A comparison was made over 2 years of sires of Suffolk and Dutch Texel breeds and ewes of Greyface (Border Leicester × Scottish Blackface), Suffolk Cheviot and Dutch Texel breeds in terms of food intake, prolificacy and lamb growth rates under a grass-based system of production. Suffolk Cheviot ewes consumed significantly more silage dry matter than the Greyface ewes in both years of the study. There was no overall difference between Greyface and Suffolk Cheviot ewes in terms of prolificacy. However lambs from Suffolk Cheviot ewes had a higher growth rate than lambs from Greyface ewes from birth to weaning in year 1 (P < 0·01). In the comparison of the three ewe breeds sired by Dutch Texel rams in year 2, Dutch Texel ewes produced a similar number of lambs to the other genotypes but had a higher incidence of difficult lambings, higher lamb mortality and consequently a lower number of lambs weaned. Purebred Dutch Texel male lambs had lower growth rates than crossbred Dutch Texel lambs (143 compared with 158 glday for lambs from Greyface ewes and 166 (s.e. 13.4) glday for lambs from Suffolk Cheviot ewes in year 1 and 183 compared with 251 and 248 respectively (s.e. 10.9) glday in year 2). Lambs sired by Suffolk rams had higher growth rates than those sired by Dutch Texel rams (252 compared with 224 (s.e. 5.4) glday) in year 2.

The pattern of follicle activity and fibre growth on the neck, mid side and rear leg of 12 Scottish Cashmere (SC) and nine Siberian (S) goat kids was examined from birth to 255 days of age. In both genotypes maximum secondary to primary follicle (S/P) ratio was reached earliest on the neck (P < 0·05) but was proportionately 0·21 and 0·28 (P < 0·001) lower than that on the rear leg and mid side respectively. Secondary follicle activity ceased earlier on the rear leg than the mid side or neck (P < 0·001) and this was associated with lower staple lengths and patch weights of undercoat. Fibre weight and diameter were compared on six body parts: neck, front leg, mid side, rear leg, rump and belly at 255 days of age. Patch undercoat weights and diameter were greatest on the neck, front leg and rump and lowest on the belly.

The estimated annual production of undercoat, calculated from patch weights and skin area measurements on the six parts of the body at 255 days of age was 138 (range 42 to 260) g for SC kids and 525 (range 377 to 661) g for S kids (s.e.d. = 39·4, P < 0·001). Mean undercoat diameter was 16·15 (range 15·32 to 17·51) and 18·94 (range 17·25 to 19·89) μm for SC and S kids respectively (s.e.d. = 0·376, P < 0·001).

Correlation coefficients between fibre traits, measured at approximately monthly intervals and estimates of annual production and undercoat diameter at 255 days were calculated. For SC kids mid-side patch undercoat weight was consistently and strongly related to estimated annual production (mean correlation coefficient, 0·85, s.e. 0·036). For S kids the only variable to show a consistently strong relationship with estimated annual production was mid-side undercoat staple length × diameter2 (mean correlation coefficient 0·66, s.e. 0·067). Thus the best fibre traits for ranking annual production differed between genotypes. In both cases the accuracy of the ranking increased with age. Undercoat fibre diameter measured from 4 to 5 months of age was closely related to estimated undercoat diameter at 255 days of age in both SC and S genotypes (mean correlation coefficient 0·92, s.e. 0·009). Prior to 4 months of age the mean correlation coefficient for SC and S genotypes was 0·53 (s.e. 0·20).

It is concluded that goat kids can be ranked for annual production and diameter of the undercoat, prior to first harvesting, based on fibre traits measured on samples of the fleece.

An experiment was conducted with 48 dairy cows grazed in treatment groups of four, eight or 16 cows per group, whose grazing, social and resting behaviour was recorded over a 53-day period. Cows in groups of four stayed closer to their nearest neighbour, moved their head more rapidly from side to side during grazing and spent more time ruminating than cows in larger groups, suggesting that they were more vigilant against a perceived prédation risk. Cows in the group of 16 were more aggressive, maintained a greater distance to their nearest neighbour and had a faster rate of stepping while they grazed, compared with cows in smaller groups, suggesting increased inter-cow competition. They also spent longer grooming themselves, which normally acts as a displacement activity and may indicate increased stress. Cows in groups of eight had a faster biting rate when grazing than cows in small or large groups and they spent the longest time lying down. There were no effects of group size on milk production but across treatment groups the high yielding cows were the first to initiate grazing and to enter the milking parlour.

The present study was performed to find out how dairy cow behaviour and the level of the adrenocortical hormone cortisol were influenced by feeding in relation to milking The experiment was designed as a Latin square and performed on 24 primiparous and multiparous Swedish Red and White dairy cows. Each treatment period lasted for 21 days, including 11 days when the cows became accustomed to the new routines. The cows were exposed to three treatments: feeding 1·5 h before milking (FBM), feeding exactly at the same time as milking (FDM) and feeding 1·5 h after milking (FAM). Recordings of individual behaviour were made with instantaneous direct observation of each cow. For the statistical analyses the recordings were divided into two groups: 0 to 1·5 h after feeding and 0 to 1·5 h after milking. Results with a P-value below 0·05 were regarded as statistically significant. The interesting findings in this study were: (a) 0 to 1·5 h after feeding, the percentage of lying was higher in FDM and the percentage of lying while ruminating was higher in FDM; (b) 0 to 1·5 h after milking, the cows in FAM had a significantly lower percentage of social interactions and a significantly higher percentage of oral activity; and (c) feeding-related level of cortisol stayed higher 30 to 60 min after feeding in FAM compared with FBM and FDM, whereas milking-related cortisol secretion tended to be lower in FDM than in FBM and FAM These results demonstrate that feeding during milking may be an important management routine, also for dairy cow behaviour.

The main objective of the experiment was to investigate whether a continuum links the development of conditioned flavour preferences and conditioned flavour aversions (CFPs and CFAs) in sheep, towards food flavours associated with intraruminal administration of increasing doses of the same nutritive stimulus: casein. A secondary objective was to investigate the effects of dose of casein administration and the number of repeated exposures to casein on the rate of establishment, magnitude and degree of persistence of developed CFPs and CFAs.

The experiment consisted of three conditioning periods (each lasted 8 days). A food with low crude protein (CP) (39.3 g/kg dry matter (DM)) and metabolizable energy (ME) (5.3 MJ/kg DM) contents was used in combination with one of two flavours, orange and aniseed, on a total of 48 Texel × Greyface male, 3-month-old sheep. The sheep were conditioned to associate one flavour added to the test food with a particular dose of casein (C) suspended in water (8.75, 17.5, 35 and 52.5 g per animal), or a different flavoured test food with an equal amount of water. Each dose was administered by gavage through a stomach tube twice daily to each animal. At the end of each conditioning period the preference for the two flavours was measured by a two choice preference test between the two flavoured test foods for 40 min. After the completion of the last conditioning period, three more preference tests (persistence tests), without any intervening exposure to the flavoured test food, were conducted at 7, 21 and 35 days. Preference for the flavoured test food paired with casein was affected by the interaction (P < 0·001) between the dose of casein and casein association respectively. Association with casein (DPR: intake of a flavoured test food paired with casein per g total intake of flavoured test foods during the preference test) led to CFPs (DPR > 0·70) at the two lowest and to CFAs (DPR < 0·30) at the two highest doses. CFPs and CFAs were established by the second conditioning and there was no difference in the rate of establishment between preferences and aversions. The persistence tests showed a strong and similar degree of persistence of both formed CFPs and CFAs, since these were not affected by time of persistence test or by any of the interactions with time. In view of these results a model is proposed which could account for the conditioned responses of sheep towards administration of increasing doses of the same nutrient. The existence of a continuum between CFPs and CFAs created by the same nutrient given at different doses, could be the basis of how ruminants select a diet which meets their nutrient requirements at a particular point in time and thereby avoid excess of nutrient intake.

Current Welfare Code recommendations suggest one nipple drinker per 10 pigs, while farmers have often used a ratio of one per 20 animals. This statement is based on information from pig farmers and advisors in the United Kingdom. Neither approach is based on empirical investigation. The use of larger group sizes in commercial herds raises further questions, since the relationship between group size and the appropriate number of drinking points cannot be assumed to be linear. The aim was to assess the two conflicting drinker allocations for their effect on welfare, as measured by drinking behaviour, social behaviour and performance, and any effect of group size on these. A total of 640 Large White × Landrace growing pigs were assigned to four treatments in a 2 × 2 factorial arrangement (60 pigs, three drinkers; 20 pigs, one drinker; 60 pigs, six drinkers and 20 pigs, two drinkers). Drinker provision had no significant effect on water use (5.10, 3.88, 4.99 and 3.45 s.e. 0.231 I per pig per day respectively) but in a larger group more water was used in less drinking time (P < 0.001). The diurnal pattern of water use was similar for each treatment. More aggression occurred at the drinker in large groups with a poorer drinker allocation (11.0 v. 3.8% of drinking bouts terminated by aggression for 60 pigs with three drinkers and mean all other treatments respectively, P < 0·05). Overt aggression (2.22, 2.27, 1.76 and 2.07 (s.e. 0.284) aggressive acts per pig per h, respectively) and lesion score counts of a sample of pigs from each pen suggested no difference between treatments. Providing one drinker per 20 animals, even in a large group, did not affect drinking behaviour, social behaviour or production. These findings should not be extrapolated to situations of different ambient temperature, water flow rate or feeding strategy.

A study was conducted at the Asella Station in the Arsi Region of Ethiopia to investigate the dairy performance of indigenous purebred Arsi and Friesian × Arsi crosses under different pre-partum and post-partum supplementary feeding regimes. A total of’343 first-lactation animals were involved in the experiment. Lactation performance was not significantly affected by pre-partum supplementation. Post-partum supplementary feeding significantly affected total lactation milk and butterfat yields of the crosses but not the purebred Arsi. Arsi crosses produced more milk (1873 (s.e. 65·1) v. 258 (s.e. 31·7) kg) and butterfat (92 (s.e. 4·0) v. 25 (s.e. 2·8) kg) than purebred Arsi. The crosses stayed in lactation longer (474 (s.e. 13·0) v. 179 (s.e. 15·4) days) than the latter. Purebred Arsi manifested much more variation in total lactation milk yield (CV: 1·27 v. 0·37), lactation length (0·91 v. 0·30) and butterfat yield (0·71 v. 0·42) than Arsi crosses. F1 crosses produced slightly more milk (+266 kg) and butterfat (+19·3 kg) but had shorter (-30 days) lactations than the backerosses.

The coypu (Myocastor coypus) is an aquatic rodent usually bred for fur production. Fluctuations in fur prices have led to coypu meat being considered as a genuine resource in commercial farms, which contribute to the diversification of agro-ecosystems. To characterize coypus as a meat resource, maternal and heterotic effects on birth weight, weaning weight, slaughter weight, number of days required to attain a weaning weight of l kg, and on two parameters of the Gompertz growth curve (asymptotic weight and maturing rate) were studied. Eight males and eight females of Standard (S) and Cognac (C) genotypes and of their reciprocal crosses (C × S) and (S × C), where the first letter denotes the paternal genotype, were used. Significant genotype, sex and (genotype × sex) interaction effects were evident for most traits. S animals were lighter than С at all ages. Hybrids with С mothers were heavier than their reciprocals. Maternal effects on the parameters of the growth curve were observed only in females. Heterotic effects were extremely significant. Favourable heterotic effects in immature animals were explained by a change in the F1 growth pattern. Males showed a dominant deviation toward low asymptotic weights and overdominance for high maturing rate. Females showed partial dominance of high asymptotic weight and over dominance for high maturing rate. This association of genetic effects would justify a productive system based on a terminal cross using С females and S males because of the higher maturing rate of both hybrids and the maternal effect of С genotype, a combination that allows higher weights at the usual slaughter age (6 months) or butchering of animals at earlier ages.

Body length and ultrasonic fat thickness measurements were taken on 86 live pigs in order to find an optimal probing site for estimation of lean meat proportion. The next day pigs were slaughtered and measurements with the Hennessy Grading Probe (HGP) were made in order to estimate the lean meat proportion.

Fat thickness, 6 cm off the dorsal mid line, increased from a value of 9·5 mm at a site 4 cm cranial to the last rib, progressively through intermediate sites to a value of 12·4 mm, 22 cm cranial to the last rib. Fat thickness measurements at different sites (live pigs) were highly correlated with HGP fat thickness at the site between 3rd and 4th from last rib (3/4 LR) and estimated lean meat proportion (carcasses); correlations ranged from 0.80 to 0.89 and -071 to -0.85 respectively. The most accurate predictor of estimated lean meat proportion from the live pig measurements was the measurement at 18 cm cranial to the last rib. Measurement at the site half the distance between the occipital bone and the base of the tail (midpoint) was the second-best for estimated lean meat proportion.

Generally, this midpoint on live pigs was situated around the 3/4 LR on carcasses. However, the range was considerable. Half of the number of animals had a midpoint in the range of -2.5 to 2.5 cm from 3/4 LR. The site midpoint is easily located on the animal and the results of this study suggest that it can be used as an accurate predictor of estimated lean meat proportion. Therefore it can serve as the probing site for classification of live pigs.

The metabolic pathways of dietary fatty acids were studied in rabbits by analysing the fatty acid profile of different tissues (liver, perirenal fat, longissimus lumborum muscle). Four groups of 24 hybrid males each were assigned to four semi-purified diets, varying in the source oflipids which differed in n-3/n-6 ratios: 180 g/kg sunflower (S), 80 g/kg flaxseed + 90 g/kg sunflower (SF), 160 g/kg flaxseed (F) and 60 g/kg fish oil (FI). The liver showed a very important rôle in fatty acid syntheses and was the tissue richest in long-chain (≥20 C) polyunsaturated fatty acids (LCP) of n-3 and n-6 series. The S diet gave the highest mono-unsaturated fatty acids and n-6 LCP (respectively, 201·9 and 384·9 g/kg, P < 0·01) also showing a clear antagonism v. n-3 LCP; the FI diet determined the highest enrichment of n-3 LCP (179·5 g/kg, P < 0·01). a-linolenic acid was efficiently converted into n-3 LCP mainly when п-ЗІп-6 ratio was high (Σn-3/С20: 4n-6: 2·74 and 3.61, P < 0·01 in flaxseed and fish-oil diet, respectively). The same trend occurred in the muscle but in a less consistent way. The adipose tissue more closely reflected the composition of the dietary fatty acids, showing variations mainly concerning polyunsaturated fatty acids (S diet), and LCP n-3 (FI diet: 44·9 g/kg, P < 0·01). Results showed the possibility of modifying the fatty acid profile of rabbit meat by dietary means and that the n-3/n-6 ratio of the food is crucial in regulating the relative presence of LCP n-3 or n-6 in meat products.

A dynamic model for simulation of growth in pigs was extended by a module to assess maximum and minimum heat loss (HLcold, HLhot) for a given pig, to compare these figures to heat production (HP), and to take thermoregulatory action when HP < HLcold (cold conditions) or HP > HLhot (hot conditions).

HLcold and HLhot were largely determined according to algorithms obtained from the literature, hut HLcold was made dependent on body fat depth through tissue insulation. Data to establish the relation (Ύ = 0.05 + 0.002 x X) between cold tissue insulation (Ύ in °C.m2 per W) and backfat depth (X in mm) independent of body weight were obtained from the literature. The same data showed that HLhot is not related to backfat depth in pigs.

Cold thermoregulatory action included an increase of ad libitum food intake. Hot thermoregulatory action included reduction of physical activity, increase of body temperature, wetting of a proportion of the skin and reduction of dia libitum food intake.

A sensitivity analysis showed that the model’s output in terms of ãd libitum food intake, HP, protein deposition (Pdep) and lipid deposition (Ldep) is strongly sensitive to the characterization of the genotype being simulated. The model was used to simulate trials from the literature. Although the model does not explicitly calculate lower and upper critical temperatures, these could be adequately predicted from its output. Comparison of model output with experimental data revealed an adequate prediction of ad libitum food intake and of the partitioning of ad libitum ingested metabolizable energy (ME) into HP, Pdep and Ldep in cold, thermoneutral and hot conditions. At restricted ME intake, and especially in cold conditions, the model tends to overestimate HP and underestimate Ldep, probably because it does not take account of long-term acclimatization.

Spreadsheet models were constructed to assess the economic impact of some 30 non-notifiable diseases of farm animals in Great Britain. A standardized methodology and common valuation base were used to derive estimates of the direct costs to livestock production of each disease, separately identifying the costs associated with disease output losses and those relating to disease treatment and prevention. Disease data limitations and uncertainties are incorporated into the estimation procedure. The spreadsheet models are highly transparent with calculations and the origin of parameter values clearly documented. The assessments of six bovine diseases, are presented: BVD, fasciolosis, lameness, leptospirosis, mastitis, and summer mastitis, and full details of the analyses of all the diseases can he accessed on the internet. The models do not consider the wider economic impacts of disease, such as effects on markets, human health and animal welfare. However, the approach is a simple and transparent one which enables exploration of the direct costs associated with a range of livestock diseases and which is easily communicated to policy makers and others.

Two experiments were conducted to corroborate or refute the theory that animals will choose a food that will allow them to use it with maximum efficiency. Pigs have been shown to utilize foods of high nutrient density more efficiently than those of low density, so the choices made by pigs when offered such foods could be used to test the above optimization theory. In experiment 1, 48 Large White × Landrace gilts were used, for an 8-week period starting at 22 kg live weight, while in experiment 2, 48 boars of the same cross but of a genetically improved strain were used from 24 to 60 kg live weight. In both experiments use was made of high nutrient density summit foods which were used alone, or diluted in the ratio 80 summit: 20 milled sunflower husk to provide the low density foods. In experiment 1, the high density diet (HI) contained 7·5 g lysine per kg and 13·20 MJ digestible energy (DE) per kg, whereas in experiment 2 two summit foods were formulated, the first diet (H2) was offered for 3 weeks from 24 kg live weight and the second (H3) followed until 60 kg live weight. Foods H2 and H3 contained 11·0 and 8·40 g lysine per kg respectively and 15·0 and 14·0 MJ DE per kg, respectively. Both experiments made use of a high (H1 and H2, respectively) and a low nutrient density (L1 and L2, respectively) control treatment in which pigs were given ad libitum access to H1 and H2/H3, and L1 and L2/L3 in experiments 1 and 2 respectively (no. =4). In addition, a medium density treatment (Ml) consisting of a 50: 50 mixture of H1 and L1 (no. = 4) was given in experiment 1. Two choice-feeding treatments where used in both experiments, the first in which H1 and H2IH3 were placed in the left bin (CL1 (no. =18) and CL2 (no. = 20), respectively) and the appropriate dilution diet in the right bin, and the second in which H1 and H2/H3 were placed in the right bin (CR1 (no. = 18) and CR2 (no = 20)). There were no differences in average daily growth rates between treatments within experiments but there were significant differences (P < 0·05) in food intakes and efficiency of food utilization (FCE) between treatments. The highest intakes and lowest FCE were obtained on the L1 and L2 treatments while the lowest intakes were recorded on the choice-feeding treatments. There were no significant differences in FCE neither between H1, CL1 and CR1 nor between H2, CL2 and CR2. Only in experiment 1 were there significant differences (P < 0·05) between choice-feeding treatments on the basis of the position of the food bin but there was no preference for a particular position. The results indicated that pigs were able to differentiate successfully between two foods on the basis of their nutrient density, that bin position was not used as a cue in the choice made, that a small amount of the ‘unwanted’ food was consumed throughout the experiment and that the diet selected maximized FCE.

Current feeding recommendations for lactating sows may be inappropriate for modern genotypes with high milk production. The introduction of the prolific but obese Meishan breed into sow lines also necessitates a review of nutrient requirements. A 2 × 2 factorial experiment was used to investigate the influence of breed type (Meishan synthetic 50% (M) and purebred European White (W) on response to dietary protein level (L = 140 g crude protein (CP) per kg, 6 g lysine per kg; H = 181 g CP per kg, 9 g lysine per kg) over a 5-week lactation. Milk yield (days 5, 9, 13,17, 21 and 28), milk composition and piglet growth and body composition were measured to quantify aspects of lactational performance. M had higher litter sizes throughout lactation (P < 0·001) and produced more milk than W(M = 10·04 W = 7·85 (s.e.d. 0·521) kg/day, P < 0·001) and milk of a higher fat content (M = 79·6 W = 75·0 (s.e.d. 5·71 g/kg, P < 0·05). Total solids were not significantly different between treatments. H produced higher milk protein content than L (L = 43·0 H = 55·7 (s.e.d. 3.01) g/kg, P = 0·05). Litter growth rates showed a breed effect (P < 0·001), diet effect (P < 0·001) and a breed × diet interaction (ML = 2·41 MH = 3·21 WL = 2·07 WH = 2·07 (s.e.d. 0·658) kg/day, P < 0·001). M piglets had higher fat deposition rates (M = 37 W = 24 (s.e.d. 4.5) g/day, P < 0·05). L piglets had a lower protein (P < 0·05) and fat (P < 0·05) deposition rate compared with H piglets. Higher litter growth rates of M sows resulted from a combination of increased milk yield and f at content and this was further enhanced by additional dietary protein. W sows showed no milk yield response to dietary protein but reduced maternal tissue catabolism.

Our laboratory recently reported that the ratio of a piglet’s weight to that of its placenta (RATIO) varies approximately three-fold within a litter, due predominantly to variation in placental size which is known to be a limiting factor in litter size. It was further determined that selection of boars and gilts with a higher than average RATIO for breeding resulted in an increased litter size and reduced placental weights. The objective of this experiment was to examine the effects of RATIO on economically important production traits (piglet survival to weaning, 21-day weights, days to 105 kg, backfat depth and loin muscle area at 105 kg) in a purebred breeding stock herd of Finnish Yorkshire and Landrace pigs. Sows were monitored throughout farrowing and each piglet was matched to its placenta. Each piglet and its placenta were individually weighed and a RATIO determined. Placental weight but not piglet birth weight exhibited a strong (P < 0·001) negative correlation with RATIO (r = -073). Up to three-fold differences in RATIO were observed within a single litter. These differences were much greater than the variation noted between litters and litter mean RATIO was not significantly associated with litter size. The distribution of individual piglet RATIOS across the entire group of pigs ranged from 2·8 to 11·4 suggesting a marked difference in placental efficiencies. No significant association was seen between RATIO and 21-day weight, days to 105 kg, backfat depth or loin muscle area. Thus, an above average ratio of a piglet’s weight to that of its placenta is indicative of a smaller more efficient placenta and appears to have no subsequent detrimental effects on growth efficiency.

Responses to intravenous glucose challenge (no. = 26) and basal metabolite and hormone concentrations (no. = 68) were determined in dairy cows selected for high (HFI) or low (LFI) milk-fat concentration but with similar 40 g/kg fat-corrected milk (FCM) yields. All cows were given a mixed diet ad libitum. Following a glucose challenge the insulin release was higher (P < 0·05) and the glucose clearance rate faster (P < 0·05) in the HFI cows compared with the LFI cows. Basal plasma concentrations of the metabolites alanine, β -hydroxybutyrate, glucose, non-esterified fatty acids and urea and the hormones insulin-like growth factor-1 (IGF-1), insulin and leptin were not influenced by selection line.

The silver fox is an extreme seasonal breeder with one reproductive season during the year. Males are sexually mature at the age of 9 to 10 months. In the present study reproductive function in yearling and adult silver fox males before and during the reproductive period was examined. The aim was to determine the age-dependent features of their reproductive system. It was found that yearling males mate with a smaller number of females and that their first mating period is shorter compared with adult foxes. A high proportion of yearling males did not mate at all (27%) or their sexual activity was reduced (26%), although the number of pups horn from mating males was normal. During the peak of male sexual activity, the number of spermatozoa in the ejaculate was lower in yearling compared with adult males. However, there was no difference in the number of abnormal forms of spermatozoa between the two groups. There was no significant difference in sperm numbers between sexually active and inactive yearlings. Before the reproductive season, yearling males did not differ from adults in plasma concentration of testosterone, while body and testes weights and level of oestradiol were lower. At the end of the breeding season, yearlings did not differ from adults in any trait. It is concluded that the reproductive capacity of yearling male foxes might he immature before the first breeding seasons but that this immaturity did not decrease their reproductive success.

Changes in the formulation and flavour of concentrate foods may temporarily reduce their acceptability to cattle, leading to reduced intake when they are offered for a limited time during milking. The rate of intake of 12 dairy cows offered 1 kg of salty or bitter concentrates was compared with a sweet concentrate, with or without an artificial sweetener to mask adverse flavours. The cows were offered the test concentrates twice a day in a Latin-square design with seven feeding occasions per period and the apparent and actual (excluding non-feeding time) food intake rates were recorded for all seven feeding occasions. Both apparent and actual intake rates were slower for the bitter compared with the salty and sweet flavoured concentrate.

For the first two feeding occasions the intake rate was recorded separately for the 1st min and the subsequent period until the end of feeding. The intake rate was faster in the 1st min because of more rapid prehension of the food and fewer interruptions to the feeding process. Where no mask was included there was no effect of flavour on the apparent intake rate in the 1st min of the first feeding occasion but in the 1st min of the second feeding occasion the apparent intake rate of the salty concentrate was less than that for the sweet or bitter concentrates. The actual intake rates of the bitter and salty concentrates were less than for the sweet concentrate. The mask increased the apparent intake rate of the bitter and sweet concentrates in the 1st min of both the first and second feeding occasions, by reducing the non-feeding time and it also increased the actual intake rate of salty concentrates.

After the 1st min the apparent intake rate of the salty concentrate was faster than that of the bitter and sweet concentrates, where no mask was included. The mask increased the apparent intake rate of the sweet concentrates at this time but reduced it for salty and bitter concentrates. It therefore reduced the acclimatization to the salty and bitter concentrates and enhanced the attractiveness of the sweet concentrates.

There was a residual effect from the previous period of concentrates which were eaten slowly i.e. salty concentrates, which reduced the 1st min intake of foods that were eaten rapidly, i.e. sweet concentrates, in the subsequent period. This was largely due to increases in the time spent pausing between bouts of food ingestion. After the 1st min the apparent intake rate of cows receiving salty concentrate for a second consecutive period was increased, suggesting acclimatization. The opposite effect was observed for the sweet concentrate, probably because the novelty of the sweetness had diminished, making it relatively less attractive to the cow. This experiment therefore provides evidence that bitter and to some extent salty concentrates are consumed at a slower rate than sweet concentrates, except for the 1st min in which they are offered to cattle and that a reduced concentrate intake rate may persist after the flavour is removed from the food. Cattle did, however, demonstrate an ability to acclimatize to salty concentrate over time.

The influence of prior exposure to high salt diets on the salt appetite and the exhibition of stereotyped behaviour patterns was investigated with individually penned calves and tethered dairy cows. In the first experiment one half of a group of 12 calves received concentrates with the sodium content increased from 4 to 9 g/kg by the addition of NaCl up to weaning at 6 weeks, the other half had no supplementary NaCl added to the concentrates. Adding the NaCl increased the food intake of the calves, the time spent ruminating and live weight. Stereotyped behaviour patterns, such as self-grooming, licking the pen or buckets and ear sucking were reduced by adding NaCl. Calves were tested for their salt preference at 6 months of age by adding varying quantities of NaCl to silage. Exposing calves to supplementary NaCl in the concentrate pre-weaning increased the preferred sodium concentration of silage from 3 to 9 g/kg dry matter (DM). In the second experiment 36 tethered dairy cows received either a restricted concentrate and forage diet with a mean dietary sodium concentration of 2 g/kg DM, or the same diet but with the sodium content increased to either 7 or 12 g/kg DM by adding NaCl to the concentrates. There was no effect of NaCl on feeding or ruminating behaviour but the total amount of stereotyped behaviour, including mouthing or rubbing the tethering chain or bars, self-grooming and nosing or pawing the ground, decreased with increasing salt in the diet. It is concluded that increasing the sodium content of the diet of young calves from 4 to 9 g/kg increased their subsequent salt appetite and that increasing the salt content of the diet of calves or cows in restricted housing conditions can reduce the amount of stereotyped oral behaviour.

Two experiments were designed to study the influence of an increase in energy supply on the utilization of exogenous glucose in food-restricted post-partum Charolais suckler beef cows. In experiment 1, 18 cows were given a basal diet (BD) providing 0·70 of energy requirements from calving with or without an energy supplement (SD) of 2 kg of rolled triticale grain starting at day 32 post partum. On day 42 post partum an injection of glucose (1·0 mmol/kg live weight) lasting 20 min resulted in a similar plasma glucose and cortisol profile in each diet group but a smaller plasma insulin increase in SD than in BD cows (146 (s.e. 37) v. 273 (s.e. 37) pmol/l, P < 0·05). Plasma non-esterified fatty acids concentrations were reduced by the glucose injection (P < 0·01). Experiment 2 compared the efficiency of an energy supplement in the form of concentrate (CS, maize grain, no. = 11) or forage (PS, maize silage, no. = 10) in oestrous-synchronized beef cows previously given a restricted diet. Glucose injection resulted in a small increase in insulin concentrations during infusion with a peak at 20 min (PS: 250 (s.e. 34) v. CS: 257 (s.e. 32) pmol/l, P > 0·05). No differences were observed between the two groups of cows for glucose, insulin and cortisol profiles (P > 0·05). Similar pregnancy rates after oestrous synchronization treatment were observed in CS and PS cows (6/11 v. 5/10). In conclusion, a period of supplementation sufficient to re-establish energy balance, but not the type of supplement, influences the insulin response to exogenous glucose in food-restricted post-partum Charolais beef cows.