The UK national scrapie plan (NSP) for sheep is based on selection for the resistant ARR/ARR genotype and elimination of susceptible types of the ovine prion protein (PrP) gene. The aim of this study was to estimate the possible association of the PrP genotype and performance traits by using data from the CAMDA Welsh Mountain flock. Four alleles (ARH, ARQ, ARR and VRQ) and 10 genotypes covering all five NSP risk groups were present in the CAMDA flock. Overall, the most common allele was ARR (35.2%), and VRQ was the least common (5.4%). The commonest genotypes were ARR/ARQ (23.7%) and ARR/AHQ (23.1%). The most resistant genotype, ARR/ARR, and the most susceptible genotype, VRQ/VRQ, were found in 10.2% and 0.3%, respectively, of the population tested. The associations of PrP genotypes with weight and ultrasonically scanned traits were investigated in three analyses, the first using genotypes, the second using risk categories and the third using number of alleles. These associations were evaluated by univariate analysis of each trait using an animal model with maternal effects where appropriate, and PrP was included as a fixed effect. Selection for scrapie resistance will not adversely affect progress in the traits considered and is consistent with improvements in muscle depth.

Fifty-four Suffolk × North Country Cheviot lambs were weaned at either 25, 33 or 41 days of age and slaughtered at either 35, 45 or 55 kg live weight.

Increasing the age at weaning reduced the growth check, increased creep feed consumption and decreased food required for fattening. For each kg increase in weight at slaughter there was an increase of 0·035 kg in dry matter required per kg gain. The female lambs had lower growth rates, lower efficiency of food utilization and a higher killing-out percentage than male lambs.

For the most efficient utilization of food, lambs should be weaned at about 33 days of age.

Responses of lambs to cimaterol (CIM), diethylstylbestrol (DES) and ovine growth hormone (GH) were examined using a mechanistic model of growing lamb metabolism. All three compounds increase growth of lean tissue (protein) and decrease fat gain, although the magnitudes of these responses vary. Our working hypothesis was that observed changes in nutrient partition between lean and fat gain were caused by alteration of rate constants for turn-over of muscle protein and fat. Individual experiments were simulated whilst varying values of the protein degradation constant (Kprolein) and Vmax for lipolysis (Kfat). Optimal parameter values were found by minimizing residual errors, calculated as the deviations of model predictions from experimental values for carcass protein and fat. Fitted values of Kfat and Kprotein (expressed as proportions of controls) for each simulation were: CIM (grazing), 1·20 (s.d. 0·05) and 0·86 (s.d. 0·025); CIM (pellet-fed), 1·11 (s.d. 0·115) and 0·87 (s.d. 0·032); DES, 1·33 (s.d. 0·111) and 0·94 (s.d. 0·024); GH, 1·77 (s.d. 0·139) and 0·97 (s.d. 0·025) respectively. These results demonstrate that different mechanisms may be responsible for the changes in carcass composition due to 3-adrenergic agonists, anabolic steroids and growth hormone. CIM probably exerts its effects via changes in protein and fat metabolism, whereas DES and GH appear to act mainly through changes in adipose tissue, with little or no effect on the rate constant for protein turn-over. Carcass composition is less sensitive to manipulation of adipose tissue metabolism than to changes in muscle protein metabolism.

Two experiments were conducted to compare the milk-producing value of dried forages in the form of cobs and pellets as replacements for a standard dairy concentrate. Four levels (0·33, 0·44, 0·55 and 0·66 kg/kg milk) of dried forage or standard dairy concentrate were offered in addition to a basal ration of 6 kg hay and 2 kg standard dairy concentrate. In both experiments the rate of eating by the cows of cobs was significantly slower (P<0·05) than that of pellets. No significant difference was found between the cobs and pellets in either experiment in their value for milk production. In Experiment 2 the standard dairy concentrate had a non-significantly higher (P>0·05) milk-producing value than the dried lucerne. Level of feeding had a significant positive effect on the milk yield (P< 0·001) of cows offered the dried grass and lucerne and on the milk solids- not-fat content (P<0·05) and live weight (P<0·01) of cows offered the dried grass, lucerne and standard dairy concentrate.

Data on the protein content of the empty body were obtained for 44 young Polish Black-and-White Lowland bulls ranging from 10-day- old calves to bulls more than 400 kg live weight. The percentage of protein of the empty body was found to be practically constant (19–19·5%) over the weight range investigated. Less than a half (up to 48 %) of the total protein content was found in the edible parts of the carcass.

A selection programme was set up in 1983 in the Ivory Coast to improve the growth and live weight of the indigenous Djallonkè sheep using an open nucleus breeding system. Selection was based on male individual weights at 80, 180 and 365 days of age. Multiple sires were used in farmers' flocks. Individual animal model, using average numerator relationship was used to estimate breeding values from which genetic trends were derived. This paper reports results of the analyses of 10 417 records of 80-day weights (WT80) of lambs born between 1984 and 1992 from 29 participating farmers, and 1978 and 849 records on 180- (WT180) and 365- (WT365) day weights, respectively, of lambs from the nucleus. Phenotypic trends exhibited substantial annual fluctuation during the study period. The heaviest weights were obtained in 1986 (10·1 kg) for WT80, 1984 (23·3 kg) for WT180 and 1985 (33·7 kg) for WT365. There was an annual decline of 152 g (P<0·05) in WT80 mainly (–180 g/year) due to negative environmental trend. The phenotypic and environmental trends for WT180 were –703 and –721 g/year, respectively, while the corresponding values for WT365 were –931 and –956 g/year. Overall mean weights of the ram lambs at the three ages were 9·9, 23·3 and 33·7 kg, respectively in the base year and 9·3, 17·8 and 28·2 kg, respectively in the final year. Breeding values increased by 28, 11 and 14 g/year for WT80, WT180 and WT365, respectively. Results of this study indicate that genetic progress can be made in growth performance of Djallonkè sheep if reasonable levels of animal management as well as selection pressure are maintained.

L-type amino acid transporter-1 (LAT1) transports large, branched-chain, aromatic and neutral amino acids. About 64 Duroc × Landrace × Yorkshire pigs were used to study the effects of dietary crude protein (CP), energy and arginine on LAT1 expression in forebrain. The results showed that LAT1 expression in forebrain was sensitive to different levels of CP, energy and arginine. On the basis of Western blot analysis, a lower level of LAT1 presented in the brain tissues of pigs fed the low dietary CP diet (P < 0.05), a higher level were found in pigs fed the higher CP diet, with moderate to intense staining seen in pigs fed the diet plus 1% arginine. In contrast, pigs fed the control-energy diet had weak LAT1 expression, and those fed the diet supplemented with 1% arginine showed lowest LAT1 expression (P < 0.05). These results showed that LAT1 was highly expressed in the forebrain, and expression of LAT1 was affected by dietary protein, energy and arginine differently.

Genetic studies on taste sensitivity, and bitter taste receptors (T2R) in particular, are an essential tool to understand ingestive behavior and its relation to variations of nutritional status occurring in ruminants. In the present study, we conducted a data-mining search to identify T2R candidates in sheep by comparison with the described T2R in cattle and using recently available ovine genome. In sheep, we identified eight orthologs of cattle genes: T2R16, T2R10B, T2R12, T2R3, T2R4, T2R67, T2R13 and T2R5. The in silico predicted genes were then confirmed by PCR and DNA sequencing. The sequencing results showed a 99% to 100% similarity with the in silico predicted sequence. Moreover, we address the chromosomal distribution and compare, in homology and phylogenetic terms, the obtained genes with the known T2R in human, mouse, dog, cattle, horse and pig. The eight novel genes identified map either to ovine chromosome 3 or 4. The phylogenetic data suggest a clustering by receptor type rather than by species for some of the receptors. From the species analyzed, we observed a clear proximity between the two ruminant species, sheep and cattle, in contrast with lower similarities obtained for the comparison of sheep with other mammals. Although further studies are needed to identify the complete T2R repertoire in domestic sheep, our data represent a first step for genetic studies on this field.

M. biceps brachii and m. tibialis anterior were studied at a fixed body weight in mice selected for high and low body weight at a fixed age. Muscle weights were approximately equal in the two lines. In general, muscles from high-line mice appeared to contain a larger number of smaller fibres than low-line mice in which there were fewer but wider fibres than in the unselected control population from which the lines were derived.

Two experiments were conducted to compare the effects of single and double suckling on the performance of Hereford × Friesian and Friesian cows at pasture. Double-suckled cows each fostered a Friesian male calf in addition to their own calf. Cows were housed from calving to turnout for 57 and 35 days in experiments 1 and 2 respectively, with corresponding grazing seasons lasting 152 and 146 days. During the grazing season the two suckling treatments were stocked on a series of adjacent plots of equal area, with the occupancy of each plot pair being reversed daily. Live weights, milk yields, herbage intakes, and daylight grazing times and nursing activities were recorded on three occasions 28 days apart.

Double-suckled cows lost significantly more weight than single-suckled cows from calving to turnout in both experiments (39·5 v. 3·3 kg and 45·7 v. 20·6 kg), gained more weight from turnout to weaning in experiment 1 (58·4 v. 23·3 kg) but gained less in experiment 2 (17·5 v. 32·3 kg). Double-suckled cows produced significantly more milk than single-suckled cows: 10·1 v. 8·3 and 13·5 v. 9 1 kg/day in experiments 1 and 2 respectively. Differences in daily milk yield in experiment 2 were apparent 28 days after calving.

Suckling treatments did not influence herbage intakes or daylight grazing times and nursing frequencies. Mean nursing intensities were 1·0 calves per single-suckled cow, compared with 1·8 calves (experiment 1) and 2·2 calves (experiment 2) per double-suckled cow. Double-suckled cows nursed significantly more ‘foreign’ calves than single-suckled cows. Total calf weight at weaning from double-suckled cows in experiments 1 and 2 was respectively 364·6 and 344·4 kg, which was 1·64 of the corresponding weights weaned by single-suckled cows (221·1 and 209·4 kg).

To explore the effects of maternal nutrition on offspring muscle characteristics, a total of 56 sows were assigned to one of the four dietary groups during gestation: control (CON), or control diets supplemented with methyl donor (MET), bisphenol A (BPA), and combined BPA and MET (BPA+MET). Compared with CON offspring, MET offspring showed a higher meat redness value, but lower glycogen content in the longissimus thoracis (LT). Moreover, compared with CON offspring, MET offspring showed lower LT glycogen synthase (GS) mRNA levels at birth and the finishing stage, and increased methylation at the GS promoter. Prenatal BPA exposure reduced the pH and redness value of meat, but increased the lightness value, lactate content, glycolytic potential and lactate dehydrogenase (LDH) enzyme activity in the LT muscle. Prenatal BPA exposure increased LDH mRNA levels in the LT muscle at birth and the finishing stage, and reduced methylation at the LDH promoter. Thus, maternal MET affects muscle GS and LDH expression via DNA methylation, thereby resulting in persistent effects on pork quality.

Wheat grain (WG) is unique in possessing extensive starch and nitrogen fermentation (i.e. >85% in ground and steam-processed WG), low cation–anion difference and high-intake properties, making it a potentially useful prepartal dietary choice. The objective was to determine the effects of WG provision to pre-partum first-calf heifers on metabolic, health and productive criteria during the transition period. WG replaced barley grain that was commonly used earlier. Fifteen Holstein heifers at 31 ± 6 days pre partum were blocked based on expected calving date and assigned to three treatments or feeding totally mixed rations containing either (i) barley grain (13.8%) and wheat bran (6.1%), (ii) 10% WG (WG10) or (iii) 18% WG (WG18; dry matter (DM) basis) from 31 days pre partum until calving. In replacing WG for barley grains, some changes in WG use and slight changes in soybean and cottonseed meals use were made to properly formulate balanced rations for net energy for lactation, CP, calcium and P. Prepartal diets contained no supplemental anionic salts. Cows were monitored until 21-day post partum and received the same early lactation diet. The prepartal provision of WG and related dietary changes reduced urine pH at 7-day pre partum, and elevated blood calcium and glucose at 7-day pre partum and at 3-day post partum. Milk fat and protein yields were increased during the 21 days post partum by prepartal WG provision and related diet changes. Blood albumin, globulins, total proteins and urea concentrations were similar among treatments. Feeding diets with WG did not affect body condition score, calving difficulty, calf weight, placenta weight and the time interval from calving to placenta expulsion. It is suggested that prepartal provision of WG with necessary dietary changes led to simultaneous improvements in energy and calcium status of the heifers experiencing their first periparturient phase without compromising parturition status.

Unchaffed Andropogon gayanus hays, harvested in July, September, early-October, late-October and November, and the July to November regrowth, were offered to White Fulani heifers at three levels of feeding.

Animals on all hays selected for protein and the mean intake of the different hays was closely related to the protein content of the consumed forage. At the low level of feeding all animals, except those on the July hay, left more than 15% residue. Nevertheless, higher levels of feeding had a marked linear effect on feed intake. This effect was largely independent of the effect of level of feeding on the protein content of the consumed ration and was associated with a strong selection for leaves.

The profitability of pig production is constrained by high incidences of peri-parturient and pre-weaning piglet mortality. Supplementing sows with either progesterone or caffeine during the last week of gestation can reduce stillbirths and improve piglet performance. However, the consequences of combining these two substances has not been investigated. The aim of the current study was to determine the effect of oral supplementation of sows with progesterone (regumate) and caffeine at the end of gestation on the timing and progression of farrowing, as well as piglet survival and growth to weaning. From days 111 to 113 of gestation, 20 Large White pregnant sows (parity 3.0±0.45) received 5 ml of Regumate Porcine (0.4 w/v oral solution; MSD Animal Health) daily on top of their morning ration. Sows were stratified according to parity and predicted farrowing date, and allocated at random to receive a diet supplemented with either 0 g caffeine/kg diet (CONT) or 2.4 g of caffeine/kg diet (CAFF) from day 113 of gestation until parturition (n=10 sows/treatment). Treatment did not affect total litter size; however, CONT sows gave birth to more live and fewer dead piglets compared with CAFF sows; 14.5±0.73 v. 11.7±1.03 and 0.7±0.20 v. 3.2±0.77; P<0.05). Mean, minimum and maximum piglet birthweight were unaffected by treatment. Compared with the control, caffeine increased the proportion of piglets with a birthweight <1 kg (0.16±0.05 v. 0.05±0.02; P=0.072) and decreased the proportion of live born piglets surviving to day 5 postpartum (0.77±0.06 v. 0.90±0.02; P<0.05) and to weaning (0.74±0.06 v. 0.90±0.02; P<0.05). Overall, the current data provided the first evidence that caffeine supplementation of sows receiving progesterone to prevent premature farrowing impaired piglet survival during, and shortly after parturition. This negative outcome may be linked to extended farrowing durations and an increase in the proportion of very light piglets at birth. These data provide compelling, albeit preliminary, evidence that caffeine and progesterone should not be used together at the end of gestation.

Although the UK is the largest lamb meat producer in Europe, there are limited data available on sheep flock performance and on how sheep farmers manage their flocks. The aims of this study were to gather evidence on the types of disease control practices implemented in sheep flocks, and to explore husbandry factors associated with flock productivity. A questionnaire focusing on farm characteristics, general husbandry and flock health management was carried out in 648 farms located in the UK over summer 2016. Abattoir sales data (lamb sales over 12 months) was compared with the number of breeding ewes on farm to estimate flock productivity (number of lambs sold for meat per 100 ewes per farm per year). Results of a multivariable linear regression model, conducted on 615 farms with complete data, indicated that farms vaccinating ewes against abortion and clostridial agents and administering a group 4/5 anthelmintic to ewes (as recommended by the Sustainable Control of Parasites in Sheep Initiative) during quarantining had a greater flock productivity than farms not implementing these actions (P<0.01 and 0.02, respectively). Flocks with maternal breed types had higher productivity indexes compared with flocks with either pure hill or terminal breeds (P<0.01). Farms weighing lambs during lactation had greater productivity than those not weighing (P<0.01). Importantly, these actions were associated with other disease control practices, for example, treating individual lame ewes with an antibiotic injection, weaning lambs between 13 and 15 weeks of age and carrying out faecal egg counts, suggesting that an increase in productivity may be associated with the combined effect of these factors. This study provides new evidence on the positive relationship between sheep flock performance and disease control measures and demonstrates that lamb sales data can be used as a baseline source of information on flock performance and for farm benchmarking. Further research is needed to explore additional drivers of flock performance.

Forty-eight gilts by Landrace sires on Large White × Landrace females were randomly allocated to eight pens and within pens to six treatment groups involving three diets and two levels of feeding from 23 to 59 kg live weight. All diets were formulated to have approximately the same ratio of digestible energy to crude protein (160 kcal DE/unit % CP) but different energy and protein concentrations: (A) 3500 kcal/kg DE and 21 % CP, (B) 3150 kcal/kg DE and 19% CP, and (C) 2800 kcal/kg DE and 17% CP. Amino acid balance was maintained relatively constant with synthetic lysine, methionine and tryptophan. The levels of feeding were such that the lower level of diet A allowed an intake of energy and protein similar to the higher level of diet B, and the lower level of B was similar to the higher level of C.

On the lower level of feeding, growth rate, efficiency of feed conversion and carcass fat content increased linearly with each increment in nutrient concentration; on the higher level of feeding growth rate and EFC increased from diet C to B but not from B to A, whereas carcass fat content increased linearly with diet from the lowest to the highest concentration. There was a non-significant tendency for the higher density diets at a similar level of nutrient intake to give better EFC and fatter carcasses than the lower density diets.

Over an 8-week period pH measurements were taken in the longis-simus dorsi muscle of 17 157 bacon-weight carcasses at 45 min post mortem (pH1 ) in one abattoir. The overall least squares mean pHt was 6·38 and 9·9% of carcasses had pHt values of 5·9 or less. Neither sex, type of dam, breed nor testing background of sire of the carcasses examined had a significant effect on muscle pHj or the incidence of values below p H 6·0. Although first-grade carcasses had a higher incidence of low pHj values relative to those in the other grades, it was of no practical significance. Carcasses of homebred pigs had a higher incidence of muscle pHt values of 5·9 and below (2%) compared with those from pigs initially purchased as weaners. There was a marked producer effect on muscle pHj and the incidence of values below pH 6·0.

1. Large White x Landrace pigs were used to study the effects of supplementation with limiting amino acids of diets based on wheat containing 13% crude protein. Measurements were made of growth rate, feed conversion, carcass composition, plasma-free amino acid concentrations, digestibility of dry matter, nitrogen and gross energy, nitrogen retention and metabolizable energy.

2. A wheat diet supplemented with lysine and threonine, the firstand the second-limiting amino acids respectively, produced almost the same growth rate and feed conversion ratio as one supplemented with fish meal and meat meal. Methionine was probably the thirdlimiting amino acid, and additional supplementation with methionine produced a further small improvement in growth rate and feed conversion ratio to the point where they were equal to those on the diet supplemented with fish meal and meat meal.

3. Supplementation of the wheat diet with lysine only produced the same growth rate and feed conversion ratio as a least-cost commercial diet; performance was, however, inferior to that on a wheat diet supplemented with fish meal and meat meal. The commercial diet had a lower dry-matter digestibility.

4. Eye-muscle area of pigs on the wheat diet supplemented with lysine was similar to that of pigs on a wheat diet supplemented with fish meal and meat meal; however, backfat thickness was significantly lower on the latter diet.

5. Except for threonine, plasma-free amino acid concentrations reflected with reasonable accuracy amino acid deficiencies in the diets.

Reproductive performance has recently been a growing concern in cattle dairy systems, but few research methodologies are available to address it as a complex problem in a livestock farming system. The aim of this paper is to propose a methodology that combines both systemic and analytical approaches in order to better understand and improve reproductive performance in a cattle dairy system. The first phase of our methodology consists in a systemic approach to build the terms of the problem. It results in formalising a set of potential risk factors relevant for the particular system under consideration. The second phase is based on an analytical approach that involves both analysing the shapes of the individual lactation curves and carrying out logistic regression procedures to study the links between reproductive performance and the previously identified potential risk factors. It makes it possible to formulate hypotheses about the biotechnical phenomena underpinning reproductive performance. The last phase is another systemic approach that aims at suggesting new practices to improve the situation. It pays particular attention to the consistency of those suggestions with the farmer’s general objectives. This methodology was applied to a French system experiment based on an organic low-input grazing system. It finally suggested to slightly modify the dates of the breeding period so as to improve reproductive performance. The formulated hypotheses leading to this suggestion involved both the breed (Holstein or Montbéliarde cows), the parity, the year and the calving date with regard to the turnout date as the identified risk factors of impaired performance. Possible use of such a methodology in any commercial farm encountering a biotechnical problem is discussed.

The effects on average daily gain of a 12 mg. implant of diethylstilboestrol has been tested in male suckling lambs and in male hoggets. In both types stilboestrol produced some mammary stimulation. One case of rectal prolapse was encountered in the hoggets. In suckling lambs, treatment did not significantly increase rate of gain nor significantly affect any of several carcass characteristics studied. In hoggets, treatment produced a highly significant increase in rate of gain (33%), a highly significant increase in pelt weight and a highly significant decrease in the percentage of fat in the last rib section. It produced a non-significant increase in muscle and bone in the last rib section. Carcass score and dressing percentage were not significantly affected by treatment.

The oral administration of L-thyroxine to suckling female lambs from 30–70 lb. live-weight did not significantly affect the rate of gain or the carcass characteristics studied.