The energy expenditure of freely grazing cattle was investigated in the National Institute of Agricultural Technology and Agricultural Science College of Balcarce, Argentina (37° 45'S, 58° 18'W), by the CO2 entry rate technique. Two experiments were carried out in the autumn in March 1994 (experiment 1) and in April 1995 (experiment 2) with animals prepared with catheters in the parotid gland (collection of saliva) and into the peritonea for infusion of a solution of 14C. Six Angus steers (259 (s.e. 11) kg) were used in experiment 1 and seven (298 (s.e. 36) kg) in experiment 2. In experiment 1 animals grazed ryegrass pastures for 5·5 h in two periods of 1·5 h in the morning and of 4 h in the afternoon and in experiment 2 animals grazed oat pasture in one period of 1 h in the morning. Twenty hours before and during the experiments a solution ofNaH14CO3 was infused at a rate of 9·4 (experiment 1) and 8·1 (experiment 2) μiCi/h for 48 h with portable peristaltic pumps carried by each animal. Saliva samples were collected at least after the first 20 h of infusion. The first sample was collected in the corral just before grazing and two samples were collected in each grazing period. Also, in experiment 1 three samples were taken during resting (noon, 1 h after grazing and the next morning). In addition, bite frequency, pasture availability, plant height, in vitro digestibility and crude protein were measured. Carbon dioxide production was calculated as the ratio between the rate of infusion of 14C (μCi/h) and the specific activity of CO2 (μCi/l CO2) in saliva samples. Bite frequency was 59 and 28 bites per min on the respective pasture of ryegrass (148 g dry matter (DM) per m2 and 10·5 cm height) and oat (228 g DM per m2 and 27 cm height). Energy expenditure (EE, kJ/h per kg M0·75) in corrals was 14·9 (experiment 1) and 14·3 (experiment 2), increasing to 22·6 (proportionately 0·52) when grazing at 59 bites per min and to 16·6 (0·16) when grazing was at 28 bites per min. One hour after grazing at 59 bites per min (experiment 1) the EE was as high as during grazing, and in the next morning (after 5·5 h) of grazing remained at 19·7 kJ/h per kg M0·75 (0·32). No differences in energy expenditure were found between periods of grazing in experiment 1. It was concluded that the increase in energy expenditure of cattle due to the activity of grazing depends on the rate of biting. Grazing for 10 h at a moderate rate may boost EE proportionately by only 0·06, however grazing at the highest rates could easily add proportionately 0·20.

Sheep from the Soay, Southdown, Finnish Landrace and Oxford Down breeds were serially slaughtered at 40, 52, 64 and 76% of their estimated mature body weight. Breed and sex comparisons of muscle distribution wee made at these degrees of maturity. Comparisons were based on 12 individual muscles obtained from the prime retailjoints. Together, these 12 muscles represented about 41 % of total weight ofmuscle in the carcass. Highly significant breed and sex differences in the weight of individual muscles were obtained, but these differences were greatly reduced when values were expressed as a percentage of total muscle weight.

On a percentage basis, there were significant changes with stage of maturity in only three of the muscles studied, although most individual muscles showed an initial percentage decrease with increasing maturity (from 40 to 52%) but almost no change thereafter. Significant breed differences in muscle distribution were found. The individual muscles examined, when combined, comprised 40·8, 43·4, 40·5 and 39·8 % of total muscle weight respectively in the Soay, Southdown, Finnish Landrace and Oxford Down. No breed was significantly above average for every individual muscle, but the Southdown had the highest percentage in 6 out of 12 and might therefore be said to have had the most preferred muscle distribution. For most muscles examined, the percentage was slightly higher for females than for males, with totals for all 12 muscles of 41·9 and 40·4% respectively.

Pannon White (n = 12) male rabbits (weight: 4050 to 4500 g, age: 9 months) received 2 ml of a suspension containing purified T-2 toxin by gavage for 3 days. The daily toxin intake was 4 mg/animal (0.78 to 0.99 mg/kg body weight (BW)). Control animals (n = 12) received toxin-free suspension for 3 days. Since a feed-refusal effect was observed on the second day after T-2 administration, a group of bucks (n = 10) were kept as controls (no toxin treatment) but on a restricted feeding schedule, that is, the same amount of feed was provided to them as was consumed by the exposed animals. On day 51 of the experiment (i.e. 48 days after the 3-day toxin treatment), semen was collected, and pH, concentration, motility and morphology of the spermatozoa, as well as concentration of citric acid, zinc and fructose in the seminal plasma, were measured. After gonadotropin-releasing hormone (GnRH) analogue treatment, the testosterone level was examined. One day of T-2 toxin treatment dramatically decreased voluntary feed intake (by 27% compared to control, P < 0.05) and remained lower (P < 0.05) during the first 2 weeks after the withdrawal of the toxin. BW of the contaminated rabbits decreased by 88% on days 17 and 29 compared to controls (P < 0.05). No effect of toxin treatment was detected on pH and quantity of the semen or concentration of spermatozoa. The ratio of spermatozoa showing progressive forward motility decreased from 65% to 53% in the semen samples of toxin-treated animals compared to controls (P > 0.05). The ratio of spermatozoa with abnormal morphology increased (P < 0.05) in the ejaculates collected from the toxin-treated animals. T-2 toxin applied in high doses decreased the concentration of citric acid in seminal plasma (P < 0.05). No effect of T-2 toxin on the concentrations of the other seminal plasma parameters (fructose and zinc) was observed. T-2 toxin decreased the basic testosterone level by 45% compared to control (P < 0.01) and resulted in lower (P < 0.05) GnRH-induced testosterone concentration. Feed restriction, that is, less nutrient intake, resulted in more morphologically abnormal spermatozoa in the semen, but it did not cause significant loss in BW, motility of the spermatozoa, composition of the seminal plasma or testosterone concentration – its effect needs further examination.

The effect of commensal microbiota and feeding corn or wheat/barley-based diets on the apparent gastrointestinal absorption of dl-methionine (MET) and 2-hydroxy-4-methylthiobutanoic acid (MHA-FA) was studied in conventional (n = 32) and gnotobiotic pigs (n = 24). Conventional pigs (CON) were vaginally delivered and sow-reared until weaning at 14 days of age. Gnotobiotic pigs were derived by caesarian section and reared in HEPA (high efficiency particulate air)-filtered isolator units with ad libitum access to a milk-based formula. Corn or wheat/barley-based diets were fed to all pigs from 14 to 24 days of age. At 24 days of age, after an overnight fast, pigs were fed 20 g/kg BW of experimental diet supplemented with 107 Bq of either 3H-l-MET or 3H-l-MHA-FA per kg of feed and chromic oxide (0.5% wt/wt). Pigs were killed for sample collection 3 h after consuming the meal. Residual 3H-MET and 3H-MHA-FA were estimated in gastrointestinal contents as the ratio of 3H : chromic oxide in digesta samples to the ratio of 3H : chromic oxide in feed. In CON pigs, feeding a wheat/barley-based diet increased (P < 0.05) total aerobes, whereas supplementation with MHA-FA increased (P < 0.05) total aerobes and lactobacilli populations in proximal small intestine (SI). Among the gnotobiotic pigs, bacterial contamination occurred such that eight pigs (two isolators) were monoassociated with a Gram-negative bacteria closely related to Providencia spp. and 16 pigs (four isolators) were monoassociated with Gram positive Enterococcus faecium. Species of monoassociated bacterial contaminant and diet composition did not affect residual methionine or MHA-FA in digesta. In both CON and monoassociated (MA) pigs, methionine and MHA-FA were retained in stomach (92%) but disappeared rapidly from proximal SI. Residual methionine and MHA-FA in digesta was not different in MA pigs; however, in CON pigs, less (P < 0.01) apparent residual methionine was found in digesta recovered at 25% (from cranial to caudal) and 75% of SI length compared with MHA-FA. Apparent residual methionine was 16% and 8% compared with 34% and 15% for MHA-FA, at the 25% and 75% locations, respectively. In proximal SI tissue, significantly (P < 0.05) higher radioactivity (cpm/mg wet tissue) was associated with MET pigs (8.56 ± 0.47) as compared to MHA-FA ones (5.45 ± 0.50). This study suggests that microbial metabolism of MHA-FA increases retention in small intestinal digesta relative to methionine and contributes, in part, to the lower bioefficacy of MHA-FA compared to methionine.

Interrelationships between carcass composition and the composition of 7 different sample joints were studied in 83 purebred Clun Forest lambs slaughtered at approximately 80 lb. live-weight and ranging in carcass weight from 29 to 42 lb. Correlation coefficients between physically separated fat, muscle and bone in the loin and in the carcass were 0·96, 0·93 and 0·84 respectively (P < 0·01). Corresponding correlations for the best-neck (7–12 rib joint) were 0·94, 0·92 and 0·76 (P < 0·01). The leg and shoulder provided the best estimates of carcass bone. The usefulness of predictions of carcass composition is discussed in relation to the maximum probable errors associated with individual and group mean predictions of carcass composition based on sample joints and with reference to the accuracy of these indices under different treatment conditions. The 5% confidence limits on individual predictions based on loin composition were ± 2.22%, ± 2.44% and ± 1.62 % for fat muscle and bone respectively; indicating that this index cannot be relied on to reflect small differences in carcass composition between individual animals.

Litter size of commercial European sow lines can be increased by the introduction of genes from the highly prolific, but obese Meishan. The introduction of these genes into sow lines may necessitate different nutritional strategies for lactation. A 2 × 2 × 2 factorial experiment was used to investigate the influence of breed type (Meishan synthetic 50% (M) or purebred European Landrace and Large White (W)) and parity (1 or 3) on response to dietery protein level (H = 178 g crude protein (CP) per kg 8 g lysine per kg, L = 136 g CP per kg 5 g lysine per kg over a 5-week lactation. M were lighter and fatter at farrowing than W (P < 0·001), consumed more food (M = 7·33 v.W = 6·98 (s.e.d. 0·17) kg/day, P < 0·05) but had higher maternal weight loss (M = 16·2 v.W = 11·9 (s.e.d. 1·88) kg, P < 0·05) and higher fat loss (M = 6·5 v. W = 26 (s.e.d. 077) mm P2, P < 0·001) during lactation. Litter growth rate was higher for M than for W (P < 0·005) and for H than for L (P < 0·005). Differences were found between breeds in the partitioning of food protein. Overall, higher correlations between lysine intake and litter growth rates were found in M (r = 0·55, P < 0·001) than in W (r = 0·13, P > 0·05). Lysine intake and sow weight loss were more correlated in W(r = 0·66, P < 0·001) than in M (r = 0·15), P > 0·05). Fat loss was correlated with initial fat depth in M (r = 0·61, P < 0·001) but not in W. Weaning to conception intervals showed a breed × diet interaction (loge days: ML = 1·38, MH = 1·55, WL = 1·73, WH = 1·43, s.e.d. 0·14, P < 0·05). It is concluded that M, with greater initial fat reserves, catabolize more body fat to support greater milk output. This is facilitated by provision of a high protein diet. The W sows do not utilize the extra protein for milk production but instead use it to minimize weight loss (maintain protein status of their own body) which may help prevent an extended weaning to conception interval.

Blood grouping was used to investigate 1000 parentage cases in Swedish cattle. The blood samples were tested for 39 antigenic factors belonging to 9 different systems. One of the two possible bulls could be excluded as the sire in about 80% of the complete parentage cases in the Swedish Friesians (SLB) as well as the Swedish Red and White breed (SRB). The additional use of the transferrin systems in 79 of these cases resulted in a considerably increased efficiency. The probability of making exclusions with the aid of the various blood grouping systems was estimated from gene frequency data and showed good agreement with the results actually obtained. In the SRB the combined use of tests for cellular antigens and transferrins is expected to give solutions in about 84% of the complete paternity cases with two possible sires.

The value of using genotypic classifications in the complex blood group systems in parentage tests is discussed. Finally, attention is given to the difficulty encountered in parentage cases involving twin-born animals with erythrocyte admixture.

Mature dry cows, 18-month-old heifers and 7-month-old female calves of the Charolais breed (eight animals of each age) were strip-grazed on moderate (15cm) or tall (52 and 32cm) cocksfoot swards over two 15-day experimental periods. The swards were leafy regrowths of 2 (short) and 8 (tall) weeks of age. Herbage intake was estimated by the alkane method, and grazing behaviour was visually recorded.

Bite weight was lower, grazing time and biting rate greater, and organic matter in take of grass (OMIG) higher on shorter swards, the latter being related to a higher in vitro digestibility and nitrogen concentration. Average OMIG per kg live weight (M) was 15·2, 19·1 and 17·0 (s.e.d. 0·49)g in cows, heifers and calves respectively. The average allometric coefficient between OMIG and M was 0·88 (similar between swards), and close to that obtained with hay after the grazing trial.

Faecal markers suggested a greater selectivity of calves compared with older cattle. Average bite weights (BW) were 310 (s.e. 40), 467 (s.e. 112) and 718 (s.e. 144)mg OM in calves, heifers and cows respectively. The allometric coefficient between BW and M was higher in short swards than in tall ones. Biting rates increased and grazing times tended to decrease with age of cattle.

The relationship between weaning stress-induced changes in stress hormone profiles and immune function was investigated in groups of 10 lambs immunized against adrenocorticotrophic hormone (ACTH; treatment A) or fi-endorphin (treatment B) to reduce the circulating concentrations of cortisol and fi-endorphin respectively. Control animals (treatment C) were immunized against a porcine thyroglobulin carrier protein. Application of weaning stress was associated with significantly elevated plasma cortisol concentrations but no significant increase in fi-endorphin concentrations in C lambs. Immunization against ACTH suppressed the post-weaning increase in cortisol concentration. This was associated with a transient reduction in the lymphocyte stimulation response to keyhole limpet haemocyanin (KLH) antigen in the A animals but there was no effect on the antibody response or interferon-y production by antigen stimulated lymphocytes. There were no significant effects of immunization against fi-endorphin on the capacity to mount antibody or cell-mediated immune responses. It is concluded that weaning stress-induced increases in cortisol did not inhibit the immune response. Since cortisol concentrations and the cell mediated immune response at 8 days after immunization were positively associated it is concluded that these indices are not independent measures of stress.

The Hennessy and Chong Fat Depth Indicator and the Ulster Probe automatic recording instruments developed for measuring fat thickness were tested against the optical probe for use in pig carcass classification and grading.

Fat thickness measurements were taken using each probe 60 mm from the dorsal mid-line over the m. longissimus at the positions of the 3rd/4th lumbar vertebrae, 3rd/4th last ribs and last rib on a total of 110 hot carcasses covering the range of market weights in Great Britain. The standard deviation of carcass lean proportion at equal carcass weight was 35·4 g/kg.

The instruments differed little in the precision of carcass lean proportion prediction: residual standard deviation (g/kg) for the multiple regression with carcass weight and the best individual fat measurement for each probe were: last rib optical probe, 22·1; last rib Ulster Probe, 22·7; and 3rd/4th last rib Fat Depth Indicator, 21/6. Residual standard deviation (g/kg) for carcass lean proportion prediction from carcass weight and all three fat measurements in multiple regression were 21·3 optical probe, 21·3 Ulster Probe and 201 Fat Depth Indicator.

Similar mean fat measurements were obtained from the optical probe and Fat Depth Indicator, and for these instruments, but to a lesser extent for the Ulster Probe, the regression relationships with each other and with fat thickness measurements taken on the cut surface of the cold carcass were also similar.

The differences recorded in precision are unlikely to be sufficiently important to influence the choice of one probe rather than another.

Twenty-one pairs of male cattle twins, 10 of which were monozygotic, were used in a study of the effects of a combined implant of trenbolone acetate (140 mg) and oestradiol-17B (20 mg) on growth and carcass composition. There were three comparisons within pairs: (1) between bulls and steers (no implants); (2) between bulls and implanted steers; and (3) between bulls and implanted bulls.

Implants were given twice, at 44 to 73 days and at 300 days of age. Animals were slaughtered at 400 days following recorded consumption of a complete pelleted diet given ad libitum. Carcasses were separated into tissues and lean and fat were chemically analysed. The effects of castration and/or implantation on growth and carcass composition were assessed by comparison with the untreated (control) bull values within each group and expressed as a ratio (treatedxontrol). These ratios were then compared between groups.

Bulls were significantly heavier than steers at slaughter (29·6 kg, P < 0·05), but were not heavier than implanted steers. Implantation of steers tended to increase appetite; it proportionately increased lean and protein production by about 0·1, and partly reversed the effects of castration on the length of limb bones and the weights of reproductive organs and hide. The proportions of carcass tissues were very similar in the untreated and implanted steers. In bulls, implantation increased the weight of fatty tissue in the subcutaneous and intermuscular depots, but it had small effects on other carcass characteristics.

The effect of feed restriction on gene expression of regulatory enzymes of intermediary metabolism was studied in two sheep breeds (Australian Merino and Dorper) subjected to two nutritional treatments: feed restriction (85% of daily maintenance requirements) and control (ad libitum feeding), during 42 days. The experimental animals (ram lambs) were divided into four groups, n = 5 (Australian Merino control (MC), Australian Merino Restriction (MR), Dorper control (DC) and Dorper Restriction (DR)). After the trial, animals were sacrificed and samples were taken from liver tissue to quantify glucose levels and gene expression of relevant intermediary metabolism enzymes (phosphofructokinase (PFK), pyruvate kinase (PK), phosphoenolpyruvate carboxykinase, fructose 1,6-bisphosphatase, glucose-6-phosphatase, glycogen synthase (GS), fatty acid synthase (FAS), glutamate dehydrogenase (GDH) and carbamoyl phosphate synthase (CPS)) through real-time PCR. During the experimental period, the MR animals lost 12.6% in BW compared with 5.3% lost by the Dorper lambs. MC and DC rams gained, respectively, 8.8% and 14% during the same period. Within the Dorper breed, restricted feed animals revealed a significant decrease over controls in the transcription of PFK (1.95-fold) and PK (2.26-fold), both glycolytic enzymes. The gluconeogenesis showed no change in the feed restricted animals of both breeds. DR feed group presented a significant decrease over the homologous Merino sheep group on GS. In both experimental breeds, FAS mRNA expression was decreased in restricted feed groups. GDH expression was decreased only in the DR animals (1.84-fold) indicating a reduced catabolism of amino acids in these animals. Finally, CPS was significantly (P < 0.05) higher in the Dorper sheep, indicating a facilitated urea synthesis in this breed. These results indicate a better adaptation of metabolic intermediate regulatory enzymes and hepatic glucose production of Dorper sheep to feed restriction concurring with the BW results in the experimental groups.

Observations were made of the behaviour of a home-range group of Scottish Blackface ewes. The group, including replacement ewe lambs, remained on the hill throughout winter and was offered supplemental feedblocks from December to April. Sheep were individually identified and data collected on ranging behaviour between 06.00 and 18.00 h GMT in autumn and winter. Additionally in winter, records were made of time spent eating from the feedblock or standing within 3 m of it.

Age was found to have a strong effect on time spent eating from the feedblock, with older ewes (4 years and over) eating more than younger animals. This was partly attributable to the ewe lambs forming peer groups in winter that were uninfluenced by the movements of mature ewes to the feedblock. Consequently, the majority (0·82) of ewe lambs did not eat feedblock in their first winter. Two- and 3-year-old ewes, although not eating significantly more often from the feedblock than ewe lambs, spent significantly more time standing within 3 m of it and were prevented from eating from it by the competitive behaviour of older ewes. The increased gregariousness of hill sheep in winter appears to be an important factor in preventing the younger ewes taking advantage of the continuous availability of feedblocks. The feedblocks were also found to reduce significantly the size of ewes' home ranges.

The results indicate that the social behaviour of hill sheep limits the use of feedblocks to the older and stronger animals in the group. In addition, feedblocks may reduce the utilization by sheep of available winter forage. Alternative strategies for more effective deployment of feedblocks are discussed.

Ninety Awassi ewes managed at different levels were used to study the effect of live weight mating on fertility over 3 years in semi-arid north-west Syria. During the 56-day pre-mating period fertile ewes had higher daily live-weight gains than infertile ewes (P < 0·01), frequency of oestrous cycles increased as live weight increased (P < 0·001) and fertile ewes tended to have more frequent oestruses than infertile ewes (P > 0·05). Ewe fertility was related (r = 0·87) to live weight at mating and twinning reached a maximum (four per 100 ewes lambing) in 51· to 56-kg ewes then decreased fP > 0·05). Maximum fertility can be expected in Awassi ewes weighing over 48 kg at mating in north-west Syria.

Poor performance and ill-health of calves in the pre-wean period can affect future productivity. Increasing numbers of producers are opting to use calf jackets as a means of mitigating the potential negative effects of low ambient temperatures, wind speed and precipitation on growth and health. This study aimed to use a range of noninvasive monitoring technologies to investigate the effects of using calf jackets in the first 3 weeks of life on calf performance and behavioural and physiological parameters. Ninety Holstein-Friesian calves were allocated to one of the two treatments: (i) Jacketed until 21 days of age and (J; n = 44) ii. Nonjacketed (NJ; n = 46). Calves were group housed and fed milk replacer (MR) and concentrate solid feed via automatic feeders. Calves were weaned at day 56, and the experiment was completed at day 63. Health assessments were conducted on a daily basis throughout the experiment using predefined faecal and respiratory scoring protocols. A range of novel, noninvasive monitoring technologies were used to examine the activity, heart rate and thermal profiles of calves on an individual basis throughout the experimental period. There were no differences in calf live weight (LWT), average daily gain (ADG) or feed conversion efficiency (FCE) in J and NJ calves between days 5 to 20. However, NJ calves consumed more MR and had more unrewarded visits to the milk feeder than J calves during this period. Although calf LWT was comparable across treatments in the week following jacket removal (days 21 to 28), both ADG and FCE tended to be greater in NJ calves. There were no treatment differences in calf LWT at the end of the study (d63). When measured over a period of 24 h and at a mean ambient temperature of 7.7°C, skin surface temperature was 6.37°C higher in J calves. Core body temperature was higher in J calves between days 5 to 20; however, there were no differences in IR eye or IR rectal temperature. No differences in lying behaviour occurred, with calves spending 18 and 17 h/day lying between days 5 to 20 and days 21 to 28, respectively. Under the climatic and management conditions described, no significant benefits to calf performance were found as a result of the provision of calf jackets to group-housed calves in the first 3 weeks of life. The higher frequency of unrewarded visits to the milk feeder in NJ calves during the first 3 weeks of life could be suggestive of a lack of satiety in these calves.

In response to increasing efforts for reducing concentrate inputs to organic dairy production in grassland-rich areas of Europe, a long-term study was conducted, which assessed the impacts of concentrate reductions on cows’ performance, health, fertility and average herd age. In total, 42 Swiss commercial organic dairy cattle farms were monitored over 6 years (‘Y0’, 2008/09 until ‘Y5’, 2013/14). In comparison with overall data of Swiss herdbooks (including conventional and organic farms), the herds involved in the project had lower milk yields, similar milk solids, shorter calving intervals and higher average lactation numbers. During the first 3 project years farmers reduced the concentrate proportion (i.e. cereals, oilseeds and grain legumes) in the dairy cows’ diets to varying degrees. In Y0, farms fed between 0% and 6% (dietary dry matter proportion per year) of concentrates. During the course of the study they changed the quantity of concentrates to voluntarily chosen degrees. Retrospectively, farms were clustered into five farm groups: Group ‘0-conc’ (n=6 farms) already fed zero concentrates in Y0 and stayed at this level. Group ‘Dec-to0’ (n=11) reduced concentrates to 0 during the project period. Groups ‘Dec-strong’ (n=8) and ‘Dec-slight’ (n=12) decreased concentrate amounts by >50% and <50%, respectively. Group ‘Const-conc’ (n=5 farms) remained at the initial level of concentrates during the project. Milk recording data were summarised and analysed per farm and project year. Lactation number and calving intervals were obtained from the databases of the Swiss breeders’ associations. Dietary concentrate amounts and records of veterinary treatments were obtained from the obligatory farm documentations. Data were analysed with GLMs. Daily milk yields differed significantly between farm groups already in Y0, being lowest in groups 0-conc (16.0 kg) and Dec-to0 (16.7 kg), and highest in groups Dec-slight (19.6 kg) and Const-conc (19.2 kg). Milk yield decreases across the years within groups were not significant, but urea contents in milk decreased significantly during the course of the project. Milk protein, somatic cell score, fat–protein ratio, average lactation number, calving interval and frequency of veterinary treatments did not differ by group and year. In conclusion, 5 years of concentrate reduction in low-input Swiss organic dairy farms, affected neither milk composition, nor fertility and veterinary treatments. Milk yields tended to decline, but at a low rate per saved kilogram of concentrate.

Whole-crop maize was harvested at 20% (L), 29% (M) and 38% (H) dry-matter (DM) content, chopped to 7·67 mm (F) or 33·3 mm (C) average particle length and ensiled. The six silages were offered ad libitum to 36 entire male calves (initially 96 kg live weight), together with supplements of urea and dried ryegrass, for 42 days. Voluntary intake and the apparent digestibility of the diets were measured. Intake of DM was not affected by the DM content of the silages, but was higher for F than C by 6·6% (P<0·01). Apparent digestibility of DM, organic matter and cell walls decreased with increasing silage DM content (P<0·001) and was higher for F than C (P < 0·01).

Farm mink (Mustela vison) have been selected on the basis of their behaviour towards man since 1988 at the Danish Institute of Agricultural Sciences and in this study were offered the possibility to mate 1 week earlier than usual. The objective was to investigate if the behaviour-related selection has affected the reproduction of the farm mink, measured as mating willingness and reproductive success. The animals belonged to three breeding groups: A: selected for curious/confident reactions (17 males, 73 females), B: selected for timid reactions (17 males, 74 females), and C: selected without any demands on reactions towards humans (18 males, 73 females). The time when an average of 50% of the population were mated was 3-6 days for group A; thus the confident were mated 1·7 to 2·1 days earlier than the timid (B) and the control (C) animals. The length of gestation was shorter in group A (46·0 (s.d. 3·0) days) than in group C (47·6 (s.d. 3·6) days) but not different from group B (47·0 (s.d. 3·2) days). Group C had a lower kit mortality from birth to day 50 (11·3%) than groups A and B (20·4 to 21·2%). No significant differences were found between the groups regarding the frequency of successful matings, the ratio of remated females, number of interrupted matings, barren females or litter size. It is concluded that 8 years of selection has led to the development of reproductive differences primarily in the time of mating readiness, whereas the differences seen in kit loss may be related more to random effects.

The rectal temperature and respiratory rates of German Brown, Friesian, German Brown/Friesian crosses, N'Dama and German Brown/N'Dama (BN) crosses were studied with a view to establishing baseline data for cattle in the humid tropical environment of Nigeria.

Mean morning (38·62°C) and late afternoon (39·19°C) rectal temperatures for the various breeds were found to differ significantly (P<0·01). However, general breed differences as well as differences between heifers, milking cows, bulls and calves were not significant. Respiratory rates (counts/min) were also significantly higher (P<0·01) in the afternoon than in the morning and appeared related to changes in atmospheric temperature and relative humidity. Breed differences in respiratory rates were also significant, being within the range 17 to 34 in N'Dama, 24 to 43 in BNs and 29 to 51 in the German Brown and Friesian.

Heat tolerance indices were very high (89 to 91) for all the breeds studied but showed that the Friesian and German Brown were less heat tolerant than the BNs, and the N'Dama and White Fulani. The results indicate the need to consider diurnal changes in rectal temperature and respiratory rates in the use of these parameters for clinical diagnostic purposes.

Nuclear genetic diversity and differentiation of 341 sheep belonging to 12 sheep breeds from Croatia and Bosnia and Herzegovina were examined. The aim of the study was to provide the understanding of the genetic structure and variability of the analysed pramenka sheep populations, and to give indications for conservation strategies based on the population diversity and structure information. The genetic variation of the sheep populations, examined at the nuclear level using 27 microsatellite loci, revealed considerable levels of genetic diversity, similar to the diversity found in other European indigenous low-production sheep breeds. Population-specific alleles were detected at most loci and in breeds analysed. The observed heterozygosity ranged from 0.643 (in Lika pramenka) to 0.743 (in Vlasic pramenka), and the expected heterozygosity ranged from 0.646 (in Lika pramenka) to 0.756 (in Dalmatian pramenka). Significant inbreeding coefficients were found for half of the populations studied and ranged from 0.040 (Pag island sheep) to 0.091 (Kupres pramenka). Moderate genetic differentiation was found between the studied sheep populations. The total genetic variability observed between different populations was 5.29%, whereas 94.71% of the variation was found within populations. Cres island sheep, Lika pramenka and Istrian sheep were identified as the most distinct populations, which was confirmed by the factorial analysis of correspondence and supported through a bootstrapping adjustment to correct for the difference in the sample sizes. The population structure analysis distinguished 12 clusters for the 12 sheep breeds analysed. However, the cluster differentiation was low for Dalmatian, Vlasic, Stolac and Krk pramenka. This systematic study identified Lika pramenka and Rab island sheep as those with the lowest diversity, whereas Istrian sheep and Pag island sheep had the highest. Conservation actions are proposed for Istrian, Rab and Cres island sheep, Lika and Kupres pramenka because of high estimated coefficients of inbreeding.