bluuebunny/crossref_metadata_2025 huggingface dataset:
Maternal performance in sheep as affected by breed, crossbreeding and other factors
Authors: Wiener Gerald , Hayter Susan
Published: September 2010

Maternal performance of female sheep of three hill breeds, Scottish Blackface, Cheviot and Welsh Mountain, and the crosses among these breeds has been studied in terms of lifetime production and some of its components. The data are based on 193 ewes, which were given the opportunity of having four annual lamb crops, and their lambs.

There was no significant variation among the breeds and crosses in ewe survival or in the proportion of barren ewes at each lambing. There was significant variation among the breeds and crosses in the number of lambs born per ewe lambing, in lamb survival and in weights of lamb at birth and at weaning. Crossbred ewes (producing crossbred lambs) had more and heavier lambs than expected from the average of the pure breeds contributing to each cross, but the three crossbred types differed in the amount of heterosis shown. Over their lifetime in the flock there were significant breed differences in the total weight of lambs weaned, with crossbred ewes producing about 9% more than the average of the parent breeds involved. The crossbred ewes produced more weight of lambs over their lifetime than pure Cheviot or pure Welsh Mountain ewes, but not as much as pure Scottish Blackface.

Effects of parity of dam and of sex, birth type, and type of rearing of lamb are given.
The rate of cutaneous evaporation in some tropical and temperate breeds of cattle in Nigeria
Authors: Amakiri S. F. , Mordi R.
Published: September 2010

The rate of cutaneous evaporation was highest in the White Fulani (Bos indicus) followed by the N'Dama and German Friesian (Bos taunts). The lowest rate of evaporation was recorded in the Muturu (Bos taurus brachyceros). In all breeds, the rate at 15.00 hr was significantly higher than at 18.00 hr.

For the sites sampled, evaporation rate was highest on the hump and mid-side, followed by the neck and lateral thigh and lowest on the dewlap and navel flap.

The possible correlation of these results with the size and distribution of the sweat glands on various sites of different cattle breeds is discussed.
An evaluation of the micronization process for preparing cereals for the growing pig. 3. A note on the effect of micronization temperature on the nutritive value of wheat
Authors: Lawrence T. L. J.
Published: September 2010

1. In two experiments the nutritive value for the growing pig of wheat which had been micronized at temperatures of 155°, 190° or 220°C, flaked (rolled) and then ground was compared with wheat which had either been ground, or rolled and then ground.

2. In the first experiment 60 pigs offered individually, restricted amounts of feed were used in a growth and efficiency of conversion study. In the second experiment 15 pigs were used in digestibility and nitrogen retention studies.

3. The highest micronization temperature gave a significant depression in growth rate and in efficiency of conversion of dietary dry matter as compared with the other treatments for which there were no significant differences.
The effect of time of weaning on the biological efficiency of meat production in sheep
Authors: Walsingham J. M. , Large R. V. , Newton J. E.
Published: September 2010

The value of E, defined as the weight of carcass produced per 100 units of digestible organic matter (DOM) consumed, was used to assess the biological efficiency of meat production in housed sheep. The effect on E of weaning lambs at 4, 6, 8, 10, 12, 14 and 16 weeks post partum was studied for a number of different breed crosses. The age at which lambs were weaned was found to have little effect on the growth rate of lambs and no significant effect on the biological efficiency with which sheep produce meat.
Factors affecting calving difficulty and gestation length in cows mated to Chianina bulls and factors affecting the birth weight of their calves
Authors: Wilson A. , Willis M. B. , Davison C.
Published: September 2010

Imported semen from 10 Italian Chianina bulls was used to inseminate beef and dairy cattle throughout England and Southern Scotland. A total of 2134 records of calving performance were subjected to least squares analyses. Dystocia score was significantly affected by county of birth, parity of dam, sire, type of birth, birth weight (P < 0·001), season of birth and sex of calf (P < 0·01). There were no significant effects of breed or size of cow. Serious dystocia was encountered in 3% of calvings, with the incidence for individual sires ranging from 1·7% to 6·7%. Arithmetic mean gestation length was 284·2 days and it was significantly affected by county, sire (P < 0·05), sex of calf (P < 0·01), and type of birth (P < 0·001). Arithmetic mean birth weight of the calves was 41·2 kg and this was significantly affected by all main effects studied except season of birth and type of herd.
Effects of plane of nutrition, diethylstilboestrol implantation and slaughter weight on the performance of Israeli-Friesian intact male cattle
Authors: Levy D. , Holzer Z. , Folman Y.
Published: September 2010

The effects of two levels of energy intake, ad libitum and 80% of ad libitum, of diethylstilboestrol implantation and no such treatment, and of two slaughter weights (‘450’ and ‘490’ kg), on the performance of Israeli-Friesian intact male cattle were studied.

Average daily gain was 1130 g and 959 g and daily carcass gain was 630 g and 553 g for animals on ad libitum and 80% of ad libitum energy intake, respectively. Average daily gain was 1038 g and 944 g and daily carcass gain was 595 g and 562 g, for diethylstilboestrol-treated and untreated animals, respectively. Slaughter weight had little effect on rate of gain.

The differences in conversion ratio of ME into live weight between treatments were small. Diethylstilboestrol-treated animals were slightly more efficient.

The non-implanted animals on the restricted plane of nutrition and which had been slaughtered at ‘490’ kg had a significantly higher dressing percentage, a higher percentage of fat trim and less bone than animals slaughtered at ‘450’ kg body weight on both levels of nutrition.

Among the diethylstilboestrol-implanted male calves, however, the animals fed at 80% of ad libitum feed and killed at ‘450’ or ‘490’ kg live weight had significantly more fat trim in the carcass and less bone than the animals fed ad libitum.
Comparative methods of testing Hereford × Friesian progeny groups for growth and carcass characters
Authors: Wood P. D. P. , Hodges John
Published: September 2010

Ways of conducting a progeny test for growth of carcass characters are discussed with reference to statistical efficiency. An intensive system (375 kg slaughter weight) is compared with a semi-intensive system (475 kg slaughter weight) and the use of intermediate results as predictors of the final outcome is discussed.

The crossbred progeny of 32 Hereford bulls (1043 calves) were admitted to a Progeny Testing Centre at 2-month intervals at 2 weeks of age over a period of 2 years, and divided between the two feeding regimes. Growth and carcass characters were measured, including taste panel assessments.

The semi-intensive system was found to have a higher power of discrimination between progeny groups, and tended to rank the bulls i n a different order from the intensive system. Truncation of the test at various intervals introduced an element of risk into the formation of the final judgement and showed little advantage as a predictor.
Within-litter variation in the performance of piglets to three weeks of age
Authors: Hemsworth P. H. , Winfield C. G. , Mullaney P. D.
Published: September 2010

In a series of observations the association between within-litter variation in growth performance of piglets to 3 weeks of age and other parameters was examined in 28 litters. Growth rate was correlated significantly with birth weight and milk intake of the piglet. Birth order and location of the preferred teat did not influence significantly the milk intake or growth performance. In a second series of observations the individual behaviour of the piglets immediately after birth was examined in relation to the within-litter variation in growth performance to 3 weeks of age in three litters. The amount of time that each teat was sucked during the period of continuous suckle was positively correlated with the growth performance of the piglet which preferred the teat at day 21 of lactation.
Influence of mating pressure and season on the semen characteristics of rams
Authors: Tomkins T. , Bryant M. J.
Published: September 2010

Two groups of 4 Suffolk rams were each subjected to mating pressures of 90 ejaculates (High) and 45 ejaculates (Low) over a 3-day period during summer and autumn. Every sixth (High) or every third (Low) ejaculate was collected into an artificial vagina and assessed for volume, sperm density, total sperm per ejaculate, motility and percentage of live and abnormal sperm.

There was a general lowering of semen quantity and quality with successive ejaculations. Rate of change of the various measures was greater on the High than on the Low mating pressure. Volume and percentage of live sperm showed a greater decline, and percentage of abnormal sperm a greater increase, during the autumn than during the summer. Density showed a greater decline in summer than in autumn.

The significance of the changes in semen characteristics observed is considered in relation to requirements for high fertility after pro-gestagen treatment.
A note on the influence of a supplement of barley and dried lucerne on the intake of barley straw by cattle
Authors: Horton G. M. J. , Holmes W.
Published: September 2010

Six castrated male cattle of 350 kg live weight were used in an incomplete Latin square design to measure intake and digestibility of barley straw offered ad libitum alone and with 5 levels, 1·5 to 7·5 kg/day, of a barley and dried lucerne concentrate. Straw intake declined and total organic-matter intake increased linearly with increasing concentrate level. On average 1 kg additional organic matter as concentrate, increased total organic-matter intake by 0·68 kg. There was no evidence that the crude protein content of the whole diet affected straw consumption.
The effects of breed, birthcoat and body weight on the cold resistance of newborn lambs
Authors: Slee J.
Published: September 2010

1. Twenty-two Scottish Blackface, 51 Welsh Mountain and 22 Tasmanian Merino lambs aged between 6 and 75 h were tested for resistance to body cooling in a climate chamber. Blackface lambs had long birthcoats, Merinos were short-coated. Welsh lambs were from two strains with long (L) and short (S) types of birthcoat. Some lambs were clipped before cold exposure.

2. Clipping reduced cold resistance in Welsh (S) and (L) lambs by factors of 3 and 13 respectively.

3. Undipped lambs showed significant breed differences, Welsh (L) and Blackfaces having the greatest cold resistance and Merinos the least. Long-coated lambs (Blackface and Welsh (L)) were on average six times more cold resistant than the average of Welsh (S) and Merino lambs; and Welsh (L) lambs were four times more resistant than the Welsh (S) type. Birth weight and age did not significantly influence cold resistance.

4. In clipped lambs there was a significant positive linear regression between cold resistance and birth weight. Breed differences in cold resistance were still significant if no adjustment was made for the effect of breed differences in birth weight.

5. Cold resistance was strongly influenced by breed differences in birthcoat morphology and probably by other physiological factors partly attributable to the different genetic backgrounds associated with birthcoat type. The breed differences in cold resistance were generally consistent with field data on mortality and body temperature regulation of lambs in severe weather, suggesting that climate chamber tests might be used to evaluate potential viability in the field.
Growth of bovine tissues 3. Genetic influences on patterns of fat growth and distribution in young bulls
Authors: Berg R. T. , Andersen B. B. , Liboriussen T.
Published: September 2010

Fat growth and distribution were studied by jointing and complete tissue separation of carcasses from 277 young bull progeny of eight sire breeds and two dam breeds, serially slaughtered at 300 kg live weight, 12 and 15 months of age. Growth impetus for fat in each joint was established from the allometric equation (Y = aXb). Differential growth of fat in different joints resulted in marked differences in percentage of fat in various joints as fattening progressed. Growth coefficients,b, for fat in each joint were homogeneous among breed groups, indicating similar fat development patterns over the weight range studied. Growth impetus for fat was lowest in the distal limbs and in the proximal hind limb. Fat growth in the proximal fore limb was proportional to total fat. Along the dorsal line, low impetus was found in neck and rump regions, increasing to a high impetus in the mid-back region. Ventrally the fat of the flank showed the highest growth impetus of all regions with fat in the brisket and flat ribs also showing an increasing proportion with increases in total fat.

Small but significant differences among sire breeds were found for the amount of fat in each joint at a standard amount of total fat in the carcass. Differences found among sire breeds in fat distribution were not associated with differences in maturity type.
A Note on inbreeding and genetic relationships among British tested pigs
Authors: Smith C. , Jordan C. H. C. , Steane D. E. , Sweeney M. B.
Published: September 2010

Five samples from tested pig herds (Large White 1972, 1975, and 1976, British Landrace 1976 and Welsh 1976) were used to estimate the current rate of inbreeding in British pig testing herds. The annual rates of inbreeding (%) were estimated at 0·32, 0·19, 0·24, 0·33 and 0·34 respectively in the five samples. Overall average estimates of 0·49 to 0·52% per generation are similar to estimates from other pig populations reported in the literature. Coefficients of relationship within farms were calculated for various sib and non-sib groups and these were used to estimate the genetic contributions to the variance components in the analysis of variance of test records.
A note on the nutritive value of wild oats
Authors: Barranco A. , Morgan D. J. , Capper B. S. , Ogilvie L. M.
Published: September 2010

The nutritive value of wild oats has been examined in two trials with growing rats. Feed consumption was reduced with diets containing 50 % wild oats and dry-matter digestibility was lower (76 and 73 %) with two diets containing 25 and 50 % wild oats compared with diets containing 25 and 50% barley (80·2 and 81·1 %). Live-weight gain was depressed when diets contained more than 45 % wild oats and it can be predicted that growth and feed conversion ratios of mono-gastric animals fed on diets containing high levels of wild oats are liable to be affected adversely. Biochemical studies indicated that any reduction in growth rate could not be attributed readily to specific toxic effects.
Chemical processing of wheat straw and cotton by-products for fattening cattle 2. Performance of animals receiving material after drying and pelleting
Authors: Holzer Z. , Levy D. , Folman Y.
Published: September 2010

Two fibrous roughages, wheat straw (WS) and cotton hulls (CH), were either untreated or treated with 30 g/kg or 60 g/kg of sodium hydroxide (NaOH), the residual NaOH was either unneutralized or neutralized with sulphuric acid, and the materials were then pelleted. The effects of these treatments on the nutritive value of the two roughages were examined in an arrangement that differed from the factorial 2 × 3 × 2 = 12 in that only one control group was included for each roughage. Digestibility trials,in vitroandin vivo, and a 7-month feeding trial were carried out. Concentrates were limited in the feeding trial to 6 kg/head per day, and roughages were offeredad libitum.

Dry matter digestibilityin vitrowas significantly higher on CH than on WS and was significantly increased by NaOH treatment. Level of NaOH and neutralization of residual alkali had no significant effect. Intake of WS was increased by treatment with 30 g NaOH/kg in the digestibility and feeding trials. Increasing the level of NaOH to 60 g/kg reduced intake of both roughages. Digestibility of organic matter of WS was increased by NaOH treatment at both levels, by 25 to 30%, while that of CH was improved significantly only by the higher level. Neutralization had no effect. The actual intake of roughages was 30 to 35% of the entire ration. The rate of gain of animals offered roughages treated with 30 g NaOH/kg was non-significantly increased, and that of animals offered roughages treated with 60 g NaOH/kg was reduced significantly in comparison with the control. Animals offered NaOH-treated roughages had a significantly higher dressing percentage, and those offered treated WS had a greater fat trim than the control animals. Efficiency of conversion of metabolizable energy into live or carcass weight for both roughages was improved only with the neutralized 30 g NaOH/kg treatment. Comparing the performance in this study with that of a former study of similar design in which the same roughages were offered wet, revealed no marked advantage from pelleting.
A note on the fracture of porcine scapulae during their withdrawal from the carcass
Authors: Thomas T. R.
Published: September 2010

In the processing of pig carcasses after slaughter the scapulae are removed mechanically. It is economically important to minimize the proportion of fractures (2 to 4%) that occur during this operation. The incidence of fractures in several hundred scapulae was investigated with a strain testing machine modified to simulate production-line techniques. The proportion of fractures occurring on the line was consistent with the relationship between the standard force employed and the standard deviation of the normal variation of the fracture load about its mean. In an attempt to raise the mean fracture load by reducing the maximum contact stress, the contact radius of the withdrawing tool was increased; this did not significantly change the mean fracture load but significantly decreased its variation.
Male reproductive characteristics of Merino and Ossimi sheep and their crosses
Authors: Galal E. S. E. , El-Gamal A. A. , Aboul-Naga A. , El-Fouly M. A.
Published: September 2010

The effects of breed type and season on semen quality and libido were examined. Tests were carried out in autumn, winter, spring and summer using 47 rams of five breeding groups, namely the the Fleisch Merino, the Ossimi, the first cross and the two parental backcrosses. All the rams were born and reared locally.

Except for the percentage of abnormal sperm cells and time to first mount, semen quality and libido were not affected by breed type. There was little consistent evidence of heterosis in any of the traits examined. All traits except time to first mount were significantly affected by season. Semen was of better quality in autumn and spring than in winter and summer. With one exception all aspects of libido were depressed in winter.

Breed × season interactions were significant in six of the 10 traits studied but showed no consistent trends.

The reproductive performance of Merino rams was not adversely affected by the environment. This indicates the feasibility of introducing new breeds so far as semen quality and male libido are concerned.
A note on the effect of prolonged salt intake from drinking water on the distribution of body water in Marwari sheep of the Rajasthan Desert, india
Authors: Singh N. , Taneja G. C.
Published: September 2010

Sixteen healthy ewes of the Marwari breed were randomized and four ewes allocated to each of the following treatments: control, 0·5%, 1·0% and 1·5% sodium chloride in the drinking water. Blood volume, total body water, extracellular fluid volume, intracellular fluid volume and interstitial fluid volume were determined. The results showed that Marwari sheep have a remarkable tolerance to saline water. There were no significant changes in body water compartments accompanying the changes in salinity of the water. It was also concluded that sheep can subsist on drinking water containing concentrations of up to 1·5% sodium chloride for a period of 6 months or more without exhibiting signs of change in body water distribution.
A comparison of bulls and steers implanted with various oestrogenic growth promoters in a 15-month semi-intensive system of beef production
Authors: Steen R. W. J.
Published: September 2010

Two experiments, each involving 48 British Friesian cattle, were carried out to examine the performance and carcass quality of bulls and steers implanted with one of three oestrogenic growth promoters in a semi-intensive system of beef production in which the animals were slaughtered at 14 to 17 months of age. The treatments used in experiment 1 were: (1) control steers (no implant); (2) steers implanted with 45 mg oestradiol in silastic rubber at 4·5 months of age and with 300 mg trenbolone acetate at 10·5 and 13·5 months; (3) steers implanted with 20 mg oestradiol and 200 mg progesterone at 95-day intervals from 4·5 months and with 300 mg trenbolone acetate at 10·5 and 13·5 months of age; (4) bulls (no implant). For treatments 1 to 4 respectively dry-matter (DM) intakes were 6·74, 7·24, 7·50 and 7·16 (s.e. 0·092) kg/day; carcass weights were 260, 283, 298 and 290 (s.e. 5·4) kg; and fat depths over m. longissimus were 6·5, 5·3, 6·3 and 3·4 (s.e. 0·53) mm. The same treatments were used in experiment 2, except that 36 mg Zeranol® was used in treatment 3 instead of 20 mg oestradiol plus 200 mg progesterone, and the bulls in treatment 4 were implanted with 36 mg Zeranol at 7·5, 11 and 14·5 months. For treatments 1 to 4 respectively DM intakes were 7·37, 7·85, 7·76 and 7·42 (s.e. 0·092) kg/day; carcass weights were 262, 285, 284 and 296 (s.e. 7·1) kg and mean fat depths over m. longissimus were 7·1, 5·9, 7·0 and 5·2 (s.e. 0·54) mm. Implantation of steers increased food intake but also improved food conversion efficiency and did not consistently affect carcass fatness or conformation. Repeated implantation with 20 mg oestradiol plus 200 mg progesterone produced a greater response in performance than a single implantation with 45 mg oestradiol-17β in a controlled-release silastic-rubber implant, while repeated implantation with 36 mg Zeranol produced a similar response to the single silastic-rubber implant. Bulls produced leaner carcasses and converted food to carcass gain more efficiently than implanted steers.
A note on lactation curves of dairy cows in Scotland
Authors: Mainland D. D.
Published: September 2010

The aim of this study was to estimate the parameters of the lactation curve of dairy cows in Scotland so as to improve the prediction of milk yield. The data used for deriving the parameters were ‘milk test’ yield values recorded by the Scottish Milk Records Association during a 2-year period. The data were grouped, according to lactation number, breed and area of Scotland, into 27 groups. The data pertaining to each group were then averaged so as to produce by regression analysis a curve for each calving week, lactation number and area. Areas and breeds were found to affect the shape of the lactation curves.
The relationship between volume of rumen contents and genetic susceptibility to pasture bloat in cattle
Authors: Cockrem F. R. M. , McIntosh J. T. , McLaren R. D. , Morris C. A.
Published: September 2010

Experiments were designed to exchange rumen contents and vary the volumes of rumen contents between two pairs of rumen fistulated cows from herds selected for high (HS) or low (LS) susceptibility o t bloat. After exchanges between HS and LS cows the animals were tested on bloat-potent lucerne. The volume of rumen contents was lower in LS than in HS cows by 3·05 1. Increasing the volume of rumen contents of LS cows caused them to bloat to a degree never previously attained. The degree of bloat (i.e. score) was related to the volume of rumen fluid (r = 0·71) regardless of its origin (HS or LS) or the susceptibility of the recipient cow. The results implied that LS cows from this selection experiment did not bloat because they had a lower relative volume of rumen digesta than HS cows.
Pattern of milk production of East Friesland and Scottish Blackface ewes and associated blood metabolite and hormone profiles
Authors: Rhind S. M. , Bass J. , Doney J. M.
Published: September 2010

Patterns of milk production and circulating blood metabolite and hormone concentrations were determined throughout a 14-week lactation in groups of 10 twin-rearing East Friesland EF) and Scottish Blackface (SBF) ewes. All ewes were offered, ad libitum, a pelleted diet throughout the experiment and milk yields were measured weekly. Pooled blood samples (six samples, 20-min intervals), collected before feeding, on 1 day of each week, were assayed for plasma glucose, non-esterfied fatty acids, 3-hydroxybutyrate (3-OHB), albumin, total protein, insulin, growth hormone (GH), cortisol, prolactin, thyroxine (T4), and triiodothyronine (T3). At weeks 2, 4,10, and 14, samples were collected at 20-min intervals for 8 h and assayed individually for plasma insulin, GH, cortisol, and prolactin. Mean daily intakes and milk yields of ewes were similar in the two breeds. Mean pre-feeding concentrations of most blood metabolites during the experiment were also similar in ewes of the two breeds but SBF ewes had higher plasma concentrations of 3-OHB (0·67 v. 0·43 mmol/l; P < 0·01) and total protein (73·2 v. 66·4 g/l; P < 0·001). SBF ewes had higher overall mean concentrations of insulin (9·53 v. 4·36 mU/l; P < 0·001), cortisol (7·59 v. 573 μg/l; P < 0·05), prolactin (457·1 v. 316·1 μg/l; P < 0·05), and T3(1.32 v. 1·12 μg/l; P < 0·001). GH and T4profiles were similar in the two breeds. Following the daily introduction of fresh food, there were significant increases in concentration of insulin (P < 0·001) and cortisol (P < 0·01) while there was a decrease in mean concentrations of GH (P < 0·001) and prolactin (P < 0·01). There were significant interactions between breed and feeding effects on insulin, GH, cortisol and prolactin concentrations. Patterns of milk production in ewes of these breeds were associated with changes in insulimGH ratios both before and after feeding which may be of a causal nature.
A comparison of silage-based and dried forage-based diets for finishing beef cattle
Authors: Steen R. W. J. , Moore Charlotte A.
Published: September 2010

Two experiments have been carried out to compare silage-based and dried forage-based diets for finishing beef cattle, and to examine the effect of supplementing the silage-based diet with additional protein. The three diets used in experiment 1 consisted of (1) grass silage supplemented with a low-protein, cereal-based concentrate (98 g crude protein (CP) per kg dry matter (DM)) (2) grass silage supplemented with a high-protein, cereal/soya-bean meal concentrate (208 g CP per kg DM) and (3) grass hay supplemented with a cereal-based concentrate (130 g CP per kg DM). The two diets used in experiment 2 consisted of (1) grass silage supplemented with barley and (2) a mixture of grass hay and artificially dried grass supplemented with barley. All the diets contained approximately 700 g forage and 300 g concentrates per kg DM except diet 3 in experiment 1 which contained 240 g hay and 760 g concentrates per kg. The silages were of high digestibility (digestible organic matter in dry matter 0·72) and were well preserved (ammonia N 36 g/kg total N). The diets were offered to castrated male cattle which were initially 384 kg in experiment 1 and 515 kg in experiment 2. For diets 1 to 3 in experiment 1 and diets 1 and 2 in experiment 2 respectively metabolizable energy intakes were, 92, 94, 94, 124 and 120 MJ/day; live-weight gains were 1·21, 1·16 and 1·21 (s.e. 0·044) and 1·25 and 1·22 (s.e. 0·060) kg/day; carcass gains were 0·76, 0·76 and 0·75 (s.e. 0·034) and 0·80 and 0·74 (s.e. 0·036) kg/day; carcass fat classifications (five-point scale; 1 = leanest, 5 = fattest) were 2·4, 2·9 and 2·2 (s.e. 0·09) and 3·6 and 3·6 (s.e. 0·18); mean subcutaneous fat depths were 6·8, 8·1 and 6·6 (s.e. 0·74) and 7·8 and 7·4 (s.e. 0·48) mm; areas of m. longissimus dorsi at the 10th rib were 66·4, 69·4 and 71·3 (s.e. 3·16) and 77·6 and 72·3 (s.e. 1·52) cm2 and marbling scores (eight-point scale; 1 = leanest, 8 = fattest) for m. longissimus were 1·7, 2·5 and 2·2 (s.e. 0·24) and 3·2 and 2·8 (s.e. 0·16). It is concluded that performance, efficiency of energy utilization and carcass fatness were similar for silage-based and dried forage-based diets, and that protein supplementation of a silage-based diet did not affect performance but tended to increase carcass fatness.
A study on consistency of differences between cows in rumen outflow rate of fibrous particles and other substrates and consequences for digestibility and intake of roughages
Authors: Ørskov E. R. , Ojwang I. , Reid G. W.
Published: September 2010

In 22 cows given complete diets of 500 g straw and 500 g concentrates per kg fresh weight the outflow rate of small fibrous particles was determined on two occasions to investigate the consistency of this measurement and its association with apparent digestibility. The correlation between the outflow rates on the two occasions werer= +0·90 and the correlation with apparent digestibility wasr= −0·80.

In a second experiment, the outflow rates of long and small particles were determined together with rumen retention time. There was no difference between outflow rate of long and small particles but rumen retention times were greater with the long particles. The correlation between the two estimates of outflow rate wasr= +0·84. The outflow rate of fish meal was found to be 0·070 while that of short fibrous particles was 0·031 per h. The average liquid outflow rate was 0·146 per h.

The three cows with the highest outflow rate and the three with the lowest outflow rate from experiment 2 were selected for experiment 3. While voluntary food intakes of the two groups were similar, the differences in outflow rates between the cows persisted both withad libitumand restricted intakes of both a high and a low roughage diet. The differences were reflected in significant differences between the two groups in apparent digestibility of the diets. The practical implications for breeding and selection are discussed.
Effect of post-partum levels of nutrition on productivity of 2-year-old heifers
Authors: Whittier J. C. , Clanton D. C. , Deutscher G. H.
Published: September 2010

Forty crossbred heifers, mated to one sire, that calved in a 20-day period were used to study the effect of varying time and level of post-partum nutrition on productivity. Heifers were individually fed for 90 days post partum beginning at parturition: (1) proportionately 1·3 National Research Council (NRC) 1984 recommendations for 45 days followed by 0·7 NRC for 45 days (130·70); (2) 1·0 NRC for 90 days (100·100); and (3) 0·7 NRC for 45 days followed by 1·3 NRC for 45 days (70·130). Milk production, growth and body condition were estimated periodically during the lactation. The 130·70 heifers maintained their weight during the first 45 days of lactation, while the 100·100 and the 70·130 heifers lost weight (−0·33 and 0·60 kg/day, respectively). During the second 45-day period, the 100·100 and 70·130 heifers gained weight (0·24 and 0·72 kg/day, respectively) while the 130·70 heifers lost weight (−0·39 kg/day). Visual condition scores paralleled weight changes during both phases of the feeding period. Milk production varied according to nutrient intake and treatment differences were greatest at 45 days post partum (8·1, 7·3 and 6·1 kg/day for 130·70, 100·100 and 70·130, respectively). Calf weight gains were unaffected by dam nutrition. Days to first oestrus, days to conception or services per conception were not significantly different (P > 0·05) among treatment groups. Based on this experiment, neither of the alternate feeding systems resulted in decreased performance when compared with feeding at a constant level. Therefore, it appears that latitude exists in the way heifers can be fed early in their first lactation, without adversely affecting production.
The effect of implantation of trenbolone acetate and oestradiol-17β in wether lambs at two initial live weights on concentrations of steroidal residues and blood glucose, urea and thyroid hormones
Authors: MacVinish Lesley J. , Galbraith H.
Published: September 2010

Thirty-two Border Leicester ♂ × Scottish Blackface ♀ wether lambs aged about 5 months were divided into two groups on the basis of live weight such that group Gl contained the 16 lightest lambs and group G2 the 16 heaviest. Lambs in group Gl were subdivided equally at random either to be sham-implanted controls (group C1) or to be implanted with 35 mg trenbolone acetate (TBA) + 5 mg oestradiol-17β (group T1) at 24 kg initial live weight. The lambs in group G2 were also subdivided into two groups (groups C2 and T2) and similarly treated approximately 1 month later at 37 kg initial live weight. The lambs were offered ad libitum a good-quality diet. They were slaughtered 60 days after implantation. Comparisons were made for the main effects of hormonal treatment and initial live weight.

Concentrations in blood of 17-β-hydroxy-trenbolone (TBOH) and oestradiol-17β (OE) measured by radioimmunoassay peaked within 1 to 3 weeks after implantation and declined thereafter. Maximum concentrations and concentrations at slaughter respectively were 1·46 and 0·32 μg/l (group T1) and 0·78 and 0·28 μg/l (T2) for TBOH and 85 and 33 μg/1 (T1) and 59 and 37 ng/l (T2) for OE. Values up to week 7 were consistently greater in implanted animals in group T1 than in group T2. Hormonal implantation decreased the concentrations of total plasma triiodothyronine and thyroxine and urea and increased values for glucose up to week 5 or 6 after implantation. The animals in group G1 compared with G2 had, on average, variably lower concentrations in plasma of triiodothyronine, thyroxine, glucose and urea.

The highest concentrations of solvent-extractable residues were obtained in samples of kidney and liver (up to about 500 ng/kg for TBOH and 180 ng/kg for OE) with intermediate levels for fat and lowest levels for muscle. Conjugated trenbolone ranging from 45 to 186 ng/kg was present in samples of kidney, liver and perinephric fat. Trenbolone acetate was detected only in samples of fat. Variable effects of live weight at implantation on residue levels were recorded.
Fatness, live weight and performance responses of sows to food level in pregnancy
Authors: Whittemore C. T. , Smith W. C. , Phillips P.
Published: September 2010

Sixty crossbred females received one of three pregnancy feeding rates over five parities: high (2·3 kg/day); medium (2·0 kg/day) and low (1·7 kg/day) to produce variation in body fatness and live weight. During a 32-day lactation all sows were fed the same allowance according to litter size. At the start of parity 5 ultrasonic P2 backfat depths for the high, medium and low treatments respectively were 11·2, 11·0 and 10·6 (s.e. 1·77) mm while live weight was 184, 177 and 167 (s.e. 8·6) kg. Averaged over five parities, backfat depths at conception were not significantly different between treatments. Sows given higher pregnancy feeding rates in pregnancy were heavier and fatter pre-partum but lost relatively more live weight and backfat during lactation. Regression coefficients for the slope of the relationship between total sow pregnancy weight (kg) and fatness (mm) change, and food intake (kg/day) were 0·2 and 0·04 respectively. Pregnancy feeding rate did not influence the number of live births but total litter weight at weaning was positively related to the weight and fatness of the sow at parturition and her subsequent rate of weight and fat loss during lactation (these characteristics of the sow also being positively related): live weight of litter at 32 days (kg) = 67 – 1·8 sow backfat change in lactation (mm) – 0·4 sow live-weight change in lactation (kg). Absolute sow live weight and fatness were positive influences on readiness to rebreed after weaning.
Selection in pigs for increased lean growth rate on a time-based feeding scale
Authors: McPhee C. P. , Rathmell G. A. , Daniels L. J. , Cameron N. D.
Published: September 2010

Selection was carried out in a line of pigs for increased growth rate of lean tissue. The selection criterion was weight of lean in the ham predicted from live backfat and weight measurements after a 12-week performance test commencing at 25 kg live weight. All pigs were given the same total amount of food over the test period. The scale was set to about proportionately 0·85 of predicted ad libitum intake. Boars selected with an intensity of 1/12 were used for 6 months and sows selected with an intensity of 1/4 were kept for two farrowings. An unselected control line was maintained concurrently.

After five generations, performances of selected and control line pigs were compared on ad libitum and scale feeding as they grew to 85 kg. Responses in the selected line on scale feeding were +51 g/day for growth rate (GR), −0·16 for food conversion ratio (FCR), −2·2 mm for backfat (F) and +0·47 kg for ham lean (HL). On ad libitum feeding, responses were much higher in the selected line, giving rise to line × food interactions. Responses were +128 g/day for GR, −0·27 for FCR, −2·3 mm for F, +1·01 kg for HL and +0·15 kg/day for food intake (FI). Estimates of the heritability of HL from variance components were 0·43 (s.e. 0·15) on scale feeding and 0·28 (s.e. 0·19) on ad libitum feeding. The realized heritability of HL on scale feeding was 0·29 (s.e. 0·04) and its co-heritabilities with the other traits on both feeding levels were of similar magnitude to its heritability. Scale feeding exposed genetic variation in the partitioning of food between lean and fat deposition and appeared to be a suitable selection regimen for performance on ad libitum feeding.
Effect of water sprinkling during the hot-dry summer season on semen quality of Holstein bulls in Saudi Arabia
Authors: Salah M. S. , El-Nouty F. D. , Al-Hajri M. R.
Published: September 2010

Ten Holstein bulls, 4 to 5 years old were used to study the effect of cooling the bulls on their semen quality. Five bulls were sprinkled with water for 15 min five times a day throughout a 6-week period of the summer season (hot-dry) in Saudi Arabia, and the other five bulls acted as the control and were not sprinkled with water. Semen quality was improved significantly during the cooling period. This improvement was evident from the significant increase in sperm motility (P < 0·01) and decrease in the percentage of both dead and morphologically abnormal (primary and secondary) spermatozoa per ejaculate of cooled bulls (P < 0·01). The effect of cooling was more marked through the last 3 weeks than during the first 3 weeks of the experimental period. Ejaculate volume, sperm concentration and hence total sperm counts did not differ significantly between the cooled and the non-cooled bulls. Concerning the type of abnormal spermatozoa, the overall secondary abnormality was higher than the primary in both the cooled and the control groups, with higher values for the control (P < 0·01). Only the mid piece showed higher primary defects than the secondary. The pyriform heads, the coiled mid pieces and tails and the bent tails were the main sources of variations (P < 0·01) in the incidence of sperm abnormality between the cooled and the non-cooled bulls. Cooling the bulls during the heat stress period also lowered their rectal temperature and increased blood haemoglobin level without affecting the packed cell volume
Effects of rapid inbreeding and of crossing of inbred lines on conception rate, prolificacy and ewe survival in sheep
Authors: Wiener G. , Lee G. J. , Woolliams J. A.
Published: September 2010

The effects of four generations of inbreeding, to achieve inbreeding coefficients (F) of 0·25, 0·375, 0·50 and 0·59, on conception rate, prolificacy, litter weight at birth and survival of breeding females, have been studied in sheep. Crosses of inbred lines were also examined. Three breeds, Scottish Blackface, Cheviot and Welsh Mountain, and the crosses among these breeds, were involved. Analyses were carried out both for the data overall and within inbred lines.

Conception rate at the first oestrus at which the ewe was mated (in each year) declined almost linearly from 0·71 (F2generation - inbreeding F = 0·0) to 0·44 (F = 0·59) with line crosses showing 0·78 conception rate. The corresponding results following up to three rounds of services at successive oestrous periods were 0·91, 0·74 and 0·97 respectively. Analyses within lines showed a steeper rate of decline in conception rate to 0·33 (F = 0·59) following first services and 0·63 following up to three successive periods. This indicates that the lines with the best conception rates survived the inbreeding process better.

Prolificacy, the number of lambs born per ewe lambing, dropped from 1·73 (F = 0·0) to 1·37 (F = 0·25) and thereafter more slowly to 1·24 (F = 0·59). Line crosses were no better than the initial non-inbred generation (F2and the purebred equivalent O2). Within-line analysis gave the same results.

The effects of inbreeding on litter weight at birth mirror closely those for prolificacy.

Ewe survival declined linearly with inbreeding. There was a 1·2-fold increase in the risk of death for every increase in the inbreeding coefficient (F) of 0·1 (analysed by using a proportional hazard model).

In general, there were no significant differences between purebred and crossbred sheep in the effects of inbreeding. For conception rate, prolificacy and litter weight (for which the point was examined) the changes with inbreeding could not be explained, statistically, in terms of dominance alone, suggesting, therefore, that epistasis is also involved.
Bone distribution patterns in sheep selected for high and low weaning weight
Authors: Perry D. , Thompson J. M. , Butterfield R. M.
Published: September 2010

The change in the proportional distribution of bone weight within the carcass skeleton from birth to maturity was examined in rams and ewes from flocks of Australian Merino sheep selected for high (weight plus) and low (weight minus) weaning weight and from a randomly selected control flock. Data from 140 animals (106 immature, 34 mature) were used. Shape parameters for the long bones of the limbs in the 34 mature animals were derived by determining the allometric relationship between bone length, diameter and individual bone weight.

Selection for increased and decreased weaning weight resulted in a concomitant increase and decrease in mature size and total bone weight. In the weight plus group, total bone as a proportion of body weight also increased but selection had little effect on the proportional distribution of bone weight within the skeleton at any stage of maturity. This was the product of similar growth patterns within the skeletal system aiming towards a similar mature distribution pattern for each strain.

Within the strains of different mature size there was a difference between mature rams and ewes in both total bone weight as a proportion of body weight and in the proportional distribution of this bone weight. This was associated with differences in the maturing patterns of the bones of the hindlimb and the pelvic girdle.

Neither selection nor sex affected the relationship between bone shape and bone weight, although the difference in bone weight between the strains and sexes at maturity meant that they also differed in bone shape at this point.
The effects of level of feeding of sows during pregnancy. I. Reproductive performance
Authors: Lodge G. A. , Elsley F. W. H. , MacPherson R. M.
Published: September 2010

1. Twelve sets of 3 litter-sister Large White gilts were mated at first oestrus after reaching 250 lb. live-weight and given daily during 3 successive pregnancies either 6 lb. (A), 3 lb. (B) or 3 lb. for 76 days then 6 lb. until parturition (C) of the same meal mixture. During an 8-week lactation all were given 4 lb. meal plus 0·8 lb. per piglet suckled.

2. There was a significant linear increase in numbers born with successive parities (P<0·05) but no significant differences between treatment or sister groups. There was a highly significant difference between treatment groups in mean piglet birth weight (P< 0·001) but no parity effect; mean birth weights were 2·76, 2·40 and 2·58 Ib. for Groups A, B and C respectively. Differences between sister groups in mean piglet birth weight were also significant (P<0·05).

3. Post-natal litter performance was poor for all groups, probably because of the presence of E. coli, but there was no evidence of treatment effects other than on 3-week weight of third litters, which was significantly greater in Group C than in A or B (P<0·05). There were no significant effects on either number or weight of piglets at 8 weeks.
A mathematical model of the culling process in dairy cattle
Authors: Robertson Alan
Published: September 2010

1. A mathematical theory of the culling process in dairy cattle has been developed. This was necessary to give a conceptual framework for the discussion of longevity in the dairy herd as a heritable character, of its genetic relationship with milk yield and of the effects of selection on the genetical analysis of yield itself.

2. Culling is assumed to take place at the end of each lactation by truncation selection of a normally distributed variate (the culling variate) of which yield itself is a component.

3. Expressions are then derived for the effect of the culling on various parameters of yield and for survival as a function of yield.

4. The derivation of expressions relevant to progeny groups is dependent on the relative values of the genetic and phenotypic regressions of the culling variate on yield.

5. Because little is known of the actual causes of culling, it is not permissible to predict the genetic gain in yield by multiplying the selection differential by the heritability. This is only justified if the genetic and phenotypic regressions of the culling variate on yield are equal.

6. A direct estimate of the genetic gain by selection can, however, be obtained from the covariance for any character between the mean relative survival of progeny groups and their mean value for the character.

7. The effect of culling on the genetic analysis of yield in later lactations is discussed, as is the effect of later culling on survival to later ages as a function of early yield. It is suggested that the regression coefficient of relative survival of progeny groups on heifer yield will be approximately linear with age whereas that of individuals will probably increase to a limiting value.

8. The heritability of survival to different ages will probably pass through a maximum at the fourth lactation.

9. Longevity itself, as a function of heifer yield, is the sum of the cumulative survival curves to each individual lactation. The regression of length of life on heifer yield, at the individual or at the progeny test level, can be related to the mean phenotypic and genetic selection applied to animals in the herd at any time.

10. Because culling is to a large extent a voluntary action of the farmer, longevity in the dairy herd, though it is under continual selection and may have a significant heritability, need not necessarily increase.