bluuebunny/crossref_metadata_2025 huggingface dataset:
A note on effect of docking on skin structure and characteristics of the fleece in Rahmani fat-tailed sheep
Authors: Marai I. F. M. , El-Gaafary M. N. , Ahmed B. A. K.
Published: September 2010

The histological characteristics of the skin of docked and undocked fat-tailed sheep were studied at 15-day intervals between birth and 90 days of age, then every 30 days until 180 days and every 3 months until 1 year of age. Data presented in this paper were recorded at birth, 30, 60, 120,180 and 360 days of age. The fleece characteristics were studied at 1·0,1·5 and 2·0 years of age.

The skin structure was similar in docked and undocked Rahmani sheep and did not differ from that of other breeds of sheep.

The effect of docking was significant at most ages of the study on internal diameter of primary follicles and on the external and internal diameters of secondary and on average diameters of wool follicles (P < 0·05). The effect of docking was highly significant on each of staple length and wool diameter.
Selection of dairy cattle for growth rate and milk production
Authors: Soller M. , Bar-Anan R. , Pasternak H.
Published: September 2010

The genetic progress in live-weight-for-age (LFA), milk production, and in overall economic value expected as a result of performance and progeny testing of young bulls with respect to milk production and LFA was computed. It was shown that performance testing can contribute considerably to overall progress in economic value, while under certain circumstances progeny testing for LFA can also contribute to genetic progress in overall economic value, but to a lesser degree than performance testing. The relative economic value of LFA and milk production was derived and found to be relatively stable under differing economic conditions.
Crossbred sheep production II. The repeatability of performance and the scope for culling
Authors: Yalçin B. C. , Bichard Maurice
Published: September 2010

There are many flocks in Britain where first-cross ewes are mated with a Down ram in order to produce offspring of both sexes to be fattened for slaughter between 3 and 12 months of age. The ewes are normally bred out of hill ewes by rams of the special crossing breeds, the Border Leicester being the most popular example. Commonly the crossbred flock is maintained by the annual buying in of young sheep at 6 or 18 months old. These replace animals lost through normal wastage and those sold after a set number of lamb crops. In such a situation the flock owner relies on others to produce his crossbred ewes and can himself do nothing to improve their performance through selective breeding. He can only attempt to cull ewes with a poor performance. Any gains from such culling are, of course, temporary and must be maintained by a regular system of culling within each separate intake of females. The success of a culling scheme depends partly upon the extent to which future production is predictable from past performances. This is normally assessed by the correlation between an individual's successive records: the intra-class correlation or repeatability (t). The work reported here estimates the repeatability of various productive traits within two crossbred ewe flocks and considers the scope for culling within such flocks.
Specialised sire and dam lines. III. Choice of the most profitable parental combination when component traits are genetically non-additive
Authors: Moav Rom
Published: September 2010

When crossbred offspring are used for production of an agricultural commodity profit is a function of three genotypes, that of the sire, the dam and the crossbred offspring. Heterosis in the component traits of profit, in any of the above genotypes, affects profit. Thus only when the final product is a four-way cross can we get crossbred parents plus a crossbred progeny and a full use of the available heterosis.

When the contributions of the sire and dam to profit are unequal, there is a justification for the breeding and use of specialised sire and dam lines, even though the component traits may be genetically additive. Multiple crosses (three- and four-way) may improve profit over two-way crosses only when there is heterosis in one or more of the component traits.

When profitability is presented as a function of productivity and repro-ductivity, five heterosis factors of the component traits may affect profit. These are: (a) Improved efficiency of production in a crossbred ‘commercial offspring’, (b) Improved viability (a component of reproductivity) in a crossbred ‘commercial offspring’, (c) Improved ‘female fertility’ in a crossbred dam. (d) Improved efficiency of the ‘commercial offspring’ through heterosis for maternal effects in the crossbred dam. (e) Improved male fertility through heterosis in the crossbred sire.

When the profit equation is non-linear, the same degree of heterosis as that measured on the component traits may have quite a different effect on profit, depending on the level of performance of the traits. By crosses and backcrosses between the parental lines the location and composition of the heterosis factors may be altered favourably.

Graphic and algebraic procedures were outlined for finding sire-dam combinations that maximise profit in the presence of heterosis when a group of genetic stocks is available.
The association between commercial cut-out yield and gross chemical composition in market pigs
Authors: Doornenbal H. , Martin A. H.
Published: September 2010

In a study of 100 pig carcasses, representing a sample of the pigs used in previously reported work, gross chemical composition of the ham, shoulder, loin, belly and half carcass were determined for one side. Percentage yield (trimmed v. untrimmed) of picnic, butt, ham and loin (PBHL), and certain carcass measurements were recorded on the other side of the carcass. From the covariance analyses, it was concluded that backfat thickness of the carcass alone was of only moderate predictive value for total chemical carcass fat.

Carcass protein could, for most purposes, be predicted with satisfactory precision from the percentages of protein in the loin or in the ham, with residual standard deviations of 0·27 and 0·36% respectively.

Although percentage yield of lean cuts may be considered satisfactory for commercial evaluation of swine carcasses, it was not an accurate index of the true leanness of a carcass expressed as the percentage of chemically determined protein.

Multiple regression equations were computed for predicting the percentage of protein in the carcass and percentage yield of PBHL from conventional carcass measurements. The residual standard deviations for predicting the percentage of protein were 0·49 for the males and 0·42 for the females; for percentage yield of PBHL these were 1·31 and 1·22 respectively. Total backfat thickness was the most important single variable in predictions. Variances among sexes were non-homogeneous for the important traits, with the females in all cases showing the greater variability. The results of regression analysis within sex indicated that, for maximum precision, a separate prediction equation for each sex was required.
Selection practices in dairy herds. 2. Selection patterns in the later lactations
Authors: Hinks C. J. M.
Published: September 2010

Selection procedure has been examined in Friesian and Ayrshire populations of dairy cattle in an attempt to determine the extent to which the relatively simple selection process in the first lactation was modified by the effects of age, by the incomplete repeatability of milk yield, and by the availability of production information from more than one lactation.

As a result of a greater intensity of selection for milk yield in the lower yielding herds, effective selection for yield was maintained at the later cullings despite increased wastage for reasons other than yield in the ageing population.

The high yielding animals that were selected by farmers in early life continued to outlive and to outyield their lower yielding first lactation contemporaries, notwithstanding a small amount of evidence that the heaviest yielding group were severely culled in the second lactation, mostly for reasons beyond the farmers' control. There was also some evidence that a high first lactation yield predisposed the animal to disposal for reasons other than yield in later life.

Survival at any particular culling was primarily determined by the milk yield in the previous lactation. In this respect, the culling after each lactation appeared to be independent of previous selection decisions, and the individual animal had to demonstrate its merit repeatedly to survive—earlier merit did not compensate for a subsequent failure.
A note on the correlations between measurements on photographs of the cut sides of Wiltshire bacon and on the live pig or newly slaughtered carcass
Authors: Ørskov E. R. , Hollier D. A.
Published: September 2010

The importance of fat thickness and size and shape of eye muscle in bacon pigs has initiated much work to establish convenient routine measurements that would most reliably estimate these qualities. Measurements taken of the muscle: fat ratios in the region of the loin have been found to be the best estimate of the whole carcass and (as discussed by Harrington, 1958) have been a valuable aid in carcass competitions, where, to ensure similarity between contests, judges have used standard photographs of cut sides. The use of routine photographic records of cut sides in nutrition and breeding work has not, however, been fully explored, but was used by American and German workers (Ferguson, Brennan and Buric, 1961; and Brohmann, 1961). The advantage of using photographic records is that the measurements can be made at the most convenient time and place and form a near permanent record. They can also be used in developing correlations with measurements on live pigs which might estimate the quality of the rashers later produced.
The nutrition of the early-weaned calf. X. The effect of replacement of fish meal with either urea or ammonium acetate on growth rate and nitrogen retention in calves fed ad libitum
Authors: Kay M. , MacLeod N. A. , McKiddie G. , Philip Euphemia B.
Published: September 2010

1. A growth trial and nitrogen balance studies were carried out on 32 early-weaned calves fed on a basal diet containing fish meal or diets in which the fish meal nitrogen was partially replaced by urea or ammonium acetate or totally replaced by urea.

2. Growth rate and feed conversion efficiency were highest on the fish meal diet and fell as urea replaced the fish meal.

3. Rumen ammonia levels and urinary nitrogen excretion were highest, and nitrogen retention lowest, in the calves receiving the diet in which fish meal nitrogen was completely replaced by urea nitrogen.
Feed intake of grazing cattle. V. A further study of the influence of pasture restriction combined with supplementary feeding on production per animal and per acre
Authors: Holmes W. , Curran M. K.
Published: September 2010

This paper reports the second of two experiments which examined the possibility of improving pasture utilisation by restricting grazing and giving cows a supplement of concentrates. Two treatments (A and B) were continuously imposed, each on a group of 10 adult Ayrshire cows, for about 4 months. Cows received either pasture alone allocated daily by electric fence (B), or half this area of pasture plus 3 Ib. cubed concentrates per 10 lb. milk (A).

Herbage intakes were estimated by grass cutting techniques and also by faecal index methods, and animal performance was recorded. Over the whole experiment the two treatments gave similar levels of production per animal. Significant differences in milk yield and live-weight gain were detected only in periods 1 and 4, respectively, when the intended restriction was not completely achieved. While production per acre of grass was doubled by treatment a about 4,000 lb. grain was considered necessary to replace one acre of grazing.

The results are discussed in relation to the previous experiment. They suggest that the method of replacing half the normal grazing with barley or other concentrated feeds could be usefully employed to alleviate pasture shortage in parts of the grazing season and might therefore facilitate the maintenance of a high stocking rate.
Wool growth regulation by local skin cooling
Authors: Doney J. M. , Griffiths J. G.
Published: September 2010

Local cooling of the skin, produced by exposure to wind was shown to depress the rate of length growth of wool. The depression was associated with reductions in skin temperature and blood flow and with increases in heat transfer in the exposed regions. Fibre diameter did not appear to be affected and there were no indications of a systemic response of wool growth rate to exposure.
Influence of rumen ciliate protozoa on conversion of food and growth rate in early-weaned zebu calves
Authors: Osman H. El-Sayed , Akkada A. R.Abou , Agabawi K. A.
Published: September 2010

The ruminal activity, daily live-weight gain and feed conversion efficiency of zebu calves inoculated with whole rumen contents from a mature cow were compared with those of calves maintained under the same conditions except that they were ciliate-free and isolated from other ruminants.

A thriving mixed population of ciliate protozoa became established in the rumen of calves two weeks after inoculation.Entodiniumwas the first genus to appear and was followed byIsotricha, Polyplastron, Ophryoscolex, DiplodiniumandDasytricha.

The ruminal volatile fatty acid and ammonia concentrations in the inoculated calves showed a pronounced rise above the values found in the uninoculated controls.

The inoculated calves grew faster and had a higher feed conversion efficiency than the uninoculated controls.
Taste responses of calves to various concentrations of different salts
Authors: Mehren M. J. , Church D. C.
Published: September 2010

Experiments were conducted to observe the taste responses of male and female calves to various levels of sodium salts, chloride solutions, and trace minerals. Animals were penned individually and given a completely pelleted ration ad libitum. Trace mineralized salt was freely available.

Using water as a basis for determination, a non-discrimination zone was established. This zone represented an intake ranging from 63 to 37%. Preference threshold was set at 80% of intake, while the rejection threshold was set at 20% of intake. Responses were determined by expressing the intake of the test solution as a percentage of the total intake during the test period. Responses at a given chemical concentration were measured during two 8-hr periods.

Taste response observations were made on the following: 0·02, 0·08, 0·32 or 1·25% sodium chloride (NaCl), sodium sulphate (Na2SO4), sodium bicarbonate (NaHCO3), sodium carbonate, monobasic sodium phosphate (NaH2PO4), dibasic sodium phosphate (Na2HPO4), ammonium chloride, potassium chloride, calcium chloride, magnesium chloride, and manganese chloride. In addition, observations were made when 0·02, 0·08, 0·32 or 1·25% NaHCO3, Na2SO4, or Na2HPO4 were offered in opposition to equal concentrations of NaCl. The responses to 5, 10, 20, 40 and 60 p.p.m. concentrations of cupric chloride, zinc chloride, molybdenum trioxide and cobaltous chloride were observed also.
Chemical processing of wheat straw and cotton by-products for fattening cattle. 1. Performance of animals receiving the wet material shortly after treatment
Authors: Levy D. , Holzer Z. , Neumark H. , Folman Y.
Published: September 2010

Two fibrous roughages, wheat straw and cotton hulls, were treated with 0, 40 and 80 g sodium hydroxide (NaOH)/kg roughage, applied in amounts of water calculated to bring the roughages to moisture contents of 30 and 60%. The effects of these factors on the nutritive values of the two roughages were examined using a 2 × 3 × 2 factorial design.

Digestibility trials,in vitroandin vivo, and a 9-mo feeding trial were carried out with the roughages soon after treatment. Concentrates were limited to 6 kg/head per day throughout the animal experiments and roughages were offeredad libitum.

Neutral detergent fibre decreased by 7·8 and 13·5% with the 40 and 80 g application rates of NaOH respectively.

The treatment of both roughages with NaOH increased considerably theirin vitrodry matter digestibility and total solubles after enzyme treatment, the increases being related to the rate of application of NaOH. Digestibilityin vivowas improved only by the 40 g NaOH treatment.

Treatment with NaOH reduced the voluntary intake of both roughages. Only the 80 g/kg treatment had a positive effect on rate of live- and carcass-weight gain. On the other hand, NaOH improved very significantly the efficiency of conversion of metabolizable energy into live and carcass weight and increased significantly the degree of fatness of the animals. These results indicate a marked improvement in the nutritional value of both roughages due to NaOH treatment. The reason for the small response in rate of gain may be explained by a shortage of protein owing to a possible reduction in its digestibility. Cotton hulls excelled wheat straw in almost every respect. Animals on NaOH-treated cotton hulls bloated chronically unless some long straw was given. Moisture level had practically no effect on performance.

The effects of the treatments on rumen or blood constituents were small.
The effects of selection on sex differences in pre-weaning growth in beef cattle
Authors: Hopkins I. R.
Published: September 2010

Pre-weaning growth data from 3822 calves reared in 11 Victorian herds were analysed. The results suggested that the superiority of males (bulls) over castrated males (steers) in pre-weaning growth was due, at least partly, to the early castration of poorly growing male calves, i.e. to the effects of early selection. The extent of this selection bias was further examined using results from similar studies and from experiments in which bulls and steers were selected without bias. These studies strongly supported the view that the superiority of bulls over steers was primarily due to selection and not to sex effects. If sex did influence the bull-steer difference it was of no statistical or practical importance.

In the Victorian data, the ratio of bulls to steers was higher in subclasses in which average growth rates were higher. When selection effects are correlated in this way with other environmental effects such as age of dam effects further biases may arise in estimation of those effects and hence in individual or mass selection.

The results indicated, therefore, that unless bulls and steers are treated as one sex biases can arise in both individual selection and progeny selection.
A note on the energy cost of walking in cattle
Authors: Ribeiro J. M. de C. R. , Brockway J. M. , Webster A. J. F.
Published: September 2010

Measurements were made of the heat production of cattle while standing at rest or walking on a treadmill at different speeds, both on the level and at a gradient of 6°. The energy cost of horizontal locomotion was about 2 J/kg per m at speeds of 40 to 85 m/min, irrespective of body weight or plane of nutrition. The energy cost of vertical locomotion was about 26 J/kg per vertical m.
Estimations of heterosis in crossbred dairy cattle
Authors: Donald H. P. , Gibson D. , Russell W. S.
Published: September 2010

In a long-term experiment, the performance of British Friesian, Ayrshire and Jersey cattle and their first and second crosses was evaluated over 526 first and 477 second lactations. Live weight at 18 mo of age and the ratios of lactation yield to live weight were examined as well as milk yield and composition of milk.

Percentage heterosis in each combination of two pure breeds was estimated. For the three first crosses combined, heterosis for 305-day milk yield averaged 6·4% in first and 3·7% in second lactations. Heterosis in live weight at 18 mo averaged 2·9%; none was found in the Ayrshire × British Friesian crosses, but the others averaged 4·7%. Second crosses overall had an average live weight near to that of first crosses, but their milk yields were lower and, in the combined lactations, approximately equalled the purebreds' total.

Components of variance due to breed and environmental factors were calculated. Breed accounted for 50% of variance in live weight at 18 mo but less than 10% of variance in milk yield.

The influence of fertility on heterosis is discussed with reference to earlier findings, and economic implications are considered.
On fitting curves to lactation data
Authors: Cobby J. M. , Le Du Y. L. P.
Published: September 2010

The usual method of fitting the model y = Anb exp(−cn) to lactation data, by a multiple regression of logey on n and logen, can result in an ill-fitting curve. An analysis of the untransformed data provides a better fit but requires more extensive computation and a simple approximation to this procedure is given. Since the parameters of this model have no direct biological interpretation two alternative models are introduced, each having a parameter measuring the persistency of lactation.
A note on the performance of fattening steers implanted with zeranol under grazing and feedlot conditions in Botswana
Authors: Shorrock C. , Capper B. S. , Light D. , Mlambo M. M. J.
Published: September 2010

Trials involving a total of 401 steers were carried out from 1974 to 1976 to determine the effect of implantation with zeranol on the performance of fattening steers under grazing and feedlot conditions i n Botswana.

Over a 180-day grazing period in 1974, 1975 and 1976 there was a significant improvement in live-weight gain of 11·9, 24·5 and 12·3% i n implanted steers over control steers. Under feedlot conditions there was a mean improvement in live-weight gain of implanted steers over control steers of 17·9% over an average stay in the feedlot of 95 days.
Free-choice feeding of cattle on swedes and grass silage
Authors: Petchey A. M. , Mohammed H. H.
Published: September 2010

In a trial of a changeover design, 12 British Friesian castrates (steers) were offered both grass silage and crushed swedes (Brassica napus) ad libitum so that they could show their preference for these feeds on a free-choice basis. Two additional dietary treatments were provided by the supplementation of either swedes or grass silage with 2 kg of rolled barley. Steers consumed 0·32 of their dry-matter intake as silage when offered a free-choice of crushed swedes and grass silage. Supplementing the diet with 2 kg of rolled barley significantly increased daily dry-matter intake but the increase was not affected by the location of the supplement, on either the silage or the roots.
Studies on a selection index for improvement of litter weight in sheep
Authors: Martin T. G. , Smith C.
Published: September 2010

The value of a selection index for 8-week litter weight as a trait of the ewe, combining information on the ewe and on five classes of female relatives, was considered. Adding records on the dam and on paternal half sibs to those of the ewe gives increases of 10 to 50% in the rates of genetic response. The index can be simplified with little loss in efficiency by weighting all records equally for relatives with 1, 2 or more records within each class of relative. In selecting breeding replacements, information on the parents of the sire of the individual being selected may increase the rates of response by a further 20 to 30 %.
Growth and gastric abnormalities in the growing pig resulting from diets based on barley in differing physical forms
Authors: Lawrence T. L. J. , Thomlinson J. R. , Whitney J. C.
Published: September 2010

Seventy-two Large White × (Large White × Landrace) weaner pigs in each of three experiments were scale-fed diets containing 850 g barley per kg which had been processed by either cold rolling (R) or grinding through 1-56 mm (O) or 468 mm (T) screens. In experiments 1 and 2 barley (0-868 dry matter) was used and group feeding was practised for 55 and 100 days respectively. In experiment 3 barley (0-838 dry matter) was used and individual feeding was practised for 107 days. In experiment 1 gastric pH was recorded at slaughter. In all experiments the stomachs of all pigs were examined for gross and histological abnormalities.

In experiments 1 and 2 growth rates and efficiencies of feed conversion were not significantly different for pigs fed the R-, O- and T-based diets. In experiment 1 the pH in the pylorus, but not in the fundus, was significantly higher in pigs fed the O-diet compared with the T-diet, and on the T-diet compared with the R-diet. Growth rates and efficiencies of feed conversion in experiment 3 were significantly poorer in pigs fed the R-diet compared with the T-diet, and on the T-diet compared with the O-diet. In experiment 1 one pig from each of the three diets showed hyperplastic changes in thepars oesophageaof the stomach. In experiment 2 no gastric abnormalities were found, but bile staining was present in the pyloric zone of one pig fed each of the three diets. In experiment 3 hyperplastic lesions of thepars oesophagea(and bile staining) were present in 19 (14), 10 (7) and 4 (1) pigs fed diets O, T and R respectively.
A note on the effects of boar presence on the performance of sows and their litters when penned as groups in late lactation
Authors: Petchey A. M. , English P. R.
Published: September 2010

When sows and their litters were grouped 21 days after farrowing, the introduction of a boar 4 days later stimulated lactational oestrus in only 2 of the 21 sows (seven groups of three sows and litters) exposed to the boar, while none of the sows in the control groups showed lactational oestrus. The boar presence in lactation affected the subsequent weaning to first service interval. This interval was 228 days for the sows exposed to a boar and 10·0 days for the control groups, the difference approaching significance (0·05<P<0·10). None of the sows in the boar treatment groups had a weaning to oestrus interval exceeding 9 days.
A note on the estimation of economic values for selection indices
Authors: Thompson R.
Published: September 2010

A procedure has recently been developed for estimating economic values which employs a profit function implying that animals with mean values for variates in the profit function give the most profit. However, the proposed index selects extreme animals, a paradox which is explained by showing that the index is appropriate for only part of the profit function. More appropriate selection indices are developed and illustrated graphically.
The effect of wilting and short-chopping of grass on the subsequent voluntary intake of silage, and live-weight gain of calves
Authors: England P. , Gill M.
Published: September 2010

Four silages were prepared from perennial ryegrass. Half the crop was picked up soon after mowing and the remainder left to wilt for 24 h. Half the unwilted and half the wilted grass was chopped by a forage harvester with its normal complement of knives; the remainder was chopped by a forage harvester with all but two of its knives removed. The ensiled material was offered ad libitum for 80 days as the sole food to 32 British Friesian male castrates initially 14 weeks of age and 111 kg live weight.

Wilting raised silage dry-matter content by 31 g/kg fresh weight and gave lower concentrations of acetic acid whilst short chopping gave lower butyric acid. Concentrations of acetic acid, butyric acid and ammonia nitrogen were high on all treatments. Organic matter digestibility was significantly increased by wilting (P < 0·001) and significantly depressed by chopping (P < 0·001). There was no response in dry-matter intake to short chopping, but wilting raised daily intake from 18·4 to 19·9 g silage dry matter per kg live weight (P < 0·001). Live-weight gain was increased from 0·42 to 0·46 kg/day by short chopping (P < 0·05) and from 0·40 to 0·48 kg/day by wilting (P < 0·01)
The energy and nitrogen metabolism and performance of pigs infected with Oesophagostomum dentatum
Authors: Stewart M. , Holmes C. W. , Smith W. C. , Charleston W. A. G.
Published: September 2010

The effect of Oesophagostomum dentatum on the performance of growing pigs over the live-weight range 20 to 80 kg was investigated. Fourteen individually-penned pigs in Experiment 1 and 16 group-penned but individually fed pigs in Experiment 2 were orally dosed once with 80 000 or 20 000 larvae respectively at about 18 kg live weight. Worm-free but otherwise similar pigs served as controls. Three energy and nitrogen balance studies were undertaken in two open-circuit calorimeters on four infected gilts and their paired worm-free counterparts on two levels of feeding at 7, 21 and 49 days after infection. Worm burdens averaging 4 255 and 4 722 in Experiments 1 and 2 respectively were recorded post mortem but performance and carcass measurements were not affected, neither were there any clinical symptoms. No significant differences between infected and worm-free pigs were recorded for either apparent digestibility of nitrogen and gross energy or for nitrogen retention. Possible reasons for the lack of measurable effects on pig performance are discussed.
The influence of wilting and season of silage harvest and the fat and protein concentration of the supplement on milk production and food utilization by lactating cattle
Authors: Peoples A. C. , Gordon F. J.
Published: September 2010

This study was designed to examine the influence of pre-wilting and season of harvesting of silage on milk production and food utilization by dairy cattle and also the response to protein and fat concentration of the supplement given with silage. Twenty-four lactating British Friesian cows were used i n a four-period, partially balanced, change-over design experiment to evaluate 12 treatments consisting of three silage types (spring harvest unwilted (lUnW), autumn harvest unwilted (3UnW) and autumn harvest wilted (3W), each offered in addition to supplements containing both two crude protein levels (160 and 210 g/kg fresh weight) and two levels of inclusion of a fat supplement (0 and 100 g/kg fresh weight) in a 3 × 2 × 2 factorial arrangement. All supplements were offered at the same rate of 6·8 kg/day. Total diet digestibility and food utilization studies were carried out on all animals at the end of the third and fourth experimental periods.

The wilted silage (3W) had a higher digestibility than the unwilted (3UnW) material and animals offered 3W silage consumed proportionately 0·18 more silage DM and produced 1·6 MJ/day more milk energy output than those offered 3UnW. The total ration digesibility and food utilization data showed the animals given the 3W silage consumed 13·5 MJ more metabolizable energy (ME) per day than those offered the 3UnW silage and were less efficient at converting the ME available for production into milk energy output than those given the 3UnW silage (efficiencies were 0·58 and 0·53 for 3UnW and 3W silages respectively).

There were no differences between the digestibilities of the spring (lUnW) and autumn (3UnW) silages with the concentrations of digestible organic matter in the dry matter (DM) being 650 and 648 g/kg respectively. However, animals offered lUnW silage consumed proportionately 0·12 more DM and produced 1·05 kg/day more fat-corrected milk than those given 3UnW silage. The food utilization data indicated that this milk production difference could be accounted for by the higher ME intake on lUnW and that the efficiencies of conversion of ME available for production to milk energy output were similar with both seasons of harvests (efficiencies were 0·57 and 0·58 for lUnW and 3UnW respectively).

Increasing the crude protein concentration of the supplement from 160 to 210 g/kg increased silage DM intake, milk yield and milk energy output by 0·2 kg, 0·66 kg and 1·9 MJ/day respectively with the response being greatest with lUnW and least with 3UnW silage. Increasing the fat concentration of the supplement depressed silage DM intake but increased milk yield by 0·53 kg/day.

The effects of the treatments on total diet digestibility, energy and nitrogen utilization, and the volatile fatty acid concentrations of rumen fluid are also given.
The evaluation of automatic probes in Spain for the new scheme for pig carcass grading according to the EC regulations
Authors: Diestre A. , Gispert M. , Oliver M. A.
Published: September 2010

An evaluation of three automatic recording probes, the Fat-o-Meater (FOM), the Hennessy Grading Probe II (HGP) and the Destron PG-100 (DST) was carried out for use in the revised European Community (EC) Pig Grading Scheme. One hundred and forty-five pig carcasses were selected from four abattoirs covering the national fatness distribution. Two fat thickness depths, one at the head of the last rib (LR) and the other at the 3rd/4th from the last rib (3/4LR fat), and one muscle depth (3/4LR muscle) taken in the same operation for recording 34LR fat were studied as predictors of EC reference lean concentration. All measurements were taken 60 mm from the dorsal mid line. The corresponding cut surface measurements were also recorded and the carcasses were dissected. The prediction of cut surface fat depths from fat depth probes was better than the prediction of cut surface muscle depth from muscle depth taken with the probes. The DST fat measurement predicted more accurately the corresponding cut surface measurements and FOM muscle depth was more precise in predicting muscle cut surface depth. The DST was better in the prediction of EC reference lean concentration with 3/4LR fat and 3/4LR muscle as predictors (residual s.d. 23·1 g/kg). By adding LR as a third independent variable FOM predicted slightly better the lean concentration (residual s.d. 22·3). For Spain, the equations with these three independent variables were submitted to the Pig Management Committee of the EC. All the methods tested predicted EC reference lean concentration with a residual s.d. less than 25 g/kg and a correlation higher than 0·8.
The effect of body reserves at farrowing on the reproductive performance of first-litter sows
Authors: Mullan B. P. , Williams I. H.
Published: September 2010

The level of body reserves in first-litter sows was manipulated by giving gilts one of three levels (high (H), medium (M) or low (L)) of food from selection (44 kg live weight) to parturition. The aim of this experiment was either to maintain or to mobilize these reserves during lactation (31·4 days) by feeding sows to appetite (high (H)) or 2·0 kg/day (low (L)).

When the level of body reserves was increased prior to farrowing (171 kg live weight, 32 mm backfat) sows had a lower voluntary food intake during lactation than those animals that farrowed with a low level of body reserves (126 kg live weight, 20 mm backfat) (H-H v. L-H, 3·4 v. 4·9 kg/day; P < 0·001). Both groups had a normal return to oestrous activity after weaning (mean interval between weaning and mating of 14 days) but the heavier animals mobilized more of their body reserves (H-H −30·7 kg live weight, -4·3 mm backfat; L-H -3·6 kg live weight +0·9 mm backfat; P < 0·001). When food intake during lactation was restricted to 2·0 kg/day the interval between weaning and mating was increased by 50% regardless of the level of body reserves present at farrowing. For the same animals, there were insufficient body reserves to support milk production at the same level as for those animals given food t o appetite.
A note on annual variation of plasma insulin-like growth factor-I concentrations and growth rates of Jersey heifers differing in genetic merit for milk production
Authors: Davis S. R. , Farr V. C. , Gluckman P. D. , Breier B. H.
Published: September 2010

A study was made of the concentration of insulin-like growth factor-l (IGF-I) in the plasma of Jersey cows differing in genetic merit for milk and milk fat production. Plasma IGF-I concentrations exhibited an annual cycle and from this study it is concluded that, in the Jersey breed, selection for increased milk and milk fat production, with the correlated responses of increases in mature live weight and live-weight gain, will not be accompanied by increased plasma IGF-I concentration.
Genetic and environmental influences on beef cattle production in Zambia 4. Weaner production from purebred and reciprocally crossbred dams
Authors: Thorpe W. , Cruickshank D. K. R. , Thompson R.
Published: September 2010

Estimates of dam reproductive performance are reported for purebred Africander, Angoni, Barotse and Boran dams, and the reciprocal crossbreds of the latter three breeds, under ranching conditions in Zambia.

Mean performances based on a maximum of 1996 records collected over six parities were: calving rate, 65·6%; weaning rate, 62·8%; calf birth weight, 26·6kg; calf weaning weight, 163·6kg; and dam live weight at weaning, 363 0 kg.

Purebred Africander and Barotse dams had significantly poorer calving rates, 542 and 57·6% respectively, than the purebred dams of the Angoni and Boran breeds, 69·1 and 66·0% respectively. Reciprocal crossbred dams of the latter two breeds had the highest calving rates, 71·2 and 74·4%. Heterosis estimates for calving rate were 0·8% for Angoni/Barotse crosses, 7·8% for Angoni/Boran crosses and 10·3% for Barotse/Boran crosses and, for weaning rate, 3·7, 6·7 and 11·5% respectively. There were no differences between reciprocal crossbred dams for calving and weaning percentages. The mortality rate of calves born to crossbred dams was 40% and that of the calves born to purebred dams of the same breeds 4·7%. Dam status at mating had an important effect on fertility with the calving rate of dams dry at mating, 89·1%, contrasting with a rate of 39·8% for those dams that were lactating at mating and that had calved late in the season.

There were large differences between breeds for calf weights but heterosis estimates were small and nonsignificant. There were no differences between the progeny weights of reciprocal crossbred dams. Sex, date and period of birth, and dam status had significant effects on calf weights.

Africander dams had the heaviest, and Angoni dams the lightest, live weights at weaning, 421·1 and 320·7 kg respectively. Heterosis estimates for dam live weights were small and non-significant, and reciprocal crossbred differences were unimportant. Dams which lost most live weight during the dry season, that had extremely light live weights at the beginning of the breeding season or that gained little weight during the breeding season had significantly poorer fertility than other dams.

Overall estimates of heritability derived by dam/daughter regression were 0·20 for calving percentage, 0·76 for calf birth weight and 0·72 for calf weaning weight.
The effects of concentrate supplements on the performance of dairy cows offered grass silage ad libitum
Authors: Laird R. , Leaver J. D. , Moisey F. R. , Castle M. E.
Published: September 2010

Ninety-six lactating British Friesian cows were offered ad libitum two grass silages having the following analyses: 181 and 241 g dry matter per kg fresh weight, 108 and 96g digestible crude protein per kg dry matter and 617 and 619 g digestible organic matter per kg dry matter. In addition, four concentrate supplements were offered, containing either 360 g crude protein per kg on an air-dry basis and given at the rate of 015 kg/kg milk or 180 g crude protein per kg given at the rate of 030, 0375 and 0·45 kg/kg milk. Large and highly significant differences were recorded in silage intake, mil yield, milk composition, live weight and condition score during the winter feeding period. These differences in performance were associated more with differences in energy than in protein intake. During the post-experimental grazing period no significant differences between treatments were recorded in milk yield and composition, with the exception of fat concentration, and by midsummer no significant differences were apparent in live weight. The results of the experiment were appraised in economic terms and implications for commercial practice discussed.
A note on the growth of Beefalo crossbred calves in Botswana
Authors: Makobo A. D. , Buck N. G. , Light D. E. , Lethola L. L.
Published: September 2010

In a trial to evaluate the growth of crossbred calves under semi-arid ranch conditions in Botswana, pure Tswana and crossbred beef cows were inseminated with Beefalo and Italian semen or mated naturally with Brahman, Simmental or Tswana bulls. The 424 calves produced were weighed at birth and at monthly intervals t o 18 months of age.

Beefalo crossbred calves were significantly lighter at birth than all other calves (P<0·05). At weaning (7 months) Brahman-sired calves were significantly heavier than Tswana calves, but no heavier than the other breed types. At 18 months of age Brahman, Italian and Simmental crosses were all significantly heavier than Tswana calves (P<0·05), but there was no significant difference between Beefalo crossbred and pure Tswana calves.

These results indicated that the Beefalo cross had no advantage over the indigenous Tswana breed and more-conventional breeds were superior when crossed with the Tswana.
The frequency of cows served twice which remain pregnant to first service: a study of results from parentage tests
Authors: Rendel J. , Bouw J. , Schmid D. O.
Published: September 2010

In 1,347 parentage cases in cattle it was determined whether conception resulted from the first or second service. Among cows served twice within short intervals (1–11 days) about 20% remained pregnant from the previous service. At an interval of one day this proportion amounted to 37%.

About three-quarters of the cows had service intervals of 18–24 days. In most of these the calving took place between the expected dates according to the two services. In 6% of the cases with intervals of 18–24 days pregnancy resulted from the first service. It was estimated that about 1% of all cows mated twice within these intervals had become pregnant from the first service.

Rules are suggested for when blood grouping should be required for registration of pedigrees in the herd book.
Carcass composition of lambs including a method of assessment using tritiated water in vivo
Authors: Davies D. A. R. , Owen J. B. , Cuthbertson A. , Read J. L.
Published: September 2010

Twenty-four Suffolk cross lambs, the progeny of three sires, were reared artificially under standardized conditions and slaughtered at 40 kg live weight.

The tritiated water technique as a means of estimating carcass composition in vivo was evaluated and carcass composition was established using both physical dissection and chemical analysis. Live-weight gain of the lambs from weaning was 389 g/day but the carcasses were lean. Dissected fat, lean and bone percentages were 20·5, 58·4 and 18·9 respectively. Differences between progeny groups were non-significant.

Fat percentage was the most variable body component, although lower than in many other reported studies. The CV for dissected fat was 15·2% and for chemically analysed fat 15·9%. The correlation between estimates for the two methods was high (r = 0·90) despite there being quantities of other constituents in the dissected fat. It was not possible to demonstrate any relationship between reciprocal of tritiated water count and fat percentage or any other measurement of the composition of the whole carcass. Other measurements made on the live animal, such as fasted live weight and ultrasonic determinations of fat thickness and area of m. longissimus dor si were also not related to carcass composition.

It is concluded that neither tritiated water count nor any of the other measurements of the live animal would be sufficiently accurate to be of value in performance testing.
A note on the performance of Assaf male lambs reared intensively on an all-concentrate diet with herring meal or toasted soya bean meal as the main protein source
Authors: Folman Y. , Eyal E.
Published: September 2010

Thirty-five Assaf intact male lambs were divided into three groups and offered an all-concentrate pelleted diet based on barley and maize and supplemented with either toasted soya bean meal, herring meal or toasted soya bean meal plus methionine to contain 20% crude protein. The live-weight gains to a slaughter weight of 57 kg were 425, 440 and 394 g/day, and the feed conversion ratios were 3·12, 3·07 and 3·38 kg dry matter/kg gain, respectively. It is concluded that, with toasted soya bean meal as the protein supplement, it is possible to obtain high growth rates that do not diifer significantly from those obtained with herring meal.
A retrospective analysis of culling in a large AI stud
Authors: Hinks C. J. M.
Published: September 2010

Of 335 British Friesian bulls at AI centres progeny tested during the period 1960–65, 19% were retained for further use in the programme following selection.

A time trend towards more intense selection was observed, from an initial selection rate of 1 in 3 to a final rate of 1 in 7. This appeared to involve increased culling for both daughter type and daughter production.

At all stages of the programme approximately 50% of the selection practised was directed towards attributes other than milk yield.

A comparison of the mean contemporary comparison (c.c.) values of the selected bulls with the values obtained following selection solely for milk yield indicated that the inclusion of daughter type as a criterion of selection reduced the c.c. value of the stud by approximately 33%.

A drastic reduction in the c.c. value of the selected bulls was observed to coincide with the appearance of subsequent groups of daughters in the sire proofs.
The flock-mating of progestagen-synchronized ewes. 1. The influence of ram-to-ewe ratio upon mating behaviour and lambing performance
Authors: Bryant M. J. , Tomkins T.
Published: September 2010

Sixteen Suffolk rams, 8 previously assessed as High libido and 8 as Medium libido, were mated to groups of 6, 12,18 and 30 ewes whose oestrous cycles had been synchronized using progestagen-impregnated vaginal sponges.

Observations over a 3-day mating period indicated that no differences occurred in mating behaviour between High and Medium libido rams. As number of ewes per ram increased, the rams achieved a greater mean total number of mounts and services, but mated a smaller mean percentage of ewes. Also the time taken and the number of services required to mate with all ewes served increased substantially.

As the number of ewes per ram increased the ewes had, on average, to wait longer for their first service and were served less often. There were no statistically significant differences between treatments in the ratio of ewes lambing to ewes served.
Estimation in vivo of the chemical composition of the bodies of mature cows
Authors: Wright I. A. , Russel A. J. F.
Published: September 2010

A number of possible indices of body composition (live weight, skeletal size, total body water as estimated by deuterium oxide dilution, blood and red cell volumes as estimated by Evans Blue dilution, ultrasonic measurements of subcutaneous fat depth and eye-muscle area, and body condition scoring) was examined using 73 non-pregnant, non-lactating, mature cows of Hereford × Friesian, Blue-Grey, British Friesian, Galloway and Luing genotypes, ranging in body condition score from 0·75 to 4·5. Direct measurements of body composition in terms of water, fat, protein and ash were made following slaughter.

Live weight, deuterium oxide dilution, ultrasonic measurements of subcutaneous fat depth and eyemuscle area, and body condition score were all considered to be potentially useful predictors of body composition. Combinations of techniques offered better predictions than did any single index. Using a combination of measurements it was possible to predict body fat and protein with a residual s.d. of 13·1 kg and 3·15 kg respectively. Breed differences in the partition of fat among the main adipose tissue depots necessitated the development of specific prediction equations for body fat based on condition score and subcutaneous fat depth for different breeds. Equations remain to be developed for predicting body composition in cows in different physiological states.