Two experiments were made to study the effects of a mist or large-droplet water spray for different lengths of time, on pig behaviour in lairage prior to slaughter and on subsequent carcass Quality. Water spraying caused more pigs to stand, chew the pen walls and root around the pen floor compared with unsprayed controls, and they also tended to fight more. The sprayed pigs produced meat of superior quality in terms of m. longissimus dorsi rate of acidification and colour. It is suggested that these benefits were due to the effects of evaporative cooling and increased water intake.

Two pig breeds, one improved (Cotswold Fl hybrid Large White × Landrace pigs = LWX) and the other unimproved (Chinese Meishan pigs = CM) were used to test the proposition that the genotype of the pig has an effect on the selection of a diet from two foods that differ in their crude protein content. From 21 to 34 kg live weight, the pigs were given access to either one of three foods or a choice of two foods with similar digestible energy concentration (16 MJ digestible energy per kg) but a different crude protein (CP) concentration. This resulted in four dietary treatments: (i) free and continuous access to low (L) crude protein food alone (130 g CP per kg, no. = 4 of each breed); (ii) free and continous access to high (H) crude protein food alone (252 g CP per kg, no. - 4 of each breed); (Hi) free and continuous access to moderate (M) crude protein food alone (206 g CP per kg, no. = 4 of each breed) and (iv) free and continuous access to both foods L and H as a choice (no. = 6 of each breed). On all treatments the LWX performed significantly better than the CM pigs in terms of live-weight gain and food conversion efficiency (P < 0·001). The LWX and CM pigs given access to a single food contained the same amounts of protein in their bodies at 34 kg live weight, but the CM pigs had a considerably higher lipid (P < 0·001) and a lower water content (P < 0·001). When given a choice, the LWX pigs selected a significantly higher proportion of foodH(521 v. 226 (s.e.d. 49) g food H per kg for LWX and CM respectively) and therefore, a higher CP content in their diet (194 v. 144 (s.e.d. 5·4) g CP per kg respectively) than the CM pigs. The performance of pigs given a choice between two foods, in terms of live weight and rate of protein gain, was comparable with the best performance achieved on a single food (M) for the LWX, and better than the best performance on a single food (L) for the CM pigs. Thus, when given a choice between an appropriate pair of foods that differ in their crude protein content, pigs are able to select a diet that meets their requirements and allows them to express the growth characteristics typical for their breed (genotype).

In an experiment of factorial design, female rabbits were given four diets, containing 13·0, 11·4, 10·4 and 9·7 kJ digestible energy (DE) per g and subjected to two remating intervals (R) of 1 to 2 days (intensive) or 9 days (semi-intensive) from parturition. The experiment lasted for 2 years during which 352 does produced a total of 1254 litters. The only major differences due to diet were that the diet with the highest energy concentration, and which contained 35 g/kg added fat, promoted a significantly higher energy intake in lactation (111 v. an average of 94 MJ DE) than the other diets, and thereby increased litter weight at weaning at 28 days (3·48 v. 2·99 kg). Diet and R showed no major interactive effects. The intensive treatment significantly reduced parturition interval (46 v. 52 days) and increased the output of weaned rabbits per doe per year (35 v. 29). As actual R was more variable than the theoretical R imposed by the treatments, further analyses were made by dividing the does into four groups according to the actual R. In these analyses, the effects of R on current and subsequent lactation performance were assessed separately. The main difference between the groups was that litter size increased significantly with R (e.g. litter size at birth in subsequent parities was 8·0, 9·2, 9·7 and 9·0 for mean intervals of 2, 10, 16 and 37 days). However, the same pattern of differences occurred in the current parity, indicating that it was litter size that affected R, rather than the reverse (i.e. does with small litters conceived earlier than those with larger litters).

The apparent and true amino acid (AA) digestibility from soya-bean meal (SBM), vetch meal (VM), field pea meal (FPM) and bitter vetch meal (BVM) were determined in the lower ileum of growing chickens force-fed on semisynthetic diets (120 g crude protein and 13·1 MJ metabolizable energy per kg dry matter) based on each meal as the sole source of protein. The average apparent and true digestibility values were 0·82, 0·73, 0·76 and 0·60 and 0·90, 0·91, 0·87 and 0·74 for diets SBM, VM, FPM and BVM, respectively. Marked differences in AA digestibility among diets were found. The apparent digestibility of methionine, the most limiting essential AA in poultry diets, was significantly higher in diet SBM than in diets FPM and BVM (P < 0·05). It is concluded that the seeds of vetch and field pea may be suitable for inclusion in poultry diets as partial substitutes for soya bean. The use of bitter vetch is not recommended.

Effects of alternative pen rearing system, stocking density, breed-type and their interactions on post-weaning rabbit performance were investigated in a replicated experiment. Californian purebred and terminal crossbred weanlings (no. = 502) were randomized amongst four pen treatments: CSD = conventional wire pen (61 × 76 × 46 cm) stocked with five rabbits; PSD = iron framed, wire-fitted, pen (76 × 244 × 46 cm) stocked with 20 rabbits; PDD = pen stocked with 40 rabbits, and PTD = pen stocked with 60 rabbits. Pen traits measured were average daily food intake (Fl), food efficiency (FE), survival rate (SR), and final weight uniformity (CV). Individual traits were initial (IW) and final (FW) weights and average daily gain (ADG) over 6 weeks.

In CSD v. PSD pen trait comparisons, FI was increased (P < 0·05), and numerically poorer FE and greater CV were detected (P > 0·05) in CSD; however, SR means were similar. Non-significant differences were observed in the PSD v. (PDD + PTD)/2 contrast (P > 0·05). For PDD v. PTD, pen FE was numerically better in the former but CV was greater (P > 0·05). Individual FW and ADG were increased (P < 0·05) in PSD v. (PDD + PTD)/2 groups; no other significant contrast differences were observed. Breed-type (B) × pen treatment (P) interaction was not significant (P > 0·05) for IW, ADG and FW; and individual sire/B × P interaction accounted for proportionately less than 0·05 of the total random variation. These results suggest the commercial potential of large pen rearing of rabbits.

Twenty-two weanling foals, about 7 months (215 days) old, were allotted to two groups. One group received high-quality protein (HP; milk powder) and the other received poor-quality protein (PP; barley protein). In addition, six foals in each group were injected intramuscularly (1 mg/kg body weight) with an anabolic steroid (Nandrolon lauras, Laurabolin vet®) at intervals of 3 weeks from weaning to 12 months (362 days) of age. Skeletal and muscular measurements from foals were also made at intervals of 3 weeks. Closure of the right distal growth plate was assessed radiographically in 13 colts in their 2nd and 3rd years of life. Blood samples were taken to investigate the blood chemistry. The HP-group foals gained weight faster from weaning to 12 months of age and were heavier at the age of 12 months than the PP-group foals. The growth of longissimus dorsi muscle and cannon bone circumference were also significantly greater in the HP-group foals. The high-quality dietary protein supplement also increased serum amino acid concentrations and haemoglobin and packed cell volume values. The foals treated with the anabolic steroid increased in body length more slowly from weaning to 12 months of age than the untreated foals. Growth plates closed about 1·5 months later in the horses treated with anabolic steroid than in the untreated horses. Weanling foals seem to require a protein supplement rich in lysine for their optimal growth. More than 31 g/day (0·46 g/MJ metabolizable energy) lysine can be recommended up to 10 months of age.

Straw-Flow is a novel housing system for growing pigs which simplifies the handling of bedding and manure by allowing pigs to take unchopped straw from dispensers. Three groups of 50, 50 and 60 Large-White × Landrace pigs were housed in Straw-Flow pens from 5 to 90 kg. They were supplied daily with 50 to 100 g unchopped straw per pig and given food ad libitum. From 30 to 90 kg, mean growth rate was 863 g/day and food conversion ratio was 2·56 kg food per kg growth. The pigs' behaviour was divided approximately into: 0·820 lying, 0·100 active, 0·075 feeding and 0·005 drinking (on a proportional basis). There were no differences (P > 0·05) between groups or different weights for any of the behaviour categories. The pigs were less active before noon than after noon (P < 0·05). The daily number of visits to the drinker between weights 5 and 25 kg fell from 23·7 to 11·0 (P < 0·05). A single drinker, of new design, appeared to be adequate for a group of 50 to 60 pigs.

A proline-free, chemically defined amino acid basal diet was compared with this same diet fortified with 4g L-proline per kg when given to 5-kg pigs. During a 28-day feeding period, daily gain, food intake, and gain: food ratio of pigs given the proline-free diet were not different (P > 0·05) from those of pigs given the proline-supplemented diet. Young pigs can apparently synthesize adequate quantities of proline endogenously to meet their needs for both growth and maintenance.

The effect of level of barley feeding (200, 400 or 600 g fresh matter per ewe per day) on the change in body condition, between weaning and mating, of ewes offered barley straw treated with ammonia was examined in experiment 1. In experiment 2, a 2 × 2 factorial design was used with two levels of restriction of metabolizable energy in lactation (proportionately 0·85 and 0·70 of the requirements) followed by two levels of feeding of barley (250 or 500 g) in the main experimental period. In experiment 1 the intake of straw was significantly lower when 600 glday was offered, and ewes given 200 g/day barky had significantly lower gain in live weight and body condition score. In experiment 2 the level of energy intake in lactation did not affect the intakes of straw, but the current level of barley feeding did.

Females of four strains of commercial turkeys, including one large strain with a characteristically high rate of oviducal prolapse, were given food either ad libitum or controlled to reach proportionately 0·8 or 0·6 of the body weight of birds fed ad libitum at 24 weeks of age. Two pens of five turkeys from each treatment were photostimulated at 24 and 30 weeks of age. Each turkey was autopsied after it had laid its first egg. The relationships between egg weight and body weight, and between the weight of abdominal fat, diameter of the vent and distance between the pubic bones and egg weight were studied by regression analysis. Egg weight was a function of body weight raised to the power 0·29 which was significantly different from the allometric relationship for Galliform species of 0·64. There was no evidence that differences existed in the quantity of abdominal fat which could impede oviposition and contribute to oviducal prolapse. There were strain differences in the diameter of the vent and distance between the pubic bones in relation to egg weight but the smallest and largest strains were similar. It was concluded that artificial selection had changed the species relationship between egg weight and body mass and that the susceptibility to oviducal prolapse in sire line turkeys was probably physiological in origin.

Two experiments were carried out from April to September 1990 at Zaragoza, Spain. Fifty-three Rasa Aragonesa (RA) ewes, weaned in April, were studied in experiment 1, whilst 33 Salz (Sz) ewes, weaned in June, were studied in experiment 2. From weaning onwards, the animals were allocated to two groups receiving two planes of nutrition: high (H) and low (L). Mean time between weaning and the first detected oestrus was 113 (s.e. 2·7) and 52 (s.e. 3·0) days for RA and Sz ewes, without any significant effect of the plane of nutrition. Ewes of the H group showed a constantly higher ovulation rate than those of the L group with a significant effect of the plane of nutrition in the second fortnight of August (P < 0·05) and of September (P < 0·001) in RA ewes (1·68 v. 1·29 and 1·89 v. 1·38 corpora lutea for H and L groups, respectively) and in September (P < 0·01) in Sz ewes (2·53 v. 2·00 corpora lutea for H and L groups).

In conclusion, a slightly higher plane of nutrition after weaning in these sheep breeds, lambing in spring, cannot advance either the reproductive resumption or increase the ovulation rate of the first cycle. The high plane of nutrition after weaning exerts a significant effect on the ovulation rate in the medium term, in the early breeding season.

Ten Large White × Landrace boars at an initial live weight of 43 kg were given free access to two isoenergetic foods with 119 (L) and 222 (H) g crude protein (CP) per kg food as a choice, for 54 days. Six more similar boars were given access to food H only. The diet selected by the choice-fed pigs (measured as the proportion of food H per kg total food intake) changed systematically with time; the CP content of the selected diet fell from 193 in the first 7 days to 146 g CP per kg food in the last 7 days. The performance of the choicefed pigs, over the 54-day period, was as good as that of those given food H only: live-weight gain was 1101 v. 1069 g/day and food conversion efficiency 0·380 v. 0·374 g gain per g food respectively. However, the choice-feeding system allowed boars to reduce the protein content of their diet as they grew. It is suggested that it might be possible to give pigs a choice between two appropriate foods during the whole growing-fattening period instead of frequently changing the composition for their single food in order to try to meet their requirements.

Thirty-two Blackface female mature sheep weighing 45 kg on average were blocked by weight and randomly allocated 60 days before slaughter to be untreated controls (C) or subcutaneously implanted with 20 (TA1), 40 (TA2) or 60 (TA3) mg trenbolone acetate (TBA). Samples of blood were collected throughout the study and post-mortem samples of selected body tissues were analysed residues.

Concentrations in blood of 17β-hydroxy-trenbolone (TBOH) peaked within 1 to 2 weeks of implantation and declined thereafter. Concentrations in blood of oestradiol-17β (OE) were elevated and generally increased with increasing dose levels of TBA. The highest concentrations of solvent extractable residues (TBOH for group TA3) ranged from 613 ng/kg in kidney to 130 ng/kg for rib muscle. Trenbolone-17β- glucuronide was detected in liver and kidney at maximum concentrations of 157 ng/kg and 94 ng/kg respectively. Implantation with TBA had no effect on concentrations of OE in any of the post-mortem tissues examined.

Zeolite, cellulose acetate phthalate (CAP) and maize starch were used as the coating materials for encapsulating pancreatic protease, which was proposed as an additive to enhance the food efficiency and growth rate of weanling pigs. In this study, microcapsules were formed by the process of coacervation in liquid paraffin media, where the deposition time was in the range of 20 to 60 min, and the concentrations of CAP, zeolite and maize starch were 20, 40 and 120 g/kg respectively. Hardening by n-hexane was achieved with 15 min of stirring. Microcapsules generated by this method were 20 to 30 mesh in diameter. They were stable for at least 3 h in simulated gastric conditions (pH 3·97), but disintegrated rapidly under simulated intestinal conditions (pH 6·82).

The relationships between body composition, live weight (LW) and subjective condition score (CS) were examined in an experiment in which 54, second to fourth parity, lactating autumn-calving Holstein-Friesian dairy cows were slaughtered at 0, 2, 5, 8, 11, 14, 19, 24 and 29 weeks post partum. Multiple regression analyses showed the weight of fat and the quantity of energy within the body were significantly correlated with both LW and CS. The weight of crude protein showed a linear correlation with LW. These results are discussed and compared with previously published investigations with non-lactating dairy cows.

The effect on sow reproductive performance of including 100 g white-flowered peas (Pisum sativum hortense, cv. Vreta and Lotta) per kg, replacing barley, wheat and soya-bean meal in gestation and lactation diets, was studied over four parities using 24 pairs of crossbred littermate sows. Net sow weight gains and changes in backfat thickness over the complete reproductive cycle were similar for both treatments. Piglet live-weight gains and mean litter size at birth were not influenced by treatment, although litter size at weaning was 0·5 pigs higher (P > 0·05) for the control sows, due to higher post-natal mortality rate in the litters from the sows given the pea diets. It can be concluded that inclusion of white-flowered peas at a rate of 100 g/kg had no adverse effect on reproductive performance, with the exception of slightly higher post-natal piglet mortality.