The study was conducted to test the hypotheses that sustained restriction of food to maintain constant body weight of market-ready pigs, hereafter terminal maintenance (TM), would (1) decrease the size of gastrointestinal and other visceral organs, (2) increase dressing proportion, and (3) increase lean and decrease fat content and improve the lean: fat ratio of carcass. Forty-eight crossbred castrated male pigs (initial body weight, 23·5 kg) were randomly assigned to eight treatment groups (six pigs per group; one pig per pen). Three comparison groups were included. The ad libitum control group (AL) was slaughtered at the target weight, 105 kg. One group was continuously restricted (CR) to 0·8 of the intake by AL and slaughtered at the target weight. The terminally restricted (TR) group was given food ad libitum to 1·1 times the target weight; then food was restricted to effect weight loss to the target weight before slaughter. Five TM groups were given food ad libitum to the target weight; then TM was administered for various periods (7, 14, 21, 28 and 42 days) before slaughter. CR either had no effect or caused enlargement of visceral organs compared with AL. TR caused reduction of viscera, especially of abdominal-digestive organs. TM caused reduction of most viscera organs (0·001 < P < 0·05). Regression analyses indicated that most abdominal organs were reduced 50 to 70 g/kg per 10 days of terminal maintenance. TM and TR also increased carcass weight (P < 0·05). Catabolism associated with reduction of viscera organs may provide nitrogenous substrates to support the continued lean accretion observed during terminal maintenance. The reduced viscera and increased carcass weight combined resulted in increased dressing proportion (P = 0·06). Regression analyses (weight v. TM-days) showed that lean mass increased (71 g/day; P < 0·05) and fat mass decreased (−52 g/day; P < 0·01). Weight of bone and belly did not change. Differential lean gain, lean gain minus fat gain, during TM occurred at a rate of about 120 g/day.

Six male lambs from each of Najdi, Azvassi and Hejazi breeds of sheep were given the same diet and serially slaughtered at 3, 6, 9 and 12 months of age. Slaughter and growth data including estimates of body maturity were collected. Allometeric growth coefficients were obtained for body components and breed differences in the proportions of the components at the same degree of body maturity or groivth rate were computed.

The live weight of lambs slaughtered at 6, 9 and 12 months of age differed between the breeds. Awassi lambs were less mature than Najdi or Hejazi lambs at slaughter. Hejazi lambs grew (relative to their mature size) faster than lambs of the other two breeds. The allometric regression coefficients of body components were similar1 in the breeds except those of the head, skin and genital organs.

Body composition of the breeds was reasonably similar at the same degree of body maturity or growth rate except skin and feet proportions were higher in Awassi and Najdi lambs, respectively, than in the other two breeds. Thus the three breeds conform to the scaling rules relating growth characteristics to mature size.

Although it is known that growth hormone (GH) influences body composition in ruminants, the precise role of the pattern of GH secretion is not known. We have studied the pulsatile release of GH and insulin-like growth factor 1 (IGF 1) secretion in the male progeny of rams from lines selected either for {fat genotype) or against (lean genotype) fatness. Seventy-two lambs (36 each of the fat and lean genotype) were kept on high-quality pasture and randomly allocated within genotype to treatment at 2, 3, 3·5, 4,5 or 6 months of age. The procedure, which was identical for each sampling period, was to sample each lamb through a jugular cannula every 10 min for 6 h, and then, following an overnight fast, to slaughter and analyse the carcass for fat. All blood samples were analysed for GH and samples taken each hour for total plasma IGF 1. The GH data were further analysed with the pulse detection routine PULSAR. Carcass fatness, adjusted for cold carcass weight, was greater for fat genotype animals than for the lean genotype. GH was pulsatile in all profiles but the pattern differed with time and genotype. Mean GH and pulse amplitude decreased with time but did not differ between genotype, although the lean genotype had higher mean GH at five of the six sampling periods. In contrast, GH pulse frequency and IGF 1 were significantly higher for the fat compared with the lean genotype lambs. GH mean and amplitude correlated negatively with carcass fatness in both genotypes and GH pulse frequency and total IGF 1 correlated positively with fatness for the lean genotype only. When carcass weight and genotype were fitted to these relationships, GH mean and total IGF 1 were found to have independent negative and positive effects, respectively, on carcass fatness. Because GH mean had a separate effect on fatness independent of genotype or cold carcass weight, it is likely that GH secretion influences composition by the same basic mechanism in both genotypes. However, although the slopes of these relationships did not differ significantly between the genotypes, the intercepts were significantly different indicating that over and above the basic mechanism, at any level of GH, the lean genotype lambs were leaner than the fat genotype lambs. This may indicate a measure ofGH resistance in the fat genotype lambs.

Plasma oxytocin was measured in 11 multiparous sows for 13 h after the start of parturition to confirm the existence of early milk ejections and determine whether they were associated with pulsatile oxytocin release. The relationship between oxytocin concentrations and duration of parturition was also analysed. Oxytocin was released in pulses during and after parturition and mean concentrations reached maximum 2 to 4 h after the first birth. Discrete milk ejections occurred during parturition but only 42% of these were associated with oxytocin peaks before 4 h post partum. After this more than 80% of milk ejections occurred with oxytocin peaks. Sow grunting increased during milk ejections and peak grunt rate increased after parturition. Oxytocin peaks without milk ejections did not lead to an increased rate of grunting. Sows with prolonged parturition had lower basal and peak oxytocin concentrations. During the first 4 h only half of the piglets were born during an oxytocin peak. Discrete milk ejections with oxytocin peaks can occur before parturition is completed. However, during the first 4 h post partum, basal oxytocin concentrations may be high enough for milk ejection to occur without further oxytocin secretion. Both milk ejection and oxytocin release are necessary for the sow to increase grunt rate. Low oxytocin concentration is associated with prolonged parturition.

Housing soivs in large groups is increasing in popularity but some group-housing systems may compromise subsequent reproductive performance. An experiment was designed to test this hypothesis using multiparous sows weaned at 21 ±2 days. Two treatments were studied: a stable group of 12 sows and a dynamic group of 18 sows. Both treatments had similar space allowances in the lying area (1·24 m2 per sow). Sows were allocated to treatment within 1 week of service and remained on treatment until after day 40 of pregnancy. Each stable treatment group remained unchanged, whereas sows were replaced weekly in the dynamic treatment. Sows were fed using a single electronic feeder for each pen. All sows were treated similarly for the rest of pregnancy. Eighty and 120 sows from the stable and dynamic treatments respectively completed pregnancy. Five second parity sows from the dynamic treatment were removed having suffered from aggression. The farrowing rate was 0·78 and 0·85 for stable and dynamic treatment sows respectively. The stable treatment sows had larger litters and a higher proportion of litters having 10 or more total piglets born (P < 0·01). The stable treatment showed a significantly heavier (P < 0·05) litter weight for total pigs born (16·9 v. 14.6 (s.e.d. 0·57) kg per litter). The parities were uneven so the data must be treated with caution. However, the results indicate that the present advice, that soivs should be housed in stable groups for the first 4 weeks of pregnancy, should remain unchanged.

Most livestock are transported at least once during their lifetime. Environmental conditions inside the transporter are critically dependent on many factors which can be controlled by well designed and carefully operated ventilation systems. Heat, moisture and carbon dioxide production of cattle, pigs and sheep are fitted to simple models as bases for ventilation design criteria. These assume that the animals are not well fed immediately before or during transport and that maintenance metabolic heat production applies. Interactions between temperature and humidity during transport are important at temperatures above 24°C.

Ventilation slots along the sides of transporters can be occluded by the bodies of the stock themselves. Relevant dimensions of pigs, cattle and sheep related to body weight are provided as additional design parameters. Stocking density interacts critically with other aspects of transport and normally recommended values are shown to be inconsistent. Space requirements should be based on species and body weight, provided that the ventilation capacity is satisfactory.

Proposed European regulations on the transport of livestock provide general guidelines for the provision of ventilation, but no means of achieving these requirements. This paper draws together detailed criteria for establishing acceptable space, thermal, psychrometric and gaseous conditions on transporters for pigs, cattle and sheep. Application of these quantitative criteria will assist shippers and regulating authorities in providing more suitable environmental conditions than are frequently achieved at present.

Using a completely randomized design, 72 individually penned pigs, comprising two genotypes (Masterbreeders Mastergilt × Large White and Sovereign × Large white progeny) with equal numbers of boars and gilts, were given food ad libitum from 25 to 60 kg live weight. From 60 to 120 kg one-third of the pigs continued to be given food ad libitum whilst the remainder were given one of two levels of restriction (0.85 and 0.925 of maintenance energy × 3.5). Diets were calculated to provide 13.8 and 13.0 MJ digestible energy (DE) per kg air-dry weight for growing and finishing phases respectively. Ultrasonic measurements of backfat at the P2 site were made at 10 kg intervals from 60 to 120 kg live weight and carcass measurements taken at slaughter. Complete dissection of ham joints was carried out. Predicted ad libitum intakes were based on established equations but daily intakes were much lower than these values and no treatment provided food restriction compared with them. Daily DE intakes (mean of both genotypes) obtained at 25, 60, 90 and 120 kg live weight were 204, 30.7, 36.2, and 414 MJ (i.e. 3.5, 3.1, 2.9 and 2.7 × maintenance). During the growing (25 to 60 kg live weight) and finishing (60 to 120 kg live weight) periods boars grew faster (P < 0.01 and P < 0.001) than gilts (881 v. 827 and 944 v. 806 g/day) with corresponding improvements in food conversion ratio (P < 0.001). Boars had lower killing-out proportions (0.787 v. 0.801; P < 0.001). Mean P2 values for boars and gilts were 13.2 and 13.9 mm respectively (excluding skin). Greater quantities of muscle were found in the hams of boars than gilts (662.7 v. 642.3 kg; P < 0.05) but no difference between the sexes for ‘eye muscle’ area was observed (43.3 v. 45.0 cm2). Results show the apparent potential of modern hybrids to achieve good growth rates despite moderate food intakes and their ability, even when given continuous access to food, to produce very lean carcasses at relatively heavy slaughter weights.

The effects of moderate indoor exercise (running/walking up to 735 m, 5 days/week) on performance, muscle enzyme activities, carcass traits and technological meat quality were studied in 20 crossbred slaughter pigs during the fattening period. Non-exercised pigs were kept only in their pens and consisted of littermates (no. = 20). Blood samples for lactate analysis and muscle samples from m. longissimus dorsi (LD) and m. biceps femoris (BF) for analyses of the activities of lactate dehydrogenase (LDH), citrate synthase (CS), 3-OH-acyl-CoA dehydrogenase and hexokinase were collected at exsanguination. The initial pH was measured approximately 1 min after exsanguination in LD and BF. The carcasses were partially cut and then the back and ham were dissected into individual muscles. Carcass length and presence of osteochondrosis were recorded. Technological meat quality parameters measured were: surface reflectance, water-holding capacity, intramuscular fat (IMF), crude protein, dry matter, ash content, shear force, ultimate pH, pigment content and extractability of muscle proteins.

In comparison with the non-exercised pigs, the exercised pigs had slightly shorter carcasses, paler meat and higher drip loss values in LD and, in BF, a lower proportion of IMF and dry matter and higher pigment content. The CS and LDH activities differed between LD and BF muscles, as also did many of the technological meat quality traits.

Four metabolism trials were conducted. Trials 1 and 2 (Tl, T2) investigated degree of saturation of fats (ratio of unsaturated to saturated fatty acids, U/S) on digestible energy (DE) content. Fats evaluated were rape oil (RO) and tallow (T) for Tl (U/S 15·67 and 0·97 respectively) and RO and palm oil (PO) for T2 (U/S 15·33 and 0·85 respectively). Three fats of intermediary U/S for each trial were produced by blending the two fats in proportions to give U/S of 3·18,2·08 and 1·49 in both trials. Trials 3 and 4 (T3, T4) investigated the effect of free fatty acid (FFA) content of fats on DE value. Fats were soya-bean oil (SO) and soya-bean acid oil (SAO) for T3 (FFA 6·2 and 626·0 g/kg respectively) and T and tallow acid oil (TAO) for T4 (FFA 44·3 and 818·2 g/kg fat respectively). Three fats of intermediary FFA for each trial were formed by blending the two fats in the ratios of 72:25, 50: 50 and 25: 75 in both trials. The FFA content of the blends were 161·2, 316·1 and 471·1 g/kg fat for T3 and 237·8, 431·3 and 624·7 g/kg fat for T4. All trials evaluated five fats by substitution, at 40, 80 and 120 g/kg into a basal diet, in a cross-over design, with 16 gilts of 25 kg initial live weight evaluating 16 diets over four time periods. Diets were offered for 10 days followed by a 5-day collection period using the marker to marker technique. Fat content of food and faeces, with methodology based on acid hydrolysis, allowed calculation of apparent digestible fat (AFD) of experimental diets. Analysis of variance gave effects of fats (P < 0·001 for Tl, T3 and T4 and P = 0·014 for T2), rates of inclusion (P < 0·001 for all trials), and fats × rates (P > 0·05, P > 0·05, P < 0·001, P < 0·01 for T1, T2, T3 and T4 respectively). Extrapolation of the function obtained by regressing AFD of diets (y) on rate of inclusion of fat (x) to × = 1000 generated values for the fats. The product of the coefficient of apparent fat digestibility of fats and their respective gross energies gave DE values for fats which were MJ/kg: T1 RO = 35·8 and T = 31·2; T2 RO = 36·7 and PO = 33·1; T3 SO = 374 and SAO = 32·8 and T4 T = 33·8 and TAO = 28·9. Data for fat blends intermediary between the two fats showed that DE improved exponentially as a function of U/S and that DE declined linearly with increasing FFA content.

Free amino acid (AA) levels in plasma, muscle and liver were measured in growing chickens given either high or low protein diets varying in quality. In experiment 1, they were force-fed once a day (09.00 h), for 4 days, at about 1·5 × M level, a nitrogen-free (NF) diet and then, on day 5, they were given either diet NF or isoenergetic (13·1 kj metabolizable energy (ME) per g dry matter (DM)) and isonitrogenous high protein diets (200 g crude protein (CP) per kg) based on casein (C), lupin (L), soya bean (SB), faba bean (FB), field pea (FP), vetch (V) or bitter vetch (B) as the sole source of protein. In experiment 2, chickens were force-fed twice a day (09.00 h and 18.00 h), for 3 days, at about 1·9 × M level, with four isoenergetic (13·1 k) ME per kg DM) and isonitrogenous low protein diets (120 g CP per kg) based on SB, FP, V or B as the sole source of protein. On days 5 (experiment 1) and 4 (experiment 2) samples of plasma, muscle and liver were taken for AA analysis over 3 to 4h after morning meal.

In general, within experiments, no significant differences in AA concentrations in plasma, muscle or liver among diets were found. However, there was a qualitative but not a quantitative agreement between the AA abundance in tissues and the AA rank of dietary protein. Moreover, when pooling data from experiments 1 and 2, significant regressions were found between the levels of threonine, aspartic acid, glutamic acid, glycine and proline in plasma, of lysine, alanine, glutamic acid, glycine and proline in muscle or that of proline in liver and the corresponding amounts ingested with the different diets. Under the conditions of these experiments, however, it was not possible to establish conclusively a direct relationship between the level of free amino acids in tissues and dietary protein quality.

The depressing effect of high rearing temperature (30°C) on body weights of heterozygous naked-neck broiler chickens was apparently less pronounced than in control broiler chickens but no effect of genotype, rearing temperature or interaction on abdominal fat pad content was found. Both genotype and rearing temperature affected plasma tri-iodothyronine but not growth hormone or insulin-like growth factor 1 levels in plasma. Rearing temperature of 20°C or 30°C had effect neither on the slope of the thermoregulatory heat production curves nor on the lower critical temperature in either genotypes except at 4 weeks of age.

The effect of exercise (walking 10.6 km/day and climbing 480 m/day) on intake of barley straw and body weight changes in 12 pregnant lactating suckler cows was investigated. Three groups of four cows received ad libitum barley straw and 4 kg per cow per day of different supplements. Neither exercise nor supplement had a significant effect on straw intake. Cows gained weight when not exercised, but lost weight during the exercise period. The experiment confirms previous findings that animals performing moderate work and given poor quality roughage, in the short term cannot increase daily intake to meet energy requirements and that intake may decrease when animals work.

In a dissection trial in The Netherlands two subpopulations were distinguished: gilts and castrated males. The sampling scheme, which emphasizes extreme values for the proportion of lean meat in the carcass, was followed for the two sexes separately, to ensure sufficient accuracy for a comparison between them. Significant differences between the prediction formulae for the lean meat proportion for the two sexes were found. Since it is not possible to use separate prediction formulae for the sexes in Dutch slaughterhouses, the formulae had to be combined into one overall prediction formula. In this paper it is shown how the separate prediction formulae for the sexes may be combined, utilizing additional data, not involving dissection, which were easily collected on the slaughterline, at little extra cost. The method can be extended to cover any number of subpopulations. Two objectives can be achieved at the same time: subpopulations may be compared accurately on the basis of a stratified sample and from the results of the comparison an efficient, unbiased, overall prediction formula may be distilled.

Commencing on day 100 ± 10 of lactation, 10 Italian Friesian cows averaging 32·6 kg milk per day were injected biweekly with recombinant bovine somatotropin (BST), while 10 other cows averaging 33-4 kg milk per day were injected with a placebo. Cows were offered ad libitum a total mixed diet throughout the lactation. The experiment lasted 16 weeks; milk samples were taken before and 16, 62 and 91 days after the commencement of BST injection. The objective was to determine the impact of biweekly injections of BST on the synthesis and proportion of milk fatty acids, particularly on cis and trans isomers and on fatty acids with an odd number of carbon atoms (C15 and C17). A decrease in the proportion of shortchain (C4 to C14) fatty acids (P < 0·001) and an increase in the proportion of long-chain (C16 to C20) fatty acids (P < 0·001) were observed in the first period of the treatment. With regard to cis and trans isomers, a considerable increase of the cis isomers (P < 0·001), particularly C18.1cis9 (oleic acid) was observed, while differences in trans isomers were not statistically significant. Concentrations of C15 (pentadecanoic acid) were not affected but heptadecanoic acid (C17) concentration showed a considerable increase (P < 0·01) but only in the sample taken after 16 days.

The possibility of using dietary variety to enhance food intake of ruminants was investigated with 36 Hereford steers. For 21 days, 18 animals were given a monotonous diet of either hay or silage, while 18 others were given a varied diet of hay and silage offered in succession, at either 12- or 24-h intervals. Dietary variety did not affect total food intake (P > 0·05). However, when offered both foods at the end of the trial, animals which had been restricted to hay showed a proportional increase of 0·15 in their acceptance of silage (P < 0·05), whereas animals restricted to silage showed an increase of 0·49 in their acceptance of hay (P < 0·05)

Twenty-five primiparous cows in mid lactation were used in a 2 × 2 Latin-square design experiment. During each 3-week period, cows were offered a diet composed either of grass silage (8.3 kg dry matter (DM) per day) or hay (10.5 kg DM per day). Each diet was supplemented with a mixture of barley, soya-bean meal and urea in proportions calculated to keep the overall rations isocaloric and isonitrogenous. Cows offered grass silage produced more milk (+1.7 kg/day, P<0.01) with less fat and protein (−1.3 g/kg and −0.8 g/kg, respectively, P < 0.01) than those offered hay. All animals gained weight, but they gained more with the hay diet than with the grass silage diet. The rheological parameters of milk were similar in both groups. Rumen juice of cows offered hay had higher concentrations of acetic acid and slightly lower concentrations of propionic and butyric acid (P < 0.01) than cows offered grass silage.

Genetic and phenotypic parameters were estimated for farmed red deer on eight farms distributed throughout the United Kingdom. Genetic parameters were estimated using restricted maximum likelihood (REML) analysis. Heritabilities for date of calving were low on seven of the eight farms (< 0–05), while repeatabilities were low to moderate (0·06 to 0·37). Heritabilities of all weights tended to be moderate to high on most farms (0·31 to 0·49; 0·22 to 0·89; 0·33 to 0·48; 0·37 to 0·45 and 0·37 to 0·90 for birth weight, weaning weight, mid-winter weight, turn-out weight and other weights respectively). The exception was farm 8 for which heritability estimates were very low (<0·08). This is attributed to inbreeding effects on this farm. Phenotypic and genetic correlations between post-weaning traits tended to be high, indicating selection at any stage of growth will be expected to lead to an increased growth at the other stages. Animals whose bloodlines originated in the forests of Eastern Europe (Yugoslavia, Hungary, Germany) were heavier at all stages indicating their usefulness as ‘terminal sire’ breeds. Hinds of mainland ‘European’ parentage also tended to calve earlier.

The definition of breeding objectives for farmed red deer in the United Kingdom (UK) was investigated. Options studied include the effects of discounting gene flow and the effect of altering variable costs/income (such as price of food or price received for sale animals). Three different herd structures were investigated. As the discount rate increased the importance of traits measured on the offspring also increased. Traits included in the economic breeding objective included number of calves weaned, carcass weights of stag calves and surplus hinds, hind calf live weight and food consumption for hinds and calves. The breeding objective derived does not include a measure of antler size, as antlers have little/no economic value in the UK market. Suggestions are made for further research.

Effects of dietary protein concentration on the amino acid composition of sow's milk was studied using 10 crossbred first-litter sows. At parturition, diets containing similar concentrations of digestible energy but with either 63 or 238 g crude protein per kg and 4.4 and 15.1 g lysine per kg respectively, were given through lactation (five sows per treatment). The ratios of other amino acids to lysine were in excess of those currently recommended for lactating sows. Dietary protein level significantly affected milk yield, gave higher milk protein output (P > 0.05) but was without significant effect on the proportions of amino acids in the milk.

A total of 1855 records were analysed using restricted maximum likelihood (REML) techniques to estimate heritabilities separately for males and females lambs on birth weight (BW), weaning weight (WW), 90-day weight (W90) and average daily gains birth to weaning (Cl) and weaning to 90 days (C2). An animal model including fixed effects of year × season, parity, litter size and rearing type; and random effects of direct genetic effect (h2D) and residual was applied. Estimates ofh2Dfor BWwere 048 (males) and 0·50 (females); for WW 0·35 (males) and 0·22 (females); for W90 0·21 (males) and 0·31 (females); for Cl 0·20 (males) and 0·25 (females); and for C2 0·18 (males) and 0·29 (females).