bluuebunny/crossref_metadata_2025 huggingface dataset:
The energy requirements of sheep for maintenance and gain. II. Grazing sheep
Authors: Coop I. E. , Hill M. K.
Published: March 2009

The intake of grazing sheep in terms of digestible organic matter, DOM, has been measured by faecal index methods, employing chromic oxide to measure faecal output and faecal nitrogen for digestibility of pasture. A regression equation for the prediction of digestibility from faecal nitrogen (organic matter basis) was developed from several series of digestibility trials with pasture, the equation being

digestibility of organic matter = 30·84 +

Four trials to measure maintenance and gain were conducted, as follows:

(i) Thirty-eight sheep, comprising twelve wethers of mean weight 112 lb., thirteen small or thin Romney ewes of mean live weight 110 lb. and thirteen large or fat Romney ewes of mean live weight 166 lb. were grazed all together for 17 weeks on a rye-grass-white clover sward at an intensity such that live weight was just maintained. Corrections to intake were made for small live-weight changes.

Daily DOM intake (lb.) for maintenance = 0·062 maintenance for a 100 lb. sheep becomes 1·48 ± 0·08 lb. DOM/day.

(ii) Thirty-six weaned Romney ewe lambs of mean initial live weight 56 lb. were grazed for 8 weeks on a rye-grass-white clover pasture and allowed to gain in weight. Regression of intake on gain gave the equation

daily DOM intake (56 lb. lamb) = 0·93 (±0·07) + 0·90 g

where g = gain in lb./day. Combining this lamb data with that of the previous trial yields the equation

DOM intake (lb.) for maintenance = 0·052

(iii) Forty ewes, comprising eight Southdowns, twelve Romneys, eight Border Leicesters and twelve Border-Romney crossbreds were grazed together on short pasture (rye-grass-white clover) for 12 weeks. The ewes were of widely differing live weight and the mean gains or losses of the groups over the period varied from + 1·5 to −4·5 lb.

Daily DOM intake (lb.) for maintenance = 0·061 which for a 100 lb. sheep becomes 1·63 ± 0·13 lb. DOM.

(iv) Seven Romney ewes were grazed in high and eight ewes in low intake groups for 8 weeks. Regression of intake on gain gave the equation

daily DOM intake (130 lb. ewe) = 1·58 (±0·06) + 1·98 g.

For a 100 lb. sheep this becomes 1·36 (± 0·06) lb. DOM/day for maintenance.

The three estimates of maintenance of a grazing sheep of 100 lb. live weight 1·48, 1·63 and 1·36 lb. DOM/day are greatly in excess of the estimate of 0·92 lb. DOM/day for pen-fed sheep. It is believed that this difference is outside experimental error and represents a true increase in energy cost due to grazing. It is suggested that the cause of this derives from the energy costs of walking and harvesting the pasture together with climatic factors wind, cold and rain. The exponent of live weight agrees well with the estimates of other workers based on pen-fed animals. The energy cost of gain is less than that of pen-fed sheep and it is suggested that this is due to the maintenance cost decreasing with increasing availability of pasture and with increasing gain.
Magnesium in forage plants. III. Magnesium distribution in pastures of low magnesium content
Authors: Todd J. R.
Published: March 2009

1. Fractionation studies are reported which show that in young spring pasture of low magnesium content, more than 50% of the magnesium is watersoluble, the proportion being higher in pasture at the seeding stage than in young leafy material.

2. Insoluble magnesium constituted about onethird of the magnesium in young leafy pasture and about one-fifth to one-quarter in pasture at the seeding stage.

3. Acetone-soluble magnesium varied from about 12% of the total in young leafy grass to 5% or less in grass at seeding.

4. Fertilizer treatments, though affecting the total magnesium contents, apparently did not affect the proportions in the different fractions.
The effect of water deprivation upon the rumination behaviour of housed sheep
Authors: Gordon John G.
Published: March 2009

The importance of water for the function of the reticulo-rumen has been stressed by the classic work of Schalk & Amadon (1928). The aspiration theories of regurgitation of Chauveau & Toussaint (Toussaint, 1875) and of Wester (1926) differ, but both imply that before rumination can proceed normally there must be a sufficiency of fluid in the reticulo-rumen. However, Kick, Gerlaugh & Schalk (1937) noted that, with cattle, rumen contents which were so firm as to be almost impossible to break up by hand did not prevent rumination. The writer has noticed a similar phenomenon in sheep. In both cases the animals were given a high level of roughage and a low level of concentrates in their diet. But, even if apparently firm ingesta can be regurgitated, it is still likely that the regurgitate is in fact of a fluid consistency and therefore water intake will be a limiting factor. Transport of ingesta in suspension from the reticulo-rumen through the omasum likewise requires an adequate supply of water.
The evaluation of cattle foods and diets in terms of the ruminal concentration of volatile fatty acids: II. Roughages and succulents
Authors: Bath I. H. , Rook J. A. F.
Published: March 2009

Information on the effect of the inclusion of typical farm foods in the diets of cattle on the ruminal concentrations of the individual volatile fatty acids (V.F.A.'s) is limited. The most extensive investigations are those of Balch & Rowland (1957) and Shaw and his co-workers (see Shaw, 1961), which have given values for a variety of hay and concentrate diets. Few figures are available for other types of cattle foods. The present paper describes a study of the V.F.A.'s in the rumen of dairy cows given various roughages or succulent foods, including a range of herbages of different species and at different stages of growth.
The sexual season of the Awassi fat–tailed ewe
Authors: Amir D. , Volcani R.
Published: March 2009

It is a general practice in Israel to breed the local fat-tailed Awassi ewe during the summer. However, data on its sexual season are not available. There are reports (Finci, 1957) of late lambings, until April in a small percentage of the mature ewes. In yearlings such lambings have been reported as a majority (Finci, 1957). It seems, therefore, that the breeding season extends under specific conditions from June to December, but it is not known if this prolongation is characteristic of a small portion of the population and special conditions, or if all the ewes can breed so late. Hafez, Badreldin & Darwish (1955) reported that in the region of Alexandria the local fat-tailed ewe can breed throughout the year.
The determination and economic analysis of relationships between plant population and yield of main crop potatoes
Authors: Sharpe P. R. , Dent J. B.
Published: March 2009

Two experiments designed to provide data for the estimation of functional relationships, which may be used to determine economically optimum plant populations and planting patterns in Desire'e potatoes, are described. Functional relationships between the number of main stems per acre and yield per acre were estimated from the results of experiment (i). Experiment (ii) investigated the relationship between stem number per tuber and seed tuber weight. ‘Square root’ functions estimated for seed yield and ware yield from the results of Exp. (i) were used to calculate a total Financial Returns curve. This returns curve, together with the Cobb-Douglas function estimated from the results of Exp. (ii), was used to calculate the stem numbers per acre, which would give maximum returns per acre and economically optimum returns in different cost/price situations.
The biuretolytic activity of the ruminal flora of sheep fed practical rations containing biuret
Authors: Gilchrist F. M. C. , Potgieter E. , Voss J. B. N.
Published: March 2009

The biuretolytic activity of the ruminal flora which developed in the ingesta of Merino sheep in response to feeding biuret with practical rations was demonstrated. The activity was determined by measuring the rate of disappearance of biuret in an in vitro fermentation system. Biuret was determined by a specific, semi-micro, colorimetric method based on the formation of a yellow nickel-biuret complex and adapted for use with ruminal fluid. The activity was evoked only when biuret was included in diets of poor quality teff hay with or without maize meal. With ruminal ingesta from sheep fed teff hay and biuret the activity was low, but when maize meal was given in addition the activity was about three times as high, and sufficient to account for the disappearance of up to 16–4 g daily in Merino sheep with a volume of ruminal ingesta of 61. The course of development of biuretolytic activity is discussed in relation to retention of biuret-nitrogen.
A study of the fauna of poultry deep litter
Authors: Byng A. J.
Published: March 2009

The ‘built-up or deep’ litter system for housing poultry came into use in America during World War II, when labour and materials were restricted. It consists of recently used Utter, at least 6 in. in depth, containing micro-organisms which produce beneficial heating, synthesizing and sanitizing effects (Halbrook, Winter & Sutton, 1951; Kennard & Chamberlain, 1951). Four requirements have been laid down by Bott, Ferguson, Berkland & Winter (1952) for proper functioning of deep litter; they are:

(1) The depth of the litter must be greater than 6 in. to ensure the absorption of fresh dropping and for effective chemical and biological activities.
Reproductive habits and fertility of indigenous cattle to artificial insemination in Uganda
Authors: Rollinson D. H. L.
Published: March 2009

1. Records are presented of observations of the sexual behaviour of indigenous Uganda cattle and the fertility to artificial insemination.

2. The mean cycle length found was 20·9 days,s.d.1·38 days. Mean length of oestrus was 2 hr. 14 min.

3. Marked pro-oestrus and metoestrus periods occurred averaging 14 hr. and 11 hr. 7 min., respectively. The mean total length of time that cows remained attractive to the bulls was 26 hr. 21 min.

4. The number of services and attempts to serve by three bulls was recorded and frequent small grunts were noted to be an important expression of excitement by the bulls.

5. The highest percentage of animals conceived to artificial insemination when inseminated between 15 and 25 hr. after commencement of pro-oestrus.
Field experiments comparing ammonium nitrate, ammonium sulphate and urea applied repetitively to grassland
Authors: Devine J. R. , Holmes M. R. J.
Published: March 2009

1. Ten experiments were carried out on grassland in various parts of England and Scotland to compare ammonium nitrate, ammonium sulphate, urea with less than 1% biuret and urea with about 4% biuret. The grass was cut a number of times during the season and each nitrogen fertilizer was applied at rates supplying 30 and 60 lb. per acre of nitrogen in spring and after each cut except the last.

2. Total yield and yields at most individual cuts of both dry matter and nitrogen in the herbage were increased by each increment of applied nitrogen.

3. Ammonium nitrate and ammonium sulphate gave similar dry-matter yields at all cuts in six experiments, while in four on calcareous soils ammonium sulphate gave lower yields than ammonium nitrate at one or more cuts. Ammonium sulphate gave lower yields at the second or third cuts in more experiments than at the first cut.

4. Urea with < 1% biuret gave lower dry-matter yields than ammonium nitrate at one or more cuts in eight of the ten experiments. Urea became less efficient relative to ammonium nitrate as the season advanced.

5. The efficiency of urea with < 1% biuret relative to ammonium nitrate in each experiment was positively correlated with the ammonia absorption potential of the soil.

6. Urea with < 1% biuret and urea with about 4% biuret gave similar yields.
Effect of rationing grass on the growth rate of dairy heifers and on output per acre, with a note on its significance in experimental design
Authors: Broster W. H. , Tuck Valerie J. , Balch C. C.
Published: March 2009

1. A series of three experiments were performed to examine grass as a food for dairy heifers.

2. Indoor feeding resulted in lower intakes of herbage and slower growth but gave greater outputs per acre of animal days and live-weight gain than grazing.

3. The maximum consumption and growth rate, obtained on young grass, were 2·84 lb. herbage dry matter per 100 lb. live weight per day and 2·2 lb. live-weight gain per day for grazing stock. The corresponding figures for indoor feeding were 2·49 lb. herbage dry matter per 100 lb. per day and 1·34 lb. live weight gain per day.

4. Live-weight gain per day was linearly related to herbage dry matter intake from 1·48 to 2·48 lb./ 100 lb. live weight/day.

5. Intake of herbage and growth rate only fell after the herbage came into full flower.

6. Increased stocking rate had small effects on growth rate because the animals grazed the paddocks more heavily.

7. 2·6–3·0 lb. grass dry matter offered per 100 lb. live weight per day was judged an adequate ration for yearling heifers. This gave growth rates of 1·60 lb./day on herbage up to the flowering stage and a consumption of 88% of the available herbage.

8. As an experimental technique zero grazing was found inadequate to replace grazing since it fails to reproduce similar intakes and rates of production. It permitted the reduction of intake to sufficiently low levels that live-weight gain per animal and per acre were reduced.

9. The greatest output per acre was found to occur between limits of intake per day of 1·8–2·4 lb. herbage dry matter per 100 lb. live weight. Above the point of maximum output per acre level of feeding had little effect on production per animal and rate of stocking controlled output per acre. Below this point level of feeding controlled production per animal. The case is advanced that these latter levels of feeding are necessary in grassland experiments.
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

Maize 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

Forty-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

Aspergillus 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

The 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

The 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

Between 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.
Effects of ammonium sulphate and calcium nitrate on the growth, yield and nitrogen uptake of barley, wheat and oats
Authors: Gasser J. K. R. , Iordanou I. G.
Published: March 2009

Barley, wheat and oats were grown in field and in glasshouse-pot experiments without fertilizer-N, and with added ammonium sulphate or calcium nitrate. In the field fertilizers supplied 50 and 100 lb N/acre, in the glasshouse 100 and 200 lb N/acre (calculated from the surface area of the pots). Plant samples were removed at various stages, dry weights were measured, percentage N determined and N uptake calculated. Those taken after the ears had emerged were divided into ear and straw. The number of coleoptiles emerging and of ears in the later samples were counted. Soil samples were taken after removing the plants grown in the glasshouse, and analysed for ammonium and nitrate.
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

Field 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.
Volatilization of ammonia from solid and liquid urea surface-applied to perennial ryegrass
Authors: Watson C. J. , Stevens R. J. , Laughlin R. J. , Poland P.
Published: March 2009

A field experiment compared the effects of urea, surface-applied either as a solid or liquid, at a rate of 100 kg N/ha, on ammonia volatilization from an established perennial ryegrass sward on three separate occasions during 1990 at the Agricultural Research Institute, Hillsborough, Northern Ireland. Total NH3 loss over 10 days from prilled urea for each of the three study periods was equivalent to 3.4, 9.1 and 4.4% of N applied. On two occasions, applying urea as a liquid significantly increased NH3 loss compared to prills, whereas on the third occasion there was no significant effect. Increasing the spray volume from 80 to 640 ml/m2 had no significant effect on NH3 volatilization.

Surface application of urea as a liquid compared to the prilled form did not lower NH3 volatilization and therefore is not a strategy that would improve the efficiency of urea as a nitrogen source for temperate grassland.
Intake and digestion in swamp buffaloes and cattle. 1. The digestion of rice straw (Oryza sativa)
Authors: Kennedy P. M. , McSweeney C. S. , Ffoulkes D. , John A. , Schlink A. C. , LeFeuvre R. P. , Kerr J. D.
Published: March 2009

Four swamp buffaloes (Bubalus bubalis) and four crossbredBos indicusxB. tauruscattle, fistulated at the rumen and abomasum or duodenum, were offered rice straw with mineral supplements in two experiments. In Expt 1, the straw was supplemented with 5% of leaf ofLeucaena leucocephala, and in Expt 2 with either urea or urea with sunflower meal and rice grain. Intake of supplements of urea or urea/sunflower/rice respectively was 935 and 681 g/kg offered in buffaloes and 566 and 789 in cattle.

Buffaloes ruminated longer than cattle (Expt 1, 635v. 452 min/day; Expt 2, 626v. 466 min/day,P< 0·01). In Expt 1, voluntary intake and frequency of ‘A’ sequence forestomach contractions of both species was not affected by species, but buffaloes had a greater (P< 0·05) contraction force in the rumen and omasum, lower rate of ‘B’ sequence rumen contractions, and faster (P< 0·001) rate of gastrointestinal passage than cattle. In Expt 2, voluntary intake of both species was similar, and addition of concentrates did not affect voluntary roughage consumption, norin siturate of digestion of rice straw. Rate and predicted extent of digestion of dietary materials did not differ between species in Expt 1, despite lower concentrations of ammonia in rumen fluid in cattle than buffaloes; however in Expt 2, the rate of digestion of rice straw was higher (p< 0·05) and predicted extent of digestion was 14–20% (P< 0·05) lower in buffaloes. Digestibility of cell wall constituents was lower (P< 0·05) in buffaloes than in cattle in both experiments, but in Expt 2, provision of concentrates reduced (P< 0·01) the proportion of digestible cell wall constituents digested in the forestomach of buffaloes, but not of cattle.
Intake and digestion in swamp buffaloes and cattle. 2. The comparative response to urea supplements in animals fed tropical grasses
Authors: Kennedy P. M. , Boniface A. N. , Liang Z. J. , Muller D. , Murray R. M.
Published: March 2009

Swamp buffaloes (Bubalus bubalis) and crossbred cattle (B. indicusxB. taurus) were offered two forages in two experiments. In Expt 1, four animals of each species were offered mature Rhodes grass hay (Chloris gayana) with a mineral supplement or with a supplement of minerals and urea (17·6 gN/d). In Expt 2, another group of four buffaloes and four cattle were offered mature spear grass hay(Heteropogon contortus) with mineral supplementation at intervals of 3 h. Four levels of urea (0, 5, 21 and 97 g/day) and35S-sulphate were continuously infused in four periods.

Rhodes grass was consumed in greater amounts by cattle, whereas buffaloes ate more spear grass. Urea supplements increased intake of Rhodes grass by 12% in buffaloes and 22% in cattle, and of spear grass by 34% in buffaloes and 41 % in cattle. Digestibility of cell wall constituents and acid-detergent fibre of spear grass was lower (P< 0·05) in buffaloes than in cattle (417v. 499; 471v. 560 g/kg respectively). In Expt 2, dry matter digestibility progressively increased (P< 0·05) from 364 to 408 g/kg with increased urea infusion. Rumen dry matter pool increased by 11–21 % on infusion of 97 g urea/day, compared with no urea. Digestion of ground forages incubatedin situin the rumen was depressed below rumen ammonia levels of 30–60 mg N/l, while digestion of cotton thread was depressed below 60–80 mg N/l (Expt 1) or 150–200 mg N/l (Expt 2).

Patterns of N content in cotton thread suggested that more microbes attached in buffaloes and there was subsequently faster detachment than in cattle, particularly with increased urea infusion.
Casting of the fleece in sheep. Estimation of experimentally induced fibre shedding rate
Authors: Doney J. M. , Smith W. F.
Published: March 2009

A simple and rapid technique for estimating changes in fibre brush-end formation rate is described. The technique was used to give a quantitative estimate of the extent of brush-end formation induced by exogenous hormonal treatment of normal sheep and to establish the time relationship between treatment, fibre brush-end formation and the subsequent casting of the fleece.
Efficiency of water use by irrigated wheat in the Sudan
Authors: El Nadi A. H.
Published: March 2009

Field experiments were conducted to study the differential responses of a wheat crop to water stress during different stages of its growth. Evidence was produced to show that both the flowering phase and the stage of grain filling and maturation were more sensitive to drought than the vegetative period of growth. Yield of wheat was not reduced when the crop suffered from cycles of water stress induced during the vegetative period, if the crop received favourable water regimes thereafter. Efficiency of water utilization from different water treatments was assessed. There was no relation between the protein and starch contents of the grain and the type of water treatment.

The effects of different water treatments on crop development and on components of yield were studied.
The artificial rearing of calves and their growth on grass diets: I. The effect of type and temperature of milk substitute given ad libitum
Authors: Tayler J. C. , Lonsdale C. R.
Published: March 2009

Two experiments were carried out to study the effect of the ad libitum feeding of whole-milk substitutes, either warm or cold, and the availability of drinking water, on the level of food intake and live-weight gain of calves. Freshly cut grass or pasture was the sole source of solid feed.

In Exp. 1 forty Hereford x Friesian male calves were reared individually indoors in a 2x2x2 factorial design experiment. The treatments were full-cream milk powder υ milk substitute, temperature at which the milk was offered, and drinking water υ no drinking water available to the calves. Fresh grass was cut daily and fed ad libitum to all animals from the sixth day of treatment.

In Exp. 2, twelve Hereford x Friesian male calves were reared at pasture on warm or cold full-cream milk during weeks 1–7, and on milk substitute during weeks 8–15.

During both experiments calves receiving warm milk drank slightly more than calves receiving cold milk; this difference was significant in Exp. 1 only. There was a tendency for calves receiving cold milk to make higher live-weight gains (0·05 < P < 0·1) when drinking water was available than when it was not. In Exp. 1, the rates of live-weight gain of calves receiving warm or cold milk substitute with drinking water available were 0·99 and 0·89 kg/head/day, respectively: for calves receiving full-cream milk powder the corresponding rates were 0·86 and 0·80 kg/head/day. When drinking water was not available the rates of gain of calves on warm or cold milk substitute were respectively 0·93 and 0·82 kg/head/day, and on full-cream milk powder, 0·94 and 0·55 kg/head/day.

In Exp. 2 the rate of live-weight gain measured during the first 7 weeks, whilst calves were receiving full-cream milk powder, was 0·88 kg/head/day irrespective of the temperature at which the milk was given. During weeks 8–14 milk substitute was given, which resulted in rates of live-weight gain of 1·05 kg/head/day for calves receiving warm milk and 0–92 kg/head/day for calves receiving cold.

The rates of gain attained on cold milk are considered adequate for rearing calves intended for an intensive system of production. It is also suggested that the use of cold milk could facilitate a marked decrease in the daily labour requirements associated with the artificial rearing of calves.