bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of the effects of environmental temperature and nutrition on growth and development
Authors: Dauncey M. J. , Ingram D. L. , Walters D. E. , Legge K. F. 
Published: March 2009

SUMMARYGrowth and development of young mammals have been investigated in relation to environmental temperature and energy intake. The experimental design and statistical analysis have allowed an evaluation of the separate and combined effects of two environmental variables and the time it takes for these effects to develop. Piglets aged 14 days lived at either 35 or 10 °C, on a high or low energy intake (the energy content of the former was twice that of the latter). The influence of each of the four treatment combinations was assessed up to 64 days of age.At 64 days of age the piglets at 35 °C on the high intake (35H) were twice as heavy as those at 10 °C on the low intake (10L). The other two groups (35L and 10H) had similar body weights, and these were between the 35H and 10L. Ambient temperature had a rapid influence on appearance and morphology: animals in the cold were shorter and squatter than those in the warm. In general, energy intake influenced the absolute size of the internal organs whereas temperature affected their size relative to body weight. Skeletal growth was faster in the warm than the cold, and on the high than the low intake. No statistically significant interactions were generally found between temperature and intake, indicating that their effects were exerted independently. Most of the effects were established after only 17 days.The present investigation has helped in interpreting earlier studies on growth which concentrated on the effects of only one of the two environmental variables of temperature and nutrition. It emphasizes the key roles of nutrition in adaptation to environmental temperature, and of ambient temperature to nutritional studies.
The lactation curve in cattle: a mathematical model of the mammary gland
Authors: Neal Heather D. St. C. , Thornley J. H. M. 
Published: March 2009

SUMMARYA simple model of the mammary gland is described. In this model secretory cells are produced by cell division from undifferentiated cells, and the rate of division is determined by the level of a postulated hormone. The total activity of the milk secreting cells depends on the number of cells, substrate supply (assumed constant), and the amount of milk currently present in the animal. The secretory cells have a finite life, although their death may be expedited by milk remaining in the animal over a longer period of time. The model gives a good description of an experimental lactation curve; it is able to simulate the removal of milk by a suckling calf and machine milking with a variable number of milking periods a day.
Experiments on the nutrition of the dairy heifer: I. Protein requirements of yearling stock
Authors: Bailey G. L. , Broster W. H. 
Published: March 2009

The literature on the protein requirements of young dairy heifers has been discussed and the wide variations noted, both in quantities estimated for particular live-weight ranges and in the suggested trends of requirements with live weight.Short-term trials have been conducted in which the effect of variation in protein intake on rate of live-weight gain of dairy heifers of various ages was studied.The response to increments of protein in the ration was found to be curvilinear with a rapid decline in response above critical levels of intake. This level varied with the live weight of the animal, being 0·8 lb. crude protein at 300 lb. live weight and 1·0 lb. at 400 and 500 lb. when rations based on hay, decorticated ground-nut meal and flaked maize were fed.These levels are somewhat lower than estimates of protein requirements quoted in the literature, though the trend indicated in them agrees with some of the published data.No marked difference was observed between the values of decorticated ground-nut meal and white fish meal as protein supplements. Urea was inferior to decorticated ground-nut meal.The overall depressant effect of straw on rate of live-weight gain is demonstrated and discussed.
The effect of seed rate and nitrogen on lodging and yield of spring barley (field experiments 1954 and 1955)
Authors: Glynne Mary D. , Slope D. B. 
Published: March 2009

The extent to which spring barley crops lodged at Rothamsted increased with seed rate and with nitrogen, and was much more severe in the wet summer of 1954 than the dry one of 1955. Although in 1954 all plots were extensively lodged by harvest there were great differences in date of lodging; 50% of the area was lodged later in plots sown with 1 than with 3 bushels/acre, the delay being 8 days with 1½ cwt. sulphate of ammonia, 14days with 3 cwt. and 21 days with 4½ cwt. The weight of unit length of the basal part of the straw was reduced by higher seed rate and to a smaller extent by nitrogen.Yield of total grain was only slightly affected by treatments; yield of dressed grain was decreased by higher seed rate in 1 year and by nitrogen in both years.
Comparison of the effects of nitrogen fertilizer on the yield, nitrogen content and quality of 21 different vegetable and agricultural crops
Authors: Greenwood D. J. , Cleaver T. J. , Turner Mary K. , Hunt J. , Niendorf K. B. , Loquens S. M. H. 
Published: March 2009

SUMMARYThe effect of level of N fertilizer on the composition, yield and quality of 21 crops was studied in experiments on adjacent sites of the same field to aid in the development of fertilizer recommendations.Yield of each of the crops first increased and then either remained the same or declined with further increases of N fertilizer. Interpretation by means of a simple model enabled response curves to be characterized by two parameters; one representing the beneficial component of the response and the other the detrimental component. Both varied greatly from crop to crop.The magnitude of the beneficial component of the response of most non-leguminous crops was largely determined by the potential demand of the crop for nitrogen; the exceptions were some root crops which responded less than would be expected on this basis. The adverse component was serious with root crops and those crops that are in the soil for only a short period. High levels of N increased the ratio of foliage to storage root dry weights even when total dry matter was unaffected. The changes were associated with a considerable increase in the % N in the dry matter of the roots.When crops were grown with their optimum levels of N fertilizer a simple linear. relationship between the mean %N in the dry matter and the total weight of dry matter per unit area covered all crops. Simple relationships also existed between total dry matter of non-leguminous crops and (a) the amount of N taken up by the crop from unfertilized soil, (b) the recovery of added fertilizer by the crop and (c) the beneficial component of the response of crops harvested before October.Percentage N in the dry matter at harvest was not a sensitive indicator of the extent to which plant growth was restricted by lack of nitrogen; a difference of 0·1% N in the plant material was associated with a 10% increase in yield.N fertilizer levels influenced the % dry matter and the incidence of crop disorders such as rotten roots and tissue discoloration, but the effects were seldom appreciable with practicable levels of fertilizer application.
Utility of Rhizobium in the phyllosphere of crop plants: two-way exchange of metabolites between Rhizobium and the host plant
Authors: Nandi A. S. , Sen S. P. 
Published: March 2009

SUMMARYThe nature of the ectosymbiotic association between Rhizobium and such legume leaves as Bengal gram and mung bean was investigated using radioactively labelled compounds. About 8% of the 14CO2 fixed photosynthetically in the 70% ethanol soluble fraction was leached out within 1 h of contact with water. The 14C-compounds leached out include sucrose, serine glycine, glutamic acid, malate, alanine and succinate. A part of the 14C-activity was incorporated by Rhizobium cells sprayed on leaves. Association with rhizobia increased the rate of photosynthesis and leaching by 129–240% and 134–281%, respectively. Bacterial metabolites are translocated along the midribs and veins to different plant parts. The beneficial effects are not restricted to members of the same cross-inoculation group.
Growth and development of water buffalo and Friesian cross-bred cattle, with special reference to growth and distribution of carcass muscle and bone
Authors: Abdallah O. Y. , Shahin Karima A. , Latif M. G. A. 
Published: March 2009

SUMMARYRight sides of carcasses of 12 buffalo, nine ½ Friesian ( Friesian x Egyptian Baladi) and nine ¾ Friesian ( Friesian x ½ Friesian) bulls slaughtered over the body-weight ranges 161–560 kg for buffaloes and 176–448 kg for cattle were cut according to the Chicago style of cutting. Allometric growth pattern and distribution of muscle and bone in the various cuts were examined.Buffaloes were similar to cattle in that muscle and bone in the limbs showed an increasing distoproximal growth gradient. On the ventral line of the trunk, muscles showed an increase in growth impetus from plate to brisket while bone followed a reverse pattern. In buffaloes, growth coefficients of muscle and bone of all dorsal cuts were similar except in the sirloin and chuck where bone was later maturing. In cattle, there appeared a posterior-anterior increase in growth impetus of muscle from the shortloin towards sticking. Within and between genotype-group results indicated that growth of a fatless cut is governed by the growth of its muscle rather than that of its bone.Compared with Friesian crosses, buffaloes had significantly greater percentages of their total muscle and muscle-plus-bone in the expensive cuts. As total muscle weight increased, the proportion of muscle in BLRC (see p. 318) decreased in cattle but remained almost constant in buffaloes. It was concluded that the previously reported inferior carcass composition of buffaloes relative to cattle is compensated by better carcass conformation and tissue distribution of buffaloes.
The effects of agronomy on C and N distribution in soil organo-mineral fractions
Authors: Adams T. McM. 
Published: March 2009

SUMMARYSoils from grass-arable cropping sequences and from an experiment where grassland had been treated with slurry were dispersed by shaking as a soil-water mixture, followed by ultrasonic treatment. Organo-mineral particle size fractions were separated by sieving and by sedimentation.Generally, concentration of C and N in the fractions decreased with increasing particle size. However, when expressed as weight of C per fraction maximum contents were in the 2–10 μm range. With N, maximum contents occurred about 2 μm. Largest differences in C and N contents between soils were found in the 0·2–20 μm size range.Identification of the source of the materials in the various fractions was attempted by interpretation of the C/N ratios, but was generally inconclusive.
Potassium (Q/I) relationships as influenced by calcium and magnesium treated as separate ionic species, and by soil submergence
Authors: Pasricha N. S. 
Published: March 2009

SummaryThe quantity–intensity relationships between gains and losses of exchangeable K of the soil, and the K-intensity in the equilibrium solution, were determined for two soils incubated at 25 ± 1 °C for 0, 2, 4, 6 and 8 weeks under submerged conditions. The Kintensity modified to include the factor (F) by which Mg differs from Ca in its behaviour on the exchange complex, i. e. aK/(a½Ca + F.a½Mg), gave significantly lower values of equilibrium activity ratio, , and higher values of linear buffering capacity (LBCK), than when measured by the simple ratio, aK/(aCa + aMg)½. The mean value of the factor, F, was 0·46 for Conlubang sandy loam and 0–49 for Luisiana clay. Submergence up to 2 weeks resulted in an increase in the equilibrium activity ratio, , by 43–3% in Conlubang sandy loam. In Luisiana clay, , increased slightly after an initial decrease. In both soils, the readily exchangeable K, , increased with submergence, more so in Conlubang sandy loam than in Luisiana clay. Linear buffering capacity, LBCk, which is a measure of the rate of release of K to the soil solution, increased markedly with soil submergence.
Studies of grazing behaviour in relation to grassland management I. Variations in grazing habits of dairy cattle
Authors: Hancock John 
Published: March 2009

1. A series of grazing behaviour observations on 10 sets of lactating identical twins is described. Four fortnights distributed over the main lactation period were covered. In three of the fortnights, the observations were made on six 24 hr. periods, while in the remaining fortnight the cows were observed on all 14 days.2. Anoutstanding feature of the grazing behaviour of dairy cattle is its variability, due to external and internal conditions.3. Of the external factors, climate (in a temperate zone) is relatively unimportant.4. The quantity and quality of the herbage offered are of importance in modifying the grazing behaviour of dairy cattle. Under adverse pasture conditions there is, in general, an increase of total working time (grazing + ruminating): grazing time increases with scarcity of herbage and with mixed quality, while ruminating time is prolonged by poor quality grass.5. Ruminating time is strongly dependent on the quantity and quality of the ingested grass, but the relationship is, for various reasons, obscured in a field trial such as the present.6. The adaptation of grazing habits to new conditions is very rapid.7. Feed requirement for milk production is the most important internal factor determining variation in the length of grazing time.8. Inheritance × environment interactions as a source of variations in grazing times are due to the following factors:(a) Differences amongst twin sets in lactational persistency, which presumably cause parallel differences in feed requirements.(b) Differences in the response of high and low producing twin sets to varying pasture conditions.(c) Non-analysable idiosyncrasies common to the members of some twin sets.9. Twin sets graze and ruminate at a characteristic rate.
Amylolytic activity in the rumen of the sheep
Authors: Nasr Hamed 
Published: March 2009

1. Rumen contents of sheep given three different diets contained free bacterial α-amylase. The method of obtaining a cell-free rumen filtrate containing the enzyme is described.2. Amylase potency in the rumen was highest in the sheep given a diet of flaked maize, intermediate in that given a mixed diet of hay and concentrate and lowest in that given a diet of casein.3. The effect of rumen amylase on structural maize and potato starches has been investigated.4. Absence of amylase from sheep saliva was confirmed.5. Where flaked maize is fed, one of the organisms responsible for amylase production in the rumen of the sheep isCl. butyricum.
The chemical composition of oats II. The nitrogen content of oats and groats
Authors: Hutchinson J. B. , Martin H. F. 
Published: March 2009

The nitrogen content of oats depends chiefly on the nitrogen content (1·4–3·9%) of the kernel and the kernel content (64–81%) of the oats, the husk containing only 3–10% of the total nitrogen in the grain.Varietal differences are significant but small in comparison with the overall variability: they reach 0·3% nitrogen in a few cases. Variation between random samples is largely due to soil differences, with region and harvest year responsible for smaller effects. The predominant factor governing nitrogen level in oats of all varieties probably is, as for wheat, the level of available nitrogen in the soil in late spring and early summer, just prior to heading and during development of the grain.Within the variety there is a pronounced inverse correlation between nitrogen and oil content which is independent of grain size: the variability of the oil content within the variety is, however, smaller than the corresponding variability of the nitrogen content. At some localities environmental factors of soil and season, particularly the former, inhibit the filling out of the grains which then ripen prematurely to give small oats with lean kernels of high nitrogen content, and favour within the variety a negative correlation between grain size and nitrogen which otherwise might not be apparent.
The availability of potassium in soils to crops as measured by its release to a calcium-saturated cation exchange resin
Authors: Goulding K. W. T. 
Published: March 2009

SUMMARYThe amounts and rates of release of the different categories of soil K were measured on 21 soils from field experiments in England, Wales and West Germany using a calcium saturated cation exchange resin. The soils contained various amounts of exchangeable, fixed and matrix K; some contained no fixed K at all. These amounts could be qualitatively related to the clay contents of the soils.Regression analyses of K removed at harvest by spring barley, winter wheat, field beans and sugar beet, grown in the field experiments, were made on the quantities measured by the Ca-resin method and on K exchangeable to M ammonium acetate (EK). The Ca-resin method proved a better predictor of K availability than EK for all four crops. A multiple regression of the amount and rate of release of exchangeable K, and the rate of release of fixed K, as measured by Ca-resin, gave the best correlation with K removed. The contribution of fixed K to the regression increased with the demand of the crop for K and with the length of time the crops had been grown without K fertilizer. For the cereals, fixed K appeared to be either completely available or unavailable depending on whether its rate of release exceeded a critical value characteristic of each crop.The Ca-resin method is probably the best method available for measuring K reserves. It is, perhaps, too laborious for routine soil analysis, but could be used to characterize the long-term K release properties of a soil.
Survival of spermatozoa in the genital tract of the mare
Authors: Day F. T. 
Published: March 2009

1. With insemination of approximately 2 billion sperms, pregnancy resulted from inseminations up to 6 days prior to ovulation, but not when inseminations were made earlier, or on the day after ovulation.2. Ovulation was induced in one mare by injecting pregnancy urine extract when a large follicle was present in one ovary, although the mare remained anoestrous, as judged by vaginal and cervical secretions. This mare became pregnant from an insemination 2 days prior to the induced ovulation.
Yield characters of selected oat varieties in relation to cereal breeding technique
Authors: Stephens S. G. 
Published: March 2009

1. Results obtained from two seasons' population studies of selected spring oat varieties in Scotland indicated that extent of tillering had little or no effect on yield. These results are in sharp contrast with those obtained by workers with wheat.2. The yield of individual plants under the conditions of the experiments became adjusted to differences in population density primarily by variation in number of grains per panicle. Spikelet weight tended to be negatively correlated both with population density (external competition) and with number of grains per panicle (intrapanicle competition). These factors tended to neutralize each other.3. The decrease in size of additional grains in spikelets with more than one grain was balanced by increased weight of the basal grains as compared with the weight of a single grained spikelet. Average grain weight per spikelet therefore tends to remain constant.
Studies of soil after fifty years of wheat or barley cropping, especially of soil made acid with sulphate of ammonia
Authors: Mann Harold H. , Barnes T. W. 
Published: March 2009

1. Monthly aqueous extracts of soils which have been under wheat and barley cropping on the Woburn light sandy loam soils, with various manuring show very great similarity in the amount and character of the materials extracted in the wheat and the barley soils.2. Water-soluble phosphoric acid and potash are in extremely small amount where these manures have not been applied during the fifty years’ treatment, but, in spite of this, the amount of these constituents does not appear to be a limiting factor in determining the yield of either wheat or barley. The phosphoric acid is much higher in the plots treated with phosphatic manures, and the potash is slightly higher in those treated with potash manures, but these facts do not seem to have secured a seriously higher yield.
Weaning weight of pigs and litter sampling with reference to litter size
Authors: Smith A. D. Buchanan , Donald H. P. 
Published: March 2009

1. Following an examination of weaning weight with respect to litter size, it is concluded that no general relation between the two exists. Although a significant regression of weight on litter size was found, it appears probable that in herds where the relation between fertility and milk yield is different, such a regression will not necessarily be found.2. A sampling experiment was carried out to determine the extent to which a sample might be expected to represent the whole litter. A correlation of 0·96 was found between the mean growth rate of samples consisting of the four pigs nearest the average at weaning and the mean of the whole litter. This represents a loss of 8 per cent of the information. With three or two pigs chosen in the same way the loss was greater. Samples of four pigs chosen at random did not give results significantly different from those of the four pigs nearest the average. The choice of the heaviest four pigs resulted in a loss of 15 per cent of the information.3. The slight difference between the results from the random sample and the sample of the four average pigs indicated that there must have been only a small correlation, between weaning weight and subsequent rate of growth. An analysis of post-weaning rate of growth showed that the intra-class correlation of pigs of the same weaning weight was 0·15. Individual weight at weaning would therefore appear to be of slight value in estimating subsequent performance.4. Intra-litter correlations of growth rate for litter classes eight and nine were found to be 0·3 and 0·5. These values are higher than those found by others, probably as a result of the inclusion of the pre-weaning period in the calculation of the growth rates. There would appear to be grounds for believing that at least a fifth of the individual variance may be accounted for by additive gene effects.