Previously published data from serial slaughter trials on growing pigs of five genotypes were reanalysed. Gompertz curves were fitted to body protein and lipid mass in order to estimate mature protein and lipid mass (P∞, L∞) and the rate parameter (BGomp J that was presumed to be equal for the protein and lipid curves. L∞ was expressed as its ratio to P∞, R L∞P∞. The maximum rate of protein deposition was derived as Pdep,max = P∞ X BGomp/e. The analysed data encompass body weights of 10 to 133 kg, 13 to 217 kg, 18 to 106 kg, 20 to 110 kg and 11 to 145 kg. The Gompertz function fitted all data sets well, as judged by the standard deviations and distribution patterns of the residual terms. Autocorrelations among the residuals were non-significant.

Averaged over sexes (females and entire and castrated males), the P estimates were all close to 31 kg; the RL∞/P∞ estmates ranged from 1·4 to 4·7 kg/kg; the BGomp estimates ranged from 0·009 to 0·017 kg/day per kg. The resulting Pdep,max estimates ranged from 110 to 193 g/day. The genotypes were placed in 1969, 1976, 1984, 1990 and 1993. Plotting the estimates against time (year) showed distinct time trends for all parameters except P∞. RL∞/P∞ seems to gradually reach a plateau around unity, whereas BGomp and Pdep/max increase linearly. These trends were confirmed by an analysis of body weight based on the same data plus data on three other genotypes that spanned the same time period. Analyses of the same protein and lipid data to fit a sigmoid growth function with a flexible point of inflexion did not change the apparently absent time trend of F. The estimates of the inflexion points of the fitted protein accretion curves, expressed as proportions ofF, were indistinguishable from the fixed 0·368 value of the Gompertz function for the earliest three genotypes and then showed a tendency to increase, up to 0·46 for the 1993 population. These time trends must be the consequence of a combination of changes in nutritional and other environmental factors and genetic changes. They cannot be the sole result of within-line selection for growth and body composition traits, since this should increase P∞. It seems as if pig breeders have repeatedly initiated their sire lines from genetic resources with small mature size, to subsequently increase this trait as an indirect result of within-line selection.

Two experiments were conducted to determine the nutritive value of extruded or raw peas (Pisum sativum as an energy and protein supplement for pigs of 33 to 100 kg live weight. Experiment 1 determined the effects of extrusion on the nutrient apparent digestibility of peas when included at 200 g and 400 g/kg in the diet. In experiment 2, performance was determined in individually fed pigs (no. = 70) offered diets ad libitum including a control (no peas, T1), 200 g/kg raw peas (T2), 400 g/kg raw peas (T3), 200 g/kg extruded peas (T4), 400g/kg extruded peas (T5). The peas were extruded at 120°С for 30 s. All diets were formulated to have similar concentrations of digestible energy (DE) and total lysine. There was a significant interaction effect (P < 0·05) between level of peas and extrusion on the digestibility of the organic matter (OM), nitrogen (N), energy and the DE content of the peas. The inclusion of 400 g/kg raw peas led to a lower estimated digestibility of OM (P < 0·001), N (P < 0·001), gross energy (P < 0·05) and DE content (P < 0·05) of the peas compared with the 200 g/kg peas. However, there was no difference (P > 0·05) between the digestibility of the 200 and 400 g/kg peas when the peas were extruded. In experiment 2, there was a significant interaction (P < 0·05) between the level of peas in the diet and extrusion. As the level of raw peas increased from 200 to 400g/kg, growth rate decreased (P < 0·01) and food conversion ratio (FCR) increased (P < 0·01). However, as the level of extruded peas was increased from 200 to 400g/ kg, there was no difference in either growth rate or FCR. It is concluded that extrusion of peas improved the nutrient digestibility and improved overall gain and FCR of the pigs.

Forty-two New-Zealand x Californian young female rabbits of 4·5 months of age were used to evaluate the use o f a computerized ultrasound system in estimating changes in body condition. In order to get a wide range of fatness, animals were randomly subjected to four food restriction regimes for 2 weeks. Female rabbits were scanned at six different back sites to estimate perirenal fat thickness, using a real-time ultrasound unit equipped with a 5·0-MHz sector probe. After scanning, all animals were weighed and slaughtered. The weights of hot carcass, cold carcass, perirenal fat, scapular fat, liver and kidneys were recorded. There was a large variation in the weight of the main fat deposits, especially for the perirenal fat (CV = 0·632), indicating its suitability for estimating changes in body condition. Ultrasound measurements of perirenal fat thickness correlated strongly with all carcass fat weight values (r = 0·692 to 0·959; P < 0·001) and the estimated carcass energy content (r = 0·777 to 0·866; P < 0·001) and seem to be more precise predictors than live weight measurements. Multiple regression equations for estimating the main fat deposit weight and estimated carcass energy content using only the live weight as an independent variable had R2 values ranging from 0·47 to 0·59. The accuracy of estimates was improved when ultrasound measurements were used in the regression model (R2 values ranging from 0·81 to 0·95). Ultrasound measurement of mean perirenal fat deposit thickness at 3 cm ahead of the 2nd to 3rd lumbar vertebrae was the best predictor for perirenal fat weight (R2 = 0·95; P < 0·001), total fat weight (R2 = 0·93; P < 0·001) and estimated carcass energy content (R2 = 0·90; P < 0·001). A validation group of 11 rabbit does was used to validate the ultrasound regression equations, showing that their mean accuracy was approximately 0·895 and 0·967 for total fat weight and estimated carcass energy content, respectively. Results suggest that ultrasound measurements of perirenal fat thickness may be an accurate method for studying changes in body condition of young female rabbits at different times.

This study investigated the efficiency of growth and the carcass characteristics of 24 Greyface (Border Leicester × Scottish Blackface), 24 Texel (12 purebred and 12 Texel × Texel-Greyface) and 24 Rouge (12 purebred and 12 Rouge × Rouge-Greyface) lambs finished on the same level of feeding. The efficiency of live-weight gain (kg/MJ) was higher in Greyface compared with Texel lambs (P < 0·01). The efficiency of empty body-weight gain (kg/MJ) was higher in Greyface (P < 0·01) and Rouge (P < 0·05) compared with Texel lambs. The efficiency of carcass gains (kg/MJ) tended to be higher in Greyface and Rouge compared with Texel lambs (P = 0·07). The efficiency of non-carcass component gains (kg/MJ) was also higher in Greyface compared with Texel lambs (P 0·05). Carcass water, protein, lipid and ash gains did not vary significantly between the genotypes, however carcass energy gain tended to be higher in Greyface and Rouge compared with Texel lambs (P = 0·08). The relative proportions of water, protein, lipid and ash in carcass gains did not vary significantly between the genotypes. At the end of the experiment carcass water content was higher in Texel compared with Greyface lambs (P < 0·05) and carcass ash content was lower in Texel compared with Greyface (P < 0·01) and Rouge (P < 0·05) lambs. The concentration of saturated fatty acids was higher in Greyface compared with Rouge lambs (P < 0·001) and higher in Rouge compared with Texel lambs (P < 0·05). Monounsaturated fatty acid concentrations were higher in Rouge compared with Greyface lambs (P < 0·05) and higher in Texel compared with Rouge lambs (P < 0·001). Polyunsaturated fatty acid concentrations were higher in Rouge and Texel compared with Greyface lambs (P < 0·01). The ratio of n-6:n-3 fatty acids was lower in Rouge compared with Greyface lambs (P < 0·05).

The efficiency of empty body gain was higher in male compared with female lambs (P < 0·05). Carcass water (P < 0·01) and protein (P < 0·05) gains were higher in male lambs. At the end of the experiment male carcasses contained a higher content of water (P < 0·05), protein (P < 0·01) and ash (P = 0·07), and a lower lipid (P < 0·05) and energy (P < 0·001) content. Carcass lipids from male lambs contained a higher concentration of polyunsaturated fatty acids (P < 0·001) and tended to contain a lower concentration of saturated fatty acids (P = 0·06).

Two different cannulation procedures (simple ileal ‘T’ cannula v. The post valve ‘T’ caecal cannula (PVTC)) and two indigestible markers (TiO2 v. Cr2O3) were studied with six male littermate pigs fitted with PVTC or simple ileal ‘T’ cannulae. Six diets were used, of which two were based on wheat and wheat bran and the other four were based on two barleys of different bushel weight without and with exogenous enzymes (ß-glucanase/xylanase). Proportional TiO2 and Cr2O3 recoveries in faeces were less than 1·00, the mean values for the six diets being 0·858 for TiO2 and 0·811 for Cr2O3. With both markers, recovery in faeces was lowest for the most digestible wheat-based diet (A). The ileal apparent digestibility (IAD) coefficients of dry matter (DM), crude protein (CP), energy and amino acids measured with Cr2O3 were significantly (P < 0·001) lower than those measured with TiO2. There was no difference in overall apparent digestibility of DM, CP and energy measured with simple ileal ‘T’ cannula and PVTC techniques. However, IAD of DM, energy and CP measured with the PVTC method were significantly higher than those measured with the simple ileal ‘T’ cannula method. The data also showed that the standard errors with the simple ileal ‘T’ cannula method were greater than when using the PVTC method. Diet significantly affected ileal and overall digestibility of nutrients (P < 0·001) with values being highest for diet A and least for the wheat bran-based diet (B). Overall digestibility (OD) of DM and energy were higher for the higher bushel weight barley-based diet (C) than for the normal bushel weight barley-based diet (E). Enzyme inclusion improved OD for both barley diets and ileal digestibility of energy (0·060) and CP (0·057) for the normal bushel weight barley.

Three diets were formulated according to the nature of the fibrous components: a concentrate low fibre diet enriched in starch (diet S, neutral-detergent fibre (NDF) proportionately 0·078 of dry matter (DM)) and two high-fibre diets enriched in either sugar-beet pulp (diet BP, NDF = 0·219 of DM) or wheat bran (diet WB, NDF = 0·187 of DM). In a first experiment, the digestibility of nutrients in these diets were determined using dry sows. In a second experiment, 24 multiparous Large White sows were offered the experimental diets in a 3 x 3 Latin-square design during three 21-day periods over pregnancy in order to evaluate physiological and behavioural effects over the nycthemeral period. On the basis of the first experiment, the daily food supply was adjusted to 2·44, 2·74 and 2-90 kg/day for diets S, BP and WB, respectively, to provide the same amount of metabolizable energy to each treatment. In the hour prior to the meal, the diet effect was nil on plasma levels of glucose, insulin, glucagon and non-esterified fatty acid and limited on cortisol plasma level. After the food delivery, the peak responses of glucose and insulin to the meal were delayed in sows given the BP diet, while their level showed a higher increase for S than for WB and BP diets. Sows offered diet BP spent less time standing than sows offered diet S. The occurrence of non-feeding oral activities over the 45 min following food distribution was significantly reduced with fibrous diets. But no difference appeared during the 45-min period following the end of each meal. It was concluded that the incorporation of beet pulp in the diet was more effective than wheat bran in extending the feeding activity and the absorption of nutrients. The diet effect was limited to the 2 h after the food delivery for these sows given a restricted amount of food.

Three hundred and twenty pigs were reared from birth to slaughter at 21 weeks in either barren or enriched environments. The barren environments were defined as intensive housing (slatted floors and minimum recommended space allowances) and the enriched environments incorporated extra space including an area which contained peat and straw in a rack. Behavioural observations showed that environmental enrichment reduced time spent inactive and time spent involved in harmful social and aggressive behaviour (P < 0·001). Each pig was individually exposed to a novel object during a novel pen test at 18 weeks of age and behavioural, heart rate and plasma cortisol responses were recorded. At slaughter plasma cortisol levels were measured, adrenal glands were weighed and hearts were examined for endothelial haemorrhages. Pigs from enriched environments appeared less fearful during the novel pen test by showing a shorter latency to contact the novel object (P < 0·001) and spending more time in contact with it (P < 0·05). Plasma cortisol responses to the novel pen test tended to be higher in pigs from enriched environments (P > 0·05) and pigs from enriched environments had significantly higher cortisol levels at slaughter (P < 0·05). Adrenal weights were greater in pigs from barren environments (P < 0·05) and it is suggested that chronic activation of the pituitary-adrenal axis in barren environments led to a suppression of cortisol responses to acute stress. The higher cortisol responses to the novel pen test in pigs from enriched environments may also have resulted from greater levels of behavioural activity. This could also explain the higher maximum heart rates in pigs from enriched environments during the 1st min of the test (P < 0-05) and during the period prior to the test when they were being driven towards the test arena (P < 0-05). However, the fact that enriched pigs also showed a greater number of lesions to the endothelium of the heart (P < 0-05) may mean they had a more reactive sympathetic nervous system.

Straw is frequently supplied as a rooting material to improve the welfare of pigs. In Denmark, organically raised slaughter pigs must have access to both straw and roughage. In order to evaluate whether roughage can he used as an appropriate rooting substrate for pigs, the effects of six different roughage types on pigs’ behaviour was examined. Pairs of 11-week-old pigs were placed in specially designed 4 m2 pens. Each pen contained a self-feeder for cereal, a water bowl, a box for roughage, a straw- bedded area and a dunging area. Four replicates were carried out, each consisting of seven pairs of pigs. In each replicate, each pair of pigs was supplied with either whole-crop silage of oats, vetch and lupin (Avena sativa, Vicia sativa, and Lupinus luteus (OVL), whole-crop silage of barley and peas (Hordeum vulgare and Pisum sativum ssp. arvense) (BP), whole-crop silage of clover and grass (Trifolium repens and Lolium perenne (CG), green grass meal (Poa ssp.) (GM), hay of clover and grass (Trifolium repens and Lolium perenne (H), fodder beets (Beta vulgaris ssp. vulgaris) (B), or no roughage (the control treatment) (CON). The pigs manipulated OVL for longer than the other roughage products (P < 0·01). When OVL was omitted from the analysis, B was manipulated for longer than CON (P < 0·05). The pigs that were offered CON manipulated equipment for a longer time than pigs offered B (P < 0·05) and tended to manipulate equipment for longer than pigs offered OVL (P = 0·065). Interestingly, OVL and B were the two products with the lowest dry-matter content. It may suggest that the amount of time spent manipulating roughage will depend considerably on the specific characteristics of the roughage offered, for instance dry matter content and complexity but probably also texture, smell and taste. In addition, the time spent manipulating other elements in the pen will depend on the type of roughage offered. In conclusion, the present study shows that some, but not all, types of roughage are suited as an enrichment of the pig’s environment.

The welfare of early-weaned pigs in different housing systems was examined using a range of indicators. Three replicates of 20 pigs were weaned at 6·4 kg live weight into either: (a) deep-straw; (b) Straw-Flow®; (c) large flatdeck; (d) small flatdeck. A kenneled lying area was provided in (a) and (b). The floor in (c) and (d) was expanded metal. Stocking densities were 0·23 m2 per pig in (a), (b) and (c) and 0·17 m2 per pig in (d). After 4 to 5 weeks (19·6 kg live weight), 16 pigs from each pen were moved into Straw-Flow grower pens (0·68 m2 per pig) and observed until slaughter at 90·6 kg. The remaining pigs were grouped together to examine the effects of mixing. At weaning, 24·1% of pigs had foot injuries. Pigs with foot injuries recovered quickly on deep-straw but the injuries increased in flatdecks immediately after weaning (Straw-Flow was intermediate). Injuries were more persistent in the small flatdeck. Deep-straw prevented adventitious bursitis of the hock. After 1 month in the grower pens, there was no residual treatment effect. Antibody response was examined by immune challenge with keyhole limpet haemocyanin (KLH). Immunoglobulin (Ig) response was greater in straw pens. Pigs mixed at 20 kg showed a decreased immune response to KLH challenge. Growth and food intake showed no treatment effects; food conversion ratio was poorer in (c) than in (b) or (d).

Two similar experiments (1 and 2) were conducted to measure the effects of a range of dietary threonine concentrations and environmental temperatures on the performance of pigs grown from 13 to 25 kg live weight. In both experiments 48 Large White x Landrace entire male pigs were assigned at 13 kg to one of six dietary threonine treatments (8·9 (T1), 7·6 (T2), 6·2 (T3), 4·9 (T4), 3·6 (T5) g/kg and T5 + supplemented threonine (T6)) and one of four temperature treatments (18, 22, 26 and 30°C). Animals were given ad libitum access to food until 25 kg live weight. There were significant interactions (P < 0·05) between temperature and threonine content on the rate of growth (ADG) with the highest gains on T1 and at 22°C. Similarly the response in food intake (FI) to dietary threonine was significantly (P < 0·01) modified by the ambient temperature. An increase in the supply of threonine in the diet resulted in significant increases (P < 0·001) in the gain per unit of food (FCE). A similar response to temperature occurred with the highest FCE recorded at 26°C and the lowest at 18°C. There was a 0·20 proportional reduction in body protein content at 25 kg live weight in pigs given T5 compared with those given T1 and similarly, excluding T6 because threonine may not have been the most limiting amino acid, the fat content was 1·37 higher for pigs on T5 versus T1, which had the lowest fat content. Similar trends occurred in protein and lipid growth rates with maximum protein deposition recorded on T1 (86 (s.e. 3·5) g/day) and maximum lipid deposition on T5 (108 (s.e. 5·8) g/day), over all temperatures. The response in total heat loss was similar to that observed in FI with the effect of decreasing threonine content being dependent on the environmental temperature. Linear regression of daily empty body threonine accretion on daily digestible threonine intake showed an average efficiency of threonine utilization for pigs between 12 kg and 25 kg live weight of 0·59 (s.e. 0·03). There were no differences in efficiency between temperatures. In conclusion, decreasing the threonine concentration below the requirement of the animal ‘resulted in a significant decrease in ADG, reduced FCE and fatter animals. Pigs given a diet deficient in threonine will attempt to maintain threonine intake as the concentration declines by increasing food intake but this compensation is dependent on the environmental temperature. Pigs are able to compensate better for a deficiency in threonine at 18°C and 22°C than at higher temperatures due to the animals being able to dissipate more heat at the lower temperatures.

Two experiments were conducted to measure the effects of a range of dietary lysine concentrations and environmental temperatures on the performance of pigs grown from 13 to 25 kg live weight. In both experiments 48 Large White x Landrace entire male pigs were assigned at 13 kg to one of six dietary lysine treatments (13·8 (L1), 11·8 (L2), 9·6 (L3), 7·6 (L4), 5·6 (L5) g/kg and L5 + supplemented lysine (L6)) and one of four temperature treatments (18, 22, 26 and 30°C). Animals were given ad libitum access to food until 25 kg live weight. There were significant differences in the rates of growth between dietary and temperature treatments with the highest gains on L2 (0·597 (s.e. 0·020) kg/day) and at 18°C (0·549 (s.e. 0·018) kg/day). Food intake (FI) increased significantly (P < 0·001) with decreasing lysine content, reached a maximum (L4) and then declined (L5). An increase in the supply of lysine in the diet resulted in significant increases (P < 0·001) in the gain per unit of food (FCE). There was an indication (P < 0·10) that the response in FCE to dietary lysine was dependent on the temperature, with maximum FCE being obtained at 22°C on LI (647 (s.e. 18·5) g gain per kg food). Dietary treatment had a significant effect (P < 0·001) on both the rate of protein (PR) and lipid deposition (LR) irrespective of the temperature. There was a 0·60 reduction in PR and a 1·36 increase in LR in pigs given L5 compared with those given L1. Similar trends occurred in the empty body protein and lipid contents at 25 kg live weight. Both temperature and dietary lysine levels had a significant (P < 0·05) effect on total heat loss (THL). The response in THL was similar to that observed in FI. The efficiency of lysine utilization at 22°C was significantly (P < 0·05) higher than at the remaining temperatures. The mean efficiency for pigs between 13 kg and 25 kg live weight was 0·64 (s.e. 0·05). In general, growth and food intake responses to dietary lysine level were independent of environmental temperature.

As a part of a study investigating the extent to which ad libitum feeding of a high fibre diet could mitigate behavioural problems associated with food restriction, the performance of sows given food at restricted or ad libitum levels was compared. Ten subgroups of five were allocated to each of the restricted (R) and ad libitum (A) feeding regimes. Five weeks after service, subgroups were introduced into one of two dynamic groups of sows housed in adjacent straw-bedded pens. R sows received a fixed daily ration (parity 1: 2·2 kg; parity 2: 2·4 kg) of a conventional pregnancy diet (13·1 MJ digestible energy per kg) from an electronic sow feeder. Sows on the A regime had unrestricted access to five single-space hoppers dispensing a high fibre diet (containing 600 g unmolassed sugar beet pulp per kg). Subgroups were maintained on these gestation feeding regimes for two consecutive parities. During both parities, A sows were heavier by day 50 of gestation (parity 1: P < 0·05; parity 2: P < 0·01) and at farrowing (parity 1: P < 0·001; parity 2: P < 0·001) than R sows. No difference was found between feeding regime in sow weight at weaning, due to a greater weight loss during lactation of A (parity 1: P < 0·001; parity 2: P < 0·001) than R sows. No difference was found between feeding regime in sow backfat thickness, sow reproductive performance or litter performance in either parity. This suggests that unmolassed sugar beet pulp diets may be used to feed sows on an ad libitum basis during gestation without compromising productivity. However, food intakes may be too high (estimated at 4·1 kg per sow per day) to make ad libitum feeding of pregnant sows an attractive option for producers.

Group-housed pigs may be prevented from expressing their desired feeding pattern by more dominant individuals in the group. Indeed, when compared with individually housed pigs, group housed pigs eat less frequent, but larger meals. Therefore, it would be advantageous for pigs to have flexible feeding patterns in order to decrease the impact of group housing. The aim of this study was to assess the flexibility of feeding patterns by restricting the time of access to food of pigs previously given food ad libitum and then returning them to 24-h access. Thirty-two Large White x Landrace pigs were used in an experiment of two blocks (16 pigs per block) each comprising three, 2-week periods. In each block; during period 1, all pigs were allowed 24-h access to food after which, in period 2, eight of the pigs had access to the feeder restricted between 11:00 and 13:00 h of each day. The remaining eight pigs continued on 24-h access to food and acted as controls. In period 3, all pigs were again returned to 24-h access to food. Daily feeding pattern and food intake were recorded throughout. Behavioural observations in the form of scan samples were made and pigs were weighed twice a week. In period 2 the restricted pigs had fewer visits to the feeder per day, 34·0 v. 70·1 (P < 0·001); of a longer duration, 98·3 v. 64·5 s (P < 0·01); with a higher food intake per visit, 64·9 v. 33·3 g (P < 0·001) than the control pigs. Daily food intake and live-weight gain were lower (P < 0·001) for the restricted pigs in period 2 than for the control pigs. Restricted pigs spent more time rooting (P < 0·05), and less time sleeping (P < 0·05) than the control pigs in period 2. In addition, there was a trend for pigs to spend more time alert in the observation session prior to access to food in the second period when they were restricted and they made attempts to gain access to the feeders in this session. An indication of flexibility was gained by comparing feeding behaviour and time budgets between periods 1 and 3. The pigs that experienced a period of restricted feeding either resumed their previous behaviour or showed the same trend as the controls. In periods 1 and 3 daily feeder visits were 66·2 and 68·1 for control pigs, and 65·6 and 67·1 for restricted pigs. Mean durations of visits were 79·3 and 47·5 s, and 74·4 and 61·7 s respectively. It was concluded that feeding behaviour was flexible and time budgets were resilient across periods.

Choice tests are an effective means of assessing the short-term environmental preferences of captive animals. The preferences shown by eight thoroughbred horses (Equus caballus) for three commonly used bedding materials (paper, straw and shavings) were investigated. For each preference test two choices were presented in separate boxes joined by an unbedded corridor. Time spent in each compartment and associated behaviours were recorded. Despite a positional bias, horses clearly showed a preference for straw bedding (42·9 (s.e. 3·6) %) over shavings (35·2 (s.e. 3·4) %, P < 0·05), straw (42·0 (s.e. 37) %) over paper (29·3 (s.e. 3·4) %, P < 0·05) and shavings (41·6 (s.e. 4·3) %) over paper (27·7 (s.e. 3·7) %, P < 0·001) based on percentage of observed time spent on the substrate. Straw bedding increased the occurrence of bedding related activities, with more of these activities in choices where straw was available (P < 0·001) and in these choices the activities being preferentially expressed in the straw alternative (P < 0·001). Straw may therefore be preferred as it allows the expression of a wider number of motivationally significant activities.

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.

Forty multiparous Large White sows were used to investigate the effects of five ambient temperature levels (18, 22, 25, 27, and 29°C) and two dietary protein contents on their feeding behaviour during lactation. At each temperature treatment, ambient temperature was kept constant over the 21-day lactation period. Dietary protein content was either 140 or 170 g/kg with essential amino acids levels calculated to he non-limiting. Photoperiod was fixed to 14 h of artificial light. The animals were given food ad libitum between the 7th and the 19th day of lactation. Feeding behaviour was not influenced by diet composition. Over the 13 days under ad libitum feeding conditions, voluntary food intake decreased from 7·80 to 3·50 kg/day between 18 and 29°C, which was achieved through a decreased daily number of meals at the highest temperature (6·8 to 4·5 at 18 and 29°C, respectively). No significant difference among temperatures was observed on meal size, even if the highest (1372 g) and the lowest (883 g) values were obtained at 18 and 29°C, respectively. Rate of food intake was not influenced by temperature and averaged 133 g/min; consequently, decreased voluntary food intake under heat exposure resulted in reduced ingestion time (61 and 29 min/day at 18 and 29°C, respectively). Hourly food intake peaked at the beginning and the end of the light period. It resulted in a mainly diurnal partition of food intake. This partition was significantly affected by temperature as proportionately 0·87 and 0·91 of total food intake occurred during the day at 27 and 29°C, respectively, v. 0·81 on average between 18 and 25°C. Number of meals was lower during the night (1·1 v. 5·2 during the day on average); it decreased with increased temperature both during the day and the night. Meal size was lower during the night (938 v. 1080 g during the day on average). The ratio between water and food intake was significantly higher at 29°C (8·1 v. 4·2 l/kg on average between 18 and 27°C). Standing activity averaged 124 min/day with no significant difference between temperatures.

Pig studies on non-starch polysaccharides (NSPs) have mainly focused on finishing and breeding animals because their digestive capacity and ability to ferment fibre are considered greater than piglets. In this study, growth and nutrient digestibility, with particular reference to NSP constituent monomers, were evaluated in piglets offered contrasting sources of NSPs. The potential for enhancing growth performance and digestibility with exogenous food enzymes (xylanase, amylase, pectinase and beta-glucanase) was investigated. A total of 240 piglets weaned at 28 days of age, in groups of six, were allocated to six treatments in a 3×2 factorial design, diet type (W, B and SBP) by enzyme supplementation (–v. +). Diet W was wheat based and formulated to supply 14 MJ digestible energy (DE) per kg. In diets B and SBP, DE was reduced to 13·25 MJ/kg by replacing wheat with barley (708 g/kg) or with 185 g/kg dried unmolassed sugar beet pulp. Growth was monitored over 4 weeks. Digestibility of diets B–, B+, SBP– and SBP+ was evaluated in 16 piglets, in groups of four, using a 4×4 Latin-square design. In the growth study, mean initial and final piglet weights were 8·1 (s.e. 0·09) and 18·0 (s.e. 0·21) kg. Piglet health remained satisfactory and food intake averaged 523 (s.e. 6·7) g/day. There were no consistent and significant effects of diet type on food intake, live-weight gain or food conversion, except in week 1 when gain on diet W was higher than on diets B and SBP, 191 v. 150 v. 125 g/day, respectively (s.e.d. 20·0, P < 0·05). Enzyme supplements enhanced the conversion of food to gain over 4 weeks (1·56 v. 1·50:1, s.e.d. 0·030, P < 0·05). Piglets given diet SBP produced faeces with a lower dry-matter content (181 v. 246 g/kg, s.e.d. 10·8, P < 0·001) but with no visual evidence of a nutritionally induced diarrhoea. There were no significant differences in apparent faecal digestibility coefficients (AFDC) for dry matter, crude protein and gross energy between diets B and SBP. AFDC for soluble, insoluble and total NSP constituent monomers were higher (P < 0·001) in diet SBP. Soluble uronic acids were the most readily digested NSP constituents in diet SBP, showing a mean AFDC of 0·96 (s.e. 0·005). Apparent faecal digestibility was not an appropriate indicator for supplementary enzyme activity in the intact digestive tract of piglets given diets rich in fermentable NSPs. Piglets given the diets supplemented with enzymes excreted increased concentrations of urinary pentoses, especially arabinose (0·113 v. 0·136 mg/ml, s.e.d. 0·0107, P < 0·05). Urinary arabinose and xylose concentrations were also increased (V < 0·001) with feeding SBP, indicating that some of the microbially released NSP sugars escaped fermentation and were directly absorbed. In conclusion, piglets were able to use simple diets, containing high and contrasting sources of NSPs to support satisfactory rates of live-weight gain. Supplementation with NSP degrading enzymes enhanced the conversion of food to live-weight gain. Urinary NSP derived sugars provided indirect evidence of NSP hydrolysis by supplementary enzymes and gut microbes.

Testicular tissue was studied in domesticated yak and in wild yak x domesticated yak (F1 and F2) bulls at 6, 12, 18 and 24 months of age by stereology for quantitative histology and by comparative studies on the lactate dehydrogenase (LDH) isoenzyme spectrum, LDH activity and the percentage content of LDH isoenzymes in testes. The results indicated that all three types of yak were similar in both the characteristics of ultrastructure of testicular tissue and the degree of germ cell development. The process of spermatоgenesis was initiated and sperm were produced for the first time at the age of 12 months in all three yak types. All yak types exhibited similar age-related increases in weight of testes, volume density of both the seminiferous tubules and seminiferous epithelium and height of seminiferous epithelium but all these indexes were slightly affected by season. The number of LDH isoenzyme bands after electrophoresis varied with age as follows: four bands were present at 6 months of age, five bands at 12 and 18 months and six bands at 24 months of age. The sixth band was LDH-x, which appeared between the LDH4 and LDH5 band. These results indicated that yak bulls reach sexual maturity at 24 months of age and that puberty is not affected by infusion of wild strains.

The effects of work stress and dietary supplementation on ovarian activity were determined in 16 multiparous Mashona cows in Sanyati Communal Area, which lies in a semi-arid environment of Zimbabwe. The cows were assigned to one of four treatments: supplemented working (SW), supplemented non-working (SNW), non-supplemented working (NSW) and non-supplemented non-working (NSNW) cows in a 2 × 2 factorial treatment arrangement with two dietary and two work levels. Cows in the SW and NSW groups pulled a cart with a 200-1 water drum for 18 km (9 km with drum empty, 9 km with drum full) every day for 5 days/week for a total of 12 weeks.

Rectal temperatures were recorded at specific points along the route to and from the river where the water was obtained. Blood samples were collected by jugular venipuncture once a week, before working, for the determination of plasma glucose and non-esterified fatty acids (NEFA). In addition, blood samples were collected once every 3 days for the determination of progesterone concentration. There were no differences (P > 0⋅05) in the rectal temperatures between SW and NSW cows. Cows in the NSW group had the highest decrease in glucose levels and also showed marked increases in NEFA concentrations. The incidence of ovarian activity was similar between SNW and SW cows (P > 0⋅05). The incidence of ovarian activity was least in NSW cows. We conclude that nutritional stress was more important in suppressing ovarian activity than work stress and that dietary supplementation can reduce the negative effects of draught on ovarian activity.

Two silages were made from a regrowth of perennial ryegr ass following a 24-h wilt using either 2·5 l/t (LF) or 5·5 l/t (HF) of Add Safe (an aqueous solution of ammonium tetraformate, Trouw Nutrition, Cheshire, UK). Composition of silages LF and HF respectively were for dry matter (DM, g/kg) 205, 217; crude protein (g/kg DM) 106, 104; digestible organic matter (g/kg DM) 665, 692, pH 3·8, 3·9; lactic acid (g/kg DM) 103, 84; neutralizing value (meq/kg DM) 1051, 892; acetic acid (g/kg DM) 18·4, 14·0. Experiment A measured the intakes of the two silages using 12 Scottish Blackface wether lambs (mean live weight 25 kg) using a cross-over design with periods of 21 days. Intakes (g DM per day) were significantly greater (P < 0·05) for silage HF (329) than for LF (268). Experiment B measured the voluntary intakes of dried silage residues following juice extraction using the same protocol as for experiment A, except that only six lambs were used. There were no significant differences in composition or intake (P > 0·05) of the dried residues from the two silages. Experiment C used a 5 × 5 Latin-square design to measure the effects on voluntary intake of adding juices from the two silages to unmolassed sugar-beet nuts (SBN) pre-feeding or administered directly into the rumen in two discrete doses per day. Sheep on treatments LED and HFD received juices added to SBN (1·5 l/kg) and water added into the rumen in equal volume to the juice consumed with the previous day’s SBN. Treatments LFR and HFR received water added to the SBN (1·5 l/kg) and juice into the rumen in equal volume to the water consumed with the previous day’s SBN. The control treatment (W) was water added both to the SBN and into the rumen. Total mean daily intakes (g/day) were 1930,1954,1296, 2034 and 1703 (s.e.d. 179) for treatments LED, HFD, LFR, HFR and W respectively. Treatment LFR gave significantly lower mean daily intakes (P < 0·05) than all other treatments. Values for pH, volatile fatty acids and ammonia in the rumen fluid were not significantly affected by treatment (P > 0·05). Differences in voluntary intake for the two silages made from the same crop using different ensilage methods were attributed to differences in the silage liquid and volatile phases and not to the non-volatile solid phase. The effects of juice composition on intake were greater when added directly to the rumen than when added to the diet suggesting that effects on taste or smell were relatively unimportant.