bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficiency of food utilization and carcass characteristics of steers marketed at different weights
Authors: Hironaka R. , Sonntag B. H. , Kozub G. C.
Published: September 2010

Hereford and Charolais x Hereford steer calves were given an all-concentrate diet ad libitum. The Hereford steer calves were marketed at about 400, 440 and 475 kg live weight. The Charolais x Hereford steer calves were marketed at about 525, 570 and 610 kg. For each kg increase in slaughter weight of Hereford steers, the digestible energy required per unit live weight gain increased by 0·024 (s.e. 0·009) MJ, the killing-out proportion increased by 0·22 (s.e. 0·08) g/kg, and the backfat thickness by 0·004 (s.e. 0·002) cm. The area of m. longissimus increased by 0·245 (s.e. 0·037) cm2 and 0·139 (s.e. 0·048) cm2 for Hereford and Charolais X Hereford steers, respectively, for each kg increase in carcass weight. Among Hereford steers, mean backfat thickness as indicated by carcass grade scores (score of 1 to 4 as backfat increases) at the two lowest slaughter weights were similar and lower than scores at the high weight. Among Charolais X Hereford steers, the carcass grade was not influenced by slaughter weight. Slaughtering Hereford and Charolais x Hereford steers at light weights does not ensure that all the carcasses will be lean when the cattle are given a high concentrate diet to appetite from weaning to slaughter.
Amino acid and energy interactions in growing pigs 1. Effects of food intake, sex and live weight on the responses of growing pigs to lysine concentration
Authors: Batterham E. S. , Giles L. R. , Dettmann E. Belinda
Published: September 2010

The responses of growing pigs to dietary lysine concentration, as influenced by food intake, sex (intact males and females) and live weight were investigated in a 4 x 2 x 2 x 2 factorial experiment involving 128 Large White pigs. Lysine concentrations were 7, 8, 9 and 10 g/kg air-dry food. The basal wheat-soya bean meal diet (14·0 MJ digestible energy per kg) was offered either ad libitum or on a restricted feeding scale to pigs from 20 to 85 kg live weight. During the 50 to 85 kg growth phase, the effects of proportionately reducing the lysine concentrations by 0·2 were investigated. Performance response was assessed in two ways; by analysis of variance for the 20 to 50, 50 to 85 and 20 to 85 kg phases, and by response surface analyses of data from successive 10-kg weight intervals.

An initial analysis of variance indicated that food intake (of pigs fed ad libitum), daily gain and food conversion ratio varied with lysine concentration, but that the responses differed with food intake, sex and phase of growth.

Analysis of the response surfaces delineated by lysine level and phase of growth indicated that for males and females with restricted food and males fed ad libitum, maximum daily gain was produced by feeding at least 10 g lysine per kg, declining to about 8 g/kg at 80 kg. With females fed ad libitum, maximum daily gain was obtained by feeding 9·9 g lysine per kg at 20 kg, declining to less than 5·6 g/kg at 75 kg.

Carcass characteristics were largely unaffected by lysine concentration.
Effect of hay pellets, pelleted ear corn or complete pelleted rations on the feedlot performance of lambs
Authors: Jordan R. M. , Hanke H. E.
Published: September 2010

Eight trials involving 522 fattening lambs were conducted to compare rations of shelled corn and either long or chopped alfalfa hay with complete pelleted rations containing various proportions of concentrate.

Feeding lambs on complete pelleted rations that contained 50–100% roughage resulted in increased feed consumption and significantly greater gains. However, efficiency of feed conversion was improved by pelleting in only one trial.

Feed consumption and rate of gain were not improved by pelleting ground ear corn. Conversely, lambs fed only pelleted alfalfa hay gained significantly faster than lambs fed only chopped hay.
The effect of level of dietary protein on the carcass composition of bacon pigs
Authors: Holme D. W. , Coey W. E. , Robinson K. L.
Published: September 2010

The paper reports the results of experiments to study the effects of different levels of dietary protein on the performance and carcass quality of bacon pigs fed on a high-energy diet: (a) to make similar rates of live-weight gain on all treatments, (b) to make similar rates of live-weight gain but with the level of protein on some treatments being reduced at 130 lb., (c) to allow ad libitum feed intake on all treatments, (d) to obtain two distinct

patterns of growth (fast-fast and slow-fast) on each of two levels of dietary protein.

In the comparison of the two contrasting patterns of growth there was no significant interaction between rate of gain during the period 40–125 lb. live-weight and level of dietary protein. Differences in carcass density and linear measurements were significant and the results suggest that irrespective of growth pattern there was a carcass response to level of protein.

Where diets of different protein content were given ad libitum or to obtain a uniform growth pattern on all treatments, growth rates were generally good, with little difference in feed intake between the treatments within each experiment; variations in level of protein therefore had little effect on growth rate. In some of the comparisons, significant carcass differences were found in terms of density, dissection data and linear measurements; in others only the density differences were significant.

The results suggest that with each of the feeding systems a level of about 17% crude protein, associated with 12% fish meal, is more likely than lower levels to give lean bacon carcasses. In the one experiment in which the protein level was reduced at 130 lb. live-weight there was no marked effect on carcass composition.
The protein requirements of rapidly growing steers
Authors: Kay M. , Bowers H. B. , McKiddie G.
Published: September 2010

1. Two growth trials and digestibility trials were carried out with 54 steers given diets containing either 11%, 14% or 17% crude protein in the dry matter and the same concentration of metabolisable energy.

2. There were no significant differences in either dry-matter intake or live-weight gain by the steers given the diets containing 14% or 17% crude protein. Dry-matter intake was lower for the steers given the diet containing 11% crude protein and their live-weight gain was lower up to 250 kg live weight. Beyond 250 kg live weight their live-weight gain was similar to that of the steers on the two other treatments.

3. Both dry-matter digestibility and apparent nitrogen digestibility were lowest for those steers given the diet containing 11% crude protein.
Components of weight loss in pregnant hill ewes during winter
Authors: Russel A. J. F. , Gunn R. G. , Doney J. M.
Published: September 2010

Live weight of 180 free-grazing Blackface ewes was measured approxim-ately every two weeks throughout a 12-month period. Mean live weight was at a maximum (47 kg) in late autumn prior to mating and declined progressively to 39 kg at about the time of parturition.

Six ewes were slaughtered in November before mating, six at about the 16th week of pregnancy, and a further 11 in April during the final week of pregnancy. The loss of weight of maternal tissues (i.e. live weight less the weight of fleece and contents of the gastrointestinal tract and gravid uterus) during this period was more than 20% (7·5 kg) and comprised 51% of the fat, 14% of the water, and 20% of the protein plus ash present at maximum live weight. During the earlier stages of pregnancy there was an appreciable loss of water from the maternal tissues, but in late pregnancy the rate of water loss decreased and that of fat increased considerably.

The distribution of fat throughout the maternal tissues at different levels of total fat content and the pattern of fat mobilization from various depots are described. The largest single contribution to fat loss during the pregnancy period was that of the subcutaneous reserves, which were depleted by 86%, most of this being lost during the first four months. At the other end of the scale bone fat reserves were reduced by only 25%, almost all of this occurring during the final month.
Relationships between chemical and physical composition of Scottish Blackface ewes
Authors: Russel A. J. F. , Gunn R. G. , Skedd E. , Doney J. M.
Published: September 2010

Chemical and physical compositions were respectively determined on right and left sides of 23 Scottish Blackface ewe carcasses. Relationships were derived whereby physical carcass composition, in terms of muscular tissue plus associated fatty tissue, subcutaneous plus perirenal fatty tissues, and bone, could be estimated from weights of chemically determined water, fat, ash, and fat-free dry matter. The use of these relationships is discussed, and it is suggested that in certain circumstances the estimation of physical carcass composition from chemically determined components could result in considerable economies of time and labour.

The use of certain readily determined physical components as indices of the chemical composition of the whole body is considered, and relevant prediction equations presented.
Estimates of genetic parameters of growth rate in sheep with reference to the method of estimation
Authors: Salah E. , Galal E.
Published: September 2010

There were 563 lambs in the study. They were single Barki lambs born during the period 1961–62 to 1965–66 in Ras El-Hekma Desert Research Station (U.A.R.). All lambs were weighed at birth and at weaning. From 1963–64 onward lambs were weighed nearly every 15 days.

Two methods of estimating growth rate were compared:

R1 = weaning weight — birth weight/age at weaning

and R2 = the regression coefficient of weight on age. The effect of method of estimation on heritabilities and genetic and phenotypic correlations was examined.

Heritability estimates of birth weight, R1 and genetic and phenotypic correlations between them were 0·18 ± 0·10, 0·24 ± 0·11, 0·50 and 0·12 respectively. From the data collected during the period 1963–64 to 1965–66 alone the heritability estimates of birth weight, R1 and R2 and the genetic and phenotypic correlations between birth weight and each of R1 and R2 were 0·15 ± 0·14, 0·39 ± 0·20 and 0·39 ± 0·20; 0·84 and 0·96; 0·28 and 0·27 respectively.

For preweaning growth rate the method of dividing the gain in weight until weaning by age at weaning was virtually as good a method as using the regression of body weight on age. The correlation between the two methods was estimated as 0·91.
Heat losses from young pigs at three environmental temperatures, measured in a direct calorimeter
Authors: Holmes C. W.
Published: September 2010

1. A direct calorimeter is described, capable of partitioning the total heat loss from individual pigs into its evaporative and non-evaporative components; tests revealed that the instrument measured non-evaporative heat loss with a coefficient of variation of 3%, and evaporative heat loss with a coefficient of variation of 5·0% at 10° and 20°C, and 5·6% at 30°C.

2. Experiments were carried out to measure the differences between heat losses at 20° and 9°C, or at 20° and 30°C, for pigs weighing approximately 26 kg and 64 kg; each measurement lasted 20 minutes and was made after an equilibration period of 3–4 hr.

3. Heat loss was proportional to body weight raised to the power of 0·6, under the present experimental conditions, over the range 26–64 kg at 20°C.

4. Total heat loss at 9°C was significantly greater than at 20°C for pigs of both sizes; total heat loss at 30°C was smaller than at 20°C for pigs of both sizes, the decrease being significant for the heavier pigs only. Nonevaporative heat loss increased significantly with decrease in temperature. Evaporative heat loss at 30°C was significantly greater than at 20°C. The increases in total and non-evaporative heat losses at 9°C when compared with 20°C, were significantly greater for the lighter pigs than for the heavier pigs. The small decrease in total heat loss at 30°C, compared with 20°C, may have been due to non-attainment of thermal equilibrium at 30°C.

5. Values for whole body thermal conductance were calculated from the measurements of non-evaporative heat loss, and these indicated that a change in tissue conductance took place between 20° and 30°C; the mean values at 9°C were 3·78 and 3·15 kcal/°C.m2.hr for the lighter and heavier pigs respectively.

6. Evaporative heat loss at 20°C amounted to 280 and 330 kcal/m2. 24. hr for the lighter and heavier pigs respectively. This component of heat loss amounted to 8% and 13% of the total heat loss at 9° and 20°C respectively for all pigs; the corresponding values at 30°C were 32% and 25% for the lighter and heavier pigs respectively. The increased evaporative loss at 30°C was accompanied by an increase in respiratory rate.

7. These results agreed well with the results of previous work with groups of pigs, for heat loss at 20°C. Comparisons with that work indicate that the increase in heat loss at 9°C, when compared with 20°C, was greater for individual pigs than for groups of pigs, of both sizes.
A note on differential mortality rates in young rabbits of esterase phenotypes A, AB, and B
Authors: Grunder A. A. , Rollins W. C. , Stormont C. , Casady R. B.
Published: September 2010

Electrophoretic variants of certain red cell esterases of rabbits (Oryctolagus cuniculus) have been shown to be under the control of two co-dominant autosomal alleles (Grunder, Sartore and Stormont, 1965). Each allele controls two zones of esterase; those controlled byEsAmigrated ahead of those controlled byEsB. The heterozygote manifests not only the zones of both homozygotes but also a ‘hybrid’ zone which appears between the A and B zones.
A note on the substitution of protein by non-protein nitrogen in beef rations
Authors: Pickard D. W. , Lamming G. E.
Published: September 2010

Many observations have been made on the metabolic effects of urea (see reviews by Reid, 1953; McLaren, 1964) and on the problem of urea poisoning (Repp, Hale and Burroughs, 1955), but little information is available on the use of urea for fattening beef cattle under conventional intensive systems. There has been considerable interest shown in the use of biuret as a source of non-protein nitrogen (NPN) as it has been found to be less poisonous than urea when consumed in large quantities (Berry, Riggs and Kunkel, 1956).
The effect of age and live weight on feed conversion and yield of saleable meat of intact Israeli Friesian male calves
Authors: Levy D. , Holzer Z. , Volcani R.
Published: September 2010

Twelve groups of five Israeli Friesian intact, individually fed, male calves, were slaughtered at different live weights. Commencing with 350 kg, the groups were slaughtered at intervals of 25 kg up to 625 kg live weight. Body and carcass composition data were obtained for each calf, and a feed conversion ratio was calculated.

Regression coefficients of age, feed conversion ratio and carcass data on empty body weight, and also the corresponding correlations, were calculated by the equations: y = b + αx for linear and y = bxα for nonlinear regressions.

Age increased at a rate very similar to that of empty body weight (α = 1·042). Increase in the amount of feed required to produce unit live weight was much slower (α = 0·045). With increasing empty body weight, dressing percentage and the percentage of kidney, channel and cod fat in the carcass increased moderately (α = 0·011 and 0·004 respectively), the percentage of the external organs decreased moderately (α = −0·010), and the percentage of bone in the carcass decreased very markedly (α = −0·277). The combined effect of these factors was to cause a marked increase in the percentage of saleable meat (α = 0·107) with increasing empty body weight.

Results indicate that it is possible to increase the marketing weight of Israeli Friesian male calves considerably without any detrimental effect on carcass composition or economy of production.
Phenotypic aspects of growth and carcass quality in veal calves
Authors: Hinks C. J. M. , Andersen B. Bech
Published: September 2010

Five hundred and ten Danish Red male calves slaughtered for the production of veal at live weights of approximately 200 kg were used to estimate carcass composition.

Regression coefficients expressing the relationships between live weight and carcass components indicated that weight at 6 months of age consisted mostly of muscle development in the breast and hindquarters.

Variation in all of the more important growth and carcass attributes was very small, which suggested that selection responses would be difficult to obtain.

There was no apparent correlation between growth rate and the muscle, fat and bone components of the carcass. The best single indicator of the muscle content of the carcass was the muscle content of the pistol cut (r= 0·79), which itself involved complicated dissection procedures. Thelongissimus dorsiarea provided relatively little information, and none of the body measurements, apart from the leg circumference, were strongly related to carcass composition.

The predictive value of many combinations of traits was examined. The best of them accounted for 90% of the variation in muscle content, but when the pistol cut was excluded, none of the multiple correlation coefficients exceeded 0·8.
A note on effect of exercise on behaviour and performance of confined swine
Authors: Morrison S. R. , Hintz H. F. , Givens R. L.
Published: September 2010

The effects of exercise on food intake, growth rate and behaviour were investigated in two trials with 32 pigs. The exercise took the form of running or walking four times the length of a concrete path twice a day. Food intake and rate of gain in body weight were decreased by exercise; the thickness of back fat was not significantly affected. Exercise increased the amount of time spent resting. It is concluded that exercise does not appear to be a practical method of producing leaner carcasses.
Factors affecting voluntary feed intake in pigs. 3. The effect of a period of feed restriction, nutrient density of the diet and sex on intake, performance and carcass characteristics
Authors: Cole D. J. A. , Duckworth J. E. , Holmes W. , Cuthbertson A.
Published: September 2010

1. Over the weight range 23–50 kg live weight, pigs were fed either ad libitum or to a restricted scale. From 59 to 91 kg live weight, eight pairs of barrows and eight pairs of gilts were fed on each of two diets varying in nutrient density. The effects of feed restriction, nutrient density of the diet and sex on voluntary feed intake, performance and carcass characteristics were studied.

2. Pigs which had been restricted grew more slowly and contained less fat and more lean at 50 kg live weight.

3. When restricted pigs were offered feed ad libitum from 59 to 91 kg live weight they ate more and had higher daily intakes of digestible energy than pigs liberally fed in early life.

4. There was evidence of compensatory growth in pigs which had received the restricted diet, but there was no significant difference in feed utilization between restricted and ad libitum pigs. It was concluded that the compensatory growth was largely the result of increased appetite.

5. Pigs finally fed on a low energy diet, in comparison with those on a high energy diet, ate more feed but less digestible energy indicating that appetite was physically limited. Efficiency of conversion of digestible energy to live weight was similar on both treatments. A higher proportion of acetic acid was produced in the caecum of pigs fed the low energy diet. Pigs receiving the low energy diet had lower killing-out percentages not entirely caused by differences in the weight of the gut and its contents. The carcasses of pigs on the low energy diet were leaner than those on the high energy diet.

6. Barrows consumed more digestible energy per day than gilts, required more feed and digestible energy per unit live-weight gain, had lower killing-out percentages, shorter carcasses, larger backfat measurements and smaller eye-muscle areas as estimated by A × B measurements. Barrow carcasses contained less dissected lean and more fat than gilts' carcasses.

7. The results are discussed in relation to other work and it is concluded that voluntary feed intake is influenced by the nutrient density of the diet and the level of energy requirement of the pig, which may be affected by previous nutritional history.
The performance of beef cattle given diets of barley supplemented with either vegetable protein or non-protein nitrogen
Authors: Walker T. , Kay M. , Preston T. R. , McDonald I. , MacLeod N. A. , Macdearmid A.
Published: September 2010

1. Four growth trials were carried out with 297 group-fed steers given diets based on barley, minerals and vitamins, unsupplemented or supplemented
with either soya bean meal or various sources of non-protein nitrogen.

2. Steers given unsupplemented barley (11% crude protein in dry matter) had inferior growth rates up to 300 kg live weight but thereafter were equal to those given barley supplemented with urea in the drinking water or soya bean meal.

3. There were no significant differences in the growth rates of steers given barley supplemented with soya bean meal and those given barley supplemented with ammonium and mineral salts of formic acid or a mixture of acids (predominantly acetic).

4. In two out of three trials, tenth-rib joints from steers given barley supplemented with ammonium salts of mixed acids contained less fat and more protein and water than those from steers given barley supplemented with soya bean meal or proprietary protein supplements.

5. A number of possible explanations for the apparent carcass differences is discussed.
Equilibrium weight in relation to food intake and genotype in twin cattle
Authors: Taylor C. S. , Young G. B.
Published: September 2010

Twenty-two Ayrshire twin female cattle were kept for up to seven years of age on six equally spaced levels of constant food intake, ranging from 35 to 140 lb per week of a complete pelleted diet. Analysis was confined to the period between 5 and 7 years when growth had practically ceased and equilibrium maintenance requirements could be determined.

Equilibrium weight maintained was directly proportional to the level of constant food intake.

This relationship obtained by controlling food intake was significantly different from the 0·73 power relationship that applies across species. In establishing the present relationship, systematic genetic differences were excluded, and this is probably the main condition required for weight eventually maintained to be proportional to food intake. In contrast, the
well-established proportionality of food intake to metabolic weight is essentially based on a species comparison and is thus due almost entirely to genetic differences.

A mathematical model is given which combines (1) the genetic relationship of proportionality of voluntary food intake to mature metabolic weight and (2) the nutritional relationship of proportionality of equilibrium weight maintained to level of constant food intake. The model is then used to partition variation into systematic and random components.

The experiment provides some indication of the extent of individual variation in efficiency of maintenance within breeds, the amount which is genetic, and the repeatability of this efficiency from age to age. Some information is also provided on variation in voluntary food intake, mature weight maintained and efficiency of maintenance on ad libitum feeding.

Methods of estimating efficiency of maintenance using ‘feed and weigh’ techniques, selection for efficiency of maintenance, the correlated response in mature weight, and selection for relative food capacity are briefly discussed.
Some aspects of fertility in purebred and crossbred dairy cattle
Authors: Donald H. P. , Russell W. S.
Published: September 2010

An account is given of the conception rates (in terms of calves born) following artificial insemination of contemporary purebred and crossbred cattle derived from purebred Friesian, Ayrshire and Jersey stock in an experimental herd. First inseminations were given to 222 purebred and 495 crossbred females approaching first pregnancy; and to 165 purebred and 347 crossbred females approaching second pregnancy. Fitted values for conception rates showed no noteworthy differences for year, season, age of female, or breed of bull. Crossbred females, however, were about 10% more likely to conceive than purebreds. Purebred females mated to bulls of their own breed showed lower conception rates than those mated to bulls of another breed.
The effect of level of feeding on the digestibility of diets for sheep and cattle
Authors: Leaver J. D. , Campling R. C. , Holmes W.
Published: September 2010

1. In the first experiment, the digestibility of diets containing ratios of 1:1 and 1:4 hay to concentrates was determined at five levels of feeding in castrated male sheep. With diet 1.1, increasing the daily dry matter intake from 600 to 1400 g resulted in a linear decline in organic matter digestibility from 74·4 to 68·6%. The same increase in level of feeding led to a curvilinear decline in the organic matter digestibility of diet 1.4 from 83·0 to 75·9%.

2. In a similar way the crude fibre digestibility of the diets declined as food intake increased. Also the increase in level of feeding caused a decrease in the mean retention time of stained hay in the alimentary tract.

3. In a second experiment the digestibility of long dried grass offered ad libitum to eight dry and eight lactating cows was measured and compared with the digestibility of similar dried grass offered at maintenance level and ad libitum to eight castrated male sheep.

4. On a metabolic live-weight basis (kg W0·73), the lactating cows ate 34% more organic matter than the dry cows and the mean voluntary intake of sheep was only 54% of the intake of dry cows.

5. The organic matter digestibility for the dry cows was 1·9 units higher than that of the lactating cows and at ad libitum intake the organic matter digestibility for the sheep was 5·6 and 3·7 units lower than that of the dry and lactating cows respectively. The results are discussed in relation to the validity of extrapolating results obtained with sheep to cattle, and with non·lactating to lactating animals.
Cold Exposure of Southdown and Welsh Mountain Sheep. 2. Effects of breed, plane of nutrition and previous acclimatization to cold upon skin temperature, heart rate, shivering and respiration rate
Authors: Sykes A. R. , Slee J.
Published: September 2010

Shorn Southdown and Welsh Mountain sheep on high or maintenance levels of nutrition were subjected to two acute (−20°C; 4 mph wind) cold exposures in climate chambers. Before and between exposures the sheep were kept in either a cold (+8°C) or a thermoneutral (+30°C) environment.

1. At +8°C, all the sheep shivered and showed sustained vasoconstriction and elevated heart rates.

2. At + 30°C, heart rates, skin temperatures on the extremities and muscular tone were all consistently higher in sheep which had previously been kept at +8°C.

3. During cooling, the onset of vasoconstriction and increase in heart rate were both delayed in sheep previously kept at + 8°C.

4. These effects (2, 3) were retained for at least 2 days but less than 12 days after the sheep returned to thermoneutrality. They decayed faster than the increased resistance to body cooling produced simultaneously in the same sheep (Sykes and Slee, 1969), since this was still detectable after 2 weeks.

5. Breed differences were mainly small.

6. It was concluded that acclimatization induced by chronic cold exposure was associated with a temporary increase in basal metabolic rate.
The British Society of Animal Production—25 years in retrospect
Authors: Maule J. P.
Published: September 2010

The Society was founded 25 years ago, in January 1944, and this is perhaps a fitting occasion to look back on its origins and to give a short account of its growth and achievements.
The effects of pattern of feed distribution during the reproductive cycle on the performance of sows
Authors: Lodge G. A.
Published: September 2010

Three groups of 10 Large White gilts were allocated on a littermate basis to 3 feeding regimes, for 3 successive pregnancies and lactations, to provide the following daily allowances:
(A) 6 lb feed per day in pregnancy and 2 lb plus 1 lb per pig suckled in lactation; (B) the same total as (A) but given as 4 lb per day in regnancy and 6 lb plus 1 lb per pig suckled in lactation; (C) a lower overall allowance distributed during pregnancy as 5 lb during weeks 1, 2, 15 and 16, 3 to 5 lb during weeks 3, 4, 13 and 14 and 2 lb during weeks 5 to 12, and during lactation increasing by 1 lb per day to appetite or a maximum of 26 lb at the 21st day, and then decreasing by 1 lb every alternate day to a minimum of 5 lb. Creep-feed was provided ad libitum from 3 weeks of age until weaning at 8 weeks of age.
Differences between groups in litter size and weight at birth were not significant but the combined measure of litter weight was significantly lower in C than in A and B (P<0·05); litter size (P<0·05) and litter weight (P<0·01) but not individual pig weight increased with parity. At 3 and 8 weeks of age there were no significant differences between groups in size or weight of litters or in individual pig weights. Pigs of Group C sows consumed significantly more (P< 0·001) creep feed (7 lb per head) than those of Groups A and B.
Sows of Group A gained double the weight of Groups B and C during pregnancy (P<0001) and lost significantly more (P<0·001) during lactation; Groups B and C did not differ significantly in either respect. Efficiencies of feed conversion (EFC) of total food into total weight by sow and litter were poorest in Group A and best in Group C.
Ammonium salts of fatty acids for milk production 2. The effect of feeding a salt solution containing ammonium acetate on the yield and fatty acid composition of Jersey milk fat
Authors: Hutton K. , Prescott J. H. D. , Seeley R. C. , Armstrong D. G.
Published: September 2010

1. The effect of feeding a salt solution containing ammonium acetate on the yield and fatty acid composition of cows' milk fat has been studied.

2. The trials involved eighteen lactating Jersey cows. In the first trial one group of 5 cows was fed the treatment diet throughout an experimental period of 10 weeks and another group of 5 cows acted as controls. In the second trial which extended over four 28-day periods, two groups of 4 cows spent alternate periods on treatment or control diets. The overall results of the two trials were in agreement.

3. The outputs of C4-C14acids and of palmitic acid per kg of milk yielded were greater than the intakes. The output of C18acids was less than the intake per kg of milk yielded. These observations were noted on both treatment and control.

4. Treatment resulted in an increased secretion of C4-C14acids and of palmitic acid and a decreased secretion of C18acids per kg of milk yielded.

5. The results have been discussed in the light of present knowledge concerning the synthesis of fat in the mammary gland.
The effect of level of feed intake in pregnancy and in lactation upon the productivity of sows
Authors: Elsley F. W. H. , Bannerman Mary , Bathurst E. V. J. , Bracewell A. G. , Cunningham J. M. M. , Dodsworth T. L. , Dodds P. A. , Forbes T. J. , Laird R.
Published: September 2010

Eight research and teaching centres have co-operated in an experiment involving 132 sows. Six treatments were used, combining three levels of feeding in pregnancy with two in lactation. Pregnancy treatments were High 3−2 kg meal/day, Medium 2·4 kg/day and Low 1·6 kg/day; in lactation either a high level, 4·1 kg plus 0·2 kg/pig (h) or a medium level, 2·3 kg plus 0·2 kg/pig (m) were given. The sows were maintained on the same nutritional regime for three parities although inevitably some sows were lost before the completion of the trial. Sow live-weight gains in pregnancy were directly related to feed intake; in lactation, losses in sow live weight were dependent on gains made in the previous pregnancy and on the level fed while suckling. After the first parity, in which animals fed the low level in pregnancy tended to produce larger litters (though the difference was not significant), there were no differences in numbers born attributable to treatments.

Increases in the feed intake of sows in pregnancy resulted in consistent and significant increases in the weight of the pigs at birth. This increase in birth weight also resulted in an increase in weight at weaning in the second and third parities. Level of feeding in lactation, which had a highly significant effect on sow live weight, had much less influence on weaning weights of pigs. There were no consistent pregnancy × lactation interactions, the effects of treatments in the two phases being additive.

An assessment is made of the relative efficiency of the six treatments and the value of the experiment is discussed in relation to other studies concerned with sow nutrition.
Single cereal diets for bacon pigs 1. The effects of diets based on barley, wheat, maize meal, flaked maize or sorghum on performance and carcass characteristics
Authors: Cole D. J. A. , Clent E. G. , Luscombe J. R.
Published: September 2010

Two experiments were carried out to compare the performance and carcass quality of pigs given diets based on barley, wheat or maize meal, and another two experiments comparing these cereals, flaked maize and sorghum. In general, differences in the utilization of feed for live-weight gain could be related to differences in the digestible energy content of the cereals used in the diet, although in some experiments pigs behaved atypically on individual diets. Flaked maize was consistently inferior to the other cereals in the efficiency of conversion of its digestible energy, possibly because of its poorer amino acid balance and its low levels of lysine and tryptophan in relation to energy. Differences between experiments in the performance of pigs fed on the various diets are also discussed. Differences between treatments in killing-out percentage and predicted lean percentage were small, and carcasses of pigs from all treatments were acceptable for bacon curing.
Studies on colostral and milk whey proteins in the sow 1. The transition of mammary secretion from colostrum to milk with natural suckling
Authors: Bourne F. J.
Published: September 2010

A dramatic fall in the colostral whey proteins of nine sows occurred within 24 hr following the birth of the first piglet. The mean levels fell from 19·6 g/100 ml to 4·1 g/100 ml, 50% of this fall occurring within 4 to 6 hr. It is suggested that as early-born piglets will be able to obtain colostrum of a much higher protein concentration this may give them some physiological and immunological advantages over later-born littermates.
The effects of feeding frequency on the growth and efficiency of food utilization of ruminants: an analysis of published results
Authors: Gibson J. P.
Published: September 2010

An analysis of published data on the effects of feeding frequency on cattle gave the following results. On average, increasing feeding frequency increased average daily gain by 16·2±4·8%. The efficiency of growth was increased by 18·7±60·%, indicating that improvements in average daily gain were due largely to improvements in efficiency of food utilization. Much of the improvement in average daily gain and efficiency of food utilization was attributable to increasing feeding frequency from one or two meals per day to four, but there was some evidence of further improvement at higher feeding frequencies.

In terms of experimentation it was concluded that, in general, nutritional or genetic comparisons of growth and efficiency should be carried out with a strict control of feeding frequency. In terms of animal production it was concluded that cattle should be fed at least four times daily to ensure maximum food efficiency for growth.

The magnitude of the response of average daily gain to feeding frequency was dependent on several experimental variables. In particular, the response appeared to be greater when the level of average daily gain was low and when the level of concentrates was high. The variables examined seemed unable to account wholly for the differences in response found in different experiments. Predicting the magnitude of the response under defined experimental conditions therefore remains extremely difficult.

Although rather more limited, results with sheep supported the conclusions drawn from the results with cattle.
Reproductive performance in purebred and crossbred commercial rabbits
Authors: Partridge G. G. , Foley S. , Corrigall W.
Published: September 2010

The reproductive performance of does of New Zealand White (N) and Californian (C) strains of rabbit was compared with that of the two reciprocal crosses, C × N and N × C (sire × dam). Both types of crossbred doe showed a reproductive performance superior to the purebred strains, having both a higher conception rate and mean litter size at birth. C × N, N × C, N and C does reared on average 6·6, 7·4, 5·0 and 4·9 pups to weaning age respectively. Expressed in terms of an estimated annual production of weanlings the N × C does produced nearly twice as many progeny to 4 weeks of age as the purebreds N and C (37 pups cf. 21 and 19 pups respectively). Total losses prior to weaning were approximately 25% in all breeds, largely from stillbirths, and subsequent chilling and/or starvation in the nest (36% and 38% of diagnosed deaths respectively). Other contributory factors are discussed.
A note on the dry-matter intake of Jersey cows
Authors: Brigstocke T. D. A. , Lindeman M. A. , Cuthbert N. H. , Wilson P. N. , Cole J. P. L.
Published: September 2010

A trial was made on a farm using seven newly calved Jersey cows to compare the actual dry-matter intake with that predicted by three commonly used multiple-regression equations. Daily average milk yields during the first 9 weeks of lactation were recorded and peaked at 27·8 kg per cow (s.e. 1·35) in week 7 of lactation. The daily dry-matter intake recorded was 19·2 kg dry matter per cow (s.e. 0·77), compared with the multiple-regression equations, which gave estimated intakes of 13·3, 16·7 and 12·5 kg/day respectively. Prediction was improved by the use of fat-corrected milk, and by taking account of source effects, such as location and the management of the herd (18·5 kg dry matter per day). A further observation trial with the same herd after 250 days from the start of their lactation indicated that the equations still underestimated the intake potential of the Jersey cow at this later stage.
Effect of degradability of protein supplements on voluntary intake and nitrogen retention in young cattle fed grass silage
Authors: Gill Margaret , England P.
Published: September 2010

Grass silage was offered ad libitum to twelve 4-month-old British Friesian steers in an incomplete Latin-square experiment. The silage was given either alone or supplemented isonitrogenously with 50 g fish meal or 63 g groundnut meal per kg silage dry matter.

Both protein supplements significantly increased the intakes of dry matter and organic matter by an amount about equivalent to the (calculated) contribution of the supplement (P < 0·05); they also increased the intakes of digestible organic matter and nitrogen (P < 0·001) but with no significant difference between supplements. Protein supplementation had no effect on the intake of indigestible organic matter.

The digestibility coefficients of dry matter and of organic matter were significantly increased by supplementation (P < 0·05) as were the digestibility coefficients of gross energy and of nitrogen (P < 0·001). Nitrogen retention was also increased from 1·4 to 8·2 g/day (P < 0·001), with no significant difference between supplements.
Estimation of rates of outflow of protein supplement from the rumen by determining the rate of excretion of chromium-treated protein supplements in faeces
Authors: Elimam M. E. , Ørskov E. R.
Published: September 2010

An experiment was conducted to study the possibility of using marker concentration in faeces to estimate rumen outflow of Cr-treated protein supplements and the liquid phase (PEG). There were no significant differences in the outflow of each marker from the rumen when determined directly from rumen or indirectly from faeces, suggesting that faeces could be used to measure the outflow from the rumen without the need for surgical preparation of the animals. The outflow rate of the liquid phase was considerably faster than Cr-treated protein supplements.
The effect of concentrate level on the intake of hays by ewes in late pregnancy
Authors: Orr R. J. , Treacher T. T.
Published: September 2010

In two experiments, ewes carrying two, three or four foetuses were offered restricted amounts of concentrates in the range 0 to 1050 g fresh weight per day and hay ad libitum from day 105 of pregnancy until lambing. The replacement rates of concentrates for forage were similar for both Teeswater × Dalesbred and Finnish Landrace × Dorset Horn ewes in experiment 1 (mean −0·63) when the ewes were offered hay which had an organic matter digestibility (OMD) in vitro of 0·56. There was no significant effect of number of foetuses carried on hay intake. As pregnancy progressed, hay intake increased slightly when hay alone was given and decreased at the higher levels of concentrates.

In experiment 2, hay intake by Finnish Landrace × Dorset Horn ewes was significantly higher when hay of higher digestibility was offered (0·52, 0·69 and 0·84 OMD) and decreased when higher levels of concentrates were given. Ewes carrying two foetuses ate more than ewes with three or four foetuses particularly when hay was offered as the sole food. Generally, hay intake decreased as pregnancy progressed and this was more evident when concentrates were offered.

A predictive equation is given to enable hay intake to be derived from hay digestibility, concentrate level, ewe live weight, number of foetuses carried and week of pregnancy.
A note on the concentrations of plasma oestradiol-17β and progesterone around the time of puberty in heifers
Authors: Glencross R. G.
Published: September 2010

In heifers, plasma progesterone levels were low (<0·3μg/l) from the 59th to about the 15th day before puberty (defined as the day when oestrus was first detectable by the fern pattern of dried cervical mucus). Plasma oestradiol-17β levels varied randomly within the range 1 to 4 ng/l over the same period, but then showed three peaks of about 6, 9 and 4 ng/l, respectively 8 days before puberty, on the day of puberty and 4 days later. The pre-pubertal oestradiol-17p peak was followed by a short period of elevated progesterone levels. Whether this oestradiol-17β peak induced ovulation is uncertain; it is however clear that a corpus luteum of normal life-span was not formed. The oestradiol-17β peaks on the day of puberty and 4 days later, when progesterone levels were rising rapidly, were typical both in magnitude and duration of those occurring before and after ovulation in post-pubertal oestrous cycles.
A note on efficacy of complete v. partial boar exposure on puberty attainment in the gilt
Authors: Deligeorgis S. G. , Lunney D. C. , English P. R.
Published: September 2010

Sixty-three Large White ♂ × (Landrace ♂ × Large White ♀) ♀ gilts were allocated to one of three treatments as follows: (i) boar contact for 20 h/day; (ii) boar influence through a mesh pen division for 20 h/day; and (iii) control, which had no boar exposure.

The experiment started when gilts averaged 156 days of age, and continued until either puberty was detected or the age of 210 days was reached. Analysis revealed significant differences between groups for proportion of gilts reaching puberty (0·76, 0·38 and 0·19), the interval from stimulation to-puberty (10·4, 34·1 and 36·7 days) and age at puberty (167·9, 192·2 and 191·2 days) respectively.
The effect of milk substitute concentration upon the intake, digestion and growth of calves
Authors: Ternouth J. H. , Stobo I. J. F. , Roy J. H. B. , Beattie A. W.
Published: September 2010

A total of 40 individually-penned British Friesian male calves were offered milk substitutes ad libitum from 2 days until 12 weeks of age. Ten milks were reconstitued from either liquid or spray-dried skim milk and a fat-filled (500 g fat per kg) powder and contained 80, 110, 140, 170 or 200 g dry matter (DM) per kg liquid. A further six calves were used in a randomized-block experiment to measure the digestibility, absorption and retention of the diets containing 80, 140 and 200 g DM per kg.

There are no significant differences in the intake, growth rate, digestibility, absorption or retention between calves given milk substitutes reconstituted from liquid or spray-dried skim milk.

At all ages, as the DM concentration of the milks increased, liquid intake decreased but DM intake and live-weight gain increased. The mean live-weight gain was 0·99, 1·13, 1·16, 1·28 and 1·27 kg/day for calves given the milk substitute diet at concentrations of 80, 110, 140, 170 and 200 g DM per kg, respectively. The DM intake to live-weight ratios were constant at all ages when live weight was expressed to the power of 0·61.

No significant adverse effect of the diets was evident from the fortnightly monitoring of jugular blood samples for packed cell volume and concentrations of glucose, urea-N, Na, total protein, albumin, globulin and haemoglobin; nor from faecal consistency, rectal temperature, heart rate and respiration rate.

There was no indication that age affected digestibility, except that digestive efficiency was reduced in calves with diarrhoea, particularly at 2 to 4 weeks of age; nor that dietary concentration influenced digestion or absorption. The true absorption of N, Ca and P from the milk diets was high with mean coefficients of 0·99, 1·01 and 0·95 respectively. The main endogenous losses of N and P occurred through the urine and of Ca through the faeces.
The live-weight gain and dry-matter and water intakes of calves offered milk substitute diets at high concentrations
Authors: Ternouth J. H. , Stobo I. J. F. , Roy J. H. B. , Beattie A. W.
Published: September 2010

Thirty-two British Friesian calves were individually offered milk substitutes ad libitum twice daily for 12 weeks. The milks were reconstituted to contain 170, 200, 230 or 260 g dry matter (DM) per kg, using spray-dried skim milk powder and homogenized fat-filled powder containing 500 g fat per kg. Drinking water was available ad libitum at all times. The last two blocks of four calves were used to measure the digestibility, absorption and retention of the constituents of the diets at 2, 6 and 11 weeks of age.

The DM intakes of the calves given the four diets were variable but generally increased with increasing DM concentration, mean values being 61·5, 59·5, 66·0 and 73·3 g DM per kg M0.75. As the calves increased in age, their intakes decreased from 67·3 g DM per kg M0.75 at 2 weeks of age to 61·1 g DM per kg M0.75 at 8 weeks of age.

The higher DM concentrations and intakes were associated with the higher rates of weight gain; the mean live weights at 12 weeks of age being 121·8, 123·9, 135·3 and 141·6 kg for the calves offered milks reconstituted at 170, 200, 230 and 260 g DM per kg respectively.

The concentration of the DM had no effect upon the coefficients of digestion or absorption nor on the retention of energy, protein, calcium or phosphorus. The digestibility of protein increased, whilst the absorption and retention of Ca and P declined with age.

Intake of drinking water did not change with age, but was higher for calves given the milk containing 260 g DM per kg than for those given the other three concentrations. The total water intakes were similar for the calves given milks containing 200, 230 and 260 g DM per kg.

The linear relationship of DM intake to DM concentration of the milk substitute suggested a lower level of intake in the present experiment, than was observed in a previous experiment (Ternouth, Stobo, Roy and Beattie, 1985b) when the milk concentrations were lower and drinking water was not available. When the concentrations of the DM were re-calculated to take into account the quantity of drinking water consumed, the relationships between DM intake and adjusted DM concentration for the two experiments were similar.