bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of soil compaction on yield and fertilizer requirement of sugar beet
Authors: Draycott A. P. , Hull R. , Messem A. B. , Webb D. J. 
Published: March 2009

SUMMARYFive experiments (1967–9) on soils formed from calcareous drift examined the effects of soil compaction on seedling emergence and yield of sugar beet, also the interaction between compaction and response to nitrogen fertilizer (N) and phosphate fertilizer (P2O5). Some seedbeds were compacted in winter, others in spring and others prepared with the minimum of compaction; each was tested with 0·6, 1·2 and 1·8 cwt/acre N plus 0·8 cwt/acre additional P2O5. All plots were given a basal dressing of 0–8 cwt/acre P2O6and enough of other major nutrients.Compaction decreased seedling populations in four experiments but increased it in one year, when the weather was dry while the seeds were germinating. However, in every experiment compaction significantly decreased yield of roots and sugar. It also interacted with the fertilizer treatments, significantly on average, increasing nitrogen requirement and decreasing phosphate requirement. On average, 0·6 cwt/acre N and 1·6 cwt/acre P2O5gave the greatest yield without compaction and 1·2 cwt/acre N and 0·8 cwt/acre P2O6with compaction.
Embryo mortality in Scottish Blackface ewes as influenced by body condition at mating and by post-mating nutrition
Authors: Gunn R. G. , Doney J. M. , Russel A. J. F. 
Published: March 2009

SUMMARYOne hundred and forty-nine Scottish Blackface ewes (aged 5 and 6 years), from two different farm sources, were group-fed over 6 weeks in such a manner that at 3 weeks before mating there were approximately equal numbers from each source in two widely different levels of subjectively assessed body condition (scores 1·5 and 3 on a scale ranging from 0 = emaciated to 5 = very fat). The majority of ewes were maintained in these levels of condition until mating after which they were allocated alternately to high and low planes of post-mating nutrition for 26±2 days.Half the ewes in each group were killed on day 26±2, or earlier return-to-service, for ovulation and viable embryo counts. Surviving ewes were fed at or above maintenance until parturition and the number of lambs recorded.Condition at mating had a significant, positive effect on both ovulation and lambing rates and had an apparent negative effect on embryo mortality up to day 26±2, although this was influenced by differences in the distributions of single and multiple shed ova. Post-mating nutrition had no effect on embryo mortality up to day 26±2. Neither condition at mating nor post-mating nutrition had any effect on embryo mortality from day 26±2 to parturition.Source of ewe had a significant effect on both ovulation rate and embryo mortality at both levels of body, condition.
Competition and yield compensation in relation to breeding sugar beet
Authors: Curtis Godfrey J. , Hornsey Kenneth G. 
Published: March 2009

SUMMARYSamples were prepared to simulate the populations which would be obtained from the random interpollination of known numbers of inbred lines. This was done by mixing together seed of a vigorous and a less vigorous genotype in calculated proportions. The less vigorous represented the inbred component which would result from selling and sibbing within the constituent lines, while the more vigorous represented the hybrid fraction. The difference in yield between the two genotypes was comparable with the level of enhancement which could be expected in the hybrids as a result of heterosis. Root yields of these populations in the field suggest that depression due to the presence of inbred individuals in a synthetic variety may be predicted by a mathematical model. Yields calculated from the model to allow for various levels of compensation enabled the order of magnitude of the compensation to be estimated. However, the presence of quite small numbers of less vigorous individuals was detectable. Given the limitations imposed by the assumptions necessary to simulate these varieties, the optimal number of lines for an open-pollinated variety may be predicted.
Effects of pregnancy and lactation in sheep on the metabolism of propionate by the ruminal mucosa and on some enzymic activities in the ruminal mucosa
Authors: Weekes T. E. C. 
Published: March 2009

SUMMARYRuminal papillae were removed at slaughter from pregnant, lactating and nonbreeding control ewes. The amounts of lactate and pyruvate formed per unit dry weight of papillae during incubationin vitrowith added propionate were not significantly affected by breeding state.When results were expressed relative to the total weight of mueosa in the rumen, the amounts of lactate and pyruvate formed were significantly greater for ewes slaughtered during the final two thirds of a 10-week period of lactation in comparison with unmated ewes slaughtered at the same time.The calculated extent of conversion of propionate absorbed from the rumen into lactate and pyruvate was small, averaging 3·0%.When results were expressed per unit weight of mucosa, breeding state did not significantly affect the activity of four of the enzymes involved in the conversion of propionate into lactate and pyruvate, namely propionyl-CoA synthetase, propionyl-CoA carboxylase, NADP-malic dehydrogenase and lactic dehydrogenase, or of aspartate aminotransferase.When results were expressed relative to the total weight of ruminal mucosa, the activities of all these enzymes and also of alanine aminotransferase were significantly greater during lactation than in control sheep slaughtered at the same time. The activities in ewes slaughtered during the last 50 days of pregnancy, however, were not significantly different from the control values.Glutamic dehydrogenase activity per unit weight of tissue was higher after the lambs had been weaned than during lactation. Alanine aminotransferase activity per unit weight of mucosa decreased during the last 50 days of pregnancy.
An assessment of chromic oxide as an indigestible marker for digestion studies in sheep
Authors: Faichney G. J. 
Published: March 2009

SUMMARYFistulated cross-bred sheep were given, by means of continuous feeders, concentrate diets containing chromic oxide (Cr2O3). Dry-matter digestibility coefficients predicted from the faecal concentration of Cr2O3 were compared with those obtained by total collection of faeces, and the concentration of Cr2O3 in spot samples of faeces taken at different times of day was compared with that in faeces bulked over an 8-day collection period. The rate of flow of digesta from the abomasum and the partition of digestion between the stomach and intestines, calculated from the concentration of Cr2O3 in samples of abomasal digesta, were compared with values obtained using two markers, one of which remained in solution while the other was adsorbed by particulate matter.Récovery of Cr2O3 in the faeces ranged from 91 to 101% and predicted dry-matter digestibilities were similar to those obtained by total collection. There was no diurnal variation but there was marked random variation in the concentration of Cr2O3 in spot samples of faeces. Cr2O3 was shown to behave independently of the particulate matter in digesta and, as a single marker, it significantly underestimated the flow of digesta from the abomasum relative to the double marker method. Cr2O3 thus overestimated digestion in the stomach and underestimated digestion in the intestines. It was concluded that Cr2O3 was not a satisfactory marker for studies of the flow of digesta and hence the partition of digestion within the gastro-intestinal tract when digesta samples are taken from a simple cannula.
The nutrition of the early weaned lamb:II. The effect of dietary protein concentration, feeding level and sex on body composition at two live weights
Authors: Andrews R. P. , Ørskov E. R. 
Published: March 2009

SUMMARY1. In an experiment with ninety-nine lambs the effects on the body composition of male and female lambs were examined when five diets containing different concentrations of crude protein (in the range 10–20%) were given at three levels of feeding and lambs were slaughtered at two live weights (27·5 and 40 kg).2. With lambs slaughtered at 27·5 kg there were significant increases in the rate of both nitrogen and fat retention with increases in levels of feeding. There were also linear increases in the rate of protein deposition and decreases in fat deposition with increases in the concentration of crude protein. This effect was particularly marked at the high level of feeding.3. With lambs slaughtered at 40 kg live weight there were also linear increases in fat and in nitrogen deposition with increasing feeding level but the effect of increasing the protein concentration on increases in nitrogen retention departed from linearity.4. While at 27·5 kg there were no significant effects of feeding level on nitrogen and ether-extract content of the bodies at slaughter, with animals slaughtered at 40 kg there was a significant linear decrease in ether-extract content with increasing feeding level and a corresponding linear increase in nitrogen content with increased level of feeding.5. Male lambs deposited more nitrogen and less fat than females. This was true of both rate of deposition and of carcass composition at 40 kg live weight.
The utilization of dietary fats by ruminants:I. The digestibility of some commercially available fats
Authors: Andrews R. J. , Lewis D. 
Published: March 2009

SUMMARYThe digestibility of some fats (beef tallow, HEF, herring oil, soyabean oil and maize oil) were studied in balance trials with sheep which had been maintained on the diets for a 35 day period of acclimatization to establish ‘steady state’ conditions. Corrected digestibility coefficients for the individual fats were calculated from a knowledge of the intake and output of lipid on a low-fat basal ration. The difference between the intake of fat and the corrected lipid output (total lipid output minus lipid output on basal ration) expressed as a percentage gave the corrected digestibility coefficients.It was found that the corrected digestibility coefficients for beef tallow was 85%; HEF, 74%; herring oil, 84%; soyabean oil, 83%; and maize oil, 70%. The values for beef tallow and HEF were comparable to similar estimates in pigs. The digestibility of the highly unsaturated soyabean and maize oil were markedly lower in comparison with non-ruminant species. Extensive hydrogenation of dietary unsaturated fatty acids was confirmed. For soyabean and maize oil the corrected output of stearic acid exceeded the dietary intake.
Woburn irrigation, 1960–8:IV. Design and interpretation
Authors: Penman H. L. 
Published: March 2009

SUMMARYResults are given for a second period of 9 years, 6 on the pattern of 1951–9, with the last 3 years used for ad hoc management experiments. The meteorological specification of a year of ‘irrigation need’ was satisfied in 4 years: there were good responses in 5 years. During the first 6 years, out of twenty-four sets of crop yields (from eight different crops), very good responses were obtained on nine, good responses on eight, and zero or very slightly negative responses on the other seven.A general theory of the inter-relationships of growth and water, and of growth and radiation, leads to an expressionk = 39ε t ha−1 cm−1,as the maximum possible response to irrigation in terms of total dry matter produced, where ɛ is the fraction of solar radiation fixed by the crop (ɛ has a range 50–100 × 10−4 for good to very good farming) when irrigation is needed. The ‘need’ is defined throughY = k(ET + De − Dm),where Y is the yield, ET is the total potential evaporation, De is a limiting deficit up to which there is no check to growth, and beyond there is no growth, and Dm is the maximum deficit experienced by the crop at the time of measuring Y. The agronomic object of the experiments is to determine De, i.e. what reserve of soil water can be used by the crop before irrigation is necessary.
Relationship between body weight and testicular size in buffalo bulls
Authors: Yassen A. M. , Mahmoud M. N. 
Published: March 2009

SUMMARYThe relationship between body weight, testes volume and circumference as computed for 42 slaughterhouse buffalo bulls (Bos bubalis). Animals ranged in body weight from 290 to 610 kg, testes volume (testes plus epididymides without scrota) from 102·5 to 296·7 ml and testes circumference (testes with scrota intact) from 21·31 cm. Relationships between body weight and testes volume, body weight and testes circumference, testes circumference and testes volume were all linear and correlations (r) were, 0·986, 0·932, 0·951 and were highly significant. Regression equations were calculated and it was clearly shown that buffalo bull testes volume is a function of body weight and could be easily predicted either from body weight or from testes circumference.Comparisons between the testicular size of the buffalo bull (B. bubalis) and domestic bull (B. taurus) based on calculations from prediction equations showed that the testes size of the buffalo bull was half that of a domestic bull of similar body weight.
Milk-fed calves: 1. The effect of milk intake upon the herbage intake and performance of grazing calves
Authors: Baker R. D. , Le Du Y. L. P. , Barker J. M. 
Published: March 2009

SUMMARYTwo trials were conducted, using 18 and 30 castrated male calves respectively, to investigate the importance of milk in the diet of calves during the first 8 months of life and its effect on herbage intake and live-weight change. Reconstituted milk substitute was fed in a manner that simulated the supply of milk for lactation, yields of 2101, 1635 and 1165 kg (Expt 1) and 1906, 1609, 1304, 1005 and 701 kg (Expt 2) over a 240-day period. Calves were purchased in mid-February, when approximately 1 week old, and housed individually until turned out to graze at 10 weeks of age. At pasture, the calves were strip grazed on swards of Lolium perenne cv. S. 23 or S. 24 and given a daily herbage allowance of 60 g D.m./kg live weight.The live-weight gain response to milk consumption was 81 g/kg milk fed during the housed period and 50 g during the grazing season. Herbage and milk intake per unit live weight were inversely related but because the grazing season responses were confounded with the treatments during the housed periods, it was not possible to determine true replacement rates. Herbage intake per head increased with time but there was no general trend when intake was expressed per unit live weight.
Nitrogen response and stocking rate of Pennisetum clandestinum pastures: II. Cattle growth
Authors: Mears P. T. , Humphreys L. R. 
Published: March 2009

SummaryIndividual live-weight gain (LWG) of Angus weaner cattle continuously grazing (Pennisetum clandestinum) pasture was negatively and linearly related to stocking rate (SR) and independent of ammonium nitrate (N) application rate at similar grazing pressures.Live-weight gain varied from 380 to 1056 kg/ha according to N rate in 1970–1 and from 637 to 1477 kg/ha in 1971–2. Calculated SR giving maximum LWG/ha was 3·4, 4·7, 7·6 and 9·8 animals/ha for the 0, 134, 336 and 672kg N/ha treatments respectively in 1970–1 and 6·1, 5·7, 9·1 and 10·6 animals/ha for the same treatments in 1971–2. Highest response to applied N (1·9 and 3·4 kg LWG/kg additional N in successive years) occurred between N131 and N336; response was greater at low and intermediate SR than at high SR. Carcass weight, quality score, depth of subcutaneous fat and area of eye muscle were negatively related to SR; SR's giving maximum output per unit area caused a reduction of ca.25% in production per head and adversely affected carcass quality at 18 months of age.LWG/head was independent of feed availability in spring and summer and was positively related to availability of green kikuyu up to 600 kg D.M./head in the autumn/winter period.
The effect of plant density, date of apical bud removal and leaf removal on the growth and yield of single-harvest Brussels sprouts (Brassica oleracea var. gemmiferaD.C.): I. Whole plant and axillary bud growth
Authors: Fisher N. M. , Milbourn G. M. 
Published: March 2009

SummaryThree field experiments are described in which the effect of plant density and date of stopping (removal of the apical bud) on the development of yield in several Brussels sprout cultivars was studied. In a fourth experiment, the effect of a leaf removal treatment was designed to assess the possible remobilization of dry matter to the buds from senescing leaves.A total plant dry weight of 1·2 kg/m2was achieved with a hybrid cultivar at commercial densities. Although the crop growth rate was low in midsummer, growth continued until mid-October. Bud dry weight yield was curvilinearly related to plant density with 2 plants/m2giving the highest yields of 0·35 kg/m2in stopped crops in November. Rapid bud growth did not begin until September but the increase in bud dry weight continued into December and January. Early stopping increased bud dry weight yield and the ratio of bud weight to total shoot weight. In November, bud dry weight accounted for 25–40% of the total shoot dry weight for most treatments.In the leaf removal experiment, estimated net photosynthetic rate of the crop was greater than the bud growth rate up to the end of the experiment and there was no significant effect of removing leaves just prior to natural senescence on bud dry weight.The production and partition of dry matter is discussed in comparison with other vegetative crops. It is found that the proportion of total dry weight partitioned to the useful parts in Brussels sprouts is comparatively low. Factors controlling the date at which rapid bud growth begins are discussed. It is concluded that the dry matter in the axillary buds is derived from photosynthesis occurring at the time of bud growth and that the remobilization of dry matter from other plant parts is not of great importance.
Liming effects on the response of potatoes and oats to phosphorus, potassium and magnesium fertilizers
Authors: Bolton J. 
Published: March 2009

SummaryIn two long-term liming experiments on a sandy-clay loam at Rothamsted and a loamy sand at Woburn the responses of potatoes in 1974 and oats in 1975 to cumulative dressings of superphosphate and potassium chloride applied since 1962 and magnesium sulphate applied in 1974 were measured at four pH levels within the range pH 4–pH 7.Yields of both crops were similar over the whole pH range when standard rates of NPKMg fertilizers were given. Without added P and Mg, yields of potatoes were much smaller on the more acid soils, but without K, yields were larger. A similar pattern of yield responses to P and Mg fertilizers occurred with oats but there were no differences between the small responses to K additions over the whole pH range.Analyses of potato leaves sampled at the 10% flowering stage showed differences related to the yield effects for K and Mg but not for P. Yield responses were associated with concentrations less than 4% K and 0·18% Mg in the dry matter of topmost fully mature leaves.The differences in yield response caused by liming were not associated with differences in ‘available’ nutrients in the soils (determined using standard methods).
Rumen fermentation and food selection in East African sheep, goats, Thomson's gazelle, Grant's gazelle and impala
Authors: Hoppe P. P. , Qvortrup S. A. , Woodford M. H. 
Published: March 2009

SummaryThe relationship between the selected food and rumen fermentation was investigated in Thomson's gazelle, Grant's gazelle, impala and Maasai haired sheep and goats. All animals were shot in the same grass-bushland area within 1 week during the dry season.According to rumen contents, sheep were almost exclusively grazers. In goats, Thomson's gazelle and impala, grass accounted for about 70% of all plant parts identified. In Grant's gazelle, browse includingAcaciaseed constituted 68% of rumen ingesta. The two gazelle species showed a very marked preference for green grass leaves.In sheep and goat rumens, concentrations of NH3-N and volatile fatty acids, andin vitrofermentation rates (262 and 272 μmoles gasNTPD/g D.M./h, respectively) were lowest. In the wild ruminants, concentrations of fermentation end-products were higher and the rate of fermentation significantly (P< 0·05) faster, namely 420 in Thomson's gazelle, 356 in Grant's gazelle and 376 in impala. Rumen pH was not significantly different between species, with mean values ranging between 6·3 and 6·0. Total VFA concentrations ranged between 124 and 178 m-equiv/1 in the rumen and around 25 m-equiv/1 in the abomasum. Acetic acid accounted for about 75% of the total VFAs.It is concluded that there are large differences in the pattern of rumen fermentation between wild and domestic mixed-feeding ruminants which reflect their respective food preferences.
Effects of fertilizer N and number of years in tillage on the protein and non-protein content of feeding barley grain (cv. Nessa) and on N uptake and recovery
Authors: Gately T. F. , McAleese D. M. 
Published: March 2009

SUMMARYThe effects of six amounts (0, 17, 34, 51, 68, 85 kg N/ha) of fertilizer N, applied at sowing time, on the crude protein (N × 6·25) content of barley grain sown as the first, second and fourth or later tillage crop after grazed pasture were studied over three seasons at a total of 126 sites. In addition, non-protein N in the grain was measured at 24 sites.The overall crude protein content was 11·3% without N, increasing to 13·4% with 85 kg N/ha. The first increment of 17 kg N/ha gave the least increase in grain protein content. The year which gave the largest yields gave the lowest grain protein contents and vice versa. The mean grain protein contents without N for 1971–3 inclusive were 10·8, 11·5 and 11·8% respectively.The mean grain protein contents without N when barley was sown as the first, second and fourth or later tillage crop after pasture were 12·6, 11·5 and 10·0% respectively; the corresponding values with 85 kg N/ha were 14·4, 13·9 and 11·8%. There was a positive relationship between grain protein content and lodging, especially in barley sown as the first tillage crop after pasture, where lodging was most severe.Non-protein N was low and only accounted for 5–8% of the total grain N content. The mean grain. N uptake with no fertilizer N applied was 82, 70 and 49 kg/ha in barley sown as the first, second and fourth or later tillage crop respectively. The apparent recovery of fertilizer N was largest in fourth or later barley.
The influence of the level of feeding on fermentation in the rumen of sheep receiving a diet of ground barley, ground hay and flaked maize
Authors: Hodgson J. C. , Thomas P. C. , Wilson Agnes G. 
Published: March 2009

SummaryFive rumen-cannulated sheep were given a diet of ground barley, ground hay and flaked maize in quantities which were increased progressively throughout the period of study. The rumen concentration of total short-chain fatty acids increased (P < 0·05) and the pH decreased (P< 0·05) as the level of feeding was raised and pH was correlated with the fatty acid concentration. There were no systematic effects of the level of feeding on the volume, outflow rate or clearance rate of the rumen liquid phase or on the ruminal concentration of ammonia. The molar percentage of acetic acid in the rumen fluid tended to decrease as the level of feeding was raised and there were compensatory increases in the percentage of propionic acid. However, there were wide variations in the composition of the mixture of rumen acids between sheep at each level of feeding and changes in fermentation pattern with level of feeding were not consistent between animals.A broad inverse relationship was observed between the molar percentage of propionic acid and the clearance rate of the rumen liquid phase which supports the suggestion that there is an important association between the pattern of fermentation in the rumen and the liquid clearance rate.