Incorporation of food intake into breeding objectives for ruminants is often difficult because the relevant genetic parameters are unavailable. A non-statistical approach to estimating the genetic relationships between food costs and genetic changes in growth and body composition traits was therefore developed.

Equations which predict additional food requirements associated with genetic changes in growth and body composition traits are derived from an interspecies growth model. In the growth model, a genotype is mainly described according to its expected mature weights of protein, lipid and a composition trait of interest in the empty body under non-limiting conditions. Other model parameters describe the expected growth of the animal in a specific environment.

An example is shown for beef cattle in the United Kingdom, where increases in carcass weight by 1 kg and carcass subcutaneous fat proportion by 0·01 result in increases in food costs by £0·97 and £7·34 respectively for a production system where animals are given an intensive silage/concentrate diet, are slaughtered at 305 kg and have a commercial fat grade 4L. A strong dependence of the results on the type of production system, especially the degree of maturity in protein at slaughter, is demonstrated.

The model is easily adapted to other breeds and ruminant species. The approach is recommended for incorporating food intake into breeding objectives for ruminants in situations where reliable estimates of the necessary genetic parameters for a more conventional specification of the breeding objective are unavailable.

In a feeding experiment β-hydroxybutyrate (BHB), glucose, albumin, total protein, globulin and urea concentrations in the plasma of twin-bearing ewes were analysed. Mature Suffolk cross ewes were given either formic acid (FA)-treated grass silage or grasslmolassed sugar-beet pulp (MSBP) silage in late pregnancy. The experiment commenced on day 91 of pregnancy and the dietary treatments were FA-treated silage (Tl), FA-treated silage + soya-bean meal (SBM) (T2), MSBP silage (T3), MSBP silage + SBM (T4), FA-treated silage + MSBP (T5), FA-treated silage + MSBP + SBM (T6) or FA-treated silage + 150 g crude protein (CP) per kg concentrate (T7). SBM was given only in the last 22 days of pregnancy aiming for a total CP intake of 220 g per ewe per day. Blood samples were collected by jugular venipuncture from each ewe 3 h following consumption of the morning dietary allowance on days 121, 128, 135 and 142 of pregnancy. Daily metabolizable energy (ME) intakes of 6·8, 11·4, 9·6, 12·8, 10·5, 13·7 and 14·7 (s.e. 0·58) MJ per ewe were recorded for Tl to T7 respectively over the last 3 weeks of pregnancy. Respective CP intakes of 72, 213, 110, 225, 109, 215 and 175 (s.e. 5·64) g per ewe were recorded for Tl to T7 respectively over the last 3 weeks of pregnancy. BHB concentrations (mmol/l) on day 121 of pregnancy of 1·18, 1·25, 0·52, 0·52, 0·56, 0·39 and 0·45 (s.e. 0·17), on day 128 of pregnancy of 1·17, 0·94, 0·52, 0·51, 0·72, 0·62 and 0·39 (s.e. 0·20), on day 135 of pregnancy of 1·53, 0·68, 0·68, 0·66, 0·71, 0·62 and 0·46 (s.e. 0·20) and on day 142 of pregnancy of 1·43, 0·60, 0·62, 0·56, 0·62, 0·56 and 0·63 (s.e. 0·20) were recorded for Tl to T7 respectively. There was a quadratic relationship between plasma BHB concentration and ME intake on days 121 (R2 = 0·538, P < 0·001), 128 (R2 = 0·324, P < 0·001), 135 (R2 = 0·429, P < 0·001)) and 142 (R2 = 0·344, P < 0·002) of pregnancy. There was a positive relationship between plasma glucose concentration and ME intake on day 222 (R2 = 0·208, P < 0·002), 228 (R2 = 0·203, P < 0·05), and 135 (R2 = 0·160, P < 0·02) of pregnancy. Albumin concentrations (gll) on day 128 of pregnancy of 21·8, 21·7, 23·6, 22·9, 22·5, 22·9 and 24·3 (s.e. 0-75), on day 135 of 20·9, 23·6, 24·2, 24·1, 22·4, 24·1 and 23·8 (s.e. 0·75), and on day 142 of 16·9, 22·6, 20·7, 22·2, 20·4, 22·7 and 21·1 (s.e. 1·05) were recorded for Tl to T7 respectively. Plasma albumin concentrations were significantly affected by SBM supplementation (P < 0·05). Despite the lower than generally recommended energy concentrations in T2 to T7, the concentrations of plasma BHB were within the normal range for healthy sheep.

Changes during growth and fattening in the number and size of adipocytes and in the activity of the lipogenic enzymes glycerol 3-phosphate dehydrogenase (G3PDH), fatty acid synthetase (FAS) and lipoprotein lipase (LPL) were studied in perirenal (PR) and subcutaneous (SO adipose depots of 28 male lambs of Rasa Aragonesa Spanish breed. Three groups of animals were slaughtered at: 32 (s.d. 6) (no. = 10), 89 (s.d. 8) (no. = 10) and 120 (s.d. 8) (no. = 8) days of age. A significant increase in the quantity of fat was observed as the age of the lambs increased (P < 0·001). Fat deposition was higher between 89 and 120 days of age. The number of adipocytes in the PR depot did not change but hypertrophy in this depot continued during the whole period studied (P < 0·001). In the SC depot a significant increase in adipocyte volume was only found between 89 and 120 days of age (P < 0·001). The increase in G3PDH activity (which estimates fatty acid esterification) and FAS activity (which estimates fatty acid synthesis) was greater in the final phase of the study. Besides, LPL enzyme activity (which estimates the uptake of plasma fatty acids) increased between 32 and 89 days of age in both depots and between 89 and 120 days in PR depot (P < 0·001).

Genetic parameters were estimated for litter size in two prolific sheep breeds, i.e. the Zwartbles and the synthetic breed Swifter. Genetic parameters and breeding values for litter size in different parities were estimated using both a repeatability and a multivariate animal model. The estimated heritability from the repeatability model was 0·10 for the Zwartbles and 0·12 for the Swifter. For the multivariate model, heritability of litter size in first, second and third parity was 0·05, 0·07 and 0·10 for the Zwartbles and 0·09, 0·12 and 0·09 for the Swifter. Genetic correlation for litter size in Swifter was 0·81 between parity 1 and 2 and 0·99 between parity 2 and 3. For the Zwartbles genetic correlations were all very close to unity. Environmental correlations between litter size in subsequent parities were not constant over parities. Phenotypic variance in litter size in both breeds was 0·309 in first parity and was almost 50% higher in later parities. Based on the results it is recommended to apply a multiple trait model.

In the experiment, four grass (tall fescue hay and Italian rye grass hay, harvested in March and May) and four legume (lucerne hay, harvested in March and May; and red clover hay, harvested in March and April) forages were used. Duplicate samples were incubated in sacco in the rumens of three fistulated mature cows for 2, 4, 8,16, 2i, 48 and 72 h and the degradabilities of dry matter (DM), nitrogen, neutral-detergent fibre (NDF), cellulose and hemicellulose were measured. The maximum degradation rate (MDR) and time of maximum degradation rate (TMDR) were calculated from the first and second derivatives of a Gompertz equation.

The MDR differed between chemical components and was generally higher for cellulose (from 2·31 to 6·95% per h) and nitrogen (from 2·06 to 6·75% per h) in all forages studied. Lignin content of forages was found to be well correlated with the MDR of the fibre components (r = -0·74 for NDF, -0·72 for cellulose and -0·84 for hemicellulose).

The TMDR values were much shorter for DM and nitrogen (< 4·2 h) than for the fibre fractions (from 6·8 to 14·0 h). Furthermore, in grasses, hemicellulose TMDR occurred before those of cellulose, while in legumes the order of TMDR was less clear. Elevated positive correlation coefficients between the fibre components and their TMDR possibly indicate that the structural arrangement and types of linkages within and between these components regulate their fermentation process.

The possibility of using the Gompertz first and second derivatives to study the synchrony of the release of nitrogen and organic matter into the rumen was examined.

An experiment was conducted to evaluate the feeding characteristics and the productive responses of lamb diets containing increasing levels of dried brewers' grains (DBG). Five groups of six 70-day-old Bergamasca lambs were housed in individual pens and given ad libitum for 9 weeks pelleted diets containing 200 g/kg of concentrate and 800 g/kg of a mixture of DBG and lucerne hay in the ratios of 0:80 (DBG0), 20:60 (DBG20), 40:40 (DBG40) 60:20 (DBG60) and 80:0 (DBG80). During the last 12 days of the experimental period, a digestibility trial was carried out for each diet. After this, all the lambs were slaughtered and the composition of the empty body weight was determined. The initial composition of the empty body was estimated from the composition of a sixth group of lambs slaughtered at the beginning of the trial.

The apparent digestibility of dry matter (DM), organic matter, crude protein, ether extract, neutral-detergent fibre and energy increased with the proportion of DBG. The daily DM intake relative to metabolic body weight (M0·75) diminished significantly with the increasing proportion of DBG in the diet, from 127 g/kg M0·75 for diet DBG0 to 83 g/kg M0·75 for diet DBG60. The daily live-weight gain and food DM conversion efficiency were highest with the intermediate diets (414 g/day with diet DBG40 and 240 g/kg DM with DBG60), showing a quadratic trend, an indication of a positive interaction between DBG and lucerne hay. The fat content of the live-weight gain was particularly high in the lambs given the diet with the highest proportion of DBG. It was concluded that DBG may be profitably used in growing-fattening diets for lambs in a proportion not exceeding about 400 g/kg DM.

Eight change-over design experiments (each a duplicated 3 × 3 Latin square design using six rumen-fistulated wether sheep, live weight 50 to 60 kg) measured rumen fermentation patterns for 24 perennial ryegrass silages. Sheep were offered 800 g dry matter (DM) per day of each silage in two equal meals at 09.00 and 17.00 h. Samples of rumen liquor were taken on days 19 and 21 of each 21-day period, at 08.50 h and at 1·5-h intervals until 16.30 h. Rumen samples were analysed by gas chromatography; silages by high-performance liquid chromatography and by near infra-red reflectance spectroscopy (NIRS) using samples scanned after drying at 100°C (NIRSdry) or in the fresh state (NIRSwet).

Mean intake of DM was 737 g/day. The range of silage composition was as follows (mean, range, s.d., g/kg DM unless specified): metabolizable energy (ME MJ/kg DM) 11·1, 8·8 to 12·6, 0·81; pH 4·0, 3·6 to 5·0, 0·34; lactic acid 86, 4 to 139, 42·6; butyric acid 4·7, 0·1 to 46·7,10·2. Rumen measurements varied substantially both diurnally and between silages. Mean diurnal rumen values for the 24 silages (mean, range, s.d.) were: pH 6·76, 6·55 to 7·09, 0·155; ammonia (mg/l) 132, 70 to 247, 47·7; total volatile fatty acids (TVFA mmol/l) 58·2, 45·8 to 72·0, 8·97; (acetate+butyrate)/propionate (ABP) 3·2, 2·2 to 4·8, 0·56.

Partial least-square models were developed to predict rumen fermentation (means for six sampling times) using either the silage chemical composition (CHEM g/kg DM unless specified: DM, ME (MJ/kg DM), crude protein (CP), ammonia (NH3, g N per kg total N), neutralizingvalue (meq per kg DM), sugar, lactic, formic, acetic, propionic and butyric acids and ethanol) or silage NIRSdry or NIRSwet. Prediction performance was assessed comparing values for R2, standard error of cross validation (SECV) and SD/SECV (s.d. of reference population! SECV) obtained by the ‘leave one out’ cross validation method. NIRSwet gave slightly better prediction accuracy overall than NIRSdry but both were superior to prediction from chemical composition. Values for R2, SECV and SD/SECV for pH were 0·23, 0·14, 1·09; 0·76, 0·08, 2·01 and 0·72, 0·08, 1·89 for CHEM, NIRSdry and NIRSwet respectively. Corresponding values for rumen ammonia (mg/l) were 0·48, 35·2, 1·35; 0·69, 27·1, 1·76 and 0·70, 26·3, 1·81; for TVFA 0·52, 6·73, 1·33; 0·80, 4·06, 2·21 and 0·93, 2·47, 3·63; for rumen ABP ratio 0·69, 0·32, 1·78; 0·76, 0·30,1·88; 0·72, 0·30,1·85. The silage predictors with greatest influence in the CHEM model for rumen ABP ratio were sugar, CP and lactic acid (negative) and butyrate and ethanol (positive). NIRS shows considerable promise as a means of predicting rumen fermentation of animals given grass silage diets.

Goat production systems increasingly involve indoor feeding. To facilitate manger design, there is need for information on the ability to reach for food, such as that for cattle given food through tombstone barriers. In the first study, 20 castrated and 20 non-pregnant female Saanens of mean live weight (M) 39·3 (s.d. 14·42) kg were trained to reach, through a vertical tombstone barrier, for concentrate meal placed on a horizontal platform attached to the barrier. The barrier allowed the neck but not the shoulders to pass through. It was hypothesized that horizontal reach forwards (F, distance from mid point of barrier to uneaten meal) and sideways (S, distances sideways from mid point of barrier to uneaten meal adjacent to barrier) would be a function of height of platform above the floor and size of goat. Because of size, eight goats (mean M, 16·4 kg) were unable to reach meal when the platform height was 75 cm. Mean (s.e.) values for F at platform heights 0, 25, 50 and 75 cm were 55·9 (0·68), 58·8 (0·64), 57·8 (0·69) and 41·1 (1·23) cm respectively. Values for S were smaller, but followed a similar pattern (49·4 (0·64), 52·4 (0·56), 53·2 (0·53), 36·6 (1·17) cm). Linear regression of either F or S on M and linear body dimensions (e.g. body length, neck and head length, neck-joint height, withers height) showed high correlations with R2 values being 0·8 or more. In the second study, 10 castrated and 10 non-pregnant females (M, 48·7 (s.d. 14·56) kg) were trained to reach through the tombstone barrier for concentrate pellets 'glued', using molasses, on to a vertical plate. It was hypothesized that vertical reach (V, distance from floor to uneaten pellets) would be a function of distance between barrier and plate (20, 30, 40, 45, 50 cm), height of step (0,14·2, 28·4, 42·6 cm) on which goats placed their forelegs and size of goat. Four goats (mean M, 29·9 kg) were unable to reach pellets when the plate was at 45 and 50 cm. Mean (s.e.) V values decreased with increasing plate distance and increased with step height (e.g. at 0 cm step, 122·4 (1·96), 116·9 (2·05), 109·4 (2·16), 103·9 (2·49) and 96·5 (2·75) at 20-; 30-; 40-; 45- and 50-cm plate distances respectively; at 20-cm plate distance, 122·4 (1·96), 137·5 (2·00), 151·3 (1·90) and 164·3 (2·00) cm at 0-; 14·2-; 28·4-and 42·6-cm step heights respectively). Linear regression of V on body weight and body dimensions (e.g. body length, heart girth, withers height) showed high correlations (R2 > 0·8). It is concluded that for practical purposes, body weight is a satisfactory predictor of reach. The results support the hypotheses. The data will facilitate the design of mangers for goats with body weights and dimensions in the range of those used in the present study.

Meishan synthetic sows and gilts have been shown to produce higher litter weights at weaning than White breed type sows and gilts. To investigate the factors contributing to this, 64 multiparous sows were used in a 2 × 2 × 2 factorial experiment to assess the influence of maternal breed type (0·50 Meishan synthetic (M) or purebred European Landrace and Large White (W)), litter size (eight (L) or 12 (H) piglets) and breed of piglet (0·25 Meishan hybrid (m) or white hybrid (w)) on sow and litter production and behaviour over a 28-day lactation. All litters were formed by cross-fostering to standardized litter rearing size 24 h after farrowing. Sows were given food twice daily to appetite. When there were no treatment interactions, main effects are presented. M sows were lighter (M = 215, W = 241 (s.e. 3·61) kg, P < 0·001) and fatter (M = 31·5, W = 21·7 (s.e. 0·72) mm, P < 0·001) at farrowing than W and had higher maternal weight loss (M = 24·7, W = 5·9 (s.e. 0·85) kg, P < 0·001) and higher back fat loss (M = 5·6, W = 2·0 (s.e. 0.28) mm, P < 0·001) in lactation. High litter size resulted in higher maternal weight loss (L = 7·4, H = 13·2 (s.e. 0·85) kg, P < 0·001) and fat loss (L = 2·9, H = 4·7 (s.e. 0·28) mm, P < 0·002) than low litter size. Litter growth rate was higher for M than for W (M = 27·0, W = 14·5 (s.e. 0·42) kg/week, P < 0·002) and for high litter size than for low litter size (L = 24·3, H = 17·3 (s.e. 0·42 kg/week, P < 0·001). The m piglets had lower litter growth rates than w piglets (m = 15·1, w – 16·5 (s.e. 0·42) kg/week, P < 0·001). There were no breed differences in the length of suckling periods but M had shorter suckling intervals than W (M = 38·1, W = 48·7 (s.e. 1·08) min, P < 0·001). It is concluded that the higher litter weights produced by M sows are due solely to maternal effects and not litter size or piglet genotype.

This study investigated the effects of weaning and sex on various aspects of production and quality characteristics in 22 male and 18 female lambs of the Rasa Aragonesa local meat breed. Half the lambs were weaned (W) at 38 to 40 days and half were left unwearied (UW). Both groups were given ad libitum concentrates and cereal straw. Average farm weight was 22·1 kg at 78·3 days. Live-weight gain was significantly different between sexes but not between W and UW lambs. Dressing proportion was higher in UW lambs. Significant differences in fatness were found between W and UW lambs and between sex of lambs. Among the meat quality traits, W lambs had redder and UW lambs paler meat judged by colour a* and haem pigment concentration. No statistical differences were found in the other traits except flavour intensity, which was higher in UW (66·8) than in W (63·6) lambs on a 1 to 100 scale. All other eating quality aspects, in grilled m. longissimus lumborum slices, tended to be higher in UW lambs. The fatty acid composition of subcutaneous and intramuscular fat depots differed significantly (intramuscular fat was more unsaturated and polyunsaturated). There were also differences between W and UW lambs in subcutaneous fat (higher unsaturated in W lambs). However in intramuscular fat composition only differences in polyunsaturated fatty acids (higher in UW lambs), but not in total unsaturated or saturated, were observed. Tatty acids of less than C16 chain length were higher, in both fat depots, in UW lambs than in W lambs reflecting greater incorporation of milk fatty acids. Palatability characteristics were not closely associated with fatty acid composition except that flavour intensity was correlated with total saturated fatty acids.

Two experiments were carried out with Scottish Blackface lambs to investigate the effects of restricted nutrition during pregnancy and lactation on voluntary food intakes (VFI) between weaning and 2 years of age. Ewes were given diets providing 0·7 (LP) or 10 (HP) of their estimated metabolizable energy requirements during the last 6 weeks of pregnancy and subsequently grazed swards with mean sward surface heights of approximately 3 cm (LL) or 6 cm (HL) during lactation. All lambs were weaned at 17 weeks of age. In experiment 1, four treatment combinations (LP-LL, LP-HL, HP-LL and HP-HL) were applied and female lambs were studied. In experiment 2, two treatment combinations (LP-LL and HP-HL) were applied and male lambs were studied. In both experiments the lambs received a common level of nutrition between weaning and 2 years of age.

In both experiments, mean live weights were proportionately 0·2 higher for HP-HL than for LP-LL lambs at weaning (P < 0·001) and in experiment 2 mean live weights and body condition scores were still higher in HP-HL than in LP-LL lambs at 2 years of age (P < 0·05). Abomasum weights were higher in HP than in LP lambs at birth and higher in HP-HL than in LP-LL lambs at weaning in experiment 1 and the weights of the rumen and dimensions of the rumen villi were greater in HP-HL than in LP-LL lambs at weaning in both experiments (P < 0·05). The treatments had no effect on lipid content or mean adipocyte diameter in the main fat depots at birth or weaning. There were no treatment effects on VFI in either experiment. It was concluded that restricted nutrition during late pregnancy and early lactation does not affect VFI between weaning and 2 years of age in sheep, even though there are differences in live weight and the development of the gastrointestinal tract at weaning and there may be long-term effects on live weight and body condition, particularly in male animals.

The potential of diets, based on maize silage (M), non-bird-resistant grain sorghum silage (NBRGS), bird-resistant grain sorghum silage (BRGS) and forage sorghum silage (FS), in different proportions with concentrate for each silage, was evaluated for the finishing of weaner lambs. On a dry basis the ratios of silage: concentrate were 70: 30, 60:40, 50:50, 40: 60 and 30: 70 respectively for each of the silages. The concentrate mixtures were composed of different quantities of maize meal and soya-bean oilcake meal in order to balance the crude protein contents of the different diets used from weaning to 35 kg live weight and from 35 kg live weight to slaughter at 140 and 110 g/kg respectively.

Better apparent digestibilities of dry matter, crude protein and acid-detergent fibre as well as food conversion to live weight were found for diets with M or NBRGS as roughage sources compared with those with BRGS and FS as roughage sources. At the lower levels of concentrate inclusion in the diets the dressing proportions, carcass grades and food conversion to carcass weight for the diets with M and NBRGS as roughage sources were also better than were those with BRGS and FS as roughage sources. Although higher levels of concentrate inclusion in the diets to a large extent rectified these biological disadvantages of the diets based on BRGS and FS, they will also cause a rise in the price of the diet.

Previous results have shown that certain phenotypes of Angora goat differ in respect of glucose metabolism and it has been proposed that this is linked to the high incidence of abortions in this breed. The aim of this experiment was to investigate adrenal function, food digestion and nutrient partitioning as possible causes of differences in glucose metabolism between a phenotype which produces a relatively large amount of mohair of a large fibre diameter (high producers) and a phenotype which produces less mohair of a smaller fibre diameter (low producers). Two groups consisting of 15 3-year-old Angora bucks each and representing two different phenotypes were given a maintenance diet for the duration of the trial. Plasma glucose concentrations during a 4-day fast were lower (P < 0·01) in high producers than in low producers and plasma glucose concentrations following insulin injection also fell to a greater extent in high producers than in low producers (P < 0·05), indicating that high producers were less able to mantain plasma glucose concentrations during periods of increased demand than low producers. The decrease in glucose concentration following insulin injection was accompanied by a rise in plasma cortisol concentrations until 60 min after the insulin injection but there were no differences between phenotypes (P > 0·05). Similarly, cortisol concentrations rose to a peak 60 min after ACTH injection and there were no differences between phenotypes (P > 0·05). In both instances, the pattern of cortisol concentrations was consistent with normal adrenal function and there were no indications of adrenal insufficiency. Although differences in digestion were observed between phenotypes (P < 0·01), these were small. There were no differences in nitrogen (N) intake or retention (P > 0·05). High producers deposited substantially more (proportionately 0·56) N as fleece than low producers (P < 0·01), and partitioned a greater proportion of N intake to fleece production (P < 0·01). It was concluded that adrenal insufficiency was not implicated in the observed differences in glucose metabolism between phenotypes but differences in digestibility and nutrient partitioning may play a role.

The effects of short-term exposure to high ambient temperatures on gas exchange, heat production (HE), respiration rate (RR) and rectal temperature were evaluated individually with boars of approximately 100 kg live weight. The boars were of different breeds with four of Yorkshire (YS), eight of Danish Landrace (DL), out of which three were found stress susceptible by the halothane test (DLH+), eight of Duroc (DR) and eight of Hampshire (HS) breeds. After 1 h rest in the respiration chamber at 17·0°C the gas exchange measurements started with al-h basal period at 17 °C, followed by 2h of heating during which temperature increased to 35·0 °C (period I) and then further to 39·7X1 (period II). Then cooling of the chamber started, and after 1 h (period III) temperature had decreased to 21·8°C, and after the 2nd h of cooling (period IV) temperature was 18·2 °C. The gas exchange was measured for each hour from 09.00 h (basal period) until 14.00 h (period IV). RR was recorded every 15 min. Rectal temperatures were measured when the animals were removed from the chamber. The gas exchange and HE increased slowly during period I but rapidly in period II, followed by decreasing values in the cooling periods. HS and DLH+ had considerably higher gas exchange and HE than other breeds in these two periods and the values remained high during period III. In period IV all breeds had gas exchange rates and HE below those of the basal period. RR increased slightly in period I and then a sharp increase followed during period II. Maximum RR was recorded in period III with an average of 183 breaths per min for all breeds. RR increased earlier and more steeply in HS and reached the highest mean value of 236 breaths per min. Four HS boars salivated heavily during heat stress and rectal temperatures of these animals were 39·7 °C when removed from the chamber compared with close to 39·0 °C for all other breeds. It was concluded that there were considerable breed differences in response to heat stress and that DLH+ and HS were more severely stressed than boars ofYS, DL and DR.

Concern for the welfare of export lambs during long-distance road transport has prompted much research and a recommended change in procedure. The latter envisages an absolute maximum journey time of 31 h and includes a rest-stop (minimum duration 1 h) for feeding and watering. In the present experiment, the physiological and behavioural responses to this new protocol have been investigated in fleeced and shorn lambs (no. = 10 per group) provided with venous catheters and heart rate monitors. The two groups were loaded on a vehicle into separate adjacent pens and driven for 14 h; then unloaded into a lairage, where their behaviour was recorded. After 1 h they were reloaded and driven for a further 15·5 h, finally arriving at a slaughterhouse where carcass condition was evaluated. Blood samples collected at 30- or 60-min intervals by experimenters travelling with the animals were analysed to determine haematocrit, plasma osmolality, plasma concentrations of glucose, creatinine phosphokinase (CPK), and the stress-responsive hormones, cortisol, prolactin, adrenaline and noradrenaline. The results showed that haematocrit increased after loading although the general trend during transport, as with osmolality, was a decline (P < 0·05). No significant changes in plasma glucose were detected but CPK increased in fleeced lambs after loading (P < 0·05). Cortisol release was stimulated by loading, especially in fleeced sheep (P < 0·001) but returned to home pen values within 6 h; heart rates changed in a similar manner. Transport did not markedly affect prolactin release although concentrations were consistently greater in fleeced sheep (P < 0·001). Noradrenaline, however, tended to be higher in shorn animals (P < 0·05). In lairage, both groups readily consumed hay, and especially concentrates, but the shorn lambs spent more time eating (P < 0·001). None of the shorn sheep, and only a few fleeced animals, drank water. There was no evidence for differences in weight loss between the two groups during the experiment and carcass quality at slaughter was within the normal expected range. The implications of these, and other related studies, for future transport policy are discussed, with particular reference to rest-stop duration and handling procedures.

An experiment was carried out to investigate the proposal that the voluntary food intake of pigs, when given foods based on bulky materials, can be accurately predicted from the water-holding capacity (WHC, g water per g dry food) values of the foods. A basal food (B), with 12·9 MJ digestible energy and 249 g crude protein per kg dry matter, was diluted to two extents by either sugar-beet pulp (S), grass meal (G) or soya hulls (H). The contents of the bulky materials in the total diets were either 320 g/kg (foods BS, BG and BH) or 800 g/kg (foods S, G and H). Each of these six foods was given ad libitum to six pigs in period I, which lasted for 21 days, with a further four given B. In period II, which lasted for 14 days and followed period I immediately, the pigs were also given their food ad libitum. Only the 36 pigs from the six ‘bulky“treatments (i.e. on treatments other than B) continued in a change-over design. Two pigs from each of the six ‘bulky’ treatments were allocated to the three foods of the same level of dilution (e.g. the six pigs from BS were changed to BS, BG and BH). Of the ‘bulk’ characteristics measured (crude fibre, acid-detergent fibre, neutral-detergent fibre, apparent digestibility of the organic matter, density and WHC) only WHC accounted sufficiently for the effects of the foods on the voluntary food intake of the pigs. The two methods of centrifugation and filtration that were used for the WHC determination were very highly correlated (r = 0·978), with food B having the lowest value, 3·86 g water per g dry food, and food S having the highest value, 8·48 g water per g dry food, when measured by centrifugation. In both periods the rate of intake was calculated as g/kg live weight per day, scaled intake (SFI). Live-weight gain and food conversion efficiency both decreased significantly (P < 0·001) as B was diluted with S, G and H. For the six ‘bulky’ feeding treatments SFI in the last 14 days of period I was proportional to the reciprocal of the WHC of the foods: SFI (g/kg per day) = 235 (s.e. 6·3). No effects of previous feeding treatment on site were observed in period II as a whole; however, intake initially increased when the food had lower WHC than the one previously offered and decreased when it had higher WHC. It was concluded that: (a) the WHC of a food is a sufficient descriptor of its ‘bulk’ and that it accounts for the effects on the voluntary food intake of pigs; (b) the detailed methods used for measuring WHC need to be standardized; (c) pigs can adapt more rapidly to bulky foods when they have had prior experience of such foods; (d) the length of time needed to observe an intake, which will be characteristic of the bulky food on offer, depends on the prior experience of the pig.

In order to investigate differences in carcass and meat quality between lines of different stress susceptibility, 150 pigs were slaughtered on 15 slaughter days, consisting of equal numbers of stress-susceptible (nn) pigs of a boar line, stress-resistant (NN) pigs of a sow line and stress-carrier (Nn) crosses of these two lines. Carcass quality was determined by a SKGII-device which combined four physical measurements into a carcass lean estimate and a conformation score, and meat quality traits were measured on the carcass and on a loin slice. Killing-out proportion was lower for the NN line compared with the Nn crosses and the nn line. Lean content increased and conformation score improved as the number of n alleles in the respective genotypes increased but the Nn genotype was closer to the nn genotype than to the NNgenotype. Similarly, a large difference in meat quality was found between the NN and the nn line, whereas the difference in meat quality between the Nn and the nn genotype was smaller than expected. This was probably due to the low-voltage stunning procedure. In addition, the method of transporting the pigs to the abattoir (by truck or by foot, for a distance 125 m) had a pronounced effect on meat quality in the loin.

In order to evaluate the effect of exercise training and spontaneous physical activity on growth performance, carcass composition, and locomotory ability 48 female and 48 entire male pigs were subjected to one of three treatments: individual housing in pens of 2-5 m2 (confined; C), individual housing and treadmill training for 15 minlday at a speed of 4 km/h, 5 days/week for a period of 70 days (trained; T) and group-housing equal to 0·9 m2 per animal (free; F). Pigs in treatment C and T did not differ with regard to daily gain, food intake, kg food per kg gain and carcass lean content. Training did, however, induce significant cardiac hypertrophy (by a proportion of 0·06). In treatment F (i.e. large pens), daily gain was 135 g lower than in treatment C. Dissection of the carcasses showed that treatment F increased the weight of m. psoas major (by 30 g) and the total carcass bone mass (by 130 g) when compared with treatment C. Proportions of carcass lean and intramuscular fat were unaffected by treatment F. Likewise, leg weakness and osteochondrosis did not differ between treatments, whereas the locomotory ability was positively affected by rearing in large pens (treatment F) but not by treadmill training (treatment T). Thus, physical activity in large pens induced various adaptations throughout the body.

An initial experiment was conducted to investigate the variability of selected metabolites in the plasma from guanacos. A second experiment directly compared plasma biochemical values for guanacos with those for sheep. During the first experiment, jugular blood samples were collected from five mature castrated guanacos using an embedded experimental design. Weekly blood samples were collected at the same time (09.00 h) on the same day each week for 7 weeks. Daily blood samples were collected at the same time each day (09.00 h) during week 5. On day 2 of week 5, blood samples were collected every 3 h from 09.00 h for a 24-h period. No evidence of a cyclical pattern of plasma parameters was observed on a weekly, daily or 3-h basis. During the second experiment, the metabolic profiles of 11 mature castrated guanacos and 11 mature barren ewes (Merino × Welsh Mountain) were compared. Significant differences in plasma concentrations of all metabolites except urea-nitrogen (guanacos -15·42 mmolll, sheep - 15·60 (s.e.d. 1·506) mmolll) were found with values for guanacos v. sheep as follows: glucose (7·63 v. 3·63 (s.e.d. 0·268) mmolll); acetate (0·26 v. 0·48 (s.e.d. 0·035) mmol/l); β hydroxybutyrate (0·06 v. 0·50 (s.e.d. 0·019) mmol/l); albumin (33·4 v. 29·5 (s.e.d. 0·93) g/l); and total protein (53·8 v. 65·6 (s.e.d. 2·12) g/l); (P < 0·001 for all previous variables); non-esterified fatty acids (0·48 v. 0·29 (s.e.d. 0·048) meq per 1; P < 0·01) and a-amino N (2·44 v. 2·66 (s.e.d. 0·088) mmolll; P < 0·05). This study indicates that the reference plasma metabolite concentrations of sheep are not suitable alternatives for use for nutritional or veterinary purposes with guanacos, but those of llamas or alpacas are. The results also suggest that energy capture and transport in camelids may be markedly different from that in conventional ruminants.

Grouping of sows and piglets during lactation can cause performance problems associated with disruption of suckling. Cross-suckling and an increase in the number of piglets at the udder during milk let-down have been observed. To investigate the role of these factors, 24 sows and litters were used to study their independent effect on sucking behaviour and performance. Control sows (C) remained in farrowing pens with crates until weaning at 28 days. In treatment 1 (Tl) on day 14 after farrowing, five piglets were removed from the resident (Rl) litter and replaced by five piglets (cross-suckers; CS1) of the same age from a different litter. In treatment 2 (T2) on day 14, five additional piglets (CS2) from other litters were added to the 10 resident (R2) piglets for a period of 24 h. Behaviours of the sows and piglets were video recorded prior to mixing and for 3 days after mixing. Litter weight gain of 11 was significantly reduced in the week after mixing (2–06,1·61 and 2·00 (s.e.d. 0·18) kg/day, P < 0·05 for C, Tl, T2, respectively). Within Tl the growth rates ofRl and CS1 piglets were not significantly different. In the 24 h after mixing, C, Rl, CS1 and R2 piglets gained weight whilst CS2 lost weight (247,186,182,151 and -116 (s.e.d. 44·2) glday, P < 0·01). On the day of mixing, the proportion of suckling attempts which resulted in milk letdown was reduced in treatment groups (0·93, 0·75 and 0·70 (s.e.d. 0·04), P < 0·02 for C, Tl, T2 respectively) and the proportion ofT2 piglets lying near the sow's udder between milk let-down was higher than on C and Tl (0·15, 017 and 0·29 (s.e.d. 0·06), P < 0·05). There was no significant difference in piglet behaviour from 2 days after mixing. Both cross-suckling and introduction of additional piglets transiently disrupted sucking behaviour and adversely affected the performance of the piglets. Increased competition had a much greater effect than unfamiliarity with the environment, with added cross-sucking piglets being greatly disadvantaged relative to substituted cross-sucking piglets.