bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaporative cooling in fowls
Authors: Hutchinson J. C. D. 
Published: March 2009

Part I1. Reasons are given for expressing the evaporative loss of the resting fowl in the following way:where C is a constant, f(tr) is a function of rectal temperature, ps is the vapour pressure of a saturated atmosphere at the temperature of the evaporative surfaces, and pa is the vapour pressure of the ambient air.2. It was found that for practical physiological purposes the rectal temperature may be taken as that of evaporation, from which ps, is deduced. The real temperature of evaporation is probably a few degrees below this, as would be expected.3. It is concluded from this, that atmospheric humidity hinders the evaporative cooling of fowls less than that of men. Therefore, a farmer cannot estimate the comfort of his fowls in hot weather from his own subjective impressions. The experiments also explain theoretically, why evaporative coolers for poultry houses are successful in practice.PART II1. The evaporative loss over a wide range of rectal temperature is plotted in Fig. 1. By applying formula (ii) it was possible to prepare curves for 28 and 5 mm. Hg atmospheric vapour pressure. These vapour pressures are near the extremes of absolute humidity, which fowls naturally encounter in hot climates. Brown Leghorns were used, and it is pointed out that the results with other breeds might not be quite the same.2. It was calculated that part of the increase in evaporative cooling in hyperthermia is due to the rise in temperature of evaporation. At high rectal temperatures its importance is comparable with that of increased pulmonary ventilation.3. There was no significant sex difference in the relation between evaporative loss and rectal temperature (Fig. 2).4. The maximum possible evaporative cooling of fowls in equilibrium with their environment was 41 Kg.cal./sq.m./hr. at a humidity of 28 mm. Hg atmospheric vapour pressure and 64 Kg.cal./sq.m./hr. at 5 mm. This is much less than the maximum attained by man and somewhat less than that of the dog. Although evaporation per unit surface area was less than in the cow, it was much the same in relation to metabolic requirements.5. Next, certain discrepancies are considered in the relation between rectal temperature and evaporative loss (Tables 3–5). At rectal temperatures near the panting threshold evaporation was found to be greater at high air temperatures and during the night. For the night tests fragmentary data only were available. These findings are tentatively attributed to a lower normal body temperature, which lowered the panting threshold.
Growth analysis of the domestic fowl: III. Effect of plane of nutrition on carcass composition of cockerels and egg yields of pullets
Authors: Wilson P. N. 
Published: March 2009

1. 101 Rhode Island Red × Light Sussex chickens have been made to conform to four major changes in the shape of their growth curves from hatching to twenty-four weeks, by control of their plane of nutrition. The four treatments (HH), (LH), (HL) and (LL), allowed comparisons to be made between birds of the same age, but different weights. As the main concern has been to find the essential nature rather than the precise extent of the effects produced by different planes of nutrition, the treatment differences were made as extreme as possible without allowing the rations to become unbalanced.2. Certain individual organs and tissues, the gonads, thyroid and thymus, and the combs and wattles have reacted differentially to the contrasted treatments when compared on a basis of equal body weight. All the organs, with the exception of the very early maturing eyes and heart, have reached significantly different weights on the basis of equal age. Those organs which have yielded treatment differences judged on both the basis of equal weight or equal age have all been late maturing. The results therefore indicate that the effect of treatment has been to restrict the development of the later maturing parts in the case of the low-plane birds, and to accelerate the development of these organs when the birds are reared on the high plane. The results are insensitive to any differential effects which may have been brought about in the early maturing organs, since the design of the experiment did not allow of the slaughtering of birds at equal weight but only at equal age. The means of Comparison of differences at equal weights was the less precise method of ascertaining whether the high- and low-plane regression lines of weight of part to total weight of bird differed significantly the one from the other.
The presence of root-inhibiting substances in cow urine and the cause of urine burn
Authors: Doak B. W. 
Published: March 2009

1. A study has been made of the cause of urine burn in pasture.2. It has been shown that urine burn could occur under dry soil conditions due to the osmotic pressure effects of the urine.3. All seeds present in the urine-affected soil are killed.4. An inhibitor of root growth, to which clover roots are especially sensitive, is present in the urine of cows and sheep.5. This inhibitor, which is not heteroauxin, is acid in character and is destroyed in soil in a few days.6. It is suggested that the inhibitor is an inhibitor-auxin complex, of which the auxin portion might be heteroauxin. The possibility that the inhibitor is an auxin precursor is discussed.7. It is contended that the reduction of clover growth relative to grass growth in a urine patch is not simply the result of shading due to increased grass growth.8. The root inhibitor, the temporarily high pH, the presence of free ammonia, and the high concentration of ammonium ions may be important factors in the reduction of clover growth.
Chewing behaviour of hay-fed cows given supplements of whole barley and oat grains
Authors: Morgan C. A. , Campling R. C. 
Published: March 2009

SUMMARYFour hay-fed cows were used to study the effects on chewing behaviour of daily supplements of 3 kg whole barley grains, 3 kg whole oat grains or 2·2 kg rolled oats. Both whole grains increased the total time spent chewing by a similar small extent, probably due to a direct physical effect of the grain. The quantity of whole oat grains voided in faeces was lower than that of barley and it is concluded that the quality of chewing is more important than duration in breaking grains and ensuring their subsequent digestion.
The effect of NaCl or NaHCO3 on digestion in the stomach of weaned calves
Authors: Kellaway R. C. , Beever D. E. , Thomson D. J. , Austin A. R. , Cammell S. B. , Elderfield Marian L. 
Published: March 2009

SUMMARYThe response to dietary inclusion of NaCl or NaHC03 at 42 and 60 g/kg (18 g Na/kg) respectively was examined in relation to rumen fermentation and the flow of nutrients to the duodenum of calves.Measurements were made with four calves on each diet at 8 and 11 weeks of age: weaning having taken place at 5 weeks of age.Osmotic pressure, pH, total VFA concentration and molar proportions of VFA were not significantly affected by the treatments imposed. Rumen dilution rate was increased by 28% on the NaHCO3 diet compared with the other two diets but this difference failed to achieve statistical significance. Mean duodenal flows of organic matter, modified acid detergent fibre and total amino acids were 0·52, 0·72 and 1·25 of the respective dietary intakes and were not significantly affected by the treatments imposed. NaHCO3, however, significantly increased the supply of α-linked glucose polymer to the small intestine (15% of dietary intake) compared with the control (4%) and NaCl (6%) diets. The results demonstrated that NaCl and NaHCO3 had small effects upon the digestion within the rumen of young calves with specific reference to flow of nutrients to the proximal duodenum. It is suggested that the stimulatory effect of NaHC03 on food intake and performance of calves may be attributable to an increase in rumen buffering capacity, and some indication of an increase in the fractional outflow rate of water and possibly particulate matter from the rumen.
Effects of the amounts of phosphate fertilizer, and of the proportions of water-soluble phosphate in the fertilizers tested on the phosphorus nutrition of sorghum
Authors: Govil B. P. , Prasad R. 
Published: March 2009

SUMMARYA field experiment was made with sorghum hybrid CSH-1 during the rainy seasons of 1968 and 1969 on a sandy loam soil to study the influence of amounts and sources of phosphate fertilizer on phosphorus nutrition. Concentration of P in the crop and uptake increased with increasing amounts of phosphate and with increasing proportions of water-soluble P in triple superphosphate-dicalcium phosphate and triple superphosphate-rock phosphate mixtures. Relative effectiveness values were calculated from P uptake at harvest by a multiple regression method. For triple superphosphate, nitrophosphate (30% water soluble P), dicalcium phosphate and rock phosphate (from Jordan) the values were respectively, 100, 74, 61 and 22.
Deposition of sulphur from the atmosphere and the sulphur balance in four soils under grass
Authors: Bristow A. W. , Garwood E. A. 
Published: March 2009

SUMMARYThe sulphur balance in eight lysimeters containing four different soils under grass was examined over a 4-year period during which the annual mean concentration of sulphur dioxide (SO2) in the air at the site decreased from 30 to 14 μg/m3. The amounts of sulphur harvested in the grass and lost in drainage were set against additions in fertilizer, rainfall and from dry deposition. A decline in annual dry-matter yield was accompanied by a decrease in the concentration of sulphur in the herbage and an increase in the ratio of nitrogen to sulphur. It was concluded that atmospheric sources and soil reserves may become insufficient to meet the sulphur requirement of grassland.
Studies on the effect of humidity on the hatchability of hen's eggs I. The determination of optimum humidity for incubation
Authors: Robertson I. S. 
Published: March 2009

An attempt to find the effect of humidity on hatchability and at the same time indicate the optimum humidity for incubation was carried out by subjecting eggs in one incubator to various levels of humidity and comparing the results with eggs hatched as a Control in a second incubator of identical design.Hatchability was depressed by excessively high levels of humidity but in general satisfactory hatches can be obtained between 40 and 70% R.H.The pattern of mortality, the incidence of Malposition I but not Malpositions II, III and VI were affected by humidity level.The optimum level found, c. 50% R.H., was lower than the previously accepted optimum and may be accounted for by a number of factors including egg size.
A comparison of wheat and fine wheat offal in the rations of fattening pigs
Authors: Braude R. , Townsend M. Jill , Harrington G. , Rowell J. G. 
Published: March 2009

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.
Genotypic and environmental effects on curd weight of autumn-maturing cauliflowers
Authors: Crisp P. , Kesavan V. 
Published: March 2009

SUMMARYTwelve genotypes of cauliflower were grown in two seasons from six seedling propagation treatments in three sequential sowings. There was a high genotypic component of variation for curd weight, indicating that this character can be improved by breeding. A large genotype × environment interaction included genotypic differences in stability to the environment, notably in the self-compatible genotypes. Mean curd weight and stability of genotypes to the environment for this trait were uncorrelated, indicating that high weight and high stability could be bred into a single variety.
Tiller development and yield of standard and semidwarf spring wheat varieties as affected by nitrogen fertilizer
Authors: Power J. F. , Alessi J. 
Published: March 2009

SUMMARYThis research was conducted to determine the effects of applying N-fertilizer to standard and semidwarf spring wheat varieties on the components of grain yield, and especially on the ability of tillers to develop and produce ears under semiarid conditions. For two growing seasons at Mandan, North Dakota, tillers were identified and tagged according to the leaf axil from which they originated. The survival and development of these tillers, identified as M, T1, T2, and T3 for main stem and tillers from axils of first, second and third true leaves respectively, were observed and measured from emergence to maturity. N-fertilizer was applied at 0, 50 and 270 kg N/ha annually, representing deficient, adequate and excessive N supply.N-fertilizer application increased grain yield of both varieties, with the increase between 50 and 270 kg N/ha being significant for the standard variety only. Most of this response to N resulted from an increase in the number of ears/ha, arising from reduced mortality of tillers, particularly T2 and T3 tillers during the latter part of the season when water was limited. For a given variety, grain production by M and by T1 tillers was seldom affected by N treatment. Although data were analysed by several means, all results indicate that improved N nutrition enables the later-developing tillers to survive and produce ears more competitively. Final grain yield was closely correlated with N content of a given tiller at the tillering stage, and to dry weight of individual tillers at both tillering and heading. Order of tiller had no appreciable effect on N content of grain. The proportion of final grain yield originating from M decreased from about 60% without N to about 36% for 270 kg N/ha, primarily because of increased survival and production from T2 and T3 tillers following the application of N-fertilizer.
An assessment of dairy bull station progeny tests carried out at two centres in Britain
Authors: Pearson Lucia 
Published: March 2009

1. Station progeny tests of twenty-four Ayrshire and twenty-two Friesian bulls were carried out by the British Oil and Cake Mills Ltd. at two centres in Britain between 1953 and 1961. The tests followed the Danish pattern: groups of ten to seventeen daughters were brought to the station approximately 6 weeks before first calving and milked under standardized conditions for an average of 270 days.2. The place of the station system in modern dairy practice in Britain and abroad was discussed.3. Earlier results had suggested that milk yield, butterfat percentage, S.N.F. percentage, milking rate and conception interval should be taken into account in a progeny test.4. Correlations were calculated between the bulls 305-day field ratings for milk yield and fat percentage and their 90- and 270-day station assessments. Possible reasons for the discrepancies were investigated.5. The selection system employed did not appear to lead normally to the choice of heifers whose dams' milk yield or fat percentage differed from the recorded averages for the breed. In two groups of special cases, deviations were apparent but the effect on the accuracy of the station test was shown to be small. It was concluded that bias due to maternal genetic variation was unlikely to be serious in the general case.
Studies on the nitrogenous manuring of winter wheat
Authors: Beveridge J. L. , Jarvis R. H. , Ridgman W. J. 
Published: March 2009

1. The problem of when to apply nitrogenous top-dressings to winter wheat has nover been satisfactorily solved. Detailed field and glasshouse experiments on the effects of nitrogenous manuring on the development of wheat plants, and a number of other experiments involving the nitrogenous manuring of wheat are described and the results discussed.2. Partial regression coefficients of grain yield on individual components of yield are used to show how variable is the relationship between grain yield and the components of yield.3. It is concluded that field experiments are never likely to determine an optimum time for nitrogen top-dressing because of the unpredictable relationships between individual yield components and grain yield, and because of the variation in response to nitrogen introduced by seasonal and environmental factors.
The nutritional value of some tropical grasses
Authors: Grieve C. M. , Osbourn D. F. 
Published: March 2009

1. Twenty feeding and digestibility trials were carried out on seven tropical grasses to determine their nutritional value at different stages of growth, and to study their suitability as possible pasture grasses.2. Content of crude protein was relatively high at immature growth stages of the forages, and declined rapidly with the onset of flowering.3. Digestibility of dry matter and gross energy increased in most of the forages tested to the 5-week stage of regrowth but declined rapidly in mature stages of forages tested at 6 or 8 weeks of regrowth. Digestibility of crude protein declined with increasing maturity of the forages.4. The Nutritive Value Index of each forage was highest at four or five weeks of regrowth. The optimum time to graze the forages tested would occur between 4 and 5 weeks of regrowth, at the stage when flowering commences. This would combine high yield of forage with high nutritional value.
The utilization of Hyparrhenia veld for the nutrition of cattle in the dry season II. Veld hay compared with in situ grazing of the mature forage, and the effects of feeding supplementary nitrogen
Authors: Smith C. A. 
Published: March 2009

Three methods of utilizing the natural Hyparrhenia grasslands for the dry-season nutrition of ranch cattle were tested in grazing trials. The feed regimes were:(A) Late-cut veld hay plus aftermath grazing.(B) The accumulated, seasonal growth of mature grass left as ‘standing hay’ for dry-season grazing.(C) A combination of both practices in which half the area was cut for hay, and half left as ‘standing hay’. These treatments were compared with and without the feeding of supplementary protein.Mature Hyparrhenia veld whether cut for hay or left as ‘standing hay’ was a stemmy, low-quality forage deficient in protein. The qualitative deficiency was such that all unsupplemented treatments were equally ineffective in preventing large cattle weight losses in the dry season.The only significant treatment effect was that due to feeding a protein supplement. Otherwise, there were no differences between the three managements, i.e. there was no marked benefit from conserving forage as veld hay compared with in situ grazing of the standing grass.The voluntary intake of veld hay was low; and with heifers, declined to negligible amounts. The feeding of supplementary nitrogen, either as protein or urea, increased the daily hay intake by 140%. As a result, a diet deficient in energy was altered into a productive ration, with consequent cattle weight gains.Although the cattle preferentially sought-after, and grazed the aftermath from late-cut veld hay; its practical nutritional value was slight, and was not reflected in cattle weight gains.
Factors affecting the water and food intakes of European and zebu-type cattle
Authors: Horrocks D. , Phillips G. D. 
Published: March 2009

1. The water and food intakes of sixteen grade Shorthorn and Boran zebu steers have been studied.2. A difference has been shown in the water requirements of Shorthorn and Boran cattle.3. Modest supplementation with salt, of animals on an otherwise sodium deficient diet, had no significant effect on either water or food consumption.4. Differences in environmental temperatures are suggested to explain the higher intake of water in one of the experimental periods. The increased water intake for the Borans was less than half that for the Shorthorns, only the increase for the latter being significant.
Grass as a food for the calf I. The value of cut grass in the diet of the unweaned calf in comparison with hay and concentrates
Authors: Chambers D. T. 
Published: March 2009

1. The relative nutritive value to the unweaned calf of concentrates-with-hay and of grass cut from pasture in spring was measured.2. No significant difference was found in liveweight gain or increase in body measurement between calves receiving these feedingstuffs.3. There was some indication that rumen development, as measured by belly girth, may have been affected by the diet.4. There was no interaction between the type of dry food consumed and the milk ration or housing conditions.5. Results indicate that good quality grass, free from parasitic infestation, is capable of replacing hay and concentrates in the diet of the unweaned calf.
Grass as a food for the calf II. The effects of feeding grass or concentrates-with-hay during the pre-weaning period on the intake and utilization of grass during the post-weaning period
Authors: Chambers D. T. 
Published: March 2009

1. Calves which had been reared for 12 weeks on three milk feeds and either cut grass or concentrates-with-hay, were introduced to an all-grass diet when weaned.2. Eight animals were kept indoors and fed herbage cut from paddocks grazed by nineteen similar calves.3. After an initial period of about 2 weeks there was a tendency for grass-reared calves to make slightly better live-weight gains.4. No difference could be shown in the intake of herbage dry matter by these groups of calves.5. There was little indication that grass-reared animals digested their food more efficiently. It appeared that they converted grass to animal tissue better, but further study is required to substantiate this.
A method of estimating the underlying input–output relations for beef cattle from large-scale experimental trials
Authors: Newbery D. M. G. 
Published: March 2009

SUMMARYThe Agricultural Research Council's system of feed evaluation provides a method of predicting the most profitable ration composition, given information about available feedingstuffs and the values of the parameters in the beef-feed production functions. Because these functions are non-linear, parametric estimation based on average data for a group of animals will give biased results. A method of determining unbiased estimators of the parameters is derived and the magnitude of the bias is shown to be small. Some simplifications of the ARC formulae are proposed.