Parameters based on probabilities of gene origin were used to evaluate the genetic variability of four Austrian cattle breeds. Effective numbers of founders, ancestors and remaining founder genomes showed that all four populations investigated are rather small genetically. Effective numbers of remaining founder genomes were 94 for Simmental, 41 for Braunvieh (Brown Swiss), 32 for Pinzgauer and 21 for Grauvieh (Grey cattle, a small mountain breed). As the value of 94 for Simmental was rather large in comparison with estimates from other populations in previous studies, the effect of population structure was investigated. A cosine measure of similarity based on differences in individual founder contributions to different subpopulations was defined and used for analysis. Subpopulations defined by regions were clearly more distinct for Simmental than for Braunvieh. The size of the cosine values depended on the method of calculating founder contributions and was overestimated when choosing the method not accounting for drift and bottlenecks (effective number of founders).

Five ruminallyfistulatedAngus steers (360 (s.e. 15·4) kg) were givenfood to maintain body weight constant: maize silage (TO) at 0·6 kg dry matter (DM) per 100 kg body weight twice a day. After a 15-day adaptation period they were infused continuously (I) for 96 h, with a solution of NaH14CO3 at a rate of 7 to 8 micro Curies (μCi) per h. On the last 2 days of infusion 30 g (Tl) and 60 g (T2) urea, respectively, were placed in the rumen at the end of the morning meal. Spot samples of urine (250 ml) were taken before and 5 h after the morning meal and after at least 24 h of infusion. Thereafter, animals continued with TO for one additional week, in which they were prepared with catheters inserted in salivary ducts and infused for 48 h, as previously described. Eighteen pairs of spot samples of urine and saliva were takenfrom three of thefive steers (369 (s.e. 20·7) kg), over a period of 5 h, after at least 24 h infusion (six per animal). Rate of carbon dioxide (CO2) production was estimated as the ratio USA (specific activity of CO2)from which energy expenditure was calculated (22 kj/l CO2). Silage composition, in situ degradability and ruminal ammonia and pH were measured. In situ degradability in thefirst 6 h was 200 g/kg and ruminal ammonia was in the range of 20·6 to 39·6 mg/l. Ammonia increased rapidly to 394·2 (T1) and 673·9 mg/l (T2) 1 h after addition of urea into the rumen but in 6 h in situ degradability was unchanged. Ruminal ammonia decreased linearly at rates (mgll per h) of89·3 in Tl (R2 = 0·57, s.d. = 21·5) and 151·6 in T2 (R2 = 0·81, s.d. = 23·3). Animal energy expenditure rates were not affected (P > 0·05) by treatment (TO = 15·6, Tl = 15·6 and T2 = 15·8 kj/h per M075). There was no difference (P > 0·05) in CO2 production rate (mllh per kg M0·75) determined from the SA of CO2 from urine (604) or saliva (630) samples. It was concluded that the energy cost associated with detoxification of the excess of ruminal ammonia was of minor importance in terms of total animal energy expenditure and that estimations ofC02 ratesfromsamples ofurine or saliva are comparable.

A statistical analysis strategy for the detection of quantitative trait loci (QTLs) in half-sib populations is outlined. The initial exploratory analysis is a multiple regression of the trait score on a subset of markers to allow a rapid identification of possible chromosomal regions of interest. This is followed by multiple marker interval mapping with regression methods within and across families fitting one or two QTLs. Empirical thresholds are determined by experiment-wise permutation tests for different significance levels and empirical confidence intervals for the QTLs' positions are obtained by bootstrapping methods. For traits with evidence for a significant single-QTL effect, an approximate maximum likelihood analysis is performed to obtain estimates of QTL effect and the probability of the QTL genotype for each parent of a group of half-sibs. The strategy is demonstrated in an analysis of previously published data on chromosome 6 and five production traits from a granddaughter design in dairy cattle. The results confirm and extend evidence for QTLs affecting protein percentage. Informativeness of markers limited the possibility of mapping more than one QTL on the same linkage group.

The objective was to determine the effect of age and dietary protein content on post-partum oestrous and ovarian cyclicity in autumn-lambing ewes. Twenty-four multiparous (age 4·5 (s.e. 0·61) years) and 24 primiparous (age 1·5 years) ewes which lambed on 28 October (s.e. 0·2) and were rearing 2·0 and. 1·7 (s.e. 0·13) lambs, respectively, were equally allocated to two dietary treatments in a 2 × 2 factorial design. Diets comprised a d libitum hay supplemented with concentrate (12·5 MJ metabolizable energy per kg dry matter (DM) and either 210 or 140 g crude protein per kg DM), offered at a daily allowance of 1·2 kg per ewe from lambing to weaning (18 December) and 0·4 kg per ewe thereafter. Throughout the study (3 November to 24 May) ewes were group-housed in straw-bedded pens under natural photoperiod at 57°N and their live weights and body condition scores were assessed at 2-week intervals. A raddled vasectomized ram was continually present with each group and ewes marked by the ram were recorded thrice weekly. Blood samples were obtained thrice weekly for measurement of peripheral progesterone concentrations and ovulation rate was determined by laparoscopy during January and March. There was no significant effect of dietary protein content on any of the variables measured. For multiparous and primiparous ewes, mean live weights and body condition scores at lambing were 79·5 (s.e. 1·41) v. 58·4 (s.e. 1·54) kg (P < 0·001) and 2·5 (s.e. 0·05) v. 2·2 (s.e. 0·05) (P < 0·001) and daily live-weight losses over the suckling period were 153 (s.e. 19·3) v. 85 (s.e. 21·1) glday (P < 0·05). Intervals from parturition to first overt oestrus were 39 (s.e. 3·2) v. 33 (s.e. 2·3) days and to the onset of ovarian cyclicity were 29 (s.e. 4·9) v. 25 (s.e. 1·5) days. Durations of ovarian cyclicity were 133 (s.e. 27·1) and 110 (s.e. 5·7) days (P < 0·01) during which 7·6 (s.e. 0·32) and 6·5 (s.e. 0·34) (P < 0·05) ovarian cycles were recorded respectively. Fifteen ewes had initial short cycles (≤10 days), six had prolonged cycles (≥21 days) and 11 had extended inter-luteal phase intervals (≥8 days). All ewes had recent ovulations at the January laparoscopy but only 19 multiparous and nine primiparous ewes had ovulations in March. Mean ovulation rates were: January 2·2 (s.e. 0·14) and 1·4 (s.e. 0·13) (P < 0·001), and March 1·6 (s.e. 0·23) and 1·2 (s.e. 0·15) for multiparous and primiparous ewes, respectively. It is concluded that, for ewes lambing at their normal time of mating, (i) the strong seasonal drive for reproduction results in the resumption of oestrous and ovarian cyclicity during the early post-partum period; (ii) initial luteal phases may be of short or extended duration; (Hi) there is no effect of age or dietary protein content, within the range studied, on the onset of ovarian cyclicity; and (iv) multiparous ewes experience a greater number of ovarian cycles and achieve higher ovulation rates than primiparous ewes.

Increasing amounts of sewage sludge will be applied to agricultural land over the next 10 years as a result of the prohibition of its disposal to the sea. The addition of potentially toxic elements (PTEs) to the soil via sewage sludge is controlled by European legislation designed to limit the accumulation of PTEs in soil which could give rise to toxicity to plants or livestock. However the possibility exists that direct ingestion of sewage sludge and soil together with grazed herbage may result in accumulation of PTEs in body tissues. To assess the extent of accumulation of PTEs by direct ingestion of soil and sewage sludge 12 groups of housed weaned lambs were given diets ad libitum comprising dried grass (900 g/kg total diet dry matter (DM)) and three different soils (100 glkg total diet DM). Soil was replaced by dried digested sewage sludge at levels ofO (level 0), 75 (level 1), 150 (level 2) and 300 g/kg soil DM (level 3). Voluntary intake of DM was markedly depressed by the inclusion of sewage sludge in the diet (on average by 24 g DM per g sewage sludge DM addition). There was no effect of sewage sludge on diet apparent digestibility. Live-weight gain was depressed (P < 0·001) by the addition of sewage sludge to the diet from 236 glday (level 0) to 141 glday (level 3). Liver and kidney weights were also reduced (P < 0·01). The apparent availability coefficients for Cd, Pb and Cu increased with increasing level of sewage sludge in the diet fP < 0·05), as did their concentrations in the liver and kidney (P < 0·01). Concentrations of Cd and Pb in liver increased from <0·07 mg/kg DM and <0·40 mg/kg DM (level 0) respectively to 0·61 mg/kg DM and 4·60 mg/kg DM (level 3) respectively at the end of the trial. Similarly the concentrations of Cd and Pb in kidneys increased from 0·19 mg/kg DM and <0·56 mg/kg DM (level 0) respectively to 0·80 mg/kg DM and 7·10 mg/kg DM (level 3) respectively by the end of the trial. No increases were observed in concentrations of Cd or Pb in muscle tissue. The main effect of type of soil on concentrations of PTEs in body tissues was not significant The daily rate of accumulation ofPb in kidney ranged from 1·1 to 51·5 uglg daily tissue DM growth during the first 57 days of the experiment and from 0·33 to 6·78 /xg/g daily tissue DM growth between day 57 and day 112. A decrease in the second period was also observed for Cd, with accumulation in kidney ranging from 0·31 to 4·44 fig/g daily tissue DM growth during the first 57 days and from 0·21 to 1·44 /jg/g daily tissue DM growth between day 57 and 112. Concentrations of Pb in liver of lambs given the highest level of sludge approached the statutory limit set for human food. The results indicate that in relation to accumulation of PTEs in liver and kidney there would appear to be little margin of safety with respect to the current United Kingdom statutory limits for the concentrations of Cd and Pb in sludge-amended soils. Confirmation of these results is required in the grazing situation.

A model which was originally developed to derive the probability density of a calving distribution for beef cows under natural breeding has been modified to incorporate the effects of using oestrous synchronization at the beginning of the breeding period.

The model has been used to investigate five oestrous synchronization strategies over four herds, each with differing calving patterns: no synchronization; every cow in the herd is synchronized; every anoestrous cow is synchronized; every cow calving more than 20 days after the date of the planned start of calving is synchronized; every cow calving 30 days after the date of the planned start of calving is synchronized. Two of the herds previously had long calving periods and two previously had short, compact calving periods.

Model results showed that synchronization improved average herd calf live weight by 21 kg in the two herds with long prior calving periods but showed little effect in the two herds with compact prior calving periods. Synchronizing cows which calved more than 20 days after the start of calving in the herd showed similar results to synchronizing every cow in the herd and thus would be more cost effective. Synchronizing cows which calved more than 30 days after the start of calving in the herd showed a smaller advantage but only in the herds with long prior calving periods. The optimal strategy for oestrous synchronization in a herd will depend on the prior calving distribution and the average duration ofanoestrus in that herd as well as the relative costs of the treatment.

A selection index which incorporates estimated breeding values of traits recorded in the United Kingdom pedigree beef cattle breeds is described. The breeding objective is made up of commercial carcass, calving difficulty and gestation length traits. Economic values for these breeding objective traits are summarized from related studies, while partial genetic regression estimates of breeding objective traits on recorded traits are derived mainly from the literature.

The selection index is described in terms of the reduction in expected genetic response from selection on the index when individual recorded traits are omitted and the expected genetic responses in breeding objective traits with selection on the index under the assumption of mass selection. Failure to record all calving traits (birth weight, calving difficulty and gestation length) resulted in a reduction in expected economic response to selection of 8% from the situation where both calving traits and production traits (400-day weight, ultrasonic fat and muscle depths, and muscling score) are recorded. With a few stated exceptions, the index is relatively robust to errors in estimates of individual parameters.

It is suggested that the total index be used to assist commercial bull and semen buyers in their selection decisions but that two sub-indices for calving and production traits also be published to allow buyers to adjust emphasis on the two groups of traits depending on their individual production circumstances.

Saliva and faecal samples were collected from hill cattle (no. = 10) given tannin-rich oak (Quercus incana) leaves in the north-west Himalayan region of India. Amino acid composition of the saliva samples after thawing to remove precipitated proteins by centrifugation, and dialysis (molecular weight cut off: 3500) to remove small moieties revealed 6·4 (s.d. 0·6) % proline, 15·6 (s.d. 0·6) % glutamine plus glutamate and 9·2 (s.d. 1·0) % glycine on molar basis. For Holstein Friesian cattle (no. = 4) which had no history of consumption of tannin-containing foods, these values were 6·5 (s.d. 0·4) %, 15·2 (s.d. 0·5) % and 9·8 (s.d. 0·7) % respectively. Proline concentration in the proteins present either as free or as tannin-protein complexes in the lyophilized faecal samples from hill cattle was 4·7 (s.d. 0·2) % (on molar basis) of the total amino acids and 5·3 (s.d. 0·2) % in Holstein Friesian cattle. In the faeces of oak-fed cattle, the tannin and condensed tannin levels on dry-weight basis were 0·81 (s.d. 0·20) % as tannin acid equivalent and 0·06 (s.d. 0·04) % as leucocyanidin equivalent respectively. For tannic acid, the relative affinity of salivary proteins, using the competitive binding assay, was about six-times higher than that of bovine serum albumin (BSA) and was of the same order as that of gelatin. Turbidity of complexes formed between salivary proteins or BSA and tannic acid showed proportionately about 0·50 lower turbidity for salivary proteins in 0-2 mol/I acetate buffer (pH 4·9 containing 0·17 mol/l NaCl) and proportionately about 0·84 lower turbidity in distilled water. The results suggest that unlike rats or mice, the proline-rich proteins do not appear to be of any physiological significance in the adaptation of cattle to tannins. However, the salivary proteins of cattle though not rich in proline, have a high affinity for tannins and these proteins have a high tendency to form soluble tannin-protein complexes.

With the objective of studying the response patterns of two biotypes of different body (structural) size to stocking rate (SR) in terms of individual growth rate (ADG), meat production per ha (PROD) and backfat thickness (BFT) under grazing conditions, 64 steers of two biotypes of the Angus breed of different body size were used: small-sized (SB: frame score of 1·3 (s.d. 0·7)) and medium-sized (MB: 2·9 (s.d. 0·6)). Four levels of SR were applied (1·8, 2·3, 2·8 and 3·3 steers per ha). The experiment lasted 241 days (April to December). Animals were weighed every 14 days, forage availability (FA) was estimated on four occasions and BFT was recorded at the end of the experiment (between 12th and 13th ribs). There were no differences between biotypes in ADG. SB tended to be earlier maturing showing higher BFT (4·39 v. 3·97 mm; P = 0·22). ADG was affected by SR and was higher at lower SR (0·612, 0·529, 0·414 and 0·375 kg/day, for 1·8, 2·3, 2·8 and 3·3 steers per ha, respectively). Individual average daily gain of the MB was more variable across the seasons of the year. None of the variables showed effects of the biotype × SR interaction but differences in ADG between biotypes as a function of the SR were observed as a trend (P = 0·29). Despite the difference in frame score between biotypes it was not possible to associate it with consistent differences in the response variables. Individual productivity (potential) of MB was not reflected in a greater productivity per surface unit. The data from this experiment do not allow the choice of a particular biotype in order to optimize the productivity of the pastoral production systems.

Current European Union legislation will increase the level of disposal of sewage sludge to agricultural land in the next 10 years. This increase may lead to an increase in ingestion, by grazing animals, of herbage with elevated levels of potentially toxic elements (PTEs) derived from sludge adhered to the herbage or sewage sludge-amended soil resulting in the accumulation of PTEs in body tissues, especially the liver and kidney. To assess the possible accumulation of PTEs from soils treated historically with sewage sludge, eight groups of housed weaned lambs were given either dried grass as a sole food (grass control), or diets comprising dried grass (0·9 of total diet dry matter (DM)) and soil (0·1 of total diet DM) from two experimental sites, plots within which had been treated 14 years previously with different quantities of sewage sludge. Soils from the two sites (Cassington and Royston) had contrasting physical characteristics, pH and contents of calcium. The soil from the site at Cassington was slightly acidic (pH 6·0) and had a concentration of calcium of 7·92 g/kg DM whereas the soil from the site at Royston was alkaline (pH 8·0) and had a high concentration of calcium (23·5 g/kg DM). Plots at each site had a range of concentrations of cadmium (Cd) in the soil up to three times the United Kingdom (UK) statutory limit of 3 mg Cd per kg DM. The soils from these two sites were designated control — no amendment with sewage sludge (0·69 mg Cd per kg DM), low (3·55 mg Cd per kg DM), medium (6·63 mg Cd per kg DM) and high (8·82 mg Cd per kg DM; Cassington soil only). Voluntary DM intake of diets by weaned lambs (mean 1436 glday) was not affected significantly by any dietary treatment. The concentrations of Cd in liver increased (P < 0·001) from 0·061 and 0·072 mg/kg DM (Royston and Cassington control, respectively) to 0·218 and 0·403 mg/kg DM (Royston and Cassington medium, respectively) and 0·500 mg/kg DM (Cassington high). The concentrations of Pb in liver increased (P < 0·001) from 0·733 and 0·627 mg/kg DM (Royston and Cassington control, respectively) to 118 and 1·25 mg/kg DM (Royston and Cassington medium, respectively) and 1·18 mg/kg DM (Cassington high). Similar changes were observed for concentrations of Cd and Pb in kidney. A depletion of the concentration of Cu in the liver was observed in all treatments containing soil in the diet. The rate of accumulation of Cd in the liver ranged from 0 to 0·35 μg/g daily tissue DM growth and in the kidney ranged from 0 to 0·44 μg/g daily tissue DM growth. The rate of accumulation of Pb in the liver ranged from 0 to 6·01 μg/g daily tissue DM growth and in the kidney ranged from 0 to 0·63 μg/g daily tissue DM growth. No significant accumulation of PTEs was observed in muscle tissue. It is concluded that the current UK statutory limits for the concentrations ofCd and Pb in soils treated with sewage sludge should be reviewed in the light of these results, though they require confirmation in the grazing situation.

Faecal nematode egg counts (FECs) were examined in lactating ewes from divergent flocks of Romney sheep which had been selectively bred from 1979 to 1996 for or against FEC in 4 to 7 month old lambs. Faecal samples were obtained from the ewes while under normal grazing management, 1 to 2 months after lambing in spring for each of 6 years between 1987 and 1996 (no. = 785 records; 298 animals). Analyses were carried out on loge (FEC + 100)–transformed data using animal-model maximum likelihood procedures, accounting for repeated records on ewes, within and between lactations. An examination of non-genetic effects indicated that there was no significant effect of age class of ewe on FEC but ewes which gave birth to single lambs had significantly lower post-parturient FECs than those bearing twins (back-transformed means of 184 v. 276 egg per g, respectively; P < 0·001). In relation to genetic effects, post-parturient FECs were significantly lower in ewes from the flock bred for low lamb-FEC than in their counterparts from the flock bred for high lamb-FEC, with ewes from the most recent birth years (1991 to 1994) showing a nine-fold difference (back-transformed means of 33 and 305 eggs per g faeces respectively; P < 0·001). This was equivalent to 69% of the divergence observed between loge (FEC + 100) in their lambs in the same years. Heritability and repeatability estimates for loge (FEC + 100) in ewes were 0·37 (s.e. 0·06) and 0·46 (s.e. 0·03) respectively. Genetic correlation estimates between a ewe's post-parturient loge (FEC + 200) and her loge (FEC + 100) as a lamb, based on analysis of (co)variance or realized responses, were 0·70 or 0·58 respectively. The phenotypic correlation between a ewe's loge (FEC + 100) and that of her lamb(s) in the same lactation was 0·29 (s.e. 0·06) (P < 0·001). From the results it is clear that substantial genetic changes in post-parturient FECs of breeding ewes can be induced through a correlated response to selective breeding for or against reduced FEC in lambs. This may have important implications for the epidemiology of nematode parasite infections in spring-born lambs, a possibility which is currently being investigated.

At an experimental farm, five camels and five cows were each given a similar basal diet for 6 months. They received oral trace element supplementation for 3 months (day 22 to 112) which included zinc, copper, selenium, manganese, iodine and cobalt and corresponded to twice the daily requirement generally recommended for cows. Plasma selenium concentrations were significantly lower in the camels (20 (s.e. 2) mg/l) compared with the cows (33 (s.e. 2) μg/l). The mineral supplementation induced a large increase in the plasma selenium concentration in the camels which reached 200 (s.e. 35) fig/l. In the cows, the increase was much smaller and did not go beyond 65 (s.e. 8) μg/l. Before supplementation the red blood cell glutathione peroxidase activity was similar in the camel and the cow varying between 4000 and 6000 IU per 100 g haemoglobin. In both species, this activity increased with mineral supplementation and remained very high even when mineral supplementation was stopped. The results suggested that selenium metabolism in camels is different from that in the cows.

A study was instigated to test whether grazing herbivores have evolved effective strategies to reduce parasite ingestion and to assess the effects of parasitism on these strategies. Two choice trials, each using five animals parasitized with O. circumcincta and five parasite naive animals, were conducted to investigate cues used by sheep to avoid grazing swards contaminated with faeces. Animals were presented with pairs of artificial swards (36 × 21 cm) and allowed to graze for short periods. In the first trial, four quantities (0 g, 5 g, 15 g and 25 g), and in the second trial a control (no faeces) and three age classes (0, 10 and 21 days old), of faeces were tested against each other. Increasing amount offaeces per sward tray was associated with a reduced proportion of bites taken from the sward and reduced bite depth and mass. The minimum amount of faeces at which sheep showed significant levels of rejection was 15 g. Decreasing age of faeces was associated with a reduced proportion of bites taken from the sward, reduced bite depth and mass. This presented the paradox that grazing swards contaminated with young faeces presented least risk of parasitism, yet fresh faeces presented the strongest stimulus for sward rejection. Parasitism altered animal grazing behaviour with parasitized animals becoming more selective when avoiding contaminated swards, taking smaller bites at reduced bite rates compared with non-infected animals. The enhancement of faeces avoidance behaviours shown by parasitized animals could act to reduce further intake of parasites and suggests that grazing behaviour is affected by nematode infection.

Data on ovulation rate, embryo survival and litter size have been analysed from the 1988-96 records collected at AgResearch's Woodlands Research Station on 2180 elite (highly prolific) ewes of three breeds: Romney, Coopworth and Perendale. The Romneys included a subgroup found to carry the sex-linked Inverdale high prolificacy gene. Foundation animals for all breeds were screened on high litter size (lambs born, alive or dead, per ewe lambing) from industry flocks. Prior to being transferred to Woodlands between 1979 and 1984, their average litter size was 2·66. Ovulation rates for descendants of the foundation ewes averaged 2·15 (Romney), 2·43 (Coopworth), 2·15 (Perendale) and 2·96 for the Romney subgroup carrying the Inverdale gene. Embryo survival averaged 0·84 except for a low value in Inverdales (0·76). Using a restricted maximum likelihood model, with full relationship matrix, the within-breed heritability of ovulation rate over all ages and breeds (excluding Inverdale) was 0·14 (s.e. 0·03), with repeatability 0·26 (s.e. 0·02). Litter size averaged 1-80 (Romney), 2·05 (Coopworth), 1·76 (Perendale) and 2·17 (Inverdale). The heritability estimate for litter size (excluding Inverdale) was 0·073 (s.e. 0·018), from data for all ages. The genetic correlation between ovulation rate and litter size was 0·91 (s.e. 0·08). The standard deviation for ovulation rate in the Inverdales was 1·75 times as great as the average of the other three breeds. Embryo survival to term for ewes conceiving to two, three or four ovulations averaged 0·89, 0·77 and 0·64, respectively, and was significantly different among breeds fP < 0·001). The greater ovulation rate in Inverdales than Romneys was sufficient to explain the Inverdale effect on reduced embryo survival. The highest embryo survival was observed in the Coopworth breed (P < 0·001).

During three journeys of 15 h in a lorry and two sets of experiments in a trailer, the relative importance of ambient noise and vehicular motion were assessed by measurements of salivary cortisol concentration, heart rate and behaviour. Mean sound levels in the lorry were approximately 96 dbA with occasional episodes at 103 dbA. Vehicular motion was assessed in terms of numbers and magnitude of acceleration events registered by a triaxial accelerometer. The three lorry journeys showed, respectively, that heart rate was correlated with vehicular motion when sheep were loosely stocked (0·41 m2 per sheep) but not when they were tightly stocked (0·28 m2 per sheep); that heart rate sometimes tended to increase when ambient sound was greater and that the effect of sound was not as consistent as that of vehicular motion. In the first trailer experiment, salivary cortisol response was the same whether sheep confined in a quiet stationary trailer (60 dbA) were or were not exposed to extra noise (90 dbA) while heart rate was higher in the former condition. In the second trailer experiment when the trailer was being towed on public roads with or without extra noise (92·3 and 100·5 dbA respectively), heart rate and salivary cortisol concentration were both elevated compared with control sheep in a pen but the extra noise had no consistent effect. The sheep showed no orientation away from the noise source, nor was there any difference in their expression of a behaviour (standing with the head below the level of the shoulders) which could indicate discomfort. Hence vehicular motion can result in poor welfare in sheep, especially at loose stocking density but ambient noise was not found to have a consistent effect.

An experiment was conducted to measure the growth and body composition changes of highly selected boars and gilts from 10 to 150 kg live weight. Thirty boars and 30 gilts were given food ad libitum and two pigs of each sex were slaughtered at 10-kg increments from 10 kg to 150 kg live weight at which time the chemical composition of the body was determined. Boars and gilts exhibited different patterns of growth, nitrogen deposition rate (NDR) and lipid deposition rate (LDR) with boars exhibiting a sharp peak in daily live-weight gain and NDR while gilts exhibited almost a flat response curve over the age and weight range tested. Gilts experienced a peak in LDR at a lighter weight than boars (75·8 v. 100·5 kg) while NDR peaked at the same weight for both sexes (70·8 kg). Maximum NDR for boars and gilts was 37·7 and 28·1 glday (235·5 and 175·5 glday protein deposition rate) respectively. The Gompertz growth equation [Y = A + C × EXP (−EXP (−B ×(X−M)))] was shown to accurately represent the growth trajectory, while the logarithmic derivative of the allometric equation [Y = aXb] was used to determine live weight and body composition relationships. Combined sex relationships indicated that total body nitrogen and lipid concentrations increased at the same rate. A quadratic equation for the prediction of NDR based on live weight was developed for this genotype (NDR = 24·06 + 0·34 W − 0·002W2). In conclusion, the results provide a basis for comparison of body composition and growth patterns between the highly selected genotype tested and pigs from other genetic backgrounds. Sex effects exist for growth and body composition but combined sex prediction equations can be used to estimate NDR potential.

Three experiments investigated differences between sheep breeds in response to supplementary feeding and very close confinement with familiar and unfamiliar sheep; and differences between individuals in response to a taming procedure prior to transport in a trailer. The first two experiments were with a mixed flock of Clun Forest lambs and crossbred lambs from Orkney. An initial tendency to feed with others of the same breed diminished over 3 weeks. Responses of heart rate and salivary cortisol concentration when one sheep (the visitor) was penned in an enclosure of 1 m2 with three other sheep of the same or the other breed (the trio group), did not depend on whether the visitor and the trio group were of the same or different breed. Clun Forest sheep showed little response while Orkney sheep showed increased heart rate and some elevation of salivary cortisol concentration. In the third experiment, 34 Beulah Speckled Face ewes were divided into two groups one of which was subjected to a taming procedure over a period of 3 weeks. Response of salivary cortisol concentration to subsequent journeys of 2h in a livestock trailer did not differ between tamed and untamed sheep. There were individual differences in the response to taming and this was correlated with the cortisol response during transport, in that those sheep which responded most to taming showed the least elevation during transport.

An experiment was conducted to examine the effects of dietary lysine/digestible energy (DE) ratio (g/MJ) and dietary energy concentration on growth performance and body composition of young hybrid gilts from 9·1 to 25·4 kg live weight. Seven pigs were assigned to each of 10 dietary treatments consisting of lysine/DE ratios from 0·6 to 1·4 in 0·2 g/MJ increments and two DE concentrations (14·25 and 16·40 MJ/kg). Food was provided ad libitum and at 25·4 kg all pigs were slaughtered and body composition was determined. Responses to lysine/DE ratios were different for each DE concentration. The pigs given the 16·40 MJ/kg DE diets had a higher daily live-weight gain (DLWG) and nitrogen deposition rate (NDR) than those given the 14·25 MJ/kg diets up to the 1·2 g/MJ lysine/DE ratio. Beyond this point no DE effects were evident. Lipid deposition rate (LDR) was higher for all 16·40 MJ/kg diets as compared with the 14·25 MJ/kg diets and decreased with increasing lysine/DE ratio. The 14·25 MJ/kg diets resulted in increasing efficiency of nitrogen and gross energy utilization with increasing lysinel DE ratio up to the 1·0 g/MJ ratio after which it declined. Efficiency of lipid utilization decreased with increasing lysine/DE ratio for all 14·25 MJ/kg diets. The 16·40 MJ/kg diets resulted in a decrease in nitrogen and gross energy utilization efficiency with increasing lysine/DE ratio while lipid efficiency decreased up to the 1·0 g/MJ lysine/DE ratio after which it increased. Young hybrid pigs given high energy diets appear to be less sensitive to dietary lysine/DE ratio than those given lower energy diets. The optimum lysine/DE ratio for the genotype tested from 9 to 25 kg live weight was of the order of 1·2 g/MJ for both DE concentrations. The maximum DLWG and NDR of the genotype tested over the live-weight range of 9 to 25 kg appears to be of the order of 620 and 17 g/day (106 g/day protein deposition rate) respectively.

An experimental programme was initiated in 1990 to investigate the consequences of selection for reduced fatness in hill sheep and to estimate genetic parameters for carcass traits in the same class of animal. Thirty-two progeny groups of lambs were born as a result of mating Scottish Blackface rams to ewes of the same breed on two Scottish Agricultural College hill farms in 1991 and 1992. Sires were from two divergent selection lines for subcutaneous back fat depth and were selected under ad libitum feeding conditions on an index combining live weight and ultrasonic fat depth at 20 weeks of age. The index was designed to alter body composition but not body weight. Weaned male progeny (reared extensively) were brought together from both farms in August of each year, reared on grass and finished for slaughter on swedes at a target condition score of 3. Measurements taken at weaning were: live weight, average ultrasonic measurements of average subcutaneous fat depth and muscle depth. At slaughter, traits measured were: pre-slaughter live weight, pre-slaughter condition score, age at slaughter, cold carcass weight, killing-out proportion, Meat and Livestock Commission (MLC) fat class and MLC conformation class. Side and shoulder dissections were made on proportionally 0·2 and 0·8 of lambs respectively and lean tissue, subcutaneous fat, intermuscular fat and bone were measured. Comparisons were made between the two genetic lines and genetic parameters were estimated from data adjusted to three different ‘end-points’: constant dissected subcutaneous fat weight, constant age at slaughter and constant cold carcass weight. Moderate to low heritability estimates were obtained for most traits: pre-slaughter live weight = 0·36, cold carcass weight = 0·39, fat class = 0·13, conformation class = 0·09, lean weight = 0·27, bone weight = 0·36 (constant subcutaneous fatness), intermuscular fat = 0·20, subcutaneous fat = 0·20 (constant cold carcass weight). Correlations between ultrasonic measurements at weaning, and slaughter and dissected carcass components were moderate to weak. However, there is sufficient genetic variation in the carcass traits to warrant inclusion in breeding goals for hill sheep. The results also show that genetic differences obtained by selection under intensive rearing conditions for divergent fatness are also seen in progeny reared under extensive (hill) conditions.

Ileal digestibility of amino acids in barley-based diets with increasing inclusion of lucerne leaf meal (LLM; 0, 50, 100 and 200 g/kg) was studied in a change-over experiment with post-valve T-caecum cannulated growing pigs. The apparent Heal digestibility of crude protein, as well as of most of the essential (EAA) and non-essential amino acids (NEAA) was not significantly affected by the dietary inclusion of LLM. The exceptions were cystine, methionine, phenylalanine, glutamic acid and serine, all of which showed a significant (P < 0·05) reduction in apparent Heal digestibility with increasing inclusion of LLM. In contrast, the calculated true Heal digestibility of all EAA (with the exception of arginine and lysine) and the NEAA glutamic acid and serine were significantly (P < 0·05) reduced with the inclusion of LLM. Associated with an increased crude protein intake, there was a significant (P < 0·05) increase in the amount of absorbed EAA when the proportion of LLM was increased in the diet. With increasing proportion of fibre in the diet, there was a significant (P < 0·05) increase in the Heal flow of glucosamine.

It can be concluded from the present data that the inclusion of LLM in a barley-based diet for growing pigs will result in an improvement in the absorbed amino-acid profile due to a significant increase in the absorption of all of the EAA.