This study compared the effect on foetal growth of shearing ewes in very early pregnancy (day 50) with the effect of shearing later in pregnancy (day 70 or 100). One hundred and sixty ewes were allocated at day 49 of pregnancy to four ‘time of shearing’ treatments — pregnancy day 50 (P50), P70, P100 (no. = 45 ewes per treatment) and unshorn (shearing of this group occurred 43 days after weaning) (no. = 25); two methods of shearing (by standard comb and cover comb); and two levels (1 or 2) of pregnancy/rearing rank. All ewes had been mated over a 28-day period and grazed pasture throughout the trial. The mid point of lambing was 27 August 1996. Live weights of ewes (corrected for fleece weight) were not influenced by shearing time at any stage except at day 45 of lactation when ewes shorn at P50, P70 or P100 were about 3⋅0 kg lighter than unshorn ewes. Shearing method had no effect on ewe live weight. Time of shearing and shearing method had no effect on ewe greasy fleece production or wool tensile strength. Shearing significantly (P < 0⋅05) influenced the birth weight of single- (by 0⋅7 to 0⋅8 kg) but not twin-born lambs. Maternal plasma triiodothyronine concentration increased proportionately by 0⋅47 to 0⋅85 (P < 0⋅05) and lasted for at least 20 days in response to shearing irrespective of time of shearing. No difference in plasma insulin concentration was detected between shearing groups but plasma glucose concentration proportionately increased by 0⋅06 to 0⋅16 (P < 0⋅05) for 10 to 20 days after shearing. These results indicate that shearing between day 50 and 100 of pregnancy can increase lamb birth weights and that the response is associated with an increase in thyroid hormone concentrations in the maternal circulation.

Energy expenditure, food intake and some physiological reactions of Brahman and Brahman × British Friesian cattle working on an inclined treadmill at 33°C were studied. The effect of work at a lower ambient temperature (15°C) and local cooling of the head region while at 33°C were also investigated. Whilst walking up a 6° gradient at 1 m/s, animals expended about four times as much energy as when standing. Heat production during work (W/kgM0·75) was similar in both breeds and was not influenced by the treatments imposed. Crossbred animals showed significantly higher respiration rates and sweating rates than the Brahmans immediately after working for 30 min at 33°C. Food intake and body-weight changes in the crossbreds at 33°C compared with Brahmans provided further evidence that these animals were less tolerant of the conditions. Head cooling during work appeared to reduce depression in food intake associated with work at 33°C in both breeds although it had no effect on physiological changes.

Three experimental diets (L, M and H) containing 135, 175 and 210 g crude protein per kg dry matter respectively were given to crossbred does in two experiments. Protein quality was constant throughout.

In experiment 1 a total of 18 does (six per diet) were given the diets during two successive reproductive cycles. Losses of nitrogen in faeces and urine were estimated for four successive 7-day periods in each 28-day lactation period. Litters were culled at birth to give ‘high’ and ‘low’ lactational loads with 8 and 4 pups respectively. Total 28-day milk yields on diets L, M and H were 3·89, 4·82 and 5·27 kg respectively with eight pups sucking, and 302, 400 and 400kg respectively with four pups. These differences in milk yield were directly reflected in the weights of the pups when weaned at 28 days of age. There was no effect of diet on milk composition, pup birth weight or litter size. Does given diet L did not always consume their allotted ration and this may have affected the results.

The proportion of digested nitrogen utilized for milk protein synthesis differed significantly between diets and lactational loads, and was at its maximum (0·72) when diet L was given to does with eight pups. Does suckling eight pups retained 005 of the nitrogen they digested in their body tissues and those with four pups 0·13; there were no differences between diets in this respect.

In experiment 2 the nitrogen retention of 18 does (six per diet) was measured during pregnancy. Nitrogen retention increased as pregnancy progressed, and overall 0·20 of digested nitrogen was retained for conceptus growth and doe body tissue accretion.

Two experiments were conducted each using one batch of six Landrace littermate, entire male, pedigree pigs in a Latin-square change-over study of the effects of energy intake on nitrogen and energy metabolism over the range 33 to 88 kg live weight. One animal from each litter was slaughtered at 33 kg body weight to obtain initial body composition data. Five feeding levels (80, 100, 120, 140 and 160g/kg M0·63) were used during five consecutive metabolism trials each of 11-days duration, excreta being collected during the last 7 days. The pigs were housed in individual metabolism cages and the diets were offered in liquid form (approx. 300 g dry matter (DM) per kg) twice daily at 09.00 and 16.00 h. Heat production was measured for 1 day during each balance period in an open-circuit respiration chamber. The average daily gain, nitrogen retention, heat production and energy retention increased linearly (P < 0·001) with increasing metabolizable energy (ME) intake. The relationship between energy intake and protein deposition was linear up to levels above the normal ad libitum consumption of energy. Protein deposition potential of these high genetic potential pigs was at least 200 g/day, and tended to be constant between 35 and 85 kg live weight. From the combined results of experiments 1 and 2, the energy requirement for maintenance was 0·982 MJ ME per kg M0·63 per day and the decrease in protein deposition was approximately 6 g/MJ reduction in ME within the range of practical energy intakes.

The effects of the halothane gene on growth and performance were estimated from British Landrace positive and negative selection lines and crosses between the lines. A total of 214 full-sib pairs were performance tested from 25 to 85 kg live weight on either ad libitum or scale (0·69 g/g ad libitum food intake) feeding. Half-sides of 45 carcasses were fully dissected.

In the crosses, growth and performance did not depend on whether the sire or the dam was from the positive line. Carcass length, conformation score, eye muscle area and incidence of pale, soft, exudative meat (PSE) were all intermediate in the crosses. Given food ad libitum, the crosses had increased appetite and growth rates which resulted in increased backfat depths. However, in the fully dissected carcasses, the crosses were intermediate for lean proportion. Although the crosses gave a net economic advantage, the incidence of PSE may be unacceptably high for commercial exploitation.

The spatial heterogeneity of grasslands determines the abundance and quality of food resources for grazing animals. As plants mature, they increase in mass, which allows greater instantaneous intake rates, but the cell wall concentrations increase too, reducing diet quality. In ruminants, daily intake rates are often constrained by the time needed for the ingesta to pass through the rumen, which is influenced by the rate of digestion. It has been suggested that the digestive constraint should have much less effect on hindgut fermenters such as equids. Horses play an increasing role in the management of grasslands in Europe, but the data on the influence of the heterogeneity of the vegetation on their daily intake and foraging behaviour are sparse. We report here the results of a preliminary study concerning the effects of sward structure on nutrient assimilation and the use of patches of different heights by horses grazing successively a short immature, a tall mature and a heterogeneous pastures (with short and tall swards). Daily nutrient assimilation was higher in the heterogeneous pasture compared to the short (+35%) and the tall (+55%) ones. The digestive constraints may have limited voluntary intake by horses on the tall swards. In the heterogeneous pasture, the mean height used for feeding (6 to 7 cm) by horses was intermediate between the heights used in the short (4 to 5 cm) and tall pastures (22 to 23 cm), and the animals may thus have benefited from both short swards of high quality and tall swards offering a higher instantaneous intake rate.

Newborn rabbits depend on a daily nursing interaction with the mother to gain milk and to survive. During this interaction, they localise and seize the nipples displaying a typical behaviour triggered by maternal odour cues. The mammary pheromone constitutes such a signal in domestic rabbits: it elicits sucking-related movements in more than 90% of the pups. However, some newborns remain unresponsive to the presentation of the pheromone, even pups apparently healthy and highly motivated to suck. The main goal of the present study was therefore to explore the link between the unresponsiveness of rabbit pups to the mammary pheromone and their growth and survival in breeding conditions. To that end, 293 newborns from 30 litters were tested for their head searching-oral grasping responses to the mammary pheromone on days 1 and 3, and their milk intake and mortality were followed up from days 1 to 21. It was hypothesised that unresponsive newborns would have subsequent difficulties in finding nipples, sucking and surviving. Early weight and success in milk intake were further considered as mediating factors in growth and viability. The results showed that pups that were unresponsive to the mammary pheromone on day 1 were less successful in gaining milk and had a higher rate of mortality than the responsive pups. However, this impact was modulated by the weight of pups: it appeared only in the lightest newborns. Moreover, this impact vanished on day 3. On the other hand, the pup weight and sucking success on days 1 to 3 strongly influenced viability and growth during the period extending from days 1 to 21. Taken together, the results show that the day-1 responsiveness of rabbit pups to the mammary pheromone can be considered as an indicator of individual viability in pups having a small weight (<48 g on day 1). The predictive validity of the pups’ pheromonal reactivity seems however time-limited as it works only during the first, but crucial, postnatal days.

Thirty-two entire male and 32 female pigs were used to investigate responses to eight concentrations of dietary protein, with constant amino acid composition ranging from 90 to 248 g/kg over different live-weight stages between 20 and 90 kg.

With increasing live weight there was a continuous decline in the concentrations of dietary protein required to support maximum growth and an increasing difference between the sexes in their response to dietary protein. Between 20 and 40 kg live weight sex had no significant effect on growth performance or on the dietary protein concentration for maximum growth (P > 0·05). Over all heavier live-weight stages entire males grew faster and more efficiently than females, and between 20 and 70, 20 and 80, 20 and 90 and between 50 and 90 kg live weight they responded to higher concentrations of dietary protein than females. During the latter stages of growth, the performance of females was also depressed on the two highest-protein diets. This was associated with a significant increase in carcass fat thickness at 90 kg.

1. The ability to resist hypothermia was measured in 265 lambs of 10 breeds immersed in a progressively cooling water bath.

2. Cold resistance varied significantly between breeds, with hill lambs showing the highest resistance. Hill breeds and feral breeds together had the highest weight-specific cold resistance.

3. Cold resistance was positively correlated with birth weight and skinfold thickness.

4. Age at test varying from 1 to 60 h did not significantly affect cold resistance.

5. Rate of recovery from hypothermia varied slightly between breeds. The feral lambs tended to recover fastest.

Fifty-five calves aged 105 days of age, of both sexes, belonging to two genetic groups (H, high or L, low) differing in their predicted breeding value (PBV) by 78 kg for fat plus protein yield, were individually penned for 3 weeks with the final 2 weeks on a diet designed to provide energy close to their maintenance requirements. The calves were then cannulated in the jugular vein and blood was sampled every 15 min for 25 h. Following this a growth hormone releasing factor (GRF) preparation was administered on up to four occasions, being one of (per kg live weight) either 0·2 or 0·4 μg GRF (treatments SGRF or DGRF respectively) or 0·2 μg thyrotropin releasing hormone (TRH). On each occasion blood samples were taken at −15, 4, 8,12,16, 20 and 45 min relative to the time of administration and up to four further occasions, one prior to and three within 32 min of administration. Samples were assayed for growth hormone (GH).

GH concentration of troughs prior to an episode of GH release was 1·19-fold greater in H compared with L calves with concentrations decreasing to 0·9 of their previous values each h. Trough and peak concentrations had repeatabilities of 0·21 and 0·26 respectively (both P < 0·05). There was no association between PBV and either peak concentrations, number of pulses (4·84 per 25 h) or mean GH concentration (13·3 μg/l).

GH released was only 1·11-fold greater after DGRF than SGRF. The difference in the regression coefficients for PBV between SGRF and DGRF was small, as it was for the difference between coefficients for the two sexes. The pooled coefficient was 0·00342 loge units per kg (s.e. 0·00157; P< 0·05) indicating a 1·31-fold greater response in H than in L calves. The correlation between responses to SGRF and DGRF was 0·482 and the repeatability of SGRF was 0·338; a pooled repeatability was estimated as 0·362(P < 0·01). The regression of GH release on PBV for TRH was 0·00345 (s.e. 0·00330). For all secretagogues, response depended on prior concentrations.

It was concluded that GH release following GRF administration was positively related to PBV in dairy calves and response was moderately repeatable; furthermore, although aspects of endogenous secretion may be related to PBV they suffer from measurement difficulties.

The occurrence of oestrus and ovarian function during the post-partum period was examined in 160 lactating beef cows of the Africander and Mashona breeds. Cows were fed either to gain 12 to 14% (High) or to lose 12 to 14% (Low) of their autumn peak live weight (early pregnancy) by mid-breeding season. Half the cows in each group were subjected to an increase (Low-High) or decrease (High-Low) in nutrient intake for a 25-day period starting at 25 days partum. Nursing was interrupted for an 8-day period in half of the cows at 50 days post partum by the application of nose plates to their calves.

Oestrus occurred significantly earlier in the high than the low plane cows (66 v. 75 days post partum respectively, P< 0·05), but short-term fluctuations in nutrient supply had no apparent effect on the incidence of oestrus. Temporary weaning significantly reduced the mean time from calving to first oestrus in the high-plane (P< 0·01) but not in the low-plane cows, and in Mashona (P<0·05) but not in Africander cows. There was a lower incidence of ‘silent’ oestrus and the mean occurrence of oestrus was significantly earlier (P< 0·001) in the Mashona when compared with the Africander cows.

Two trials were conducted to examine the influence of dietary oil type and rate of inclusion on fatty acid profiles of adipose tissue and eating quality of griddled pork. Trial 1 was based on three sources high in specific fatty acids: palm oil (palmitic acid), tallow (stearic acid) and linseed oil (linolenic acid) each at three rates of inclusion (palm at 44·6, 88·7 and 133·3 g/kg; tallow at 44·1, 87·6 and 131·7g/kg; linseed oil at 40·1, 79·8 and 120·0g/kg into a synthetic fat-free diet. Trial 2 was based on systematic replacement of soya-bean oil (incorporated at a rate of 0, 34, 69 and 104 g/kg diet) with olive oil (rate of 62, 46, 29 and 13 g/kg diet) to alter dietary concentrations of oleic acid. Diets were offered to pigs over the live-weight range 55 to 90 kg. Samples of subcutaneous fat were analysed for fatty acid composition and samples of loin assessed for meat quality with taste panels. There were no significant effects (P > 0·05) of treatment on daily live-weight gain, food conversion ratio or gross carcass composition, with the exception of anterior loin fat for trial 1 (P < 0·05) although not in a manner that was consistent between treatments and, in trial 2, anterior loin fat, minimum loin fat and posterior loin fat (all P < 0·05) but, again, not consistently between treatments allowing no meaningful conclusions to be drawn. Fatty acid profiles of adipose tissue reflected dietary levels to a variable degree, the more so with oleic acid and the greatest for linoleic and linolenic acids. The quality of the pig meat as measured by sensory analysis was related to the fatty acid profile in the situation where the most extreme changes in fatty acid profile occurred, as was apparent for the diets based upon linseed oil. No other major influences on meat quality were obtained.

Four experiments with sheep fitted with rumen cannulae were conducted to investigate whether the rate of digestion of ammonia-treated straw, estimated as disappearance of dry matter from nylon bags in the rumen, might be increased by supplements of either soya bean meal, sucrose or sugar beet pulp at a level of 0·1, or by increasing the concentrations of dietary soluble micro and macro minerals.

There were no differences among treatments in rate and extent of digestion of straw due to supplementations.

In another experiment, the effect of increasing the proportion of molassed sugar beet pulp or rolled barley on rate of digestion of ammonia-treated straw was investigated. A greater proportion of sugar beet pulp (0·45) could be included in the diet before the rate of digestion was decreased in comparison with rolled barley (0·35).

Assuming that the digestibility of the sugar beet pulp and the rolled barley was not changed by the increasing proportion in the diet, it could be calculated that the digestibility of straw was reduced from 0·538 with straw alone to 0·403 with the sugar beet pulp and to 0·218 with the rolled barley supplement when the supplements were included at a level of 0·70.

A targeted quantitative metabolomics approach was used to study temporal changes of serum metabolites in cows that normally released their fetal membranes and those that retained the placenta. We identified and measured serum concentrations of 128 metabolites including amino acids, acylcarnitines, biogenic amines, glycerophospholipids, sphingolipids and hexose at −8 and −4 weeks before parturition, during the week of retained placenta (RP) diagnosis, and at +4 and +8 weeks after parturition. In addition, we aimed at identifying metabolite signatures of pre-RP in the serum that might be used as predictive biomarkers for risk of developing RP in dairy cows. Results revealed major alterations in the metabolite fingerprints of pre-RP cows starting as early as −8 weeks before parturition and continuing as far as +8 weeks after calving. Biomarker candidates found in this study are mainly biomarkers of inflammation which might not be specific to RP. Therefore, the relevance of serum Lys, Orn, acetylornithine, lysophophatidylcholine LysoPC a C28:0, Asp, Leu and Ile as potential serum biomarkers for prediction of risk of RP in dairy cows will have to be tested in the future. In addition, lower concentrations of LysoPCs, Trp, and higher kynurenine in the serum during prepartum and the week of occurrence of RP suggest involvement of inflammation in the pathobiology of RP.

Over a 15-year period nearly 2000 young females were exposed to the ram at 6 to 9 months of age. These Clun Forest females were born between January and April in the Cockle Park experimental flock, and mated between October and December of the same year. On average nearly 42% of those present at lambing did not produce a lamb. Analyses are presented of the reproductive efficiency of these animals and of some of the possible causes of their failure to lamb. Observations in 10 of these years suggested that only 12% had not been mated and might therefore be assumed to be prepuberal. Age at first oestrus for those animals achieving puberty in their first autumn was inversely related to date of birth. The number which lambed increased by 1·1% per kg increase in live weight before mating.

In 3 years simple nutritional and housing treatments were applied to groups of female lambs. Feeding a cereal supplement to animals at pasture before, during and after mating, and housing 1 to 2 weeks after mating, appeared to increase the percentage which lambed. It is suggested that the effect was to reduce the amount of early embryo death caused by nutritional and climatic stresses on the normal grazing animal.

When designing environments for animals, the quality of space as well as the amount of space should be considered. In this study the influence of an opaque barrier on the aggressive behaviour and growth of Large White Χ Landrace piglets that were weaned at 24 days was examined. The behaviour and weight gain of 120 piglets were recorded during a 4-week period following weaning. These piglets were housed in either a conventional flat-deck pen or a straw pen, with or without an opaque barrier. There was no significant difference between the two types of accommodation in the frequency of aggressive interactions that occurred during the weaning period but where a barrier was present the frequency of aggressive interactions was 40% lower during the 1st week after weaning and growth rate was proportionately 0·15 greater. Piglets that were the recipients of most aggressive behaviour used the barrier most frequently during the weaning period and barrier users gained the most weight during the week immediately following weaning.

It was concluded that a barrier improved the weaning environment because it offered piglets an escape route during the period when most aggressive interactions occurred. A barrier may be an effective way of improving the welfare of animals housed in confined conditions.

The research was carried out to evaluate the effect of different α-tocopherol concentrations in lamb meat on oxidative stability during storage in high-oxygen atmosphere. Thirty-six lambs were randomly distributed to four groups and given diets containing four levels of vitamin E (20, 270, 520 and 1020 mg vitamin E/kg feed) from an initial weight of 13.2 ± 0.5 kg to a slaughter weight of 26.2 ± 0.3 kg. Supplementation of the diet with vitamin E increased (P < 0.001) the concentration of α-tocopherol in the meat and concentrations were obtained in the 0.46 to 4.14 mg/kg meat range. Broken-line analysis of data indicated a target dietary vitamin E supplementation of 287 mg/kg feed, which corresponded with a concentration of 2.26 mg α-tocopherol/kg meat. α-Tocopherol in meat was highly correlated with the oxidation of lipids and pigments. Broken-line analysis of data indicated the target α-tocopherol concentration in lamb for improved protection against lipid and pigment oxidation during 14, 21 and 28 days of storage in high-oxygen atmosphere was in the range 1.87 to 2.37 mg/kg meat. These concentrations of α-tocopherol in the meat made it possible to maintain the indicator values of lipid and pigment oxidation below the values considered in the bibliography as unacceptable to the consumer.

Livestock farming has recently come under close scrutiny, in response especially to environmental issues. Farmers are encouraged to redesign their livestock farming systems in depth to improve their sustainability. Assuming that modelling can be a relevant tool to address such systemic changes, we sought to answer the following question: ‘How can livestock farming systems be modelled to help farmers redesign their whole farming systems?’ To this end, we made a literature review of the models of livestock farming systems published from 2000 to mid-2009 (n = 79). We used an analysis grid based on three considerations: (i) system definition, (ii) the intended use of the model and (iii) the way in which farmers’ decision-making processes were represented and how agricultural experts and farmers were involved in the modelling processes. Consistent rationales in approaches to supporting changes in livestock farming were identified in three different groups of models, covering 83% of the whole set. These could be defined according to (i) the way in which farmers’ decisions were represented and (ii) the model's type of contribution to supporting changes. The first type gathered models that dynamically simulated the system according to different management options; the farmers’ decision-making processes are assumed to consist in choosing certain values for management factors. Such models allow long-term simulations and endorse different disciplinary viewpoints, but the farmers are weakly involved in their design. Models of the second type can indicate the best combination of farm activities under given constraints, provided the farmers’ objectives are profit maximisation. However, when used to support redesigning processes, they address neither how to implement the optimal solution nor its long-term consequences. Models of the third type enable users to dynamically simulate different options for the farming system, the management of which is assumed to be planned according to the farmers’ general objectives. Although more comprehensive, these models do not easily integrate different disciplinary viewpoints and different subsystems, which limits their usefulness as support tools for redesigning processes. Finally, we concluded about what specific requirements should be for modelling approaches if farmers were to be supported in redesigning their whole livestock farming systems using models.

Goat meat is considered healthy because of its low fat content, but it is often rather tough. Tenderness is the most important attribute of quality during meat consumption and there is scarce information about the expression of genes involved in the meat tenderization process in goats. The aim of this trial was to assess certain meat quality traits and the expression, at the messenger RNA (mRNA) and protein levels, of specific genes involved in the tenderization process of the longissimus lumborum (LL) in young male goats (Capra hircus) at different ages. Samples of LL were collected at slaughter from 32 Alpine goats that were divided into three categories: 9 suckling kids (Sk) at 5.4±0.15 weeks of age, 16 chevons (Ch) at 17.1±0.55 weeks of age and 7 post-puberal goats (Pu) at 34.3±2.5 weeks of age. Animal and carcass variables (live weight gain, live weight, carcass weight and fat deposits) and quality traits of meat (lipid content, ultimate pH, color parameters, cooking loss and shear force) were determined. The mRNA abundances of calpain-1 (Capn1), calpain-2 (Capn2), calpastatin (Cast), caspase 3 (Casp3), caspase 9 (Casp9), αB-crystallin (Cryab), heat shock protein 27 (Hsp27), heat shock protein 40 (Hsp40) and heat shock protein 70 (Hsp70) were detected by quantitative PCR. Capn1, Cast, Cryab and Hsp27 protein expression was investigated by ELISA. The Sk group had the leanest carcasses. The meat of the Pu group was the darkest (P<0.05) and the toughest (P<0.05). The redness of meat increased with the age of the goats. The Sk group showed lower mRNA abundances for the Capn2/Cast ratio, Casp3, Cryab, Hsp27, Hsp40 and Hsp70 than the Pu group (P<0.05). Intermediate values were found for the Ch group. Similar results were highlighted for the protein expression of Cryab and Hsp27. The experiment acknowledged a differentiation of the experimental groups based on performance, carcass and meat characteristics, and the genes considered. Moreover, Sk and Pu groups, characterized by a different tenderness of their meat, were clearly discriminated by a different expression of the Hsp.