bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experiments on the nutrition of the dairy heifer IV. Protein requirements of 2-year-old heifers
Authors: Broster W. H. , Tuck Valerie J. , Balch C. C. 
Published: March 2009

1. In the winters of 1959–61 three randomized block experiments were carried out to study protein requirements of heifers of 800–1000 lb. live weight. 24 animals were used in each experiment. Half the animals were kept indoors; the remainder stayed out of doors except for 1 hr. per day when they came into covered yards to receive their concenrates ration.2. Rations were based on straw, cereals and roots. The intake of crude protein was varied by replacing cereals by decorticated ground nut meal. The estimated level of energy intake varied from 7·2–8·2 lb. starch equivalent/day between experiments, but the level was constant for all treatments within an experiment.3. At the end of each feeding trial the nitrogen balance was measured for 2 animals from each treatment. The results confirmed the estimated levels of digestible crude protein intakes upon which the experiments were based.4. An increase in intake of digestible crude protein (as determined in the metabolism trials) from 0·35 lb./day to 0·72 lb./day gave a marked response of 0·45 lb./day in the rate of live-weight gain. Further increases in protein intake gave little response in live-weight gain. It was concluded that for heifers of 800–900 lb. live weight the protein requirement for maintenance and a live-weight gain of 1·2 lb./day was 0·70 lb. digestible crude protein/day.5. Comparison of the estimated starch equivalent intakes in the three experiments showed that in heifers receiving 0·52 lb. digestible crude protein per day the rate of gain increased from 0·25 to 0·90 lb./day as the level of energy intake increased from 0·78 lb. starch equivalent/100 lb. live weight per day to 1·01 lb./100 lb. live weight.6. Biological value of the dietary nitrogen decreased as level of protein intake increased. The values for individual animals ranged from 61·3 to 82·4. The mean value was 69·5.7. The weather during these experiments was typical of winters in south-east England with mean minimum ground temperatures about 30° F. and mean maximum and minimum air temperatures of about 50° F. and 35° F., respectively. Snow fell occasionally only; 3½–5½ in. of rain fell in the period 1 January to 31 March. In 2 years out of 3 the outdoor group grew slightly faster than the indoor groups. In the third year this trend was reversed.
Effect of plant density and detopping following silking on cob growth, fodder and grain yield of maize (Zea mays)
Authors: Roy S. K. , Biswas P. K. 
Published: March 2009

SUMMARYMaize was grown al the Regional Agricultural Research Station, Hathazari, Bangladesh during 1988/89 and 1989/90 to study fodder yield, cob growth and grain yield together with the contribution of pre-silking stem reserves to grain. Population densities were 33300, 44400 and 66600 plants/ha. Plants were either detopped after silking and pollen shedding, keeping 0, 2 or 3 leaves above the cob, or were left entire.The results showed that the maize crop could successfully be detopped for fodder with little or no adverse effect on grain yield. Fodder yield increased with increased plant density and among the detopping treatments the highest fodder yield was obtained when the plants were detopped just above the cob. Cob growth followed a sigmoid pattern and the highest dry weight per cob was obtained from the lowest plant density and from entire plants. The number of cobs/m2 increased with increased plant density but detopping treatments did not give any significant difference in relation to densities. The number of grains/cob was highest with 33300 plants/ha but, among the detopping treatments, plants detopped just above the cob had the lowest number of grains/cob in both years. Weight of 1000-grain decreased with increasing plant density but it was increased by detopping plants just above the cob during 1988/89, although it was decreased in 1989/90. The highest apparent translocation of pre-silking reserves was obtained using densities of 44400 plants/ha but detopping treatments did not show any consistent effect, although the highest apparent translocation (20%) and harvest index (58%) were obtained from plants detopped just above the cob.
Urea as a nitrogen fertilizer for grass cut for silage
Authors: Lloyd A. 
Published: March 2009

SUMMARYForty-one experiments were carried out in England and Wales between 1983 and 1985 to compare ammonium nitrate and urea as N top dressings for multicut silage.The results showed that relative dry matter yields from the two fertilizers differed considerably between sites. However, compared with ammonium nitrate, there was a mean yield decrease with urea of 2% at the first cut and 5% at the second cut. Mean herbage N contents and apparent N recoveries were lower with urea than with ammonium nitrate at both the first and second cuts. It appeared, at least for first-cut dressings applied in early spring, that urea effectiveness increased with the amount of rain falling within 3 days of fertilizer application. The effect was much less obvious at the second cut.Urea effectiveness was not markedly reduced on soils of high pH or light texture, where higher ammonia volatilization losses might have been expected.
Influence ofAspergillus oryzaefermentation extract on rumen fermentation and blood constituents in sheep given diets of grass hay and barley
Authors: Newbold C. J. , Frumholtz P. P. , Wallace R. J. 
Published: March 2009

SUMMARYAspergillus oryzaefermentation extract (AO; 2 g/day) was added to the diet of sheep fed grass hay supplemented with 30 or 70% barley. AO decreased the proportion of propionate in rumen volatile fatty acids with both levels of supplementation (146 and 163 mmol/mol with AOv. 157 and 186 mmol/mol with no addition for the low and high barley diets respectively;P< 0·05), and also caused a small reduction in L-lactate concentration in the high barley diet (1·15 mM v. 1·43 mM in the absence of AO). Rumen pH was not changed significantly. Total viable bacteria in the rumen were stimulated with AO (2·12 and 2·46v. 0·97 and 1·80 × 109/ml respectively). Numbers of cellulolytic bacteria and ciliate protozoa were unchanged. Hay suspended in nylon bags in the rumen tended to be degraded more rapidly with AO, but the effect was not statistically significant. Neither barley nor AO significantly altered the plasma concentrations of glucose, urea, insulin, gastrin or cholecystokinin. It was concluded that the effects of AO were generally similar for both levels of barley supplementation and that changing the composition of the diet had no detectable effect on the measured indicators of nutritional status in blood.
Cation-anion relationships in crop nutrition: VI. The effect of part, age and species of plant and some soil characteristics
Authors: Cunningham R. K. 
Published: March 2009

SUMMARYThe effects of part, age and species of plant and some soil characteristics on the relationships between (a) sum of the cations (Σ cations)–% total N and (b) ratio of sum of the cations sum of the anions (R)–% organic N relationships in crops were tested in four experiments in the glasshouse. Crops were grown in soil and given four or five amounts of N03-N and sometimes a uniform dressing of other nutrients.Results confirmed that there was a positive linear relationship between S cations in plants and their % total N when N03-N was supplied and the proportions of cations and anions entering roots from the soil solution (R values) were not constant but were in some way related to the elaborated nitrogen status of the plant, suggesting they may be linked with nitrogen metabolism. The cation-anion relationships were of the same general type regardless of the part of the plant that was analysed, its age or species, or of the type of soil in which it was grown. Analysis of leaves adequately reflects relationships in whole plants. Although the relationships had the same form with all species, dicotyledons had greater Σ cations and R values than monocotyledons at equal % total N and organic N respectively. Within the group of relationship curves obtained with different soils, at equal % total and organic N, 2 cations and R values were greater in grass grown in alkaline than in acid soil. Soil properties that affect the proportions of NH4-N and N03-N presented to plant roots probably have an important influence on the relationships. These cation–anion relationships in crops were not changed when yields varied greatly.
Rotation responses of cotton in the Sudan Gezira: II. The effect of fertilizer nitrogen on the reponse to rotation
Authors: Jackson J. E. , Burhan H. O. 
Published: March 2009

SUMMARYThe interactions between nitrogen fertilizer and crop rotations in their effects on the yield of cotton in the Sudan were studied by superimposing fertilizer treatments on a rotation experiment which was already more than 30 years old. This experiment compared ten rotations comprising various combinations of cotton with fallow and an alternating crop of dura (a sorghum millet) and lubia (Dolichos lablab. L.). The results support the concept that low basic yields in the absence of a nitrogen dressing are primarily due to nitrogen deficiency. In general the response to nitrogen was greater on rotations which led to low yields of cotton so that rotational effects were greatly reduced or eliminated when a nitrogen dressing was given. Although in some cases cotton following fallow out-yielded cotton following dura, in general rotations containing dura and lubia gave higher yields of cotton than rotations with the same intensity of cotton cropping combined with fallows only. These beneficial effects of other crops instead of fallows in the rotation, although not in agreement with the long-term averages wereto be expected from the long-term trends in yields with time. Combined with the finding that even the most adverse effects of dura could be largely compensated for by a fertilizer dressing, this indicates that cropping in the Gezira could be considerably intensified without loss of cotton yield per acre per year. The difficulties of such intensification would centre around weed, disease and pest control rather than soil fertility. Further experiments are required to determine the fertilizer nitrogen requirements of cotton following different crops.
Machine thinning of sugar beet: field trials with low seed rates
Authors: Hanbury L. F. , Maughan G. L. 
Published: March 2009

SUMMARYBetween 1964 and 1966 thirty-one field trials were completed in twelve factory areas of the British Sugar Corporation to examine the feasibility of using mechanical thinning in conjvinction with low seed rates (3–6 in spacing) and chemical weed control to minimize the demand for labour in the spring. The results showed that where chemical weed control was effective in machine-thinned crops no hand labour was required for establishment, but there were mean losses in yield of 1·3 tons per acre (7%) compared with similar crops that were hand singled. These losses in yield were unaffected by variations in seed rates. Mechanical harvesters worked more efficiently in low seed rates, especially where monogerm seed was used.
Frequency of cutting and sward production
Authors: Anslow R. C. 
Published: March 2009

1. Swards of perennial ryegrass (S 24) were grown under conditions of high fertility and were cut at intervals of (a) 3 weeks, (b) 6 weeks, (c) 3 weeks changing to 6 weeks at later points in the growing season.2. The rate of herbage production (kg D.m./ha/day) was higher throughout the season (April to November) under the longer cutting interval. Plots which were changed from 3- to 6-weekly cutting intervals subsequently showed the same rate of production as those cut every 6 weeks throughout.Inflorescences emerged from a higher proportion of tillers after long growth periods; this could explain the higher rates of production up to July.
The prediction of pig carcass composition from measurements of carcass density
Authors: Holme D. W. , Coey W. E. , Robinson K. L. 
Published: March 2009

1. Two cuts, the leg and the loin, were taken from the right sides of 102 pig carcasses. Their densities were determined by weighing in air and in water and the cuts were dissected into fat, muscle, bone, skin and connective tissue. Samples of the muscular and fatty tissues were taken to obtain a measure of the analytically determined fat content. The weights of each tissue were expressed as a percentage of the weight of each cut and related to density by the methods of correlation and regression. Correlation coefficients and regression equations were calculated separately for legs, loins and the composite leg plus loin for each pig and for legs and loins rogarded as 204 separate pieces of pig carcass.2. Correlations and regressions were used to relate the composition of the loin cut to three measurements of backfat thickness taken over the eye muscle at the level of the last rib, and to eye muscle area. These allowed a comparison of density and backfat thickness as measures of the fat and lean content of the loin cuts.3. There was evidence of a high degree of association between the fat or muscle contents of the cuts and the density or the reciprocal of density. In no case was the simple correlation coefficient between muscle and density or fat and density less than 0·84. The greatest standard error of estimate of any of the regressions of porcentage fat or percentage muscle on density was 3·3% fat, for the regression of percentage separable fat on the reciprocal of the density of the loin cuts. Density was found to be a better measure of the muscle or fat content of the loin cuts than eye muscle area or any of 3 measurements of backfat thickness taken over the eye muscle.4. Dissection data from 25 whole sides supported these results showing a high correlation between density and percentage fat or percentage muscle.5. There was a low correlation,r= 0·41, between percentage bone and density of 102 leg cuts. That between density and percentage bone of 25 whole sides wasr= 0·47; suggesting that bone content has but a small influence on carcass density.6. It is suggested that carcass density is a better measure of carcass fatness or leanness than measurements of backfat thickness or eye muscle area.
The effects of age of calves at castration on growth rate, carcass composition and feed efficiency
Authors: Carroll M. A. , Pearce J. , Basset J. M. , Gillard P. B. , Lawrence T. L. J. 
Published: March 2009

An experiment is described in which four pairs of individually fed identical twin calves were used to investigate the effects of castration at 1 and 7 months, on growth, efficiency of food utilization and carcass composition and conformation.The results indicate that up to 28 weeks of age the late-castrated animals wore superior in liveweight increase, width of head and efficiency with which they converted food to live weight. By slaughter time, at about 18 months, these differences, except width of head, had been eliminated.The carcasses from both treatments were very similar except that a slightly greater percentage of the total muscle occurred in the thoracic and abdominal muscles of the late-castrated animals than in the early-castrated ones. A statistically significant higher percentage of the total fat occurred as subcutaneous fat in the late-castrated animals than in the early-castrated ones.
The use of thein vitrofermentation technique to estimate the digestible energy content of some Egyptian forages II. Thein vitroproduction of total volatile fatty acids and organic acids as criteria of energy content
Authors: El-Shazly K. , Akkada A. R. Abou , Naga M. M. A. 
Published: March 2009

1. Fourin vitrofermentation experiments, in duplicate, were carried out over 24 hr. periods, to estimate the production of v.f.a. and o.a from forages.2. A new technique for determining the total organic acids produced in the rumen is described.3. The o.a. produced in the earlier part of the fermentation are considerably higher than the v.f.a. but the difference then diminishes. There is practically no difference in the amounts produced after 24 hr.4. Highly significant correlations were found between thein vitroproduction of v.f.a. or o.a. and d.e./kg. d.m., for all the roughages tested. Nonlegumes gave a more highly significant correlation than legumes.5. Regression equations show that o.a. or v.f.a. were more accurate thanin vitrocellulose digestion for predicting the d.e./kg. d.m. of non-legume forages. It is concluded that V.F.A. productionin vitrois the best criterion in this respect.
The herbage intake and milk production of strip- and zero-grazed dairy cows
Authors: Greenhalgh J. F. D. , Runcie K. V. 
Published: March 2009

1. A group of four Ayrshire and four Friesian cows was strip grazed on a cocksfoot-dominant sward while a second, similar group was zero grazed on herbage cut from the same field. The experiment consisted of five 10-day periods, two in the spring and three in the summer.2. The intakes of all cows were calculated from values for faeces output, estimated by using chromic oxide, and for herbage digestibility, estimated from faeces nitrogen. The regressions used for predicting digestibility were determined with the zero-grazed cows, digestibility coefficients being calculated from measured intake and estimated faeces output values.3. Over the whole experiment there was no difference between treatments in milk yield, herbage digestibility or intake. The solids-not-fat content of the milk of strip-grazed cows was significantly higher than for zero-grazed cows.4. In both spring and summer the increasing maturity of the herbage caused declines from one period to the next in herbage digestibility and intake, and there were declines also in milk yield and solids-not-fat content. The declines were greater for the zero-grazed cows, apparently because they, unlike the strip-grazed animals, were unable to select the more digestible and palatable components of mature herbage. The effects of selective grazing on digestibility, however, were evidently small, for the difference in between the treatment groups was never greater than one unit.5. The estimated energy intakes of both treatment groups corresponded quite well with their theoretical requirements of energy for maintenance, milk production and live-weight gain, and there was no evidence of the energy cost of free grazing being appreciably greater than that of zero grazing.
Effect of live-weight and live-weight change on the lambing performance of ewes
Authors: Tribe D. E. , Seebeck R. M. 
Published: March 2009

A flock of 320 Border-Leicester × Merino ewes was used to study the effects of pre-flushing and flushing treatments on subsequent lambing performances during the years 1958, 1959 and 1960. The flock was kept on non-irrigated perennial pastures in southern Victoria.In 1958 groups of ewes that lost a mean of 17, 5 and 0 lb. during the 4 weeks immediately prior to flushing gave average lambing percentages of 94, 98 and 101, respectively.In 1959 and 1960 flushing for a period of 3 weeks immediately prior to joining produced increased lambing percentages of 13 and 9, respectively. These increases were due almost entirely to increased twinning rates. The response to flushing was not related to the live-weight changes that occurred during flushing. However, the live-weights of the ewes at joining, and, to a lesser extent, before flushing, were related to subsequent lambing performances. The heavier ewes gave more twins than did the lightweight ewes.
Observations on the grazing habits of Grade and Zebu cattle II. Their behaviour under favourable conditions in the tropics
Authors: Lampkin G. H. , Quarterman J. 
Published: March 2009

1. The behaviour of six grade and six zebu steers in a temperate environment was compared with their behaviour when moved to a tropical climate.2. Reaction of both groups to the heat was demonstrated by seeking shade, increased water consumption and an alteration of grazing times. The similarity in their behaviour was, however, the most striking feature. The grades lay down slightly longer than the zebus, but showed no other differences and were not apparently distressed by heat.3. The greatest difference found was in ruminating times and it is suggested that differences in food conversion may be more important than differences in heat tolerance, provided the animals are given the opportunity to adapt themselves fully to their environment.
The feeding of urea supplements to sheep and cattle: the results of penned feeding and grazing experiments
Authors: Coombe J. B. , Tribe D. E. 
Published: March 2009

1. A number of penned feeding and grazing experiments are described in which sheep and cattle, fed diets of low-quality roughage, were given supplements of urea and molasses, or urea and starch.2. Starch was unsatisfactory as a source of supplementary carbohydrate, and it was concluded that this was mainly due to its low palatability. Molasses added without urea to a diet of straw for penned sheep increased intake and reduced the rate of live-weight loss in one experiment, but had no effect in another.3. In general, supplementing low-quality rough-age with urea and molasses in both penned feeding and grazing experiments increased food intake and reduced the rate of live-weight loss. A supplement of urea alone increased food intake, but did not affect live-weight loss. The addition of ethanol or phosphoric acid to urea-molasses supplements had no additional beneficial effect. Supplementation with urea and molasses increased wool growth, but this increase was not always significant.4. The general effect of urea on rumen contents was to increase pH, V.F.A. and ammonia N levels; the effect of molasses was to decrease pH and ammonia N levels, and increase V.F.A. levels.5. Spraying of dry, standing herbage with urea and molasses increased the crude protein (N × 6·25) content, but this effect disappeared in 3–4 days. Sprayed herbage was markedly preferred by grazing animals, and generally one third of the sprayed herbage was removed within 24 hr. of spraying.6. The advantages and disadvantages of the pasture-spraying technique, and the possibilities of other methods of feeding supplements containing urea to grazing animals, are discussed.7. In no experiment where unsupplemented animals were losing weight did urea and molasses supplementation cause substantial increases in weight. It is concluded that the main value of supplementing low-quality roughage with urea and molasses would be for the survival, and possibly the maintenance, of animals.
Effect of planting density on growth and yield of irrigated maize (Zea mays) in the Batinah Coast region of Oman
Authors: Esechie H. A. 
Published: March 2009

SUMMARYField studies were conducted in 1989 and 1990 to investigate the effect of planting density on growth and yield of maize under irrigation in the Batinah Coast region, an arid zone in the Sultanate of Oman. Two maize cultivars, Eperon and Challenger, were grown at three densities (24000, 48000 and 74000 plants/ha). Grain yield was highest at 48000 plants/ha. Leaf area index (LAI) increased with increase in plant density but was not related to grain yield. Lodging was highly correlated with shelling percentage.