38% of all the plants sampled. The seed-setting capacity was affected to an even greater extent, 44% of the plants giving seed-set values decidedly below those obtained for plants grown from new seed. Where pollen fertility had been much reduced, seed-setting also was usually low, but there were some instances of satisfactory pollen fertility associated with a low seed set.

Notes: Three grazing managements (set stocking, 4-paddock rotation, 8-paddock rotation), each with an undivided lateral creep area, were studied. Each of these managements carried 2 stocking rates (6 ewes and twin lambs per acre, 10 ewes and twin iambs per acre) and the sub-divided managements were grazed at 2 severities of grazing.Stocking rate had a major effect upon the lambs' liveweights but did not significantly affect the ewes’ liveweights. Lambs on set-stocking managements had a significantly higher rate of liveweiglit gain than lambs on managements with sub-divided ewe areas. Under lax grazing, for much of the experimental period, the lambs had a significantly higher rate of liveweight gain and the ewes had significantly higher liveweights than under severe grazing.

Notes: A suggested new method for studying the depth of grass seed germination and emergence is described.

Notes: Book review in this article:WORDEN, A. N. SELLERS, K. C. TRIBE, D. E. Animal health, production and pastureSTAPLEDON, G. [WALLER, R. Ed.] Human ecology.

Notes: The effects of three stocking rates on fat-lamb production were examined. These stocking rates were imposed upon four grazing systems. The grazing managements had no significant1 effects upon the rate of liveweight gain or the total liveweight of lamb produced per acre, nor were the ewes’ liveweights significantly affected. Reasons are suggested. The lambs’ rate of liveweight gain was related negatively and the total liveweight of lamb produced per acre was related positively to stocking rate. The ewes’ liveweights were similarly affected, there being the highest losses of liveweight under the high stocking rate. In all cases significant differences existed between the stocking rates and there was a significant linear relationship between them. It is concluded that high stocking rates are essential to obtain the maximum fat-lamb production on a ‘per acre’ basis.

Notes: An hypothesis relating to the circulation of nitrogen between soil, plants and animals in fertilized grassland is presented. It embodies the results of small-plot experiments and grazing trials on serai grassland in South Africa. Where the value of land is low in comparison with the cost of fertilizer, it is essential that the maximum response be obtained from fertilizer as well as from excretal N. The assumption that 80% of herbage N is returned as excreta, of which 25% is recovered by the grasses in the first season and 25% in the second season, appears to be in accord with liveweight data. Using average values of soil N and fertilizer recovery under local conditions, it is argued that applying 30 lb N per acre (with an initial heavy dressing) should provide higher percentage recoveries of fertilizer N than fixed annual dressings of 60 Ib N per acre. In grazing trials over five years, in which these systems are compared, the apparent recoveries of fertilizer N in animal liveweight were respectively 22.4% and 11.6%.A distinction is drawn between the initial build-up of nitrogen in circulation and the long term maintenance of a nitrogen level providing maximum recovery of fertilizer N.

Notes: Twin steer calves were used to compare the effects of early weaning indoors with those of rearing on the bucket at pasture. Calves born in the autumn and reared indoors joined their twins at pasture when about 6 months old; those born in the spring were approximately 12 months old when turned out.There was little difference between the performance of indoor- and outdoor- reared calves born in the autumn. Usually, the spring-born calves indoors were about 150 lb heavier than their twins at 12 months of age. This difference normally disappeared by the end of the grazing season and twins became fit for slaughter at the same time. No difference could be found in carcass conformation.

Notes: The water activity of juice available for fermentation, after breakdown of the cell walls during the ensiling of plant material, depends largely on the moisture content of the sample. Water activity increases with moisture content, but probably never becomes so high as seriously to limit lactic-acid fermentation, although high moisture contents have other detrimental effects. With low moisture contents, the limited availability of the juice rather than its lowered water activity is most probably the factor primarily responsible for poor lactic-acid production.

Notes: During the interval from seed set to advanced shedding in a crop of S24 perennial rye-grass, a study was made of: seed drying, the increase in germinating capacity and weight of seed, and the shedding of florets. The seed in early-emerged heads dried more rapidly than that in later heads, and the seed in the upper parts of each spike was drier than in the lower parts. Seeds in early heads attained maximum germination values about 18 days after anthesis. The maximum value was lower in later heads and was not reached until approximately 26 days. Seed in early heads was 67% heavier than that in late heads and the basal florets in each spikelet contained heavier seed than more distal ones. The maximum weight of individual seeds was reached at about the same time in early-emerged and intermediate heads, at about 22 to 26 days after anthesis. Seed in late heads continued to inerease during the whole interval studied. Shedding began before seed reached maximum dry weight and continued at a constant rate. The combination of these processes led to the maximum yield of seed, of 100% germination, being obtainable over a period between 20 and 26 days after anthesis. Criteria are given which would permit this stage to be recognized.

Notes: Seeds of four legumes and four grasses were germinated in the presence of aqueous extracts of the same species, using distilled water as a check. Measurements were taken to determine the effect of the extracts on germination, root growth and shoot growth. Based on the number of significant reactions to the extracts, the species may be classified in the following order of decreasing inhibition: alfalfa, birdsfoot trefoil, Ladino clover, red clover, reed canary grass, brome grass, timothy and orchard grass. Conversely, alfalfa and timothy were the species least affected by the extracts while reed canary grass was the most susceptible. Other species were in an intermediate range. With the exception of alfalfa, extracts of aerial portions of the plants had greater inhibitory effects than root extracts.

Notes: Tools and technique for sampling pit silage to determine dry matter and density are described.

Notes: A survey was made of the flowering responses of 47 annual, biennial and perennial grasses, to measure the extent of any winter requirement for floral induction, and to see how far this could be provided by controlled cold or short-day treatment.The annual species showed little or no inductive requirement, nor did the perennials Arrheuatherum elatius, Ceratochloa unioloides, Phleum pratense and Poa nemoralis. Most perennials possessed a definite inductive requircinent. A few species, such as Lolium perenne, responded to both cold and short-day given to the young seedling, while others, such as Phleum nodosum, Agrostis alba, A. canina, A. stolonifera and A. tenuis, responded to short-day induction but not to cold.Many temperate perennials, however, including Cynosurus cn'status, Dactylis glomerata, Festuca pratensis, F. rubra, Poa pratensis and P. trivialis did not respond to seedling induction and possibly have a juvenile stage before they are able to respond to inductive conditions.The sequence of flowering responses in the temperate perennial grasses is evidently more complex than was previously thought, and the perennial habit can be achieved by many different developmental pathways.

Notes: A small-scale conservation experiment is described in which molasses, zinc bacitracin and dried sugar-cane juice were compared as additives to grass silage. The results indicate that all these additives improved the quality of the silage, but do not suggest any significant decrease in dry-matter loss due to the use of preservatives.