Up to half of dairy cows are affected by at least one of metritis, purulent vaginal discharge, endometritis or cervicitis in the postpartum period. These conditions result from inadequate immune response to bacterial infection (failure to clear pathogenic bacteria from the uterus) or persistent inflammation that impairs rather than enhances reproductive function. The degree of mobilization of fat and how effectively it is used as a metabolic fuel is well recognized as a risk factor for metabolic and infectious disease. Release of non-esterified fatty acids has direct effects on liver and immune function but also produces pro-inflammatory cytokines (tumor necrosis factor α and interleukin-6), which contribute to systemic inflammation and to insulin resistance. Therefore, reproductive tract inflammatory disease may be a function of both local and systemic inflammatory stimuli and regulation as well as regulation of fat metabolism. Better understanding of variables associated with insulin resistance and inflammatory regulation in the liver and adipose tissue may lead to improvement of reproductive tract health. This paper reviews factors that may contribute to postpartum reproductive tract inflammatory diseases in dairy cows and their inter-relationships, impacts and treatment.

There are significant costs associated with reproductive inefficiency in pasture-based dairy herds. This study has quantified the economic effect of a number of key variables associated with reproductive inefficiency in a dairy herd and related them to 6-week calving rate for both cows and heifers. These variables include: increased culling costs, the effects of sub optimum calving dates, increased labour costs and increased artificial insemination (AI) and intervention costs. The Moorepark Dairy Systems Model which is a stochastic budgetary simulation model was used to simulate the overall economic effect at farm level. The effect of change in each of the components was simulated in the model and the costs associated with each component was quantified. An analysis of national data across a 4-year period using the Irish Cattle Breeding Federation database was used to quantify the relationship between the 6-week calving rate of a herd with survivability (%), calving interval (days) and the level of AI usage. The costs associated with increased culling (%), calving date slippage (day), increased AI and intervention costs (0.1 additional inseminations), as well as, increased labour costs (10%) were quantified as €13.68, €3.86, €4.56 and €29.6/cow per year. There was a statistically significant association between the 6-week calving rate and survivability, calving interval and AI usage at farm level. A 1% change in 6-week calving rate was associated with €9.26/cow per annum for cows and €3.51/heifer per annum for heifers. This study does not include the indirect costs such as reduced potential for expansion, increased costs associated with failing to maintain a closed herd as well as the unrealised potential within the herd.

This study examined the relationship of residual feed intake (RFI) with digestion, body composition, carcass traits and visceral organ weights in beef bulls offered a high concentrate diet. Individual dry matter (DM) intake (DMI) and growth were measured in a total of 67 Simmental bulls (mean initial BW 431 kg (s.d.=63.7)) over 3 years. Bulls were offered concentrates (860 g/kg rolled barley, 60 g/kg soya bean meal, 60 g/kg molasses and 20 g/kg minerals per vitamins) ad libitum plus 0.8 kg grass silage DM daily for 105 days pre-slaughter. Ultrasonic muscle and fat depth, body condition score (BCS), muscularity score, skeletal measurements, blood metabolites, rumen fermentation and total tract digestibility (indigestible marker) were determined. After slaughter, carcasses and perinephric and retroperitoneal fat were weighed, carcasses were graded for conformation and fat score and weight of non-carcass organs, liver, heart, kidneys, lungs, gall bladder, spleen, reticulo-rumen full and empty and intestines full, were determined. The residuals of the regression of DMI on average daily gain (ADG), mid-test metabolic BW (BW0.75) and the fixed effect of year, using all animals, were used to compute individual RFI coefficients. Animals were ranked on RFI and assigned to high (inefficient), medium or low groupings. Overall mean ADG and daily DMI were 1.6 kg (s.d.=0.36) and 9.4 kg (s.d.=1.16), respectively. High RFI bulls consumed 7 and 14% more DM than medium and low RFI bulls, respectively (P<0.001). No differences between high and low RFI bulls were detected (P>0.05) for ADG, BW, BCS, skeletal measurements, muscularity scores, ultrasonic measurements, carcass weight, perinephric and retroperitoneal fat weight, kill-out proportion and carcass conformation and fat score. However, regression analysis indicated that a 1 kg DM/day increase in RFI was associated with a decrease in kill-out proportion of 20 g/kg (P<0.05) and a decrease in carcass conformation of 0.74 units (P<0.05). Weight of non-carcass organs did not differ (P>0.05) between RFI groups except for the empty weight of reticulo-rumen, which was 8% lighter (P=0.05) in low RFI compared with high RFI bulls. Regression analysis indicated that a 1 kg DM/day increase in RFI was associated with a 1 kg increase in reticulo-rumen empty weight (P<0.05). Of the visceral organs measured, the reticulo-rumen may be a biologically significant contributory factor to variation in RFI in beef bulls finished on a high concentrate diet.

The commercial applicability of bovine artificial insemination (AI) depends on the effectiveness of diluents for maintaining sperm fertility. Challenges faced by the AI industry due to recent advances in assisted reproduction, and the limitations inherent in using fresh and frozen-thawed sperm for AI, could be overcome with the development of better semen diluents. Research into the different microenvironments of bovine sperm as they progress towards maturity, capacitation and fertilisation is revealing various mechanisms that could be exploited to improve the formulation of semen diluents. These are reviewed here. A rationale for a more detailed investigation of bovine cervical mucus for factors that may allow further progress towards this goal are also discussed.

The long-term effects of adding chestnut (CHE; Castanea sativa) and valonea (VAL; Quercus valonea) tannin-rich extracts to sheep feed were investigated. In Experiment 1, sheep (65 kg BW) were fed 842 g/day of a ryegrass-based hay. The control-treated animals (CON) received 464 g/day of concentrate, and tannin-treated animals received the same amount of concentrate additionally containing 20 g of the respective tannin-rich extract. Hay and concentrates were offered together in one meal. After the onset of treatment, methane release was measured in respiration chambers for 23.5-h intervals (nine times) in a 190-days period. Faeces and urine were collected three times (including once before the onset of the tannin treatment) to assess digestibility and urinary excretion of purine derivatives. Based on the results obtained from Experiment 1, a second experiment (Experiment 2) was initiated, in which the daily tannin dosage was almost doubled (from 0.9 (Experiment 1) to 1.7 g/kg BW0.75). With the exception of the dosage and duration of the treatment (85 days), Experiment 2 followed the same design as Experiment 1, with the same measurements. In an attempt to compare in vitro and in vivo effects of tannin supplementation, the same substrates and tannin treatments were examined in the Hohenheim gas test. In vitro methane production was not significantly different between treatments. None of the tannin-rich extract doses induced a reduction in methane in the sheep experiments. On the 1st day of tannin feeding in both experiments, tannin inclusion tended to decrease methane release, but this trend disappeared by day 14 in both experiments. In balance period 3 of Experiment 1, lower dry matter and organic matter digestibility was noted for tannin treatments. The digestibility of CP, but not NDF or ADF, was reduced in both experiments. A significant shift in N excretion from urine to faeces was observed for both tannin-rich extracts in both experiments, particularly in Experiment 2. In balance period 2 of Experiment 2, an increased intake of metabolisable energy for VAL was observed. The urinary excretion of purine derivatives was not significantly different between treatments, indicating that microbial protein synthesis was equal for all treatments. Thus, we concluded that both tannin-rich extracts temporary affect processes in the rumen but did not alter methane release over a longer period.

One of the main goals of selection schemes in beef cattle populations is to increase carcass weight at slaughter. Live weights at different growth stages are frequently used as selection criteria under the hypothesis that they usually have a high and positive genetic correlation with weight at slaughter. However, the presence of compensatory growth may bias the prediction ability of early weights for selection purposes. Recursive models may represent an interesting alternative for understanding the genetic and phenotypic relationship between weight traits during growth. For the purposes of this study, the analysis was performed for three different set of data from the Pirenaica beef cattle breed: weight at 120 days (W120) and at 210 days (W210); W120 and carcass weight at slaughter at 365 days (CW365); W210 and CW365. The number of records for each analysis was 8592, 4648 and 3234, respectively. A pedigree composed of 56323 individuals was also included. The statistical model comprised sex, year-season of birth, herd and slaughterhouse, plus a non-linear recursive dependency between traits. The dependency was modeled as a polynomial up to the 4th degree and models were compared using a Logarithm of Conditional Predictive Ordinates. The results of model comparison suggest that the best models were the 3rd degree polynomial for W120-W210 and W120-CW365 and the 2nd degree polynomial for W210-CW365. The posterior mean estimates for heritabilities ranged between 0.29 and 0.44 and the posterior mean estimates of the genetic correlations were null or very low, indicating that the relationship between traits is fully captured by the recursive dependency. The results imply that the predictive ability of the performance of future growth is low if it is only based on records of early weights. The usefulness of slaughterhouse records in beef cattle breeding evaluation is confirmed.

We conducted an experiment to determine whether early-life social learning of feeding site selection in lambs was sex-specific. Sixteen ewes and their new born lambs were used in a controlled experiment. Eight ewe–lamb pairs included a male lamb and the remaining eight a female lamb. All pairs were individually exposed to an experimental arena containing a safe and unsafe artificial feeding site (SFS, UFS) each consisting of nine bowls which contained either ground Bermuda grass hay (SFS) or ground alfalfa hay (UFS). The bowls in UFS were surrounded by bright orange traffic cones (visual cues). Half the ewes were trained with controlled electric shock to avoid UFS. Thus, pairs were randomly assigned to: (1) shock aversion training (SAT) to mothers of male lambs (MS); (2) SAT to mothers of female lambs (FS); (3) no aversion training (NAT, control) to mothers of male lambs (MC); and (4) NAT (control) to mothers of female lambs (FC). None of the lambs were subjected to SAT. During training, testing, extinction, and retraining ewe–lamb pairs were exposed to the arena together. Ewes were then removed from the experiment and two additional extinction phases were conducted with weaned lambs alone. Fear conditioning elicited UFS avoidance of both the trained ewes (means±s.e.m. % times observed in UFS during testing phase: FC=95.3±1.70; MC=94.4±4.87; FS=1.6±1.63; MS=0 ±0; P<0.01) and their naïve lambs (FC=83.8±6.07%; MC=76.6±6.56%; FS=30.4±7.90%; MS=33.9±9.23%; P<0.01). UFS avoidance in lambs occurred regardless of sex and tended to persist after weaning (% times observed in UFS during 1st post-weaning extinction phase: FC=92.6±4.50%; MC=89.8±6.09%; FS=45.1±10.57%; MS=43.5±10.42%; P=0.06). Fear conditioning in mothers appeared to alter sex-related differences in mother–infant behavioral synchrony by increasing and decreasing feeding synchrony of male and female lambs, respectively (FC: r=0.52, P<0.01; MC: r=−0.02, P=0.86; FS: r=0.14, P=0.26; MS: r=0.46, P<0.01). During the extinction phase mothers of ram lambs were observed feeding more often (FC=85.0±2.33%; MC=92.7±1.45%; FS=47.3±8.81%; MS=72±5.68%; P=0.02) and standing less often than ewes with daughters (FC=7.3±2.40%; MC=2.7±0.83%; FS=39.3±9.04%; MS=18.0±5.29%; P=0.06). This study suggests that social conditioning at an early age could be a viable tool to induce learning of feeding site avoidance in female and male lambs alike.

Globally, pressure on concentrate feed resources is increasing, especially in the tropics where many countries are net importers of food. Forage plants are a possible alternative, but their use as feed ingredients for pigs raises several issues related to their higher fibre and plant secondary metabolites contents as well as their lower nutritive value. In this paper, the nutritive value of several forage species and the parameters that influence this nutritive value in relationship to the plant family, the physiological stage, the plant part and the preservation method (fresh, hay and silage) are reviewed. The influence of the breed and the physiological status of the animal on animal voluntary intake of fibre-rich ingredients, digestibility as related to gastrointestinal volume and transit time and growth performances are also discussed. The final section highlights the advantages and drawbacks of forage plants in pig diets and stresses the need for proper economic evaluation to conclude on the benefits of the use of forage plants in pig feed.

The aim of the present work was to examine how different fats commonly used in the feed industry affect broiler performance, nutrient digestibility and microbial fermentation in the gastrointestinal tract of broiler chickens challenged with virulent Clostridium perfringens strains. Two experiments were carried out, each including 480-day-old male broilers (Ross 308), which were randomly distributed to eight experimental groups using six replicate pens per treatment and 10 birds per pen. In Experiment 1, birds were fed diets containing soybean oil, palm kernel fatty acid distillers, rendered pork fat and lard. In Experiment 2, birds were fed diets containing rapeseed oil, coconut oil, beef tallow and palm oil. In both experiments, the birds were either not challenged or challenged with a mixture of three C. perfringens type A strains. Irrespective of the fat type present in the diet, C. perfringens did not affect broiler chicken body weight gain (BWG) and mortality in either of the two experiments. The BWG was affected by dietary fat type in both experiments, indicating that the fatty acid composition of the fat source affects broiler growth performance. In particular, the inclusion of animal fats tended to improve final BW to a greater extent compared with the inclusion of unsaturated vegetable oils. In Experiment 2, irrespective of the dietary fat type present in the diet, C. perfringens challenge significantly impaired feed conversion ratio in the period from 14 to 28 days (1.63 v. 1.69) and at 42 days (1.65 v. 1.68). In both experiments apparent metabolizable energy values were affected by dietary fat type. Irrespective of the fat type present in the diet, C. perfringens challenge decreased the digesta pH in the crop and ileum, but had no effect in cecal contents. Moreover, in Experiment 1, total organic acid concentration in the ileum was two to three times lower on soybean oil diets as compared with other treatments, indicating that C. perfringens as well as dietary fat type significantly affects microbiota activity in the broiler chicken gastrointestinal tract.

Because of an increasing demand for animal-source foods, an increasing desire to reduce poverty and an increasing need to reduce the environmental impact of livestock production, tropical farming systems with livestock must increase their productivity. An important share of the global human and livestock populations are found within smallholder mixed-crop–livestock systems, which should, therefore, contribute significantly towards this increase in livestock production. The present paper argues that increased livestock production in smallholder mixed-crop–livestock systems faces many constraints at the level of the farm and the value chain. The present paper aims to describe and explain the impact of increased production from the farm and farmers’ perspective, in order to understand the constraints for increased livestock production. A framework is presented that links farming systems to livestock value chains. It is concluded that farming systems that pass from subsistence to commercial livestock production will: (1) shift from rural to urban markets; (2) become part of a different value chain (with lower prices, higher demands for product quality and increased competition from peri-urban producers and imports); and (3) have to face changes in within-farm mechanisms and crop–livestock relationships. A model study showed that feed limitation, which is common in tropical farming systems with livestock, implies that maximum herd output is achieved with small herd sizes, leaving low-quality feeds unutilised. Maximal herd output is not achieved at maximal individual animal output. Having more animals than required for optimal production – which is often the case as a larger herd size supports non-production functions of livestock, such as manure production, draught, traction and capital storage – goes at the expense of animal-source food output. Improving low-quality feeds by treatment allows keeping more animals while maintaining the same level of production. Ruminant methane emission per kg of milk produced is mainly determined by the level of milk production per cow. Part of the methane emissions, however, should be attributed to the non-production functions of ruminants. It was concluded that understanding the farm and farmers’ perceptions of increased production helps with the understanding of productivity increase constraints and adds information to that reported in the literature at the level of technology, markets and institutions.

A consequence of increasing litter size in sheep is that a portion of the lambs have to be reared artificially. Detailed information about the pattern of milk consumption of artificially reared lambs would help improve their management. The purpose of this study is to describe the individual and group feeding behaviour of 94 Romane artificially reared lambs from 5 to 28 days of age using an electronic automatic lamb feeder. Animals were located in four pens of 8 to 15 lambs of similar age with one teat per pen. They were fed ad libitum. In our experimental situation (group rearing, continuous lightning) on average a lamb made 1.4±0.7 visits to the teat per meal and 9.5±3 meals per day. Mean meal duration was 247±158 s and the mean daily time spent feeding was 38±25 min. The mean quantity of milk intake was 176±132 ml per meal and 1.68±0.8 l per day. With age, the number of daily meals and their duration decreased while the quantity of milk consumed per meal and per day increased. Females tended to make more visits to the teat per meal and perform more meals per day but their milk consumption per meal was lower. The feed conversion ratio was 1.36±0.2. Synchrony in feeding (group meal) was estimated as the percentage of lambs that wanted to access the teat within the same short period (relative group meal size). On average 65% of lambs in the pen wanted to access the teat within the same period, but for 35% of group meals the relative group meal size was >90%. There was no consistency in the order in which lambs accessed the teat during a group meal. Our evaluation suggested that electronic automatic lamb feeders are tools that can provide, on a large scale, data describing the feeding behaviour of artificially reared lambs. It is then possible to study factors influencing these traits in order to improve the outcome of artificially reared lambs.

Feed production is a significant source of greenhouse gas (GHG) emissions from dairy production and demands large arable and pasture acreage. This study analysed how regional conditions influence GHG emissions of dairy feed rations in a life cycle perspective, that is the carbon footprint (CF) and the land area required. Factors assessed included regional climate variations, grass/clover silage nutrient quality, feedstuff availability, crop yield and feed losses. Using the Nordic feed evaluation model NorFor, rations were optimised for different phases of lactation, dry and growing periods for older cows, first calvers and heifers by regional feed advisors and combined to annual herd rations. Feed production data at farm level were based on national statistics and studies. CF estimates followed standards for life cycle assessment and used emissions factors provided by IPCC. The functional unit was ‘feed consumption to produce 1 kg energy corrected milk (ECM) from a cow with annual milk yield of 9 900 kg ECM including replacement animals and feed losses’. Feed ration CF varied from 417 to 531 g CO2 e/kg ECM. Grass/clover silage contributed more than 50% of total GHG emissions. Use of higher quality silage increased ration CF by up to 5% as a result of an additional cut and increased rates of synthetic N-fertiliser. Domestically produced horse bean (Vicia faba), by-products from the sugar industry and maize silage were included in the rations with the lowest CF, but horse bean significantly increased ration land requirement. Rations required between 1.4 to 2 m2 cropland and 0.1 to 0.2 m2/kg semi-natural grassland per kg ECM and year. Higher yield levels reduced ration total CF. Inclusion of GHG emissions from land use change associated with Brazilian soya feed significantly increased ration CF. Ration CF and land use depended on ration composition, which was highly influenced by the regional availability and production of feedstuffs. The impact of individual feedstuffs on ration CF varies due to, for example, cultivation practices and climate conditions and feedstuffs should therefore be assessed in a ration and regional perspective before being used to decrease milk CF. Land use efficiency should be considered together with ration CF, as these can generate goal conflicts.

A survey of management practices in 309 Irish dairy herds was used to identify risk factors for the presence of antibodies to Salmonella, Neospora caninum and Leptospira interrogans serovar hardjo in extensively managed unvaccinated dairy herds. A previous study documented a herd-level seroprevalence in bulk milk of 49%, 19% and 86% for Salmonella, Neospora caninum and leptospira interrogans serovar hardjo, respectively in the unvaccinated proportion of these 309 herds in 2009. Association analyses in the present study were carried out using multiple logistic regression models. Herds where cattle were purchased or introduced had a greater likelihood of being positive to leptospira interrogans serovar hardjo (P<0.01) and Salmonella (P<0.01). Larger herds had a greater likelihood of recording a positive bulk milk antibody result to leptospira interrogans serovar hardjo (P<0.05). Herds that practiced year round calving were more likely to be positive to Neospora caninum (P<0.05) compared to herds with a spring-calving season, with no difference in risk between herds that practiced split calving compared to herds that practiced spring calving. No association was found between presence of dogs on farms and prevalence of Neospora caninum possibly due to limited access of dogs to infected materials including afterbirths. The information from this study will assist in the design of suitable control programmes for the diseases under investigation in pasture-based livestock systems.

Physicochemical characteristics were determined in the longissimus lumborum muscle, after 8 days of ageing of steers (n=12) and bulls (n=12) from Mertolenga breed slaughtered directly from pasture (day 0) or after a finishing period of 50, 100 and 150 days in a feed-lot facility. Bulls and steers presented similar live weight (averaging 388 kg), carcass weight (CW; averaging 213 kg), dressing percentage (averaging 60%), carcass fatness (11.9% CW) and carcass fat thickness (averaging 3.03 mm). Live weight, CW, carcass fatness and fat thickness increased along time-on-feed. Gender only had a negligible effect on meat characteristics, with b* and h* being the only parameters of colour affected by gender, also presenting a significant interaction gender×time-on-feed. Nevertheless, both the genders presented a high-quality grade concerning tenderness (Warner–Bratzler shear force (WBSF)). L* increased until 50 days on feed and decreased afterwards, whereas a* and C* values increased along time-on-feed. Pigment content was also affected by time-on-feed and showed a gender×time-on-feed interaction. Beef colour became darker and redder along time-on-feed, but still in a colour range highly acceptable by Portuguese consumers. Despite the increase in intramuscular fat and myofibrillar fragmentation index, as well as the decrease in collagen content of steers and bulls along time-on-feed, it did not affect the tenderness/hardness, indicating a small effect of time-on-feed in meat characteristics. Despite only small differences in carcass characteristics and meat-quality parameters that have been noticed along time-on-feed, those differences were only significant after 100 days on feed. Principal component analysis (PCA) was performed. The first PC axis (39.6% of the total variance) included colour variables a*, b* and C*, and carcass fatness, fat thickness, CW and live weight, whereas the second one (12.7% of the total variance) included h*, cooking losses and dressing-out. The principal component (PC) analysis confirmed the lack of differences between bulls and steers and indicates a differentiation of the first two periods of feeding (0 and 50 days on feed) from the two latter (100 and 150 days on feed) periods of feeding.

An a posteriori granddaughter design was applied to estimate quantitative trait loci genotypes of sires with many sons in the US Holstein population. The results of this analysis can be used to determine concordance between specific polymorphisms and segregating quantitative trait loci. Determination of the actual polymorphisms responsible for observed genetic variation should increase the accuracy of genomic evaluations and rates of genetic gain. A total of 52 grandsire families, each with ⩾100 genotyped sons with genetic evaluations based on progeny tests, were analyzed for 33 traits (milk, fat and protein yields; fat and protein percentages; somatic cell score (SCS); productive life; daughter pregnancy rate; heifer and cow conception rates; service-sire and daughter calving ease; service-sire and daughter stillbirth rates; 18 conformation traits; and net merit). Of 617 haplotype segments spanning the entire bovine genome and each including ~5×106 bp, 5 cM and 50 genes, 608 autosomal segments were analyzed. A total of 19 335 unique haplotypes were found among the 52 grandsires. There were a total of 133 chromosomal segment-by-trait combinations, for which the nominal probability of significance for the haplotype effect was <10−8, which corresponds to genome-wide significance of <10−4. The number of chromosomal regions that met this criterion by trait ranged from one for rear legs (rear view) to seven for net merit. For each of the putative quantitative trait loci, at least one grandsire family had a within-family contrast with a t-value of >3. Confidence intervals (CIs) were estimated by the nonparametric bootstrap for the largest effect for each of nine traits. The bootstrap distribution generated by 100 samples was bimodal only for net merit, which had the widest 90% CI (eight haplotype segments). This may be due to the fact that net merit is a composite trait. For all other chromosomes, the CI spanned less than a third of the chromosome. The narrowest CI (a single haplotype segment) was found for SCS. It is likely that analysis by more advanced methods could further reduce CIs at least by half. These results can be used as a first step to determine the actual polymorphisms responsible for observed quantitative variation in dairy cattle.

The aim of this study was to investigate whether fatty acid (FA) profile, oxidative stability of lipids and other meat quality traits differed between high (HW: 1.8 to 2.2 kg) and low (LW: 0.8 to 1.2 kg) birth weight piglets. Forty new-born male pigs (n=20 HW, n=20 LW) were reared in separate pens until the finishing period, when they were slaughtered at 150 days of age, and pH and temperature were measured in the carcass. Afterwards, the Longissimus dorsi muscle was excised from the carcass, and samples were collected for subsequent meat quality analyses (thaw loss, cooking loss, shear force, chemical analysis and sensory analysis for tenderness). Birth weight had minor impacts on meat quality traits, which were limited to higher shear force in the LW group (P<0.01). Chemical components (moisture, protein, fat, ash), cholesterol levels and lipid oxidation (thiobarbituric acid-reactive substances) were not affected by birth weight (P>0.05). FA profile and the amount of saturated, monounsaturated and polyunsaturated fatty acids were similar, but HW pigs had higher atherogenic index than their LW counterparts (P<0.01). Notwithstanding the higher shear force presented by the lower birth weight pigs, in the sensory test, the panelists did not detect any differences in the tenderness of pork from HW and LW animals. Therefore, our results suggest that low birth weight has minimal impact on meat quality.

Feeding dietary supplements containing trans-10, cis-12-conjugated linoleic acid (t10,c12-CLA) has been shown to induce milk fat depression in cows, ewes and goats. However, the magnitude of the response is apparently less pronounced in lactating goats. The objective of this study was to evaluate the effects of increasing doses of CLA methyl esters (CLA-ME) on milk production, composition and fatty-acid profile of dairy goats. Eight Toggenburg goats were separated in two groups (four primiparous and four multiparous) and received the following dietary treatments in a 4×4 Latin Square design: CLA0: 45 g/day of calcium salts of fatty acids (CSFA); CLA15; 30 g/day of CSFA+15 g/day of CLA-ME; CLA30: 15 g/day of CSFA+30 g/day of CLA-ME; and CLA45: 45 g/day of CLA-ME. The CLA-ME supplement (Luta-CLA 60) contained 29.9% of t10,c12-CLA; therefore, the dietary treatments provided 0, 4.48, 8.97 and 13.45 g/day of t10,c12-CLA, respectively. Feed intake, milk production, concentration and secretion of milk protein and lactose, body condition score and body weight were unaffected by the dietary treatments. Milk fat secretion was reduced by 14.9%, 30.8% and 40.5%, whereas milk fat concentration was decreased by 17.2%, 33.1% and 40.7% in response to CLA15, CLA30 and CLA45, respectively. Secretions of both de novo synthesized and preformed fatty acids were progressively reduced as the CLA dose increased, but the magnitude of the inhibition was greater for the former. There was a linear reduction in most milk fat desaturase indexes (14:1/14:0, 16:1/16:0, 17:1/17:0 and 18:1/18:0). Milk fat t10,c12-CLA concentration and secretion increased with the CLA dose, and its apparent transfer efficiency from diet to milk was 1.18%, 1.17% and 1.21% for CLA15, CLA30 and CLA45 treatments, respectively. The estimated energy balance was linearly improved in goats fed CLA.

The objective of the study was to evaluate the effect of screen size (1, 2 and 3 mm) and microbial phytase (0 and 1000 FTU/kg as-fed) on phytate degradation in maize (100% maize), soybean meal (100% SBM) and maize–SBM (75% maize and 25% SBM) incubated in water for 0, 2, 4, 8 and 24 h at 38°C. Samples were analysed for pH, dry matter and phytate phosphorus (P). Particle size distribution (PSD) and average particle size (APS) of samples were measured by the Laser Diffraction and Bygholm method. PSD differed between the two methods, whereas APS was similar. Decreasing screen size from 3 to 1 mm reduced APS by 48% in maize, 30% in SBM and 26% in maize–SBM. No interaction between screen size and microbial phytase on phytate degradation was observed, but the interaction between microbial phytase and incubation time was significant (P<0.001). This was because microbial phytase reduced phytate P by 88% in maize, 84% in maize–SBM and 75% in SBM after 2 h of incubation (P<0.05), whereas the reduction of phytate P was limited (<50%) in the feeds, even after 24 h when no microbial phytase was added. The exponential decay model was fitted to the feeds with microbial phytase to analyse the effect of screen size and feed on microbial phytase efficacy on phytate degradation. The interaction between screen size and feed affected the relative phytate degradation rate (R d ) of microbial phytase as well as the time to decrease 50% of the phytate P (t $\scale70%{\vskip3pt{{\scale60%{\vskip-7pt1}{\hskip-3pt\vskip-5.6pt\rot160/}{\scale60%{\hskip-4pt\vskip0pt2}$ ) (P<0.001). Thus, changing from 3 to 1 mm screen size increased R d by 22 and 10%/h and shortened t $\scale70%{\vskip3pt{{\scale60%{\vskip-7pt1}{\hskip-3pt\vskip-5.6pt\rot160/}{\scale60%{\hskip-4pt\vskip0pt2}$ by 0.4 and 0.2 h in maize and maize–SBM, respectively (P<0.05), but not in SBM. Moreover, the screen size effect was more pronounced in maize and maize–SBM compared with SBM as a higher phytate degradation rate constant (K d ) and R d , and a shorter t $\scale70%{\vskip3pt{{\scale60%{\vskip-7pt1}{\hskip-3pt\vskip-5.6pt\rot160/}{\scale60%{\hskip-4pt\vskip0pt2}$ was observed in maize compared with SBM in all screen sizes (P<0.05). However, a higher amount of degraded phytate was achieved in SBM than in maize because of the higher initial phytate P content in SBM. In conclusion, reducing screen size from 3 to 1 mm increased K d and R d and decreased t $\scale70%{\vskip3pt{{\scale60%{\vskip-7pt1}{\hskip-3pt\vskip-5.6pt\rot160/}{\scale60%{\hskip-4pt\vskip0pt2}$ in maize and maize–SBM with microbial phytase. The positive effect of grinding on improving microbial phytase efficacy, which was expressed as K d , R d and t $\scale70%{\vskip3pt{{\scale60%{\vskip-7pt1}{\hskip-3pt\vskip-5.6pt\rot160/}{\scale60%{\hskip-4pt\vskip0pt2}$ , was greater in maize than in SBM.

The production of pork with high amounts of intramuscular fat (IMF) without an increase in subcutaneous fat is highly desirable for the pig industry and consumers. Herein, we question the impact of dietary protein reduction (18% v. 13%) on fat deposition in the subcutaneous adipose tissue (SAT) and longissimus lumborum (LL) muscle using genetically diverse pigs for body fatness (lean v. fat). A clear effect of genotype was observed on plasma insulin (P=0.004) and leptin (P<0.001), as well as on backfat thickness (P<0.001), with the fat pigs having higher values. Accordingly, IMF was higher in the fat pigs, when compared with their lean counterparts (P=0.003), which was supported by enlarged adipocytes (P<0.001). The area of lipid droplets within the LL fibres (P=0.039) and extramyocellular lipids number (P=0.017) were increased in pigs fed reduced protein diets, regardless of genotype, which is consistent with higher levels of plasma triacylglycerols (P=0.002). The gene-expression pattern of lipogenic factors in the SAT was distinct from the LL muscle. In the SAT, PPARG expression was similar among genotypes (P>0.05), whereas in the LL muscle it was higher in the lean pigs (P=0.023), especially when fed on low protein diet (P=0.057). The CEBPA and FABP4 mRNA levels were increased in the SAT of fat pigs (P<0.001), without changes in the LL muscle (P>0.05). The influence of diet on FABP4 expression in the SAT was dependent on pig’s genetic background (P=0.005). In conclusion, fat deposition was clearly influenced by genotype and, to a lesser extent, by dietary protein level, the SAT being more sensitive than the LL muscle. One can speculate that the pathways involved in lipid metabolism are downregulated in intramuscular adipocytes when compared with SAT fat cells. This result might be a direct consequence of the relatively low proportion of adipocytes found in the LL muscle.

Genomic prediction utilizes single nucleotide polymorphism (SNP) chip data to predict animal genetic merit. It has the advantage of potentially capturing the effects of the majority of loci that contribute to genetic variation in a trait, even when the effects of the individual loci are very small. To implement genomic prediction, marker effects are estimated with a training set, including individuals with marker genotypes and trait phenotypes; subsequently, genomic estimated breeding values (GEBV) for any genotyped individual in the population can be calculated using the estimated marker effects. In this study, we aimed to: (i) evaluate the potential of genomic prediction to predict GEBV for nematode resistance traits and BW in sheep, within and across populations; (ii) evaluate the accuracy of these predictions through within-population cross-validation; and (iii) explore the impact of population structure on the accuracy of prediction. Four data sets comprising 752 lambs from a Scottish Blackface population, 2371 from a Sarda×Lacaune backcross population, 1000 from a Martinik Black-Belly×Romane backcross population and 64 from a British Texel population were used in this study. Traits available for the analysis were faecal egg count for Nematodirus and Strongyles and BW at different ages or as average effect, depending on the population. Moreover, immunoglobulin A was also available for the Scottish Blackface population. Results show that GEBV had moderate to good within-population predictive accuracy, whereas across-population predictions had accuracies close to zero. This can be explained by our finding that in most cases the accuracy estimates were mostly because of additive genetic relatedness between animals, rather than linkage disequilibrium between SNP and quantitative trait loci. Therefore, our results suggest that genomic prediction for nematode resistance and BW may be of value in closely related animals, but that with the current SNP chip genomic predictions are unlikely to work across breeds.