Animal sociability measurements based on inter-individual distances or nearest-neighbour distributions can be obtained automatically with telemetry collars. So far, all the indices that have been used require the whole group to be observed. Here, we propose an index of the variability in affinity relationships in groups of domestic herbivores, whose definition does not depend on group size and that can be used even if some data are missing. This index and its estimators are based on a function that measures how frequently an animal is closer than another one from a third animal. When no data are missing, we show that our estimator and the variance of the sociability matrix sensu Sibbald (considered as the reference method) are strongly correlated. We then consider two cases of missing data. In the first case, some animals are randomly missing, that is, to account for random breakdown of telemetry collars. Our estimator is unbiased by such missing data and its variance decreases as the number of observation dates increases. In the second case, the same animals are missing at all observation dates, that is, in large herds where there are more individuals to be observed than available telemetry collars. Our estimator of affinity variance within a group is biased by such missing data. Thus, it requires changing animals equipped with telemetry collars regularly during the experiment. Conversely, the estimator remains unbiased at the population level, that is, if several independent groups are being analysed. We finally illustrate how this estimator can be used by investigating changes in the variability of affinities according to group size in grazing heifers.

Five ewes, with a wool depth of approximately 5 mm, were placed in a neutral (20 + 2°C) environmental temperature on day 139 of pregnancy, and five similar ewes were placed in a cold (0±2°C) temperature. They remained in these environments until their lambs were 8 days old. Samples of udder secretions, when present, and right-atrial blood were taken from the ewes at 12-h intervals.

Milk from ewes in the neutral environment had a high fat concentration for a brief period after parturition, before the full development of lactose secretion occurred.

In ewes exposed to the cold environment, plasma cortisol concentration was increased during the 2 days before parturition. Cold exposure had no effect on the onset of milk lactose secretion but increased the concentration of fatty acids in milk during the period −0·5 to +4·5 days relative to parturition.

The effect of including full-fat Colombian rice polishings, at 250 or 500 g/kg dry matter (DM) or defatted Colombian rice polishings (at 500 g/kg DM) on the fermentation of a basal diet of dried grass and medium-quality hay, in the rumen simulation technique (Rusitec), was investigated. With diets which contained 0, 0·25, 0·50 full-fat or 0·50 defatted, proportions of rice polishing, values for pH were depressed (7·22, 7·19, 7·11, 7·06 (s.e.d. 0·05)) and total volatile fatty acid concentrations were increased (52·8, 52·5, 75·5, 754 (s.e.d. 2·1) mmol/l) at the high levels of inclusion of rice polishings. Concentrations of ammonia (130, 140, 228, 209 (s.e, d. 64) mg/l) and total bacterial numbers (2·32, 2·70, 3·55, 442 (s.e.d. 0·82) × 108 per ml) were elevated by rice polishings inclusion. Numbers of cellulolytic bacteria (2·52, 1·74, 1·84, 2·10 (s.e.d. 0·60) × 106 per ml) and protozoa (19·8, 16·2, 15·8, 22·2 (s.e.d. 1·51) × 103 per ml were depressed (the latter significantly P < 0·01) by the inclusion offull-fat, but not by defatted, rice polishings.

The influences of age at first pregnancy and number of suckling young on maternal performance of mice were studied. Mean mating ages for early-pregnant and normal-pregnant females were 27 and 52 days respectively. Litter size from parturition (day 0) to day 12 of lactation was standardized to either 8 or 12 pups. The more rapid (P<0·01) growth rate and feed conversion efficiency of early-pregnant dams from mating to parturition continued from 0 to 12 days of lactation but occurred primarily in the first 3 days of lactation, so that there were no differences in body weight or feed intake from days 3 to 12 of lactation. There were no age at pregnancy effects on total mammary gland DNA, RNA or RNA/DNA ratio at day 12 of lactation or on individual progeny weights or feed conversion efficiency of litter growth from 3 to 12 days of lactation. Dams suckling eight young had a lower (P<0·01) feed intake, gain and feed conversion efficiency from 0 to 3 days of lactation. From 0 to 12 days of lactation, these dams were smaller, consumed less feed and their individual progeny weights were larger (P<0·01). Dams suckling eight pups had smaller (P<O01) mammary glands, less (P < 0·05) mammary gland DNA and a higher (P<0·05) RNA/DNA ratio. Interactions between pregnancy age and number suckling were not significant. Feed intake of the dam from 0 to 12 days of lactation was influenced more by litter weight gain (34%) than either dam weight gain (5%) or metabolic body size (6%). Maternal performance of mice, based on pup growth and mammary gland growth and function, was not affected by early pregnancy.

In this study, an industry terminal breeding goal was used in a deterministic simulation, using selection index methodology, to predict genetic gain in a beef population modelled on the UK pedigree Limousin, when using genomic selection (GS) and incorporating phenotype information from novel commercial carcass traits. The effect of genotype–environment interaction was investigated by including the model variations of the genetic correlation between purebred and commercial cross-bred performance (ρX). Three genomic scenarios were considered: (1) genomic breeding values (GBV)+estimated breeding values (EBV) for existing selection traits; (2) GBV for three novel commercial carcass traits+EBV in existing traits; and (3) GBV for novel and existing traits plus EBV for existing traits. Each of the three scenarios was simulated for a range of training population (TP) sizes and with three values of ρX. Scenarios 2 and 3 predicted substantially higher percentage increases over current selection than Scenario 1. A TP of 2000 sires, each with 20 commercial progeny with carcass phenotypes, and assuming a ρX of 0.7, is predicted to increase gain by 40% over current selection in Scenario 3. The percentage increase in gain over current selection increased with decreasing ρX; however, the effect of varying ρX was reduced at high TP sizes for Scenarios 2 and 3. A further non-genomic scenario (4) was considered simulating a conventional population-wide progeny test using EBV only. With 20 commercial cross-bred progenies per sire, similar gain was predicted to Scenario 3 with TP=5000 and ρX=1.0. The range of increases in genetic gain predicted for terminal traits when using GS are of similar magnitude to those observed after the implementation of BLUP technology in the United Kingdom. It is concluded that implementation of GS in a terminal sire breeding goal, using purebred phenotypes alone, will be sub-optimal compared with the inclusion of novel commercial carcass phenotypes in genomic evaluations.

Thirty-six Landrace × Large White sows were allocated at random to one of three treatment groups. Sows on treatment A (no. = 6) did not lactate at all and the piglets from these sows were removed at birth. Sows on treatment B (no. = 15) lactated for 1 day after parturition and sows on treatment C (no. = 15) acted as controls and lactated for 42 days. The reproductive performance of each treatment group was recorded and all sows were bled every 2nd day from parturition to 30 days post partum. All blood samples were assessed for oestradiol-17β and progesterone concentrations. In treatments A and B, a high proportion of anoestrous sows was seen (0·28). None of the sows in treatment C became anoestrous. The mean interval from weaning to the onset of oestrus for treatments A and B (19·0 (s.e. 6·5) days and 19·7 (s.e. 3·8) days respectively) were not significantly different, while that for treatment C (5·6 (s.e. 0·4) days) was significantly shorter (P < 0·01). The number of piglets born alive at the subsequent farrowing for treatments A, B and C respectively was 7·3 (s.e. 0·8), 9·1 (s.e. 0·8) and 10·5 (s.e. 0·67) (P < 0·05). The calculated annual sow productivity (piglets born alive per sow per year), excluding the first litter born, for treatments A, B and C respectively was 18·4, 22·8 and 22·9. Weaning at, or close to, parturition did not, therefore, influence sow productivity compared with weaning after 6 weeks of lactation.

In formulating a genetic index for use in cow and sire evaluation, there is a need to account for all environmental factors which influence an animal's yield. To this end, milk production records are currently adjusted for, amongst other things, age at calving and month of calving. In Norway, Sweden and West Germany, records are corrected for calving interval, i.e. the number of days between subsequent calvings (Philipsson, Dommerholt, Fimland, Gaillard, Gjøl-Christensen, Lederer, McClintock and Mocquot, 1978), but in Britain no account is taken of calving interval or days dry. Analysis has shown (McClintock, 1982) that both these factors have a significant effect on yield, and hence further investigation into the value and methods of adjusting for these factors was required.

The management of an arable flock is more complex than that of any other livestock enterprise : it involves a more intimate crop-livestock association than exists in any other farming system, and to some extent the great decline in arable sheepfarming that has taken place during the past fifty years is due to the fact that it is a difficult way of farming ; there are of course, other reasons why the decline in arable sheep farming has taken place and I propose to deal with these very briefly.

I feel it is first necessary to point out that agricultural scientists and research workers have contributed practically nothing that would benefit the arable flock owner. Since the days of the late Professor Wrightson no eminent agriculturist has shown any interest in the fortunes of the arable sheep farmer, with the exception of the late Sir Daniel Hall, who once wrote an account of an ill-fated flock of Hampshire Downs kept on unsuitable land in Hampshire.

Total milk yield of sows is positively correlated with litter size (Bonsma and Oosthuizen, 1935; Wells, Beeson and Brady, 1940; Smith, 1952; Allen and Lasley, 1960) even though the amount of milk obtained by each pig decreases with increasing litter size. Positive correlations between sow milk yield and the creep feed consumption of her litter and between weaning weight and milk production have been reported by Bonsma and Oosthuizen (1935), and by Allen and Lasley (1960). Braude (1964) has comprehensively reviewed the literature on the associations between litter size, birth weight and weaning weight. Ward, Rempel and Enfield (1964) reported a positive correlation between weaning weight and post-weaning growth rate in swine.

Twenty-one pairs of litter sister gilts of similar live weight were selected at 150 days of age and one member of each pair was allocated randomly to the following treatments at approximately 170 days (80 kg live weight): 1. stimulation by mature boar; or 2. an intramuscular injection of oestradiol benzoate. The two groups were fed to appetite and slaughtered at approximately 180 days of age. Examination at slaughter indicated greater ovarian and uterine development in response to oestradiol relative to boar treatment (P < 0·01). The results indicate that oestradiol treatment of gilts followed by post-slaughter examination of the reproductive tract is a sensitive method for evaluating the effects of prior treatments on reproductive development. Significant family and pre-weaning growth effects on reproductive development were also evident on both evaluation methods.

Ruminant fat is often perceived as having a negative impact on human health; however, the composition of the fat is under complex biochemical control and can be improved through strategic manipulation of the animal’s diet. There were two major objectives of this study, namely (i) to develop and validate a primary bovine intramuscular adipocyte cell line and (ii) to examine the effect of eicosapentaenoic acid (EPA) on the transcriptional regulation of Δ-9 desaturasein vitro using the novel cell line. Intramuscular adipose tissue was obtained from the Musculus longissimus thoracis of a beef heifer. Mature adipocytes were isolated and cultured, and subsequently harvested and evaluated for lipid accumulation and the expression of genes regulating key functional adipocyte protein markers at passages 10, 20 and 30. Isolated cells were shown to accumulate lipid in culture over time. Fatty acid analysis by gas chromatography was carried out at passage 30. Thirteen fatty acids ranging from tetradecanoic acid (C14:0) to the polyunsaturated fatty acid, docosahexaenoic acid (C22:6), were easily detected and measured. High-quality total RNA was isolated from adipocytes and the expression of peroxisome proliferator-activated receptor-γ, fatty acid synthase, fatty acid-binding protein-4, adipocyte lipid-binding protein, CD36, Δ-9 desaturase, sterol regulatory element-binding protein (SREBP), microsomal triglyceride transfer protein and leptin genes were identified by reverse transcriptase-PCR and sequence analysis. Expression of the negative control, liver-specific hepatocyte nuclear factor-1alpha, was not detected. Adipocytes were subsequently incubated in medium containing 0, 50 or 100 μM EPA for 24 h. Increasing the EPA concentration of the culture media led to a linear increase in adipocyte EPA concentration (P < 0.01). Expression of Δ-9 desaturase mRNA was decreased five- and seven-fold, respectively, following 50 and 100 μM EPA incubation compared to the control. Gene expression of SREBP-1c was decreased by 6- and 18-fold in cells supplemented with 50 and 100 μM EPA, respectively, compared to the control. Regression analysis showed a negative linear relationship between EPA concentration and the gene expression of both Δ-9 desaturase (P < 0.001) and SREBP-1c (P < 0.001), while a significant positive relationship was observed between Δ-9 desaturase and SREBP-1c gene expression (P < 0.001). This is the first report demonstrating that EPA treatment of bovine intramuscular adipocyte cells decreased gene expression of both Δ-9 desaturase and SREBP-1cin vitro. The bovine adipocyte cell line developed here is an important resource for future studies facilitating less-expensive, rapid screening of research hypotheses and circumventing the limitations associated with the use of experimental animals including cost, inter-animal variation, pre-experimental management and ethics.

The present study was conducted to investigate the effects of ghrelin on gastric acid and pepsin secretion, as well as the mRNA expression of gastrin, somatostatin (SS) and receptors for growth hormone (GH) and insulin-like growth factor-1 (IGF-1) in gastric mucosal cells in vitro. Gastric mucosal cells were isolated from 5-week-old weanling piglets and exposed for 4 h to 3×10−2, 3×10−1, 3, 3×10 and 3×102 nmol/l of h-ghrelin, respectively after 30-h incubation in DMEM/F-12. Pepsin activity in culture medium, cell viability and H+-K+-ATPase activity, as well as mRNA expression of gastrin, SS, GHR and IGF-1R in gastric mucosal cells were determined as response criteria. The experiment was repeated three times. Ghrelin significantly (P<0·05) increased H+-K+-ATPase activity of gastric mucosal cells at 3×10−1, 3 and 3×10 nmol/l of h-ghrelin. However, no significant changes were observed either in pepsin activity or the cell viability after ghrelin treatment. The mRNA expression of gastrin and SS was significantly increased in gastric mucosal cells exposed to h-ghrelin at 3×10−1 and 3 nmol/l (P<0·05). H-ghrelin significantly increased IGF-1R but not GHR mRNA expression at 3×10−1, 3 and 3×10 nmol/l of h-ghrelin (P<0·05). Ghrelin acts on gastric mucosal cells from weanling piglets to regulate the H+-K+-ATPase activity and mRNA expression of gastrin, SS, and IGF-1R in vitro.

To evaluate how rearing programmes could affect resources allocation and reproductive performance of primiparous rabbit females, a total of 118 rabbit females were used to evaluate the effects of five rearing feeding programmes on their performance from 1st to 2nd parturition: CAL, fed ad libitum C diet (11.0 MJ digestible energy (DE), 114 g digestible protein (DP) and 358 g NDF/kg dry matter (DM) until 1st parturition; CR, fed ad libitum with C diet until 12 weeks of age and then C diet restricted (140 g/day) until 1st parturition; F, fed ad libitum with F diet (8.7 MJ DE, 88 g DP and 476 NDF/kg DM) until 1st parturition; FC, fed with F diet ad libitum until 16 weeks of age, and C diet ad libitum until 1st parturition; FCF, fed with F diet ad libitum until 16 weeks of age, then C diet ad libitum until 20 weeks and then F diet ad libitum until 1st parturition. From 1st parturition, C diet was ad libitum offered to all the experimental groups until 2nd parturition. CAL females presented lower feed intake than females of F, FC and FCF groups in the 1st week of lactation (on av. −16.6%; P<0.05). During 1st lactation, the perirenal fat thickness change in CAL females was not different from 0 (+0.02 mm), while in the other four groups it increased (on av. +0.44 mm; P<0.05). Plasma of females fed with F diet during rearing (F, FC and FCF) had lower non-esterified fatty acids content than those exclusively fed with C diet (–0.088 and –0.072 mmol/l compared to CAL and CR, respectively; P<0.05). FCF litters had higher weight than F litters at day 21 of lactation (+247 g; P<0.05), but FCF litter had significantly lower weight than FC litters at weaning (+170 g; P<0.05). CR females had the shortest average interval between the 1st and 2nd parturition (49 days) and FCF females the longest (+ 9 days compared to CR; P<0.05). At 2nd parturition, liveborn litters of F females were larger and heavier than litters of FCF females (+2.22 kits and +138 g; P<0.05), probably due to the lower mortality at birth of F litters (–16.5 percentage points; P<0.05). In conclusion, rearing females on fibrous diets seems to increase the ability of primiparous rabbit females to obtain resources, especially at the onset of lactation.

Two temperature regimes were compared in relation to the growth and feed conversion ratio of groups of cage-reared pigs between 10 and 38 days of age. The treatments were: 27°C at 10 days reducing by 1°C every 4 days to 20°C at 38 days; and 27°C at 10 days reducing by 1°C daily to 20°C at 17 days and then remaining constant. Twelve replicates using 244 pigs were completed, the group size varying between 9 and 12 pigs. The mean growth rates on the two temperature regimes were respectively 234 and 243 g/day, and in both cases feed conversion ratio (kg DM/kg gain) averaged 1·03. It is concluded that temperatures lower than those currently recommended for pigs weaned at 14 to 16 days into controlled-environment houses would support satisfactory performance with direct savings in heating costs under winter conditions.

Twenty-four twin-bearing mature Mule ewes were used to evaluate the effects of feeding ensiled red clover (Trifolium pratense), lucerne (Medicago sativa) or perennial ryegrass (Lolium perenne) during late pregnancy on subsequent ewe and lamb performance. Eight weeks prior to lambing the ewes were individually penned and offered one of the treatment forages ad libitum (no. = 8 per silage). All ewes were supplemented with molassed sugar-beet shreds to avoid dietary energy being a limiting factor and to ensure the responses were primarily attributable to the forage protein content. Individual intakes of the ewes were determined daily and weekly measurements of ewe live weight and body condition score were made. The ewes were also scanned weekly for depths of subcutaneous fat and longissimus dorsi (LD) muscle. Blood samples were taken at 6, 4, 2, and 1 week(s) before lambing, 24 h after lambing and at 3 weeks after lambing and were analysed for serum concentrations of total protein (TP), albumin, urea, beta-hydroxybutyrate (BHB) and plasma concentrations of glucose and non-esterified fatty acid (NEFA). After lambing all ewes and their lambs were turned out to graze together on a ryegrass sward. The lambs were weighed at birth and at weekly intervals thereafter until 12 weeks post partum. The lucerne silage offered had a higher dry matter (DM) content than the red clover and ryegrass silages (367, 305 and 314 g DM per kg fresh matter, respectively; P < 0·001). Forage type significantly affected crude protein (CP) concentration (240, 215 and 182 g CP per kg DM for lucerne, red clover and ryegrass silages, respectively) and metabolizable energy (ME) density (11·1, 11·6 and 10·8 MJ ME per kg DM respectively). Ewes offered the legume silages had higher intakes of DM, CP and ME than ewes offered ryegrass silage (P < 0·05), which was reflected in higher ewe live-weight gain (P < 0·05) but not in litter birth weight (P > 0·05). Silage treatment affected serum concentrations of TP, albumin, globulins and urea during the last 4 weeks of pregnancy (P < 0·05). Lambs born from ewes offered lucerne and red clover silages prior to lambing had higher growth rates from birth to 3 weeks of age than those from ewes offered ryegrass silage (320, 323 and 282 g/day, respectively; P < 0·05). Lamb live weight at 12 weeks of age was higher for lambs from ewes that had been offered the red clover silage, at 29·1 kg compared with 26·7 and 27·1 kg for lambs from ewes previously offered lucerne and ryegrass silages (P < 0·05). In conclusion, the results showed that red clover and lucerne silages are better able to meet nutrient requirements of ewes in late pregnancy than grass silage.

At farrowing time, sows are normally confined in barren environments which prevent the performance of normal behaviour patterns. It has been argued that both the sows welfare and productivity may suffer as a result of these conditions, (Vestergaard and Hansen, 1984). Investigations into the feasibility of an alternative system in which the sows are not restricted have therefore been initiated. The main objective of the present study was to establish design criteria for voluntary accessed farrowing pens which will attract sows by providing them with their preferred environmental requirements.

Previous observations, not reported here, were made of the pre-farrowing behaviour of sows housed individually in large pens which contained a deep sand floor and a straw dispenser. All the sows showed nest building behaviour which culminated in the production of a recognisable nest. Typically they had the following characteristics: a shallow depression; a straw lining and a nest rim which formed a low barrier around the nest. The experiments described here were designed to establish the preferences of the peri-parturient sow for preformed lying areas which incorporated these features.

The use of malt distillers grains (draff) in ruminant diets is limited both by its moderate digestibility and variable intake. This is due to the low digestibility of its fibre and to the inhibitory effects of its unsaturated oil on rumen cellulolysis. Treatment of draff with Ca(OH)2 may ameliorate these limitations in two ways. Firstly, alkali treatment increases fibre digestibility due to hydrolysis of lignocellulosic linkages. Secondly, under alkaline conditions and in the presence of calcium ions, the unsaturated fatty acids of the draff oil form insoluble calcium soaps, thus reducing their inhibitory effects on rumen function.

Thirty Blackface-cross lambs were allocated by sex and weight to three groups of ten. The animals were penned in pairs and were offered hay ad libitum and supplemented with 350g DM/d of either mineralised draff (MD), limed draff (LD - draff treated with 80g Ca(OH)2 /kg DM, held at 60°C for 18 hours and then dried at 60°C), or a proprietary lamb finishing concentrate (C - Premium Sheep Fattening Pellets, Carrs Farm Foods, Solway Mills, Silloth). The supplements were gradually increased to 1200g DM/d over 60 days. Dry matter intakes of hay and supplements were measured daily and animals were weighed weekly. The lambs were condition scored ‘blind’ on day 60 and were assessed for slaughter.

1. Two-thousand and sixty serum samples from indigenous cattle in Central Africa were examined for serum transferrin type. The breeds studied were Manguni, Mashona, Tuli, Angoni and Afrikander.

2. The variation in gene frequencies from breed to breed is presented. With the exception of one Angoni herd, the remaining herds fall into distinct breed groups.

3. The Mendelian hypothesis was tested on eight herds including at least one herd of each breed. With two exceptions good agreement with this hypothesis was obtained. The two exceptions were traced to two bulls, a Mashona (TfB/TfD) and a Tuli (TfD/TfF), both of which contributed TfD to their progeny at a rate in excess of Mendelian expectation.

4. The Hardy-Weinberg equilibrium hypothesis was tested for thirteen herds and good agreement was obtained in all cases.

5. In Angoni cattle no evidence was found to reject the hypothesis of independent segregation at the haemoglobin and transferrin loci.

A total of 120, 6–7-month-old fat-tailed uncastrated Kellakui lambs were randomly allotted to three groups, given fattening diets for 93 days and then slaughtered. The diets contained 10 (A), 20 (B) or 30% (C) coarsely chopped wheat straw; the latter was increased at the expense of dried beet pulp. All diets contained 45% ground barley, 10% beet molasses and 1% ground oyster shells; there were minor adjustments in the cottonseed meal percentage to maintain a similar protein level in all diets.

The three diets were also given in sequence to six adult male Kizil (fat-tailed) sheep in a digestibility trial. Further digestion trials were made with chopped wheat straw given alone or supplemented with 400, 800 and 1200 g of a concentrate consisting of 75% dried beet pulp and 25% cottonseed meal; an all-concentrate treatment was also included.

Daily gain (g), feed efficiency (kg feed/kg gain) and dressing percentages for lambs given diets A, B and C were, respectively: 154, 9·78, 54·5; 159, 9·85, 53·5; 127, 11·30, 53·1. A significant decrease in daily gain occurred with the highest straw level and considerably more feed was required per unit of gain. Supplementing straw with 400 g of concentrate increased daily dry-matter intake per sheep from 645 g to 1214 g, with further but smaller increases at higher levels of supplementation. Almost linear increases were observed in dry-matter digestibility as more concentrate was given.

1. High and low dry-matter silages were fed to fattening bullocks on the self-feed system giving daily live-weight increases per head per day of 2·6 lb. and 1·7lb. respectively, over a feeding period of 10 weeks.

2. Chemical data on the composition of a low dry-matter silage and high dry-matter silage are presented.

3. Digestibility studies using sheep were carried out to obtain the starch equivalent values of the two types of silage. The starch equivalent of the high dry-matter silage was 12·4 while that of the low dry-matter silage was 9·9. This difference in starch equivalent explains the extra 0·9 lb. per head per day live-weight increase made by the bullocks on the high dry-matter silage.

4. Mineral balances were carried out. The results show that the low dry-matter silage would supply an inadequate amount of calcium for satisfactory production.