The Meat Standards Australia (MSA) grading scheme has the ability to predict beef eating quality for each ‘cut×cooking method combination’ from animal and carcass traits such as sex, age, breed, marbling, hot carcass weight and fatness, ageing time, etc. Following MSA testing protocols, a total of 22 different muscles, cooked by four different cooking methods and to three different degrees of doneness, were tasted by over 19 000 consumers from Northern Ireland, Poland, Ireland, France and Australia. Consumers scored the sensory characteristics (tenderness, flavor liking, juiciness and overall liking) and then allocated samples to one of four quality grades: unsatisfactory, good-every-day, better-than-every-day and premium. We observed that 26% of the beef was unsatisfactory. As previously reported, 68% of samples were allocated to the correct quality grades using the MSA grading scheme. Furthermore, only 7% of the beef unsatisfactory to consumers was misclassified as acceptable. Overall, we concluded that an MSA-like grading scheme could be used to predict beef eating quality and hence underpin commercial brands or labels in a number of European countries, and possibly the whole of Europe. In addition, such an eating quality guarantee system may allow the implementation of an MSA genetic index to improve eating quality through genetics as well as through management. Finally, such an eating quality guarantee system is likely to generate economic benefits to be shared along the beef supply chain from farmers to retailors, as consumers are willing to pay more for a better quality product.

We determined whether plant diversity and sequence of plant ingestion affected foraging when cattle chose from plants that varied in concentrations of alkaloids, tannins and saponins. We hypothesized cattle that ate high-alkaloid grasses (endophyte-infected tall fescue (TF) or reed canarygrass (RCG)) would prefer forages high in tannins (birdsfoot trefoil, BFT+) or saponins (alfalfa, ALF+), because tannins and saponins can bind to alkaloids, presumably reducing their absorption. We further hypothesized that forages with tannins or saponins consumed before, rather than after, foraging on high-alkaloid grasses would promote greater use of those grasses presumably by binding to alkaloids, thereby reducing their absorption. In Phase 1, cattle (n = 32) grazed on either high (+) or low (−) alkaloid grass (TF or RCG) pastures for 30 min each morning at 0600 h and were then offered a choice of BFT+, BFT−, ALF+ and ALF− for 60 min each day for 12 days. In Phase 2, cattle (n = 32) were first offered a choice of BFT+ or ALF+ for 30 min at 0600 h and then placed on grass (TF+ or −, or RCG+ or −) pastures for 60 min for 12 days. In both phases, we had four spatial replications of four treatments with 2 per calves assigned to each of the 16 replications per treatment combinations. Scan samples of individuals at 2-min intervals were used to determine incidence of foraging on each plant species (%). Cattle grazed more on RCG than on TF in Phases 1 (62% v. 27%; P = 0.0015) and 2 (71% v. 32%; P = 0.0005). In Phase 1, cattle that first foraged on RCG+ or TF− subsequently preferred ALF over BFT, whereas cattle offered RCG− or TF+ foraged on ALF and BFT equally. Foraging by cattle on RCG was cyclic during Phase 1, whereas cattle foraging on TF markedly decreased incidence of use of TF from 41% to only 16% by the end of the 12-day trial (P = 0.0029). Contrary to the cyclic (RCG) or steadily declining (TF) use of grasses in Phase 1, cattle steadily and dramatically increased foraging on both RCG and TF throughout Phase 2, when they first grazed BFT+ or ALF+ followed by high-alkaloid grasses (P = 0.0159). Our findings suggest that in plant species the sequence of ingestion influenced foraging behavior of cattle and that secondary compounds influenced those responses.

The objective of this study was to estimate the genetic parameters for thermoregulation traits and the relationships with performance of Large White lactating sows reared in a tropical humid climate. The thermoregulation traits were rectal temperature (RT), cutaneous temperature (CT) and respiratory rate (RR) during lactation measured in the afternoon (1200 h) and in the morning (0700 h). The production traits were sow’s average daily feed intake (ADFI), litter BW gain (LBWg) and sow’s proportion of BW change between farrowing and weaning (BWc). Complete data included 931 lactating performance on 329 Large White sows from the INRA experimental unit in Guadeloupe (French West Indies). Random regression models using linear spline functions were used for longitudinal data (RT, CT, RR and daily feed intake). Results showed that when ignoring values at the beginning and the end of lactation, the traits studied can be treated as the same trait throughout days of lactation, with fairly constant heritability and variance. However, largest heritabilities and genetic variances were estimated in mid-lactation. Heritability estimates on average performance during lactation were low to moderate for thermoregulation traits (0.35±0.09 for RT, 0.34±0.12 for CT and 0.39±0.13 for RR). Heritability estimates for production traits were 0.26±0.08 for ADFI, 0.20±0.07 for BWc and 0.31±0.09 for LBWg. Significant genetic correlations between thermoregulation traits and production traits were only obtained for ADFI and RR (0.35±0.12). From this study it can be concluded that thermoregulation traits are heritable, indicating that there are genetic differences in heat stress tolerance in lactating Large White sows.

This study was conducted to evaluate the effect of early rearing conditions on physiological, haematological and immunological responses relevant to adaptation and long-term stress in white Leghorn hens with intact beaks housed in furnished cages (FC) or conventional cages (CC) during the laying period. Pullets were cage reared (CR) or litter floor reared (FR). From 16 to 76 weeks of age, hens were housed in FC (eight hens per cage) or in CC (three hens per cage). As measures of long-term stress at the end of the laying period, adrenal reactivity was quantified by assessing corticosterone responses to adrenocorticotropin challenge, and immune response was assessed by measuring antibody responses after immunization with sheep red blood cells (SRBC) and keyhole limpet haemocyanin (KLH). Heterophil to lymphocyte (H/L) ratio was employed as an indicator of stress. Rearing conditions significantly affected anti-SRBC titres (P < 0.0001) and tended to affect H/L ratios (P = 0.07), with the highest values found in FR hens. Layer housing affected H/L ratio (P < 0.01); the highest ratio was found in FR birds housed in FC during the laying period. This study shows that early rearing environment affects immunological indicators that are widely used to assess stress in laying hens. However, while results on H/L ratio indicated that FR birds experienced more stress particularly when they were housed in FC during the laying period, the immune responses to SRBC in FR hens was improved, indicating the opposite. This contradiction suggests that the effects on immune response may have been associated with pathogenic load due to environmental complexity in FR and FC hens rather than stress due to rearing system or housing system per se.

Most gait-scoring scales for pigs have a limited number of categories, supposedly to improve repeatability. However, reducing the number of categories could lead to loss of information if the observers’ discriminative capacities are underused. With a recently estimated within-herd prevalence of sow lameness of 8.8% to 16.9% in the European Union and the associated losses, the availability of reliable tools for the timely detection of initial cases warrants attention. This study investigated the intra- and inter-observer repeatability (intra-OR and inter-OR) of three gait-scoring scales for sows: a continuous ‘tagged’ visual analogue scale (tVAS, measured in mm), a 5-point and a 2-point ordinal scale (5P and 2P), all with the same descriptors. Veterinary medicine students (n=108) were trained to use the scales and then asked to score 90 videos (30 per scale) of sows with normal and abnormal gait. Thirty-six videos were shown once and 18 were randomly shown three times, of which one mirrored horizontally. The students’ opinions on the scales were also collected. Intra- and inter-OR were higher with the tVAS than the 2P scale (inter-OR: 0.73 v. 0.60; P<0.05. Intra-OR: 0.80 v. 0.67; P<0.05). Intra-OR was higher with the 5P (0.81) than the 2P scale (0.67; P<0.05). For all three scales, repeatabilities were lower (P<0.05) for non-lame sows (gait score of ⩽45 mm on the tVAS) than for sows showing some signs of lameness (gait score>45 mm). Video order (first 45 v. last 45 clips), mirroring, users’ opinions on the scales, and previous declared experience in handling pigs or scoring lameness in other species had no effect on repeatabilities. Correlations between the students’ and experts’ scores were high (tVAS=0.92; 5P=0.91; 2P=0.88) but the association for the 2P was not linear and the frequency distribution showed lower correlations for a group of students. This study confirms recent evidence that it is possible to design high-resolution gait-scoring scales that do not reduce observer repeatability. Visual gait-scoring scales with fewer than five categories are likely to entail loss of information on lameness in individual sows.

When embryos are cultured individually or in small groups, blastocyst yield efficiency and quality are usually reduced. The aim of this work was to investigate the effect of supplementation of the embryo culture medium (CM) with several growth factors (GFs) on embryo development and apoptosis rate when a reduced number of embryos were in vitro cultured. Two experimental studies (ES) were carried out. In ES 1, five treatments were tested to study the effect of GF on embryo development: Control (∼30 to 50 embryos cultured in 500 μl of CM); Control 5 (Five embryos cultured in 50 μl microdrops of CM), without addition of GF in either of the two control groups; epidermal GF (EGF); IGF-I; and transforming GF-α (TGF-α) (Five embryos were cultured in 50 μl microdrops of CM with 10 ng/ml EGF, 10 ng/ml IGF-I or 10 ng/ml TGF-α, respectively). In ES 2, following the results obtained in ES 1, four different treatments were tested to study their effect on embryo development and quality (number of cells per blastocyst and apoptotic rate): Control; Control 5; EGF, all three similar to ES 1; EGF + IGF-I group (five embryos cultured in 50 μl microdrops of CM with 10 ng/ml EGF and 10 ng/ml IGF-I). In both ESs, it was observed that a higher proportion of embryos cultured in larger groups achieved blastocyst stage than embryos cultured in reduced groups (22.6% v. 14.0%, 12.6% and 5.3% for Control v. Control 5, IGF-I, TGF-α groups in ES 1, and 24.9% v. 17.1% and 19.0% for Control v. Control 5 and EGF in ES 2, respectively; P < 0.05), with the exception of embryos cultured in medium supplemented with EGF (18.5%) or with EGF + IGF-I (23.5%), in ES 1 and ES 2, respectively. With regard to blastocyst quality, embryos cultured in reduced groups and supplemented with EGF, alone or combined with IGF-I, presented lower apoptosis rates than embryos cultured in reduced groups without GF supplementation (11.6% and 10.5% v. 21.9% for EGF, EGF + IGF-I and Control 5 groups, respectively; P < 0.05). The experimental group did not affect the total number of cells per blastocyst. In conclusion, this study showed that supplementation of the CM with EGF and IGF could partially avoid the deleterious effect of in vitro culture of small groups of bovine embryos, increasing blastocyst rates and decreasing apoptosis rates of these blastocysts.

It is known that microbial activity in the hind-gut of pigs influences the amino acid composition of faeces (Mason, 1984), yet contributes little to protein nutrition (Just, Jørgensen and Fernández, 1985). This diminishes the extent to which amino acid digestibility determined by faecal collection from intact pigs adequately represents nutritional value. In order to minimize the interference of hind-gut microflora, pigs for digestibility trials have been surgically modified to create a by-pass of the large intestine by ileo-rectal anastomosis (e.g. Green, Bertrand, Duron and Maillard, 1987 and 1988). This involves transection of the ileum approximately 100 mm anterior to the ileo/caecal valve. The modification can be considered as an alternative to collecting digesta from cannulas fitted in the ileum. The attributes of ileo-rectal anastomosis are that all digesta, rather than spot samples, can be collected and the animals remain in good health for many months of trial work. There is, however, concern that because the anastomosis operation involves complete severance of the ileum, digestion in the ileum may be abnormal. Of particular concern is the by-pass of the ileo-caecal valve which is suspected to have a restraining rôle on digesta passage (Gazet and Kopp, 1964; Laplace and Borgida, 1976), and therefore a possible influence on digestibility. When using ileo-caecal valve, by fitting the anterior digesta, other workers have attempted to preserve a complete ileum, and functional ileo-caecal value, by fitting the anterior cannula immediately posterior to the valve (Laplace, 1986)

Herbage from first and second regrowths of perennial ryegrass based swards was directly ensiled following treatment with formic acid (850 g/kg) at 2·53 and 2·58 l/t, sulphuric acid (45% w/w) at 3·09 and 3·04 l/t, an inoculant of Lactobacillus plantarum (Kickstart, United Distillers Ltd) at 2/24 and 2/14 l/t, or no additive (control). First regrowth herbage had mean dry matter (DM) and water-soluble carbohydrate concentrations of 168 and 27·0 g/kg fresh weight with comparable values for second regrowth herbage of 164 and 16·9 g/kg respectively. All silages preserved well, although both the rate and extent of fermentation, as indicated by pH and lactic acid levels, were greater in control and inoculant-treated silages. Additive treatment had little effect on nutrient recovery following ensilage with the exception of a slightly greater recovery of both DM and energy with inoculant treated, second regrowth material. The silages were evaluated in two experiments, with 9 and 4 week periods for first and second regrowths respectively, using 48 British Friesian dairy cows. Animals were housed in individual stalls and, in addition to the treatment silages, received 5 kg/day fresh weight of a supplement containing 197 g crude protein per kg DM. Treatment of first regrowth material with formic acid significantly increased silage DM intake (P < 0·02) with a smaller, though positive effect being obtained with inoculant treatment. Treatment with either formic acid or inoculant had no significant effect on DM intake with second regrowth material. In contrast sulphuric acid tended to depress intake of first regrowth material whereas a marginal increase in intake was obtained with second regrowth material. Inoculant treatment had no significant effect on milk yield with either first or second regrowth material, although there was a tendency for small, though consistent, increases in milk fat and protein concentrations. Formic acid treatment resulted in marginal increases in fat plus protein yield whereas effects of sulphuric acid were less consistent with animal performance being decreased with first regrowth material and little effect observed with second regrowth material.

The aim of this experiment was to study the effect of stimulation of pre-mating energy intake on reproductive performance at the subsequent mating or parturition of rabbit does during four successive cycles. In the C (control, no. = 59) and R (restricted, no. = 67) groups, females had free access to the M diet (9·92 MJ/kg dry matter (DM)), except from 18 to 31 days of gestation when R females were given 150 glday. In the E group (high energy diet, no. = 64), females were given ad libitum the H diet (12·19 MJ/kg DM) from 1 to 14 days of lactation, with the M diet for the rest of the time. Females were presented to the male 10 toll days after parturition during four cycles. For primiparous does, the experimental design had no effect on pre-mating energy intake, acceptance or conception rate and litter size or weight. However, for multiparous does, pre-mating energy intake was higher for the E and the R group females than for the C group females (+0·08 and +0·04; P < 0·01). Acceptance rate of the male (47·1% v. 69·0%) and weight of the young rabbits at birth (-0·09) were lower in the R group than in the other groups (P < 0·001). The mortality of sucking rabbits was lower (6·5% v. 24·7%) and conception rate for the fourth litter was higher (97·1% v. 78·4%) in the E group than in the other groups (P < 0·05).

These results suggested that increased pre-mating energy intake could have a positive effect on conception rate. However, inadequate pre-partum energy intake (food restriction) has a detrimental effect on receptivity and litter weight.

The objective of this study was to determine the effect of growth rate on muscle fibre characteristics, concentration of nucleic acids (RNA and DNA) as indicators of muscle protein synthesis capacity and activity of the calpain system at time of slaughter in m. longissimus lumborum (LL) and m. supraspinatus (SS) from calves, in order to elucidate the effect of growth rate on muscle protein turn-over at time of slaughter. Twenty-four Friesian heifer calves were allocated to two different feeding regimens that allowed for a moderate/moderate (MM) or high/high (HH) growth rate from 5 days of age to 90 kg body weight (BW) (period I) and from 90 kg BW to slaughter at 250 kg BW (period II), respectively. The growth rates in the two periods and the weight of LL and SS at slaughter were recorded. Within 30 min after exsanguination, samples were removed from LL and SS, snap-frozen, and later analysed for muscle fibre type frequency and cross-sectional area, DNA and RNA concentration and the activity of the calpain system. High growth rate (i.e. 895 g/day and 1204 g/day in periods I and II, respectively), compared with moderate growth rate (678 g/day and 770 g/day in periods I and II, respectively) had a marked effect on muscle weight and muscle characteristics. High compared with moderate growth rate resulted in hypertrophic growth of type I, IIA and IIB fibres in LL and of type IIA and type IIB fibres in SS, but had no effect on the muscle fibre type frequency in either of the muscles. High growth rate increased total DNA and RNA content and the RNA: DNA ratio in LL, indicating a greater potential for protein synthesis in this muscle, whereas the effect of growth rate was smaller in SS. The activity of µ-calpain, m-calpain and calpastatin was higher in the red SS muscle compared with the whiter LL muscle. However, these enzyme activities were not affected by growth rate, and thus, did not indicate a higher myofibrillar proteolysis in vivo in calves exhibiting high growth rate compared with moderate growth rate. Overall the results showed that different types of muscles react differently to high versus moderate growth rate. High growth rate induced muscle hypertrophy and increased protein synthesis capacity especially in LL and less in SS, but the activities of the enzymes in the calpain system did not show any concomitant increase in muscle protein degradation that would be in favour of improved meat tenderness.

The live-weight changes of 48 sows were recorded over three reproductive cycles. All sows were given standard amounts of feed in gestation and one of four energy allowances during lactation. The daily intakes of digestible energy during lactation ranged from 12·2 to 182·2 Meal in the first, 122·9 to 192·6 Meal in the second and 132·2 to 202·2 Meal in the third lactation. Weight change in lactation responded to energy intake; sows on the lowest energy intake lost weight whilst those on the highest intake gained. At weaning of their third litters, sows on the highest energy allowance weighed 44 kg more than those on the lowest level and this was equivalent to a carcass difference of 372·3 kg at slaughter.

All the sows were slaughtered after the third litters had been weaned and the carcasses were dissected into lean, subcutaneous fat+skin, and bone. Sows from all treatments had less subcutaneous fat+skin and more muscle and bone than non-pregnant gilts killed at a mean weight of 129 kg, a weight equivalent to that of the experimental animals at their first mating.

The reduction in fat reserves was linearly correlated with dietary energy intake of the sows. Sows receiving the lowest energy intake in lactation possessed fat reserves which were estimated to be only 25% as great as in gilts comparable to those used to initiate the experiment. This reduction in body reserves has implications with regard to the long-term effects of feeding lactating sows low intakes of energy during 6-week lactations.

As water is the major component of the pig body its accurate prediction is of importance in pig growth models. It has become conventional to predict the weight of water, WA kg, from the weight of protein, P kg. The purpose of this paper is to find how this can be done across pig genotypes of different mature size. The widely used equation to relate WA to P is of the form: WA = a.Pb. This equation is examined theoretically. It is concluded that the form of the equation is reasonable and, that while the value of the exponent b is likely to be constant across genotypes, the value of the scalar a is not. It is proposed that the value of the scalar a is best estimated as a = WAPRm Pm1·b where WAPRm is the water: protein ratio in the body at maturity and Pm is the weight of protein in the body at maturity. The value of the parameter WAPRm is assumed to be constant across genotypes with a value in the range of 3·04 to 3·20, depending on the methods used for measuring body composition. The general value of b = 0·855, taken from published work, is confirmed. A consequence of the argument quantified in the paper is that the value of a is predicted to vary from a = 4·69 for a pig with Pm = 20 kg to a = 5·36 for a pig with Pm = 50 kg. The general equation is expected to give more accurate predictions of the weight of water and, hence, of body weight, in models intended to predict pig growth, food intake, body composition and efficiency.

A study of the determinants of inter- and intra-litter variation in muscle fibre number was carried out on five litters of Large White piglets. Fresh frozen, whole mid-belly sections of m. semitendinosus were stained to demonstrate acid-stable myosin adenosine triphosphatase activity. From these sections it was possible to identify which fibres had developed as primary and which as secondary fibres. Estimations of total muscle fibre number, total primary fibre number and ratio of secondary fibres to primary fibres were made for each animal. Results demonstrated that primary fibre number varied between litters (P<0·01) and was responsible for the variation in total muscle fibre number (P < 005) between litters since there was no significant variation in secondary: primary ratio. Within-litter differences in total fibre number could be attributed to both the secondary: primary ratio and primary fibre number, in almost equal contributions. However, when only the largest and smallest extremes of the litters were compared, variation in fibre number was due to the significant difference in the secondary: primary ratio (P<0·01). Taken as a whole, the results appear to show that primary fibre number is responsible for all the variation in muscle fibre number between litters, and also makes a significant contribution, with secondary: primary fibre ratio, to the variation present within a litter. The factors responsible for variations in primary and secondary fibre numbers are discussed.

The meat quality of chicken is an important factor affecting the consumer’s health. It was hypothesized that n-3 polyunsaturated fatty acid (n-3 PUFA) could be effectively deposited in chicken, by incorporating antioxidation of soybean isoflavone (SI), which led to improved quality of chicken meat for good health of human beings. Effects of partial or complete dietary substitution of lard (LA) with linseed oil (LO), with or without SI on growth performance, biochemical indicators, meat quality, fatty acid profiles, lipid-related health indicators and gene expression of breast muscle were examined in chickens. A total of 900 males were fed a corn–soybean meal diet supplemented with 4% LA, 2% LA + 2% LO and 4% LO and the latter two including 30 mg SI/kg (2% LA + 2% LO + SI and 4% LO + SI) from 29 to 66 days of age; each of the five dietary treatments included six replicates of 30 birds. Compared with the 4% LA diet, dietary 4% LO significantly increased the feed efficiency and had no negative effect on objective indices related to meat quality; LO significantly decreased plasma triglycerides and total cholesterol (TCH); abdominal fat percentage was significantly decreased in birds fed the 4% LO and 4% LO + SI diets. Chickens with LO diets resulted in higher contents of α-linolenic acid (C18:3n-3), EPA (C20:5n-3) and total n-3 PUFA, together with a lower content of palmitic acid (C16:0), lignoceric acid (C24:0), saturated fatty acids and n-6:n-3 ratio in breast muscle compared to 4% LA diet (P < 0.05); they also significantly decreased atherogenic index, thrombogenic index and increased the hypocholesterolemic to hypercholesterolemic ratio. Adding SI to the LO diets enhanced the contents of EPA and DHA (C22:6n-3), plasma total superoxide dismutase, reduced glutathione (GSH)/oxidized glutathione and muscle GSH content, while decreased plasma total triglyceride and TCH and malondialdehyde content in plasma and breast muscle compared to its absence (P < 0.05). Expression in breast muscle of fatty acid desaturase 1 (FADS1), FADS2, elongase 2 (ELOVL2) and ELOVL5 genes were significantly higher with the LO diets including SI than with the 4% LA diet. Significant interactions existed between LO level and inclusion of SI on EPA and TCH contents. These findings indicate that diet supplemented with LO combined with SI is an effective alternative when optimizing the nutritional value of chicken meat for human consumers.

Strategies of introgressing a transgene into a pig nucleus undergoing mass selection for net merit were deterministically evaluated. They consisted of systematically backcrossing hemizygous transgenic sires to females from the selection nucleus, or vice versa, followed by intercrossing of hemizygous individuals, assuming different levels of heritability (h2), polygenic breeding value of the founder animal, inbreeding depression and constraints in availability of resources. The polygenic breeding value of the founder transgenic animal and inbreeding depression were of negligible importance if backcrossing lasted for at least three generations, and there was little advantage in extending backcrossing much further. The best introgression strategy examined was to backcross selection nucleus sires to hemizygous females, but this was a less efficient strategy in terms of testing transgene effects. Testing the survival of homozygous carriers requires approximately five and 100 matings among hemizygous individuals to detect a reduction in viability of 0·5 and 0·1, respectively. Comparing several candidate transgenes in the first generations of backcrossing is feasible, and does not result in substantial delays in improvement of polygenic breeding value in the selected transgene. If resources are limited, the magnitude of the transgene effect (as a proportion of the mean) that compensates for the genetic lag incurred by its introgression is about 0·1 for most economic traits in pigs. To compensate for less selection while backcrossing and for risk in use, transgenes must have an appreciable effect on economic merit to make their introgression worthwhile, even when the additional costs of transgene production are ignored.

Although food from grazed animals is increasingly sought by consumers because of perceived animal welfare advantages, grazing systems provide the farmer and the animal with unique challenges. The system is dependent almost daily on the climate for feed supply, with the importation of large amounts of feed from off farm, and associated labour and mechanisation costs, sometimes reducing economic viability. Furthermore, the cow may have to walk long distances and be able to harvest feed efficiently in a highly competitive environment because of the need for high levels of pasture utilisation. She must, also, be: (1) highly fertile, with a requirement for pregnancy within ~80 days post-calving; (2) ‘easy care’, because of the need for the management of large herds with limited labour; (3) able to walk long distances; and (4) robust to changes in feed supply and quality, so that short-term nutritional insults do not unduly influence her production and reproduction cycles. These are very different and are in addition to demands placed on cows in housed systems offered pre-made mixed rations. Furthermore, additional demands in environmental sustainability and animal welfare, in conjunction with the need for greater system-level biological efficiency (i.e. ‘sustainable intensification’), will add to the ‘robustness’ requirements of cows in the future. Increasingly, there is evidence that certain genotypes of cows perform better or worse in grazing systems, indicating a genotype×environment interaction. This has led to the development of tailored breeding objectives within countries for important heritable traits to maximise the profitability and sustainability of their production system. To date, these breeding objectives have focussed on the more easily measured traits and those of highest relative economic importance. In the future, there will be greater emphasis on more difficult to measure traits that are important to the quality of life of the animal in each production system and to reduce the system’s environmental footprint.

The relative contribution of ruminal short-chain fatty acid (SCFA) absorption and salivary buffering to pH regulation could potentially change under different dietary conditions. Therefore, the objective of this study was to investigate the effects of altering the ruminal supply of rapidly fermentable carbohydrate (CHO) on absorptive function and salivation in beef cattle. Eight heifers (mean BW±SD=410±14 kg) were randomly allocated to two treatments in a crossover design with 37-day periods. Dietary treatments were barley silage at 30% low forage (LF) or 70% high forage (HF) of dietary dry matter (DM), with the remainder of the diet consisting of barley grain (65% or 25% on a DM basis) and a constant level (5%) of supplement. The LF and HF diets contained 45.3% and 30.9% starch, and 4.1% and 14.0% physically effective fiber (DM basis), respectively. Ruminal pH was continuously measured from day 17 to day 23, whereas ruminal fluid was collected on day 23 to determine SCFA concentration. Ruminal liquid passage rate was determined on day 23 using Cr-ethylenediaminetetraacetic acid. Eating or resting salivation was measured by collecting masticate (days 28 and 29) or saliva samples (days 30 and 31) at the cardia, respectively. On days 30 and 31, the temporarily isolated and washed reticulo-rumen technique was used to measure total, and Cl−-competitive (an indirect measure of protein-mediated transport) absorption of acetate, propionate and butyrate. As a result of the higher dietary starch content and DM intake, the ruminal supply of rapidly fermentable CHO, total ruminal SCFA concentration (118 v. 95 mM; P<0.001) and osmolality (330 v. 306 mOsm/kg; P=0.018) were greater in cattle fed LF compared with HF. In addition, feeding LF resulted in a longer duration (2.50 v. 0.09 h/day; P=0.02) and a larger area (0.44 v. 0.01 (pH×h)/day; P=0.050) that pH was below 5.5. There was no diet effect on total and Cl−-competitive absorption (mmol/h and %/h) of acetate, propionate, butyrate and total SCFA (acetate+propionate+butyrate), but eating salivation was less (131 v. 152 ml/min; P=0.02), and resting salivation tended to be less (87 v. 104 ml/min; P=0.10) in cattle fed an LF diet. In summary, lower ruminal pH in cattle with greater rapidly fermentable CHO intake was attributed to an increase in SCFA production and decrease in salivation, which were not compensated for by an increase in epithelial permeability.

The objectives of this study were to assess the relationship between blood lactate variation measured at the plant, and pork quality variation on a large sample size and under commercial preslaughter handling conditions. A total of 600 pigs were randomly chosen on arrival at a commercial slaughter plant and blood samples taken from the ear vein at unloading (UN), after lairage (LA), in the restrainer (RE; before stunning) and at exsanguination (EX) were analysed for lactate content using a Lactate Scout Analyzer (LSA). In order to have a large range of measures, pigs were distributed into two groups; one kept in lairage overnight (G1) and the other for 2 to 3 h (G2) before slaughter. Meat quality was assessed in the Longissimus thoracis (LT), Semimembranosus (SM) and Adductor (AD) muscles by measuring the pH 30 min postmortem (pH1) and at 24 h postmortem (pHu), the colour and the drip loss. Blood lactate levels did not differ between G1 and G2 (P>0.05). A reduced muscle lactate and glucose contents (P=0.02 and P=0.004, respectively) resulting in a lower (P<0.001) glycolytic potential (GP) was observed in the LT muscle of G1 pigs when compared with G2 loins. In the LT muscle of G1 pigs, the lower GP resulted in an increased pHu (r=−0.67; P<0.001), decreased drip loss (r=0.57; P<0.001) and darker colour (r=0.50; P<0.001) compared with G2. In both G1 and G2 pigs, the lower GP was correlated to higher pHu value in the SM and AD muscles (r=−0.73; P<0.001). The greatest correlation was observed in G2 between blood lactate levels at LA and pHu value of the SM and AD muscles (r=0.46 and r=0.44, respectively; P<0.001 for both muscles). The second greatest correlation was found between blood lactate levels at EX and pH1 value in the SM muscle in both groups (r=−0.37 and r=−0.41, respectively; P<0.001 for both groups). Based on the results of this study, it appears that blood lactate levels, as measured by the LSA, reliably reflect the physiological response of pigs to perimortem stress and may help explain the variation in pork quality.

The effects of prebiotics on digestibility, short-chain fatty acid (SCFA) concentrations and bacterial populations in the faeces and immunity in dogs were evaluated by meta-analyses. Overall, data from 15 published studies containing 65 different treatment means of 418 observations from different breeds of dogs were included in the data set. Feeding of prebiotics to dogs did not affect the nutrient intake (P > 0.10), nor did prebiotics change (P > 0.10) the digestibility of dry matter (DM) and fat. However, crude protein (CP) digestibility tended to decrease quadratically (P = 0.06) with increasing dosages of prebiotics, although the degree of prediction was low (R2 = 0.33). The concentration of total SCFA (P = 0.08; R2 = 0.90) tended to increase linearly, whereas concentration of acetate (R2 = 0.25), propionate (R2 = 0.88) and butyrate (R2 = 0.85) increased quadratically with increasing dosage of prebiotics in the faeces of dogs. The numbers of beneficial bifidobacteria (P < 0.01; R2 = 0.62) increased quadratically, but lactobacilli (P < 0.01; R2 = 0.66) increased linearly with increasing supplementation of prebiotics. The changes in healthy bacterial numbers were affected by the interaction of initial bacterial numbers and dose of prebiotics; bacterial numbers increased relatively more when initial bacterial numbers were low. Dietary composition did not influence the response of prebiotics on lactobacilli and bifidobacterial numbers in this study. The numbers of pathogenic Clostridium perfringens and Escherichia coli were not affected by prebiotics. Prebiotics did not affect the serum immunoglobulin (Ig) concentrations such as IgG, IgA and IgM in dogs. Although prebiotics may tend to have an adverse effect on CP digestibility, prebiotics at doses up to 1.40% food intake (DM basis) might increase the beneficial bacterial populations and SCFA concentrations in the faeces of dogs. Thus, the feeding of prebiotics has a great prospective to improve the intestinal health of dogs.

Chemical compounds that mimic or block some of the actions of the steroid hormone oestradiol, have created public concern primarily because of potential adverse reproductive effects in wildlife and humans. Many studies, in vivo and in vitro, have revealed abnormal reproductive function following exposure to these compounds. The number of chemicals known to have the potential to modulate endocrine functions is increasing. In contrast to humans and wildlife, the potential reproductive effects of exposure of domestic animals to endocrine disrupting compounds (EDC) have been studied little. The aim of this overview is to evaluate the possible contribution of EDC to reproductive failure in domestic ruminants.

Sources and classes of EDC are discussed as well as their structure and the modes of hormone disruption. Endocrine disrupting agents may interfere with the reproductive processes of both males and females at several points of the reproductive cycle and through a range of physiological mechanisms. Extrapolating from the results obtained with laboratory animals, the mechanisms whereby infertility in domestic ruminants might be expressed by exposure to EDC through contaminated food and drinking water are addressed.

A preliminary risk assessment is included and it is concluded that under certain circumstances there may be a significantly enhanced intake of oestrogenic hormones and EDC through sewage-contaminated water or soil-contaminated herbage. The physiological consequences for domestic ruminants of EDC ingestion, at the rates estimated, are largely unknown. However, the levels of exposure to oestrogenic hormones and phthalates in grazing ruminants are such that when studying fertility problems in high-yielding dairy cattle the impacts of exposure to endocrine disruptors via the food and drinking water cannot be neglected.