The aim of this study was to test for the existence of causative genetic variation affecting body composition traits within or adjacent to the porcine insulin-like growth factor 2 (IGF2) gene beyond the known IGF2-intron3-G3072A mutation. A focussed quantitative trait loci analysis using four microsatellite markers within the telomeric region of porcine chromosome 2p was conducted in a large resource population comprising 2741 F2 offspring. The analysis of two subsets of animals that were alternatively homozygous for the in3G3072A mutation provides evidence for additional genetic variation significantly contributing to the overall quantitative trait nucleotide variance within our population.

The aim of this study was to evaluate nitric oxide (NOx) concentration in infected and non-infected mammary quarters of dairy heifers before and after calving. The relationship between bacterial species and NOx concentrations, as well as correlation between NOx concentrations and postpartum somatic cell count (SCC), was assessed. Coagulase-negative staphylococci, Staphylococcus aureus and Escherichia coli were the bacteria commonly isolated during the pre- and postpartum period. Infected quarters had greater NOx concentrations than non-infected quarters before (30.81 v. 22.83 μM/ml, P < 0.05) and after (9.56 v. 5.77 μM/ml, P < 0.0001) calving. It was determined that the interaction between sampling period and infectious status had no effect on NOx concentration (P < 0.16). Infected quarters had greater SCC (log10) than healthy quarters (4.95 v. 4.39; P < 0.0001). NOx concentrations, however, did not correlate with SCC (r = 0.02). In summary, changes in NOx concentration were mainly dependent on the infectious status of the quarters with variations among the bacterial species (P < 0.05).

It has been shown (Robinson, 1951) that in the ewe the number of ova shed can be increased by the injection of a single dose of mare serum gonadotrophin (P.M.S.) if this is given during the follicular phase of the oestrous cycle. The investigations described here were made to examine the usefulness of this treatment for increasing the lamb crop in commercial flocks.

Observations were made on 594 ewes of 3 breeds in 11 flocks (Romneys, 9; Cheviot, 1; Southdown, 1). Most ewes were purebred from old-established flocks. The Romneys were running on the marshlands and mixed farms of Kent and East Sussex, the South-downs were near Glynde, in Sussex, and the Cheviots were on a farm near Brampton in Cumberland. Management within the flocks followed the practice normal for the different breeds. Most ewes were 2½ to 4½ years old at the start of treatment; a few younger ewes (1½ years) and some aged ewes were also involved.

Microarray technology is a powerful tool for animal functional genomics studies, with applications spanning from gene identification and mapping, to function and control of gene expression. Microarray assays, however, are complex and costly, and hence generally performed with relatively small number of animals. Nevertheless, they generate data sets of unprecedented complexity and dimensionality. Therefore, such trials require careful planning and experimental design, in addition to tailored statistical and computational tools for their appropriate data mining. In this review, we discuss experimental design and data analysis strategies, which incorporate prior genomic and biological knowledge, such as genotypes and gene function and pathway membership. We focus the discussion on the design of genetical genomics studies, and on significance testing for detection of differential expression. It is shown that the use of prior biological information can improve the efficiency of microarray experiments.

Farming systems can expose animals to chronic mild stress which is known to induce negative affective state. Affective state in animals, as in humans, can be assessed through behavioral cues. This study aimed to describe the effect of a chronic mild stress, known to induce a negative affective state, on sheep health through their response to vaccination. The study used 15 lambs subjected to a model of chronic mild stress for 15 weeks and 15 lambs reared under conventional farming as a control group. After 7 weeks of stressful treatment, the lambs were individually exposed to a judgment bias test to assess a putative stress-induced ‘pessimism.’ After 15 weeks of stressful treatment, antibody immune response was measured after an injection of a live vaccine challenge (Chlamydia abortus attenuated vaccine strain 1B). Stressed lambs displayed a pessimistic-like perception in the judgment bias test, revealing a negative affective state. Stressed and control animals showed different immunological reactions to vaccine challenge: stressed sheep had lower hemoglobin concentrations and higher platelet, granulocyte and acute-phase protein concentrations. Antibody response induced by the vaccine strain was not different between stressed and control sheep. Our results suggest that negative affective state induced by chronic stress treatment may induce a stronger inflammatory response to vaccine challenge in sheep. Improvement of animal health may be achieved through consideration of stressors that may affect the emotional and immunological state of sheep.

Erythropoietin (EPO) gene therapy can be used for several purposes; however, its effects on reproductive performance are unknown. The aim of this study was to evaluate the toxicological effects of non-viral (EPO) gene transfer on sperm motility, viability, morphology and concentration. Rabbit EPO cDNA was cloned into a pTarget mammalian expression vector. Rabbits were administered with: (1) pTarget/EPO vector, (2) recombinant human EPO (rHuEpo) and (3) saline (control). Both pTarget/EPO and rHuEpo significantly increased (P < 0.05) hematocrit levels 1 week after injection and they remained significantly higher than the control for up to 5 weeks (P < 0.05), showing that both EPO treatments were effective in stimulating the production of red blood cells in rabbits. The EPO gene transfer or rHuEPO administration had no significant effect (P > 0.05) on sperm motility, vigor, viability, concentration or morphology in the testis.

Access to an outdoor range has many potential benefits for laying hens but range use can be poor due to factors only partly understood. Techniques to monitor individual range use within commercial flocks are crucial to increase our understanding of these factors. Direct observation of individual range use is difficult and time-consuming, and automatic monitoring currently relies on equipment that is difficult to use in an on-farm setting without itself influencing range use. We evaluated the performance of a novel small, light and readily portable light-based monitoring system by validating its output against direct observations. Six commercial houses (2000 hens/house) and their adjacent ranges were used, three of which were equipped with more structures on the range than the others (to determine whether cover would influence monitoring accuracy). In each house, 14 hens were equipped with light monitoring devices for 5 discrete monitoring cycles of 7 to 8 consecutive days (at 20, 26, 32, 36 and 41 weeks of age). Light levels were determined each minute: if the reading on the hen-mounted device exceeded indoor light levels, the hen was classified as outside. Focal hens were observed directly for 5 min/hen per week. Accuracy (% of samples where monitoring and direct observations were in agreement) was high both for ranges with more and with fewer structures, although slightly better for the latter (92% v. 96% ± 1 SEM, F1,19 = 5.2, P = 0.034). Furthermore, accuracy increased over time (89%, 94%, 95%, 98% ± 1 SEM for observations at 26, 32, 36 and 41 weeks, respectively, F3,19 = 3.2, P = 0.047), probably due to progressively reduced indoor light levels resulting from partial closing of ventilation openings to sustain indoor temperature. Light-based monitoring was sufficiently accurate to indicate a tendency for a greater percentage of monitored time spent outside when more range structures were provided (more: 67%, fewer: 56%, SEM: 4, $\chi_1^2 = 2.9$, P = 0.089). Furthermore, clear and relatively consistent individual differences were detected. Individuals that were caught outside at the start of the experiment ranged more throughout its duration (caught outside: 72%, caught inside 51%, SEM: 4, $\chi_1^2 = 10.0$, P = 0.002), and individual range use was correlated between monitoring cycles (for adjacent monitoring cycles: $r_s^2 = 0.5-0.7$, P < 0.0001). This emphasizes the importance of studying range use on an individual level. In conclusion, our light-based monitoring system can assess individual range use accurately (although accuracy was affected by house characteristics to some extent) and was used to show that both cover availability and individual characteristics affected range use.

This experiment evaluated different strategies for allocating first-cut grass silages to dry dairy cows that had low body-condition score (BCS) at drying off. A total of 48 moderately yielding Holstein-Friesian cows were used, receiving one of three dietary treatments in the dry period and a single lactation diet based on a flat-rate of concentrates and grass silage ad libitum. Throughout the dry period, one group received a low-digestibility silage (harvested 15 June 1998; LL; metabolisable energy (ME) = 10.3 MJ/kg dry matter (DM)) and a second group received a high-digestibility silage (harvested 9 May 1998, HH; ME = 11.7 MJ/kg DM). A third strategy (LH) offered the low-digestibility silage in the early dry period and the high-digestibility silage in the final 3 weeks before calving. The silages had very different crude protein concentrations (144 and 201 g/kg DM) and intakes were widely divergent (10.1 v. 13.5 kg DM/day) across the dry period. No concentrates were fed during the dry period. Silage quality had a very large effect on liveweight change, with treatment means of 0.32 and 1.75 kg/day for LL and HH, respectively. BCS changes followed a similar pattern, though no cows became over-conditioned and blood metabolites were within normal ranges. Increased silage digestibility in the late dry period led to a substantial increase in milk fat concentration and a smaller increase in milk protein concentration, the latter confined to the first full week of lactation. Depression of milk fat appears related to low blood glucose when dry cows in low body condition are fed at a low level. The LH strategy avoided the tendency for lower milk yields and fat concentration that resulted from feeding the low-digestibility silage until calving. This strategy also avoided the higher calf weights that resulted from feeding the high-digestibility silage in the early dry period.

Development of new systems of lamb finishing for the late winter/spring market involving an extended housed store period on a predominantly straw diet are constrained by unacceptable reduction in muscle mass arising from inadequate protein supply during dietary adaptation from grass to straw. Problems with subsequent finishing on forage brassicas fedin situ arise from carcass contamination due to soiled wool of crossbred lambs which grow long fleeces over the extended store I finishing period. In order to study the effect of fish-meal supplementation on dietary change over from grass to straw 116 Mule wether lambs were allocated to four treatments, three of which received a supplement of 100 glday fish meal for 28 days from housing and introduction of a diet of straw ad libitum and 225 glday grain distillers' dark grains, the fourth group received no fish meal and was unshorn (No F/US). Shearing treatments of shorn (F/S), unshorn (F/US) and crutched (F/C) were applied to fish-meal supplemented group's. After 112 days, the housed lambs were grazed outside on swedes (Brassica napus) and effects of treatments on performance and bacterial contamination of carcasses (shearing treatments only) were studied. Fish-meal supplementation significantly reduced weight loss on dietary change by 2·2 kg after 45 days (P< 0·001). Of fishmeal supplemented lambs 83% eventually ‘finished’ (defined as Meat and Livestock Commission fat class 3LI3H) v. 34% of unsupplemented lambs. Shearing or crutching had little effect on store or finishing performance indicating adequate fleece regrowth for insulation purposes after turn-out. Shorn and crutched lambs had lower levels of bacterial carcass contamination with reductions of 0·06, 0·42 and 0·40 in counts for colony forming units per cm2, coliforms and Escherichia coli on leg sites (P < 0·05). Economic evaluation indicated financial advantage from fish-meal supplementation with an increase in margin over food costs of €3·50 as a result of heavier carcass weight and a reduced need for remedial concentrate feeding in the store period.

Two experiments were made to determine the effects on digestion characteristics and live-weight (LW) gain of cattle consuming bermudagrass of supplementing with ground maize, soya-bean meal or a maizegluten— blood meal mix alone or maize plus the protein supplements. Experiment 1 was a Latin-square design with 14-day periods using six beef cows fitted with rumen and duodenal cannulas (490 kg). Cows were given bermudagrass hay at 12·7 g/kg LW alone (control, C) or with 2·4 g/kg LW of ground maize (M), 0·98 g/kg LW of soya-bean meal (S), 0·53 g/kg LW of maize-gluten plus 0·17 g/kg (dry matter basis) of blood meal (GB), M plus S (M + S) or M plus GB (M + GB). Nitrogen (N) intake was 106, 123, 143, 148, 166 and 166 g/day; total N at the duodenum was 101, 124, 117, 126, 140 and 161 (s.e. 5·91) g/day; and post-ruminal N disappearance was 61, 77, 72, 84, 87 and 110 (s.e. 5·6) g/day for C, M, S, GB, M + S and M + GB, respectively. In experiment 2, 96 crossbred beef heifers (203 kg LW) implanted with 200 mg testosterone and 20 mg oestradiol benzoate were allotted to 12 groups by LW (two groups per treatment). Heifers grazed bermudagrass paddocks for 84 days in two 42-day periods and supplement treatments were those in experiment 1. A period × treatment interaction in LW gain was noted (P < 0·05). LW gain was 0·78, 0·81, 0·79, 0·76, 0·70 and 0·95 kg in period 1 and 0·46, 0·51, 0·56, 0·53, 0·64 and 0·61 kg in period 2 for C, M, S, GB, M + S and M + GB, respectively (s.e. 0·049). In conclusion, duodenal flow and post-ruminal disappearance of N were similar for the protein sources when offered singularly, but when given with maize values were greater for the mix of protein meals high in ruminal undegradable protein as compared with soya-bean meal. LW gain by heifer calves grazing bermudagrass was increased only by supplementation with ground maize plus the protein meal mix of low ruminal degradability.

Milk production, reproduction, blood composition and health were studied in two groups of British Friesian cows given food either twice daily in the parlour (IPF group) or through automatic out-of- parlour food dispensers (OOPF group) in the first 14 weeks of two consecutive lactations. The numbers of cows in the IPF and OOPF groups were 28 and 29 respectively in year 1 and 40 and 35 in year 2.

There were no differences in milk production or reproduction in year 1 but in year 2 the OOPF group had significant proportional increases in the yield of fat (+0·079) and protein (+0·072) and the median time from calving to conception was reduced by 43·5 days. In the IPF group body condition score was lower than in the OOPF group in year 1 (2·27 v. 2·59; P < 0·001) and in year 2 (2·37 v. 2·57; P < 0·01); as were serum total protein (75·8 v. 77·5 g/l; P < 0·05) and (73·9 v. 75·8 g/l; P < 0·01) and plasma glucose concentration (215 v. 2·32 mmol/1; P < 0·001) (2·28 v. 2·42 mmol/l; P < 0·01). In year 2 only, serum urea was lower (5·52 v. 6·07 mmol/l; P < 0·001) and serum copper higher (131 v. 11·9 μmol/l; P < 0·001) in the IPF group; the activities of aspartate amino transferase (1·66 v. 1·62 logm i.u. per 1; P < 0·05) and of glutamate dehydrogenase (1·00 v. 0·70 logm i.u. per 1; P < 0·001) were higher, despite no significant difference in fat deposition in the liver. The only significant difference in the incidence of disease was fewer cases of mastitis in the OOPF group in the second year (21 v. 12 cases).

The similarity in concentrate intakes, together with higher concentrations of blood glucose and total protein and better condition score, indicate either a more efficient utilization of energy in the OOPF group or a lower consumption of forage in the IPF group. The increased activities of liver enzymes and the high serum copper coupled with the increased incidence of mastitis and poorer fertility may indicate the release of endotoxin following chronic lactic acidosis in the IPF group.

The amylase (Ami) phenotypes have been determined in sera collected from 244 heifers before 6 months and after 2 years of age. Fifty of these animals exhibited a change in phenotype from Ami C to an apparent Ami BC with age. Using a modified electrophoretic technique these apparent heterozygotes were reclassified as Ami C(E). Eight hundred and nineteen cows, which had previously been shown to have a highly significant excess of heterozygotes at the Ami locus, were also retyped by this modified technique. The apparent heterozygote excess was not found as it was now possible to differentiate between Ami C(E) and Ami BC.

The effect of exercise (walking 10.6 km/day and climbing 480 m/day) on intake of barley straw and body weight changes in 12 pregnant lactating suckler cows was investigated. Three groups of four cows received ad libitum barley straw and 4 kg per cow per day of different supplements. Neither exercise nor supplement had a significant effect on straw intake. Cows gained weight when not exercised, but lost weight during the exercise period. The experiment confirms previous findings that animals performing moderate work and given poor quality roughage, in the short term cannot increase daily intake to meet energy requirements and that intake may decrease when animals work.

The growth and efficiency of live-weight gain of 36 calves confined in pens was studied between 30 and 210 days of age. They were weaned individually at 30, 90 or 150 days old and offered one of three solid foods which contained 200, 300 or 400 g milled roughage/kg both before and after weaning. From 30 to 90 days and from 90 to 150 days weaned calves consumed more (P<0·001) solid food than sucking calves. During both these periods sucking calves consumed more (P< 0·001 and P<0·05 during the first and second periods respectively) metabolizable energy (ME), gained more (P<0·01) body weight and also gained more body weight/MJ ME consumed than weaned calves. Composition of solid food had little effect on calf performance.

The combined efficiency (kg calf weight gain/MJ ME consumed by cow and calf unit) was higher (P<0·001) for suckling cows and calves than for weaned cows and calves between 30 and 90 days. Between 90 and 150 days, weaning had no effect on combined efficiency.

Eight similar calves which were reared by their dams on veld until 210 days of age were heavier at 90 (P< 0·001) and 150 (P<0·05) days than penned calves which had been given concentrates ad libitum since weaning at 30 days. The body weights of these two groups were similar at 210 days.

Muscle to bone weight relationships within anatomical regions (proximal-distal division into pelvic, thigh and lower leg groups) and subregions (division within regions into gluteal, intrinsic pelvic, cranial, caudal and medial thigh, and cranial and caudal lower leg groups) of the hind limb and also of its most important muscles (no. = 11) were compared between goats and sheep using the method of multivariate analysis of the centred data. In this comparison, a total of 39 animals was considered: 13 male kids of the Alpine breed (K) and a sample of 26 male lambs derived from different breeds or crossbreeds representing, in equal numbers, lambs having good conformation (LGC) and poor conformation (LPC). Lambs were chosen on the basis of the hindlimb length the means of which were 22·9 (s.e. 1·5), 29·3 (s.e. 1·8) and 29·1 (s.e. 2·5) cm for LGC, LPC, and K, respectively. Corresponding cold carcass weights were 19·71 (s.e. 347), 17·28 (s.e. 1·77) and 10·84 (s.e. 0·56) kg.

In both comparisons (K-LGC and K-LPC) the two species were systematically distinguished by the size of the following ratios: (pelvic muscles/os coxae + leg muscles /tibia) relative to thigh muscles/femur (for regions), which was lower in lambs than in kids; intrinsic pelvic muscles/os coxae relative to caudal thigh muscles/femur (for subregions), which was higher in kids than in lambs. For individual muscles, they were distinguished by the size of the following ratios: rectus (emoris/femur relative to semimembranosus/femur (or gluteus medius/os coxae) in the comparison K-LGC, which was higher in lambs than in kids, and vastus lateralis/femur relative to sum of pectineus + gracilis/femur (or gastrocemius/tibia) in the comparison K-LPC, which was lower in kids than in lambs. The results show that the muscle-bone ratios of the anatomical regions, subregions and the most commercially important muscles in the hindlimb can be used as discriminant characteristics of species.

When comparing progeny-testing schemes with individual performance selection, one should use equivalent selection intensities and population structures in the two systems. Adapting formulae from open-nucleus theory, the relative efficiency of progeny testing has been tested for a range of heritabilities, fertility levels, upward gene-transfer rates, mating ratios and numbers of sires selected. In sheep and beef cattle breeding, the heritability of the trait under consideration has usually to be very low to make progeny testing worth-while. High fertility increases genetic gains but does not change the relative efficiency of progeny testing. Opening the nucleus to females from the base increases genetic gains and reduces relative efficiency of progeny testing, both effects being of small magnitude. For fixed mating ratios, only a small fraction of females should be in the nucleus, but for fixed sire numbers approximately one-third of the population should be mated to proven sires. In these analyses, variances were adjusted for the effects of repeated selection and for the effects due to mixing groups with different means. This adjustment did reduce absolute genetic gains, but did not change conclusions on progeny testing efficiency and optimum design.

Breeding programmes for Wakwa and Ngaundere Gudali cattle breeds were initiated in Wakwa (Cameroon) in 1952 and 1965, respectively, to improve growth performance of the indigenous breeds. Animals were selected on 240-day weaning weight (WWT). Data analysed covered the period 1971 through 1985 and consisted of 2211 calf birth weight (BWT) and 1409 WWT records on Gudali and 1196 BWT and 763 WWT records on Wakwa. Selection responses in BWT and WWT were estimated as regressions of average sire estimated transmitting abilities (ETAs) and average dam estimated breeding values (EBVs) on year of calving. ETAs and EBVs were predicted using best linear unbiased prediction procedures. Estimated annual changes in sire ETAs for WWT were 0·67 (s.e. 0·17) and 1·69 (s.e. 1·13) kg/year for Gudali and Wakwa, respectively. Corresponding trends in dam EBVs were –0·03 (s.e. 0·03) and –0·24 (s.e. 0·19) kg/year. Estimated correlated trends in BWT among Gudali and Wakwa sires were 0·09 (s.e. 0·05) and –0·14 (s.e. 0·04) kg/year, respectively. Corresponding correlated trends in BWT associated with dam selection were essentially zero, being –0·001 (s.e. 0·001) and –0·01 (s.e. 0·01) kg/year. Environmental trends were negative for all traits except Gudali WWT. Phenotypic trends were all positive, except that of Wakwa BWT. Overall, selection on WWT yielded moderate selection reponse despite substantial infrastructural constraints in the breeding programme. Trends in sire ETAs and dam EBVs for WWT jointly accounted for estimated genetic gains of 8·60 kg in Gudali and 20·4 kg in Wakwa over the study period. Overall correlated response in BWT during the study period was significant (P < 0·001) and negative for Wakwa. It was positive but not significant for Gudali.

Piglets were weaned at 21 days of age, and given diets containing 13·5 or 17·0g crude protein per MJ digestible energy and either 14·7 or 16·8 MJ digestible energy per kg in a 2 × 2 factorial experiment until 56 days of age. There was no effect on performance or food intake when the diets were offered ad libitum, but energy intake was increased with the higher concentration of dietary energy. The higher levels of both protein and energy improved performance in a metabolism experiment with food intake restricted to 0·80 of ad libitum intake, and the higher protein level increased nitrogen retention (g/day per kg live weight) and plasma urea nitrogen. These results suggest that the level of food intake can affect the response to changes in dietary energy and protein concentrations, and indicate that conclusions from metabolism experiments using restricted feeding may be inappropriate under other conditions.

The silage intake and growth rate of naturally suckled calves after weaning was less than that of similar groups of artificially reared animals that had received lower quantities of milk over the period to 8 months of age. Although the silage intake of all groups was linearly related to the level of herbage intake prior to weaning, those calves consuming least herbage had the higher rate of increase in silage intake. It was concluded that silage intake can be influenced for a considerable time after weaning by the level of herbage consumption achieved during the suckling period.

1. Nitrogen balance studies were conducted on 16 steers in two separate trials. The steers were fed on four diets containing respectively dry rolled barley; dried, steamed and rolled barley; dried, crimped barley and barley that had been stored in a sealed silo and rolled.

2. There were no significant differences in the dry-matter intake of any of the diets.

3. No consistent differences between the diets in dry-matter digestibility or nitrogen retention were observed.