bluuebunny/crossref_metadata_2025 huggingface dataset:
Consequences of inbreeding for financial returns from sheep
Authors: Wiener G. , Lee C. J. , Woolliams J. A.
Published: September 2010

The effects of inbreeding on the gross financial returns from ezues have been studied in a flock of sheep comprising three hill breeds and Ihe crosses among them. Each of these groups mis represented In non-inbred sheep (purebred and crossbred, designated O2, and F2, respectively) and four classes of inbreeding (inbreeding coefficients (F): 0·25, 0·375, 0·50 and 0·59). A second non-inbred class ums represented by crosses of inbred lines.

Gross lifetime income per eive derived from the sale of lamps for slaughter, cast ezves and wool was reduced by inbreeding in an almost linear fashion (between the O2/F2 and the F 0·50 class) at a rate of £1·27 (at 1992 prices) for ench 0·01 (percentage point) increase in the level of inbreeding — an overall reduction to 0·35 of the O2/F2 level. Line crosses gave a better return than the other non-inbred sheep. When expressed in terms of ewe metabolic body weight (M0·73) the decline with inbreeding was less —an overall reduction to 0·4 of the O2/F, income. Inbreeding of Ihe lamb caused a further decline in output independent of the inbreeding of the ezve.
Lactational oestrus in the sow 4. Variation in the incidence and timing of lactational oestrus in groups of sows
Authors: Bryant M. J. , Palmer G. , Petherick D. J. , Rowlinson P.
Published: September 2010

Eighty multiparous Camborough hybrid female pigs (sows) and their litters, on average 15 days post partum, were housed in groups of five in multi-accommodation pens. The sows were fed ad libitum on a proprietary diet containing 160 g crude protein per kg from grouping to 30 days post partum, when they were fed to scale twice daily in individual feeders until weaning at 42 days post partum. One of four Large White male pigs (boars) was introduced to each group on the day following grouping, each boar being run with four groups.

Oestrus occurred in 62 sows, on average 10·2 ± 3·3 days after grouping. The differences between groups in the interval from grouping and boar introduction to the onset of oestrus were statistically significant (P < 0·01). Neither the incidence nor the timing of oestrus could be related to the identity of the boar.

Regression analysis revealed relationships between a number of independent variables and the incidence and timing of lactational oestrus. Sows which gained more live weight from farrowing to weaning and whose litters consumed more creep food were more likely to show lactational oestrus. Sows were slower to show lactational oestrus when they gained little weight from farrowing to weaning, had lower live weights at weaning and gained less weight from the previous weaning, despite eating comparatively more food during grouping. The sows which took longer to show lactational oestrus also had heavier piglets at grouping and more piglets in their litters at weaning. The difficulties arising in the interpretation of these results are discussed.
Food intake, growth and mature size in Australian Merino and Dorset horn sheep
Authors: Thompson J. M. , Parks J. R.
Published: September 2010

The pattern of food intake as a function of age, and live weight as a function of food consumed was examined from soon after weaning to maturity in groups of fine and strong wool Merino rams and Dorset Horn rams and wethers. Each group, which initially comprised 20 sheep and from which individuals were removed for slaughter at approximately 6-kg increments in live weight, was fed a pelleted ration ad libitum for 98 and 77 weeks for the Merino and Dorset Horn groups respectively.

The pattern of food intake was similar for all groups of sheep, in that food intake increased to a maximum at approximately 50 weeks of age and then declined with age with a regular oscillation superimposed on this curve. In all three groups of rams, but not in the Dorset Horn wethers, the oscillations in food intake were on an approximate annual cycle with a decrease in food intake in summer and an increase in winter.

Estimated mature live weights for the strong and fine wool Merino rams were 120·5 and 97·6 kg, and for the Dorset Horn rams and wethers 108·6 and 101·4 kg. Variation between breeds in the level of food intake, food efficiency and consequently the pattern of growth, was largely a function of mature size. The Dorset Horn rams were slightly more efficient at converting food to live weight than the wethers.
The effect in an intensive production system of type of cereal and time of weaning on the performance of lambs
Authors: Ørskov E. R. , Fraser C. , Gill J. C. , Corse Elizabeth L.
Published: September 2010

Two experiments were conducted to study the effect of type of cereal and time of weaning on the performance and voluntary intake of lambs.

In the first experiment 20 early-weaned entire male lambs were given diets ad libitum during the fattening period from 15 to 40 kg live weight. The diets were based on either kibbled maize or rolled barley. A high feed efficiency and growth rate were achieved with both diets and differences between them were not statistically significant. The growth rates were 428 and 430 g/day. The cold carcass weights at 40 kg live weight were 19·0 and 19·9 kg and the conversion ratios of dry matter to live-weight gain were 2·33 and 2·22 for the rolled barley and kibbled maize diets respectively.

In the second experiment a comparison was made of the performance of 36 sets of twin lambs, one of each set being weaned at either 6, 13 or 20 weeks of age and the other being left to suck the ewe outdoors. The lambs weaned at 6 weeks had better conversions of dry matter to live-weight gain than lambs weaned at 13 and 20 weeks. The respective conversions of dry matter to live-weight gain were 3·36, 5·64 and 5·52. The lambs weaned at either 13 or 20 weeks had a greater weight at weaning, a greater growth check at weaning and a lower rate of feed intake.
Prenatal and postnatal competition among twin lambs
Authors: Burfening Peter J.
Published: September 2010

Twin-born Rambouillet, Targhee and Columbia lambs were used to study the effect of sex of lamb and its co-twin on birth weight, weight at 60 days of age and weaning weight. Mean birth weights of female lambs were lower than those of males, and lambs born co-twin to males had a lower mean birth weight than those born co-twin to females. Lambs born co-twins to females grew faster from birth to 60 days of age and had a greater chance of surviving from birth to weaning than did lambs that were co-twins to males.
Design of experiments to estimate offspring-parent regression using selected parents
Authors: Hill W. G. , Thompson R.
Published: September 2010

Heritability or the genetic regression of one trait on another, for example live-weight gain in field v. performance test station conditions, can be estimated efficiently by rearing offspring only from high- and low-ranking individuals, and estimating the regression of offspring on parent performance. Formulae are given for the optimum proportion of available animals to select as parents when the relative numbers of individuals in the parent and progeny generation are fixed. Although the optimum depends on the value of the parameter to be estimated, the designs are very robust to poor estimates.
Performance of sows first mated at puberty or second or third oestrus, and carcass assessment of once-bred gilts
Authors: MacPherson R. M. , Deb Hovell F. D. , Jones A. S.
Published: September 2010

1. Of 80 gilts reared on a restricted plane of nutrition, 75 were allocated to one of four groups. Group 1; 17 gilts mated at puberty were slaughtered after farrowing their first litter. Group 2; 20 gilts mated at puberty were observed for three parities. Group 3; 18 gilts mated at second oestrus were observed for three parties. Group 4; 18 gilts mated at third oestrus were observed for three parities. Group 5; nine additional gilts reared on feed ad libitum and mated at first oestrus were observed for three parities. All animals received the same ration after the first mating.

2. The mean age (±SD) of the restricted gilts at puberty was 186 ± 17 days at a weight of 89 ± 9 kg. The gilts fed ad libitum were significantly (P<0·01) older and heavier at puberty (203 ± 15 days and 120 ± 27 kg).

3. Conception rates were 83, 86, 94 and 82% for Groups 1 and 2 combined, 3, 4 and 5 respectively.

4. Gilts mated at first, second and third oestrus produced, respectively, 7·8, 9·8 and 10·4 ± 2·2 piglets in the first parity. Group 5 gilts had 11·0 ± 2·2 piglets. All significant differences were confined to the first parity.

5. By the end of the third parity there were no differences between the restricted gilts mated at first, second or third oestrus in total number of piglets born or reared.

6. The gilts slaughtered (at 135 kg) after producing one litter yielded carcasses which were heavier but leaner than those from contemporary maiden gilts grown to 120 kg on a semi-restricted feeding scale.
Fertility in Cheviot ewes. 2. The effect of level of pre-mating nutrition on ovulation rate and early embryo mortality in North and South Country Cheviot ewes in moderately-good condition at mating
Authors: Gunn R. G. , Doney J. M. , Smith W. F.
Published: September 2010

In two experiments over 2 years, 57 North Country Cheviot and 82 South Country Cheviot hill ewes were differentially group-fed indoors over a 2-month period to achieve either good or moderate body con- dition. Over 5 weeks prior to mating, ewes in good condition were brought down in condition by restricted feeding and ewes in mod- erate condition were raised in condition by a high level of feeding. The ewes were thus in moderately-good condition at mating. After mating, ewes were maintained in this condition until killed either on return to service or at 29 ± 8 days for counts of corpora lutea and viable embryos.

Ovulation rate in each breed was positively related to the level of pre-mating food intake at the condition level studied. Embryo mortality, as ova loss, was not influenced overall by the level of pre-mating food intake but loss of multiple-shed ova was greater than that of single-shed ova in ewes which had been on restricted feeding before mating. Although a greater proportion of ewes in the North Country Cheviot breed were not pregnant at slaughter, this could not be identified as a breed difference since the breeds were studied in different years.
A note on live weight and intake and digestibility of food by draught cattle after supplementation of rice straw with the fodder tree Ficus auriculata
Authors: Pearson R. Anne
Published: September 2010

One group of five oxen in the Koshi hills of Nepal ate rice straw plus 4 kg fresh weight per day of the fodder tree Ficus auriculata. Another group of five oxen ate only rice straw. Calculations showed both diets were low in rumen degradable nitrogen (RDN). The animals which ate the tree fodder had a higher dry matter (DM) intake than those eating rice straw alone. Both groups consumed less food and lost weight in weeks when they worked for 5 to 6 h (walking 16 km, climbing 600 mlday) than in weeks when they were not walking. No significant differences in digestibility of food were seen. In the weeks after work the group receiving the tree fodder regained weight, while cattle eating only rice straw remained at a lower weight. Supplementation of rice straw with tree fodder rather than expensive concentrate may be acceptable when feeding working oxen although both diets are likely to be deficient in RDN.
A note on supplements for dairy cows offered silage of high digestibility
Authors: Castle M. E. , Retter W. C. , Metcalfe J. D.
Published: September 2010

Grass silage with a dry-matter content of 20·7%, and containing 18·9% crude protein and 67·0% digestible organic matter in the dry matter was self-fed to 20 lactating dairy cows for 18 weeks. In addition, 9 kg of brewers' grains with a dry-matter content of 28·8% was offered to each cow daily. The two supplement treatments were a barley mix and a groundnut cube containing 11·9 and 33·5% crude protein in the dry matter respectively. The barley was given at the rate of 4 kg/10 kg milk, and the groundnut at 1·5 kg/10 kg milk. The mean daily yields of milk were 18·9 and 19·4 kg/cow on the barley and groundnut treatments respectively and did not differ significantly.
The nutrition of the veal calf 6. The effect of ultra-high (68 per cent) fat milk powders added to liquid skim milk, and a comparison with spray-dried skim milk powder containing 20 per cent margarine fat
Authors: Roy J. H. B. , Stobo I. J. F. , Gaston Helen J. , Shotton Susan M. , Ganderton P.
Published: September 2010

1. Fifty-one Jersey, Ayrshire and British Friesian male calves were reared from birth to veal weights on one of three liquid diets.

2. Two ultra-high fat milk powders containing 680 g fat, either beef tallow (T) or a mixture of coconut oil and beef tallow (CT)/kg dry matter were prepared and mixed with liquid skim milk (35 g powder/kg) to give diets TLS and CTLS, containing 200 g fat/kg dry matter. A third diet consisted of reconstituted spray-dried skim milk powder containing 200 g margarine fat/kg (MDS).

3. The incidence of diarrhoea and of nasal discharge for all breeds, and of a high rectal temperature for the Ayrshire breed was greatest for calves given diet MDS and lowest for those given diet TLS. The incidence of lung lesions at slaughter was 100, 72 and 57% for the Jersey, Friesian and Ayrshire breeds respectively. Severity of lung lesions was lowest for calves given diet TLS.

4. Dry-matter intake and live-weight gain, especially for the Ayrshire breed, were greater for calves given diets containing liquid skim milk and the ultra-high fat powders (TLS and CTLS).

5. Fat digestibility was lowest on diet TLS. Protein digestibility increased with age. Digestibility of dry matter and lactose, and absorption of ash and calcium decreased with age. Calcium and N retention were lowest on diet MDS.

6. Killing-out percentage was highest for the Friesian and lowest for the Jersey breed. Perirenal fat deposition was highest for the Jersey and lowest for the Ayrshire breed. Skin weight/kg0·73was higher for the Ayrshire calves than for the other two breeds.
Selection in a population with overlapping generations
Authors: Bichard Maurice , Pease A. H. R. , Swales P. H. , Özkütük K.
Published: September 2010

A theoretical investigation is reported into the effects of overlapping generations on the prediction of genetic gain from repeated within-population truncation selection for a quantitative trait. The gain resulting from the selection process produces genetic differences between the groups of breeding animals of different ages, and between the means of their progeny. These differences are not allowed for in the usual prediction formula. The correct allowances to make for the genetic effects of maternal age are derived for a simple situation. The implications of these allowances on the overall rate of genetic progress, and on the optimum age structure for maximum progress, are shown in a model pig breeding programme. The normal prediction formula underestimates the genetic gain which can be achieved if females are kept for five litters by 10 to 12%, and overestimates the disadvantages of keeping females for more than one or two litters.
The performance of early-weaned calves offered concentrates or artificially dried grasses
Authors: Marsh R.
Published: September 2010

In two experiments dried grass cobs or concentrate were offered to calves for 20 weeks after weaning. In Experiment 1 the grasses were harvested in the autumn and in Experiment 2 in the spring. Within each experiment three grasses differing in quality and two levels of concentrate were compared.

Dry-matter intake of the dried grasses highest in digestibility was lower than that of medium digestibility grass, and hardness of package, palatability and mould infestation were implicated as possible causal factors.

Live-weight gains by calves were closely correlated with digestible organic matter (DOM) intake. There was no significant difference between spring harvested grasses and concentrate in efficiency of utilization of DOM for live-weight gain but autumn grasses were used less efficiently than concentrate. At similar rates of gain the replacement value (dry-matter basis) of dried grass for concentrate averaged 142: 1.
Comparative digestibility experiments with growing pigs and adult sows
Authors: Fernández J. A. , Jørgensen H. , Just A.
Published: September 2010

The digestive ability of growing pigs and large adult sows was compared in digestibility experiments with 26 foodstuffs and diets. In all cases, the sows showed superior digestibility of nutrients. On average, the sows digested 150 g more crude protein, 100 g more crude fat, 300 g more crude fibre per kg diet and proportionately 0·09 more gross energy than the young animals. The superior ability of the sows to digest gross energy was negatively correlated with the soluble carbohydrate and gross energy concentration of the food. A close linear relationship between digestibility in growing pigs and that in sows was found, making it possible to apply digestibility data for growing pigs in practical diet formulation for sows.
Circadian variation in composition of duodenal and ileal digesta from pigs fitted with T-cannulas
Authors: Graham H. , Åman P.
Published: September 2010

Circadian variation in the composition of digesta was examined in pigs fitted with replaceable T-cannulas in the proximal duodenum and terminal ileum. The pigs were fed twice daily with a cereal-based diet containing Cr2O3, as a marker. Digesta were collected hourly for 16 h following morning feeding (pig live weight (LW) 25 and 65 kg) or as a 12-h composite collection (pig LW 45 kg), and analysed for pH, dry matter (DM), ash, crude fat, crude protein, starch, neutral-detergent fibre (NDF) and Cr2O3,.

No statistically significant differences were found in the composition of digesta from pigs weighing 25 or 65 kg LW. Calculated relative to Cr2O3, recoveries in 12-h composite samples of duodenal and (ileal) digesta were 1·19 (0·34) for DM, 1·28 (0·31) for crude protein, 0·97 (0·05) for starch and 0·93 (0·79) for NDF. Composition of both duodenal and ileal digesta varied considerably during the sampling period and was particularly influenced by giving food. Between-hour coefficients of variation for the samples taken hourly were, in general, greater at the duodenum (mean 017) than at the ileum (mean 0·11), while mean within-hour (between pigs) coefficients of variation (0·19 and 0·18, respectively) were greater than those between hours. The Cr2O3 marker generally followed the flow of dietary matter through the gastrointestinal tract, although there was an indication of a partial separation of NDF from other dietary components in the stomach. Composition of the 12-h composite samples of digesta did not differ from that of the mean of the samples taken hourly for 16 h.
Relationships between whole-body chemical composition, physically dissected carcass parts and backfat measurements in pigs
Authors: Rook A. J. , Ellis M. , Whittemore C. T. , Phillips P.
Published: September 2010

Log-linear relationships between various measurements of the chemical and physical body composition of the pig were obtained in four datasets representing a range of sexes, genotypes and feeding treatments. One of these datasets (dataset 1) comprised genetic control and selection line Large White pigs. There were significant differences between datasets for most of the relationships investigated. The causes of the differences cannot be determined. Within datasets, relationships between various body components and the weight of crude protein in the whole body were unaffected by genotype or sex. The relationships of both intermuscular fat and trimmed carcass lipid with whole body lipid differed significantly between the control and selection lines in dataset 1. Fat thickness measurements taken over the m. longissimus at the last rib were less at the same body lipid in the selection line than the control line suggesting a redistribution of fat away from this area as a result of selection. Relationships between viscera, lungs and empty body weight were significantly affected by line while those between trimmed carcass, liver, kidneys and empty body weight were significantly affected by sex. Selection line pigs had less perinephric and retroperitoneal fat than controls at the same whole body fat weight and less subcutaneous fat at the same cold carcass weight. There were no significant line effects on lean or bone weight distribution. Selection line pigs had significantly less subcutaneous fat in the collar joint and more intermuscular fat in the ham. There were few significant sex effects on tissue weight distribution.
A note on the effect of castration on the ease of movement and handling of young cattle in yards
Authors: Hinch G. N. , Lynch J. J.
Published: September 2010

The ease with which cattle can be handled during routine husbandry operations is a major concern to producers. Ease of handling is difficult to define but includes the case with which cattle can be moved through yards, through a race or held in a crush or scales. Few studies have attempted to measure ‘ease of handling’ of animals. ‘Temperament scores’ of cattle of various breeds, sexes and ages based on the scoring system originally described by Tulloh (1961) were recorded by Hearnshaw, Barlow and Want (1979). These scores were highly repeatable between scorers and within animals although some decline in scores occurred with repeated measurements. Hearnshaw et al. (1979) suggested that the scores were a measurement of ease of handling rather than temperament.
The value of indicator traits in the genetic improvement of dairy cattle
Authors: Woolliams J. A. , Smith C.
Published: September 2010

The value of indicator traits (7), such as physiological or biochemical traits in the genetic improvement of dairy cattle for milk yield (M) was studied. First, some corrections were made to the base rates of genetic change possible by improvement systems based on progeny testing and on multiple ovulation and embryo transfer (MOET), and on combinations of these. Efficient field progeny-testing systems can be competitive with current adult MOET nucleus herd schemes but juvenile MOET nucleus herd schemes offer substantial increases in rates of response. With high co-heritability, selection for the T alone may allow greater rates of response than those currently considered feasible using progeny testing. However, faster rates are obtained with combined selection. When breeding values are accurately measured by pedigree and performance records on M, as in the progeny test, the extra rates of response with combined selection may be small. Where breeding values are less accurately assessed, as in juvenile MOET nucleus schemes, the extra rates of response can be appreciable. For T with co-heritability (hMrGhT) of 0·27 and the CV for M from 0·15 to 0·20, response rates of 2·0 to 2·7% of the mean per year possible by traditional methods could be increased to 2·2 to 2·9% in progeny testing schemes, 2·3 to 3·1% and to 4·3 to 5·7% for adult and juvenile MOET nucleus schemes respectively.

A possible useful indicator trait is blood urea nitrogen (BUN) measured in young animals after a short fast. Results from four experiments with calves having high or low genetic merit for M were summarized. The pooled co-heritability estimate was —0·27 (s.e. 0·05). With this, or even a more modest effect, BUN would be a useful indicator trait in selection for milk production. Its use in practice in high and low selection lines or in a section of the industry, would allow assessment of the merit of the method.
Accuracy and consistency of prediction of pig carcass lean concentration from P2 fat thickness and sample joint dissection
Authors: Planella J. , Cook G. L.
Published: September 2010

Commercial carcass grading measurements and sample joint dissection were evaluated as predictors of carcass lean concentration using a data set of 1320 pig carcasses from four breeding companies. Entire males, castrated males and gilts from White-type and Meat-type populations were reared on ad libitum or restricted feeding regimens and slaughtered to achieve a carcass weight of either 52·5 kg or 72·5 kg. A model was fitted which examined the accuracy and stability of regression equations for different populations, sexes and feeding regimens, and different values of P2 and carcass weight. The regression slope of lean concentration on P2 differed by sex and population. Lean concentration decreased faster with increases in P2 among gilts than among entire or castrated males. At the same level of P2 and carcass weight, pigs fed ad libitum contained 5 g/kg less lean in the carcass than pigs fed at a restricted level. Biases among populations, sexes and feeding regimens were also found when carcass lean concentration was predicted from additional measurements: muscle depth at P2, fat thickness and muscle depth at 3/4 last ribs, and eye-muscle area. The regression slope of lean concentration on sample joints showed little evidence of variation among populations (except for the hand joint), sexes or feeding regimens. There were important differences in the intercept for different populations. The ham was the most accurate (residual s.d. = 11 g/kg) and least biased joint.
Genetic components of carcass and meat quality traits in Meishan and Large White pigs and their reciprocal crosses
Authors: Serra J. J. , Ellis M. , Haley C. S.
Published: September 2010

The prospect that genes from the Chinese Meishan pig will be used to improve reproductive performance of European pigs requires that the Meishan is evaluated for traits of economic importance and the genetics of any breed effects investigated. Entire male and female pigs of four genotypes; purebred Meishan (MS) and Large White (LW) pigs and both reciprocal Fl crossbred genotypes (MS ♂ × LW ♀and LW ♂ × MS ♀), were fed ad libitum and slaughtered at about 70 kg. After slaughter, carcass weight, dimensions and conformation were recorded and fat depths at the shoulder, mid back and loin were measured on the carcass, together with fat depths and eye muscle dimensions recorded on a section cut at the last rib position. Drip loss, muscle reflectance and pH were measured and subjective assessments of fat firmness, fat separation, muscle marbling and muscle colour were made. Genotypic means and genetic crossbreeding effects (direct additive and heterosis effects and maternal additive effects) were estimated using restricted maximum likelihood procedures. When compared with the LW, MS carcasses had a similar killing-out proportion but were shorter with a poorer conformation. MS carcasses had substantially greater fat depths and reduced eye muscle dimensions in comparison with the LW. Differences between genotypes for fat depths and muscle dimensions were largely controlled by direct additive gene action, there was little evidence of direct heterosis and hence Fl crosses were intermediate between the purebreds. Significant genotype × sex interaction meant that genotypic differences for these traits were much greater in females than in males. Significant direct additive genetic differences between female genotypes were found for fat firmness, fat separation and drip loss, but these effects may in part have been a consequence of subcutaneous fat depth differences between genotypes. The degree of marbling was greater in MS females than in females of the other three genotypes and these genotypic differences did not seem to be associated with subcutaneous fat depth. Muscle from MS males was darker in colour with a lower reflectance than that from LW males. Genotype × sex interaction was such that genotypic differences for meat and fat quality traits differed between sexes.
The effect of straw on farrowing site choice and nest building behaviour in sows
Authors: Arey D. S. , Petchey A. M. , Fowler V. R.
Published: September 2010

Farrowing site choice was examined in 40 sows. In group 1, the preference of 16 sows was tested for pre-formed lying areas which incorporated the characteristics of previously observed farrowing nests: a hollow (H), a mattress (M), a nest box (B) and a flat control (C). None of the sows farrowed on C which indicated that choice was based on some evaluation of the lying surface. However, there was no significant preference for the three nest features: H6, M6, B 4. In group 2, C was replaced by a straw area (S). Four different amounts of straw were offered: 18, 9, 4·5 and 2·25 kg with four, four, eight, eight sows on trial at each amount respectively. All the sows farrowed on S at the 18, 9 and 4·5 levels; at 2·25 kg, three farrowed on S and five moved the straw to other lying areas on which they farrowed. The results indicated that the location of nest material has an important influence on farrowing site choice because it allows the performance of nesting behaviour. Although performance of the behaviour was not affected by the amount of straw available, 2·25 kg appeared to be inadequate for a satisfactory nest.
Teat productivity in second lactation sows: influence of use or non-use of teats during the first lactation
Authors: Fraser D. , Thompson B. K. , Rushen J.
Published: September 2010

Previous research has shown that piglets using the sow's more anterior teats tend to have greater average weight gains, but this difference is often slight in the first lactation and increases in subsequent lactations. In this study, 27 sows were used to determine whether this difference develops because of the piglets' preferential use of the anterior teats during the first lactation. In their first lactation, 14 sows had their anterior teats (pairs 1 to 3) and 13 sows had their posterior teats (pairs 4 to 7) covered so that the piglets could use only one end of the udder. In the second lactation, all the teats were left uncovered and the sucking positions and weight gains of the piglets were studied. Piglets in the second lactation showed the usual preference for anterior teats regardless of which teats had been used in the first lactation. Where the anterior teats had been covered in the first lactation, there was no difference in weight gain between anterior- and posterior-sucking piglets in the 1st week of the second lactation, but a degree of anterior superiority had developed by the 3rd week (P < 0·01). Where posterior teats had been covered in the first lactation, piglets using anterior teats showed substantially greater weight gains than those using posterior teats throughout the first 3 weeks of the second lactation (P < 0·001). Thus, non-use of a teat in the first lactation tended to reduce its productivity, at least in the early part of the next lactation. We conclude that previous non-use of posterior teats can contribute to their tendency for lower productivity, but the effect does not explain completely the greater piglet weight gains usually associated with using the anterior teats.
Estimates of the energy required for maintenance by adult sheep 1. Housed sheep
Authors: Langlands J. P. , Corbett J. L. , McDonald I. , Pullar J. D.
Published: September 2010

Eight adult ewes were fasted for 114 hr. During the last 48 hr. the heat emission of each sheep was measured by direct calorimetry and was found to be 35·2 kcal./kg.0·87/24 hr., that is, 973 kcal./24 hr. for a sheep of 45·4 kg. (100 lb.) live-weight. From this value it is estimated that the 100 lb. sheep would require daily 0·79 lb. digestible organic matter (DOM) from pasture herbage for maintenance.

In a second experiment, 49 adult sheep were kept indoors and fed on fresh herbage for a period of 72 days. Measurements were made of the mean daily DOM intake (D), mean live-weight (W) and mean daily weight gain (G) of each sheep. The regression of D on Wk and G, and the underlying or functional relationship between D, Wk and G were both estimated for k = 0·73 and k = 1·0. From the underlying relationships, the preferred equations, the maintenance requirement of a 100 lb. sheep was estimated to be 0·82 lb. DOM daily. This value and those calculated for other live-weights are approximately two-thirds of the corresponding values given in ‘Rations for Livestock’ (Evans, 1960).
Intensive beef production 1. Performance of cattle given complete ground diets
Authors: Preston T. R. , Whitelaw F. G. , Aitken J. N. , Macdearmid A. , Charleson Euphemia B.
Published: September 2010

1. Seventeen Friesian steers, 25 Aberdeen-Angus crossbred steers and 33 Aberdeen-Angus crossbred heifers were fed on complete ground diets from 3 months of age until slaughter.

2. The average time taken from 84 days of age to reach a slaughter live-weight of 400 kg. was 334 days for Friesian steers and 356 days for the crossbred steers. The crossbred heifers took 354 days to reach a slaughter live-weight of 350 kg. Feed conversion efficiency was best for Friesian steers and poorest for crossbred heifers.

3. The ratio of hindquarter to forequarter in the carcass did not differ between breeds. There were marked differences in fat development, this being most pronounced in the crossbred heifers and least in the Friesian steers.

4. The commercial value of the carcasses was assessed by a score card based on measurements, analysis of the tenth rib cut and visual appraisal. There was no difference between the scores for crossbred steers and heifers but the mean score for the Friesians was considerably lower.
Perinatal deaths among calves in a crossbred dairy herd
Authors: Donald H. P.
Published: September 2010

An analysis has been made of still-births and difficulties at parturition in a dairy herd in which purebreds and crossbreds of Friesian, Ayrshire and Jersey origin were kept. There were 2,049 calvings including 28 involving twins.

Purebred heifer dams produced 14·7% dead purebred calves (mostly Friesian and Jersey) and 6·4% dead crossbred calves (P < 0·05). For older dams the corresponding values were 2·4% and 3·6% (P > 0·05). Losses were smaller with crossbred dams. Crossbred heifer dams (two-breed crosses) with 6·5% dead calves exceeded older crossbreds with 1·9% dead calves. Three-breed crossbred dams gave similar results (8·2% and 1·2%). An intermediate size of cow of second or later parity was associated with the lowest mortality.

Friesian and Hereford sires, the calves by which were heavier than those by Ayrshire and Jersey sires, were associated with greater losses than were the latter but this applies to heifer dams and not to the same extent if at all, to older dams.

Of 52 parturitions described as difficult, 31 resulted in dead calves. Malpresentation accounted for 32 cases; the majority of these were ‘hindfeet first’. Friesian and Hereford bulls sired a higher proportion of the calves involved in difficult cases than Ayrshire and Jersey sires.
The nutrition of the early-weaned calf III. Protein solubility and amino acid composition as factors affecting protein utilisation
Authors: Whitelaw F. G. , Preston T. R.
Published: September 2010

1. Nitrogen balance studies have been conducted on 16 early-weaned calves given four diets containing groundnut meal or herring meal, the protein of which had been rendered soluble or insoluble by different methods processing.

2. There were highly significant differences in nitrogen retention between ‘soluble’ and ‘insoluble’ herring meals but no differences between ‘soluble’ ‘insoluble’ groundnut meals.

3. ‘Insoluble’ herring meal gave retention values which tended to be higher (significantly so, in one experiment), and ‘soluble’ herring meal gave values significantly lower, than either type of groundnut meal. Mean daily live-weight gains tended to follow the same pattern.

4. Blood-urea concentration was significantly lower on the diets containing herring meal than on those containing groundnut meal but within each type meal did not differ according to solubility.

5. These results are discussed in the light of in vitro studies on the effect of pH on protein solubility.

6. It is concluded that solubility is of minor importance in groundnut meals but of major importance in fish meals when these are included in early weaning diets for calves.

7. Under conditions of low or ‘potentially low’ solubility the amino acid content of the protein source appears to be of considerable significance.
Effects in bacon pigs of differing levels of nutrition to 20 kg. body weight
Authors: Nielsen Henning E.
Published: September 2010

Sixteen blocks of eight littermate pigs were weaned at 3 weeks of age and each divided into four groups. Various levels of nutrition were applied to the pigs so that the four groups reached 20 kg. at 59, 68, 80 and 91 days of age, respectively.

Only small differences were observed between groups in feed conversion ratio to 20 kg.; however, Group 4 required more feed per kg. gain than the three other groups.

During the second period (20–90 kg.) the pigs in each group were divided into two sub-groups, which were on a high and a low plane of nutrition respectively. In both sub-groups the type of feeding before 20 kg. influenced the average daily gain and feed conversion ratio. The older the pigs were at 20 kg. the higher the daily gain and the lower the feed conversion ratio in the following period. There was an increase in daily feed intake with increased age at 20 kg. for pigs fed ad lib. during the second period.

An increase in age at 20 kg. caused a significant decrease in thickness of backfat, a greater area of eye muscle and a smaller area of fat overlying muscle. For pigs fed ad lib. the area of eye muscle was significantly increased by a higher age at 20 kg. live-weight.
Genetic correlation during growth of twin cattle
Authors: Taylor C. S. , Craig Jean
Published: September 2010

All possible inter-age genetic correlations were calculated for each of twelve linear body measurements taken at 3-monthly intervals up to 2 years of age on 120 pairs of uniformly reared, liberally fed one-egg and two-egg twin dairy heifers. Genetic correlations between first and second-year mean size are also given. The influences of age, age interval, degree of maturity and body part on genetic correlation are examined.

Genetic correlation was in general very high. No significant difference was found between body parts in mean genetic correlation over the period studied. For a fixed age interval, genetic correlation increased with age; from a fixed age, it decreased with lengthening age-interval.

The main systematic trends found in the data were accounted for in terms of the amount of development taking place. Genetic correlation appeared to decrease exponentially with difference in degree of maturity, and a formula is given for calculating an approximate value for the expected genetic correlation between size at any two ages. Its range of applicability and its place in a general study of the genetic properties of a population of growth curves are discussed.
An egg transfer study of litter size, birth weight and lamb survival
Authors: Bradford G. E. , Taylor C. S. , Quirke J. F. , Hart R.
Published: September 2010

In an egg-transfer experiment, seven breeds of sheep differing widely in mean mature ewe weight were used: Oxford Down, 96 kg; Borderm Leicester, 77; Finnish Landrace, 55; Southdown, 52; Tasmanian Merino, 42; Welsh Mountain, 34; and Soay, 22. Body weight and gestation length of recipient ewes are briefly examined. Of 60 recipient ewes, 95% became pregnant. Embryo survival averaged 69% and appeared to be independent of breed of embryo. Litter size of Welsh Mountain, Border Leicester and Finnish Landrace ewes each given four eggs averaged 2·6, 2·9 and 2·9 respectively so that most of the normally observed breed differences are mainly due to differences in ovulation rate. Observed birth weights were in general agreement with those predicted from litter size and donor and recipient ewe weights. The maternal capacity of Finnish ewes was close to average. Litter size affected survival mainly through its effect on birth weight. For Oxford lambs in litters of 3 to 5 from Finnish recipients, birth weight was 42% that of normal single-born Oxfords and only 42% survived. For Soays the corresponding values were 59% for birth weight and 85% for survival. Finnish lambs were exceptionally small at birth but had the highest viability of all breeds. Lamb mortality was higher for males (18%) than females (9%) especially in large litters (26 v. 11%) but about the same in both sexes for Finnish lambs.
Relationships between haemoglobin type and copper concentrations in whole blood and its components in sheep of different breeds
Authors: Wiener Gerald , Hall J. G. , Hayter Susan , Field A. C. , Suttle N. F.
Published: September 2010

Copper concentrations were determined in whole blood, plasma and caeruloplasmin and calculated for red cells and non-caeruloplasmin copper in plasma in 215 female sheep, 9 months old, belonging to the Scottish Blackface, Cheviot and Welsh Mountain breeds of sheep and their crosses. Copper determinations were also made on red cells and plasma, and calculated for whole blood, of a contemporary group of 107 female sheep of the same breeds at the age of 4 years. Further, plasma copper concentrations were determined for these 107 sheep from samples taken on several occasions some years earlier.

Within breed, sheep of type Hb B had significantly higher levels of copper than sheep of type Hb A in whole blood and most of the blood components. The biggest differences were found in plasma and were 19 ng/100 ml for one group and 37 Jig/100 ml for the other. Type Hb AB sheep were intermediate in copper level. The differences in plasma copper level associated with Hb type were present and of similar magnitude at different ages, seasons and average flock levels of copper.

After adjustment for the effects of Hb type, breed differences in copper levels were significant for whole blood and all components but much less pronounced for red cells than for plasma. Copper levels in plasma and red cells were only moderately correlated (r = 0·23–0·40).

Combined evidence suggests the existence of a gene with a marked effect on copper level which is linked to the locus for Hb type.
Genetic aspects of voluntary food intake in the pig and their association with gain and food conversion efficiency
Authors: Wyllie D. , Morton J. R. , Owen J. B.
Published: September 2010

Data from 1357 boarsad libitumfed on a performance testing scheme were analysed to explore the genetic aspects of voluntary food intake. The heritabilities of food intake, daily gain and food/gain were found to be 0·23, 0·41 and 0·18 respectively. The correlations obtained between gain and intake of 0·63 (phenotypic) and 0·89 (genetic) were typical of those reported forad libitumfeeding but greater than those reported for semi-restricted. Estimates of genetic correlation between gain and efficiency ranged from 0·64 to zero and for the phenotypic correlation from 0·44 to zero and were smaller than those reported for restricted feeding. Correlations between intake and efficiency were highly negative on the phenotypic level but small and of variable size genetically, in contrast to reports of small phenotypic and positive genetic correlations under restriction.
A note on the heritability of litter traits in pigs
Authors: Strang G. S. , Smith C.
Published: September 2010

Estimates of heritability for 9 litter traits were derived from data on 38 000 Large White and 35 000 Landrace litters by daughter-dam regression (parities 1 to 5) and by a three-level nested half-sib analysis (parities 1 to 3). The regression and half-sib heritability estimates were similar and overall the estimates were quite low, averaging 7% across traits and breeds. This is in general agreement with estimates from two other large-scale European analyses of field data. Some other reports, including lesser experimental material, show rather higher heritability values.
Coordinated trials on the protein requirements of sows 2. A comparison of two levels of dietary protein in gestation and four in lactation
Authors: Greenhalgh J. F. D. , Baird Barbara , Grubb D. A. , Done S. , Lightfoot A. L. , Smith P. , Toplis P. , Walker N. , Williams D. , Yeo M. L.
Published: September 2010

1. Gestation diets formulated to contain A, 9 or B, 11 % protein, and lactation diets with C, 13; D, 15; E, 17 and F, 19 % protein provided eight treatment combinations. They were given at 2 kg/day in gestation and approximately 5·7 kg/day in lactation to sows at eight centres, which remained on experiment for 3 to 5 parities and produced in total 529 litters. Mean results for parities 1 to 3 are given in this summary.

2. Sows given more protein during gestation (i.e. diet A v. B) gained more weight in gestation (18·3 v. 22·5 kg net gain) but lost more in lactation (—1·7 v. —5·2 kg). Their offspring were significantly heavier at birth (1·31 v. 1·36 kg) and at 3 weeks old (5·28 v. 5·49 kg), but not at 6 weeks old (weaning).

3. Giving more protein in lactation caused linear increases in piglet weights at 3 and 6 weeks, and a linear reduction in creep feed consumption. From a sample of sows whose milk yields were recorded, extra protein appeared to increase milk yield and its protein content. Extra protein for lactating sows also reduced their live-weight loss in lactation, but this effect was partially counterbalanced by smaller gains in gestation.

4. No treatment had consistent significant effects on litter size or on the interval from weaning to conception. There were no significant interactions between gestation and lactation protein concentrations.

5. The generally large differences between centres were in a few cases associated with centre × treatment interactions, but these were not such as to cast doubt on the general applicability of the main findings of the experiment.

6. From this and an earlier experiment the minimum protein level for diets based on barley was concluded to be 11 % during gestation and 15% during lactation. For lactation diets, however, the economic optimum level may be > 15 %.
The inheritance and effect on production of polledness in four crossbred lines of beef cattle
Authors: Frisch J. E. , Nishimura H. , Cousins K. J. , Turner H. G.
Published: September 2010

Changes in the frequency of the poll gene and the effect of polledness on production were measured from 1970 to 1979 in four closed lines of crossbred cattle. The lines were Africander cross (AX), Braham cross (BX) and two Hereford × Shorthorn (HS lines, one selected for production (HSS) and one a control line (HSR).

Calves were classified as horned, polled or scurred. Except in the HSS line, horned males were more common than horned females. Horned HS bulls sired only horned calves when mated to horned cows but corresponding matings of AX and BX breeds produced some polled progeny. The incidence of scurs was highest in the AX line, lowest in the HS lines and higher in males than females. These observations are discussed in relation to existing models of inheritance of horn-type.

Prior to 1970 the frequencies of the poll gene declined from their initial values in the BX and HS lines and increased in the AX line. These changes were ascribed to random genetic drift. After 1970 the frequency of the poll gene remained stable in all lines.

No significant differences were observed between horned and polled cattle in live weight, fertility or mortality rates indicating that polledness had no detrimental effect on production in these lines.
Digestible energy content of meat meals and meat and bone meals for growing pigs
Authors: Batterham E. S. , Lewis C. E. , Lowe R. F. , McMillan C. J.
Published: September 2010

1. The digestible energy content of 14 meat meals and meat and bone meals produced from different regions in eastern Australia was determined using growing pigs. The relationship between digestible energy content and chemical constituents in the meals was investigated.

2. Digestible energy ranged from 9·4 to 13·9MJ/kg (air-dry basis). This variation in digestible energy was best described by the regression equation:

3. Simpler equations, with only gross energy or crude protein and ether extract were:

4. Digestibility of the energy and crude protein in the meals ranged from 0·63 to 0·77 and 0·73 to 0·91 respectively. These variations were not related to any of the major chemical constituents of the meals.