In livestock, many studies have reported the results of imputation to 50k single nucleotide polymorphism (SNP) genotypes for animals that are genotyped with low-density SNP panels. The objective of this paper is to review different measures of correctness of imputation, and to evaluate their utility depending on the purpose of the imputed genotypes. Across studies, imputation accuracy, computed as the correlation between true and imputed genotypes, and imputation error rates, that counts the number of incorrectly imputed alleles, are commonly used measures of imputation correctness. Based on the nature of both measures and results reported in the literature, imputation accuracy appears to be a more useful measure of the correctness of imputation than imputation error rates, because imputation accuracy does not depend on minor allele frequency (MAF), whereas imputation error rate depends on MAF. Therefore imputation accuracy can be better compared across loci with different MAF. Imputation accuracy depends on the ability of identifying the correct haplotype of a SNP, but many other factors have been identified as well, including the number of genotyped immediate ancestors, the number of animals with genotypes at the high-density panel, the SNP density on the low- and high-density panel, the MAF of the imputed SNP and whether imputed SNP are located at the end of a chromosome or not. Some of these factors directly contribute to the linkage disequilibrium between imputed SNP and SNP on the low-density panel. When imputation accuracy is assessed as a predictor for the accuracy of subsequent genomic prediction, we recommend that: (1) individual-specific imputation accuracies should be used that are computed after centring and scaling both true and imputed genotypes; and (2) imputation of gene dosage is preferred over imputation of the most likely genotype, as this increases accuracy and reduces bias of the imputed genotypes and the subsequent genomic predictions.

Selection of Quarter Horses for different purposes has led to the formation of lines, including racing and cutting horses. The objective of this study was to identify genomic regions divergently selected in racing line of Quarter Horses in relation to cutting line applying relative extended haplotype homozygosity (REHH) analysis, an extension of extended haplotype homozygosity (EHH) analysis, and the fixation index (F ST) statistic. A total of 188 horses of both sexes, born between 1985 and 2009 and registered at the Brazilian Association of Quarter Horse Breeders, including 120 of the racing line and 68 of the cutting line, were genotyped using single nucleotide polymorphism arrays. On the basis of 27 genomic regions identified as selection signatures by REHH and F ST statistics, functional annotations of genes were made in order to identify those that could have been important during formation of the racing line and that could be used subsequently for the development of selection tools. Genes involved in muscle growth (n=8), skeletal growth (n=10), muscle energy metabolism (n=15), cardiovascular system (n=14) and nervous system (n=23) were identified, including the FKTN, INSR, GYS1, CLCN1, MYLK, SYK, ANG, CNTFR and HTR2B.

The organogenesis of the digestive system was described in the Amazonian pimelodid catfish species Pseudoplatystoma punctifer from hatching (3.5 mm total length, TL) to 41 days post-fertilization (dpf) (58.1 mm TL) reared at 28°C. Newly hatched larvae showed a simple digestive tract, which appeared as a straight undifferentiated and unfolded tube lined by a single layer of columnar epithelial cells (future enterocytes). During the endogenous feeding period, comprised between 20 and 96 h post-fertilization (3.5 to 6.1 mm TL), the larval digestive system experienced a fast transformation with the almost complete development and differentiation of most of digestive organs (buccopahrynx, oesophagus, intestine, liver and exocrine pancreas). Yolk reserves were not completely depleted at the onset of exogenous feeding (4 dpf, 6.1 mm TL), and a period of mixed nutrition was observed up to 6 to 7 dpf (6.8 to 7.3 mm TL) when yolk was definitively exhausted. The stomach was the organ that latest achieved its complete differentiation, characterized by the development of abundant gastric glands in the fundic stomach between 10 and 15 dpf (10.9 to 15.8 mm TL) and the formation of the pyloric sphincter at the junction of the pyloric stomach and the anterior intestine at 15 dpf (15.8 mm TL). The above-mentioned morphological and histological features observed suggested the achievement of a digestive system characteristic of P. punctifer juveniles and adults. The ontogeny of the digestive system in P. punctifer followed the same general pattern as in most Siluriform species so far, although some species-specific differences in the timing of differentiation of several digestive structures were noted, which might be related to different reproductive guilds, egg and larval size or even different larval rearing practices. According to present findings on the histological development of the digestive system in P. punctifer, some recommendations regarding the rearing practices of this species are also provided in order to improve the actual larval rearing techniques of this fast-growing Neotropical catfish species.

Most plant-origin fiber sources used in pig production contains a mixture of soluble and insoluble non-starch polysaccharides (NSP). The knowledge about effects of these sources of NSP on the gut microbiota and its fermentation products is still scarce. The aim of this study was to investigate effects of feeding diets with native sources of NSP on the ileal and fecal microbial composition and the dietary impact on the concentration of short-chain fatty acids (SCFA) and lactic acid. The experiment comprised four diets and four periods in a change-over design with seven post valve t-cecum cannulated growing pigs. The four diets were balanced to be similar in NSP content and included one of four fiber sources, two diets were rich in pectins, through inclusion of chicory forage (CFO) and sugar beet pulp, and two were rich in arabinoxylan, through inclusion of wheat bran (WB) and grass meal. The gut microbial composition was assessed with terminal restriction fragment (TRF) length polymorphism and the abundance of Lactobacillus spp., Enterobacteriaceae, Bacteroides–Prevotella–Porphyromonas and the β-xylosidase gene, xynB, were assessed with quantitative PCR. The gut microbiota did not cluster based on NSP structure (arabinoxylan or pectin) rather, the effect was to a high degree ingredient specific. In pigs fed diet CFO, three TRFs related to Prevotellaceae together consisted of more than 25% of the fecal microbiota, which is about 3 to 23 times higher (P<0.05) than in pigs fed the other diets. Whereas pigs fed diet WB had about 2 to 22 times higher abundance (P<0.05) of Megasphaera elsdenii in feces and about six times higher abundance (P<0.05) of Lactobacillus reuteri in ileal digesta than pigs fed the other diets. The total amount of digested NSP (r=0.57; P=0.002), xylose (r=0.53; P=0.004) and dietary fiber (r=0.60; P=0.001) in ileal digesta were positively correlated with an increased abundance of Bacteroides–Prevotella–Porphyromonas. The effect on SCFA was correlated to specific neutral sugars where xylose increased the ileal butyric acid proportion, whereas arabinose increased the fecal butyric acid proportion. Moreover, chicory pectin increased the acetic acid proportion in both ileal digesta and feces.

A total of four diets with different carbohydrate composition were investigated in a 4×4 Latin square design experiment with four Norwegian Coldblooded trotter horses. The objective of the present study was to increase the fermentable fibre content and reduce the starch intake of the total ration obtained by partly substituting mature hay and barley with sugar beet pulp (SBP), a soluble fibre source. The diets investigated were hay only (HAY), hay (85% of dry matter intake (DMI)) and molassed SBP (15% of DMI) (SBP), hay (68% of DMI) and barley (32% of DMI) (BAR), and hay (68% of DMI), barley (26% of DMI) and SBP (6% of DMI) (BAR+SBP). The feeding level was 18.5, 17.3, 15.7 and 15.7 g DM/kg BW per day for the HAY, SBP, BAR and BAR+SBP diets, respectively. Each diet was fed for 18 days followed by 10 days of data collection, where apparent total tract digestibility (ATTD), total mean retention time (TMRT) of ytterbium-labelled hay, water balance, digestible energy (DE) intake and nitrogen balance were measured. An enzymatic chemical dietary fibre (DF) method was used to get detailed information on the composition and ATTD of the fibre fraction. Inclusion of SBP in the diet increased the ATTD of the constituent sugars galactose and arabinose (P<0.01). Feeding the HAY and SBP diets resulted in a lower TMRT owing to a higher DF intake than the BAR and BAR+SBP diets (P<0.01). There was no difference in water intake between HAY and SBP, but faecal dry matter was lower for HAY than the other diets (P=0.017), indicating that water was more tightly bound to fibre in the HAY diet. The diets were iso-energetic and provided enough DE and protein for light to moderate exercise for a 550 kg horse. In conclusion, this study showed that the DF intake had a larger effect on TMRT than partly substituting hay or barley with SBP, and that highly fermentable pectin-rich soluble DF from SBP maintains high nutrient utilization in horses.

A total of 156 plant species from 35 botanical families collected from diversified grasslands in the French Massif Central were screened in vitro for their potential to combine high nutritive value for ruminants and a reduced impact on the environment. The vegetative part of plants were analyzed for their chemical composition and incubated in a batch system containing buffered rumen fluid at 39°C for 24 h. The gas production and composition were recorded, and the fermentation end-product concentrations in the incubation medium and the in vitro true organic matter digestibility (IVTOMD) were determined. The results were expressed relative to perennial ryegrass (PRG) values used as a reference. We observed that no relationship between methane (CH4) and volatile fatty acids (VFA) was evidenced for 12 plants, the fermentation of these plants producing significantly less CH4 for a similar level of VFA production. In all, 13 plants showed 50% less CH4 production per unit of organic matter truly digested (OMTD) than PRG. Among these plants, two reduced CH4 by more than 80% and four species had an IVTOMD higher than 80%. The underlying modes of action seem to be different among plants: some result in an accumulation of H2 in the fermentation gas, but others do not. In terms of nitrogen (N) use efficiency, the fermentation of 37 plants halved the ratio between ammonia (N–NH3) and plant N content compared with PRG, of which six showed a complete absence of N–NH3 in the medium. Among these plants, four maintained the IVTDMO at values not significantly different from PRG (P>0.05). Considering the multi-criteria selection, 16 plants showed simultaneously a reduction of more than 80% in N–NH3 production and 30% in CH4 emission per unit of OMTD compared with PRG, including three with an IVTOMD higher than 80%. Overall, the botanical families that reduced simultaneously CH4 and N–NH3 most efficiently were the Rosaceae, Onagraceae, Polygonaceae and Dipsacaceae. The Onagraceae also gave high values for IVTOMD.

Twenty ruminally cannulated beef heifers were fed a high corn grain diet in a randomized block design to determine the effect of three direct fed microbial (DFM) strains of Propionibacterium on ruminal fermentation, nutrient digestibility and methane (CH4) emissions. The heifers were blocked in five groups on the basis of BW and used in five 28-day periods. Dietary treatments included (1) Control and three strains of Propionibacterium (2) P169, (3) P5, and (4) P54. Strains were administered directly into the rumen at 5×109 CFU with 10 g of a maltodextrin carrier in a gel capsule; Control heifers received carrier only. All heifers were fed the basal diet (10 : 90 forage to concentrate, dry matter basis). Rumen contents were collected on days 15 and 18, ruminal pH was measured continuously between days 15 and 22, enteric CH4 emissions were measured between days 19 and 22 and diet digestibility was measured from days 25 to 28. Mean ruminal pH was 5.91 and was not affected by treatments. Similarly, duration of time that pH<5.8 and 5.6 was not affected by treatment. Likewise, total and major volatile fatty acid profiles were similar among all treatments. No effects were observed on dry matter intake and total tract digestibility of nutrients. Total enteric CH4 production (g/day) was not affected by Propionibacterium strains and averaged 139 g/day. Similarly, mean CH4 yield (g CH4/kg of dry matter intake) was similar for all the treatments. The relative abundance of total Propionibacteria in the rumen increased with administration of DFM and were greater 3 h post-dosing relative to Control, but returned to baseline levels before feeding. Populations of Propionibacterium P169 were higher at 3 and 9 h as compared with the levels at 0 h. In conclusion, moderate persistency of the inoculated strains within the ruminal microbiome and pre-existing high propionate production due to elevated levels of starch fermentation might have reduced the efficacy of Propionibacterium strains to increase molar proportion of propionate and subsequently reduce CH4 emissions.

A meta-analysis was conducted to evaluate the effects of protozoa concentration on methane emission from ruminants. A database was built from 59 publications reporting data from 76 in vivo experiments. The experiments included in the database recorded methane production and rumen protozoa concentration measured on the same groups of animals. Quantitative data such as diet chemical composition, rumen fermentation and microbial parameters, and qualitative information such as methane mitigation strategies were also collected. In the database, 31% of the experiments reported a concomitant reduction of both protozoa concentration and methane emission (g/kg dry matter intake). Nearly all of these experiments tested lipids as methane mitigation strategies. By contrast, 21% of the experiments reported a variation in methane emission without changes in protozoa numbers, indicating that methanogenesis is also regulated by other mechanisms not involving protozoa. Experiments that used chemical compounds as an antimethanogenic treatment belonged to this group. The relationship between methane emission and protozoa concentration was studied with a variance−covariance model, with experiment as a fixed effect. The experiments included in the analysis had a within-experiment variation of protozoa concentration higher than 5.3 log10 cells/ml corresponding to the average s.e.m. of the database for this variable. To detect potential interfering factors for the relationship, the influence of several qualitative and quantitative secondary factors was tested. This meta-analysis showed a significant linear relationship between methane emission and protozoa concentration: methane (g/kg dry matter intake)=−30.7+8.14×protozoa (log10 cells/ml) with 28 experiments (91 treatments), residual mean square error=1.94 and adjusted R2=0.90. The proportion of butyrate in the rumen positively influenced the least square means of this relationship.

The objective of this study was to determine the effects of pistachio by-product silage (PBPS) as a partial replacement for corn silage (CS) on chewing activity, nutrients digestibility and ruminal fermentation parameters in Holstein male calves over a 6-month assay. For this purpose, 24 Holstein male calves (4 to 5 months of age and 155.6±13.5 kg BW) were randomly assigned to one of the four dietary treatments (n=6). In these treatments, CS was substituted with different levels of PBPS (0%, 6%, 12% and 18% of dry matter (DM)). Nutrient digestibility was measured at the end of the experimental period (days 168 to 170). Ruminal fermentation parameters were determined on days 90 and 180 and chewing activity was determined on days 15 of the 3rd and 6th month of the experiment. Results showed that calves fed rations containing 6% PBPS spent more time ruminating (P<0.05) than the control group on the 3rd and 6th months. Feeding PBPS was found to have no effects on DM, organic matter (OM), ether extract or ash digestibility, but apparent digestibility of CP, NDFom and ADFom linearly decreased (P<0.01) with increasing substitutions. On days 90 and 180, ruminal concentrations of volatile fatty acids and NH3–N linearly decreased (P<0.01) with increasing levels of PBPS in the diets; however, ruminal pH and molar proportions of acetate, propionate and butyrate were similar across the treatments. It was concluded that partial substitution of CS with PBPS (6% or 12%) would have no adverse effects on nutrient digestibility, total chewing activity and ruminal fermentation parameters.

Several in situ studies have been conducted on maize silages to determine the effect of individual factors such as maturity stage, chop length and ensiling of maize crop on the rumen degradation but the information on the relationship between chemical composition and in situ rumen degradation characteristics remains scarce. The objectives of this study were to determine and describe relationships between the chemical composition and the rumen degradation characteristics of dry matter (DM), organic matter (OM), CP, starch and aNDFom (NDF assayed with a heat stable amylase and expressed exclusive of residual ash) of maize silages. In all, 75 maize silage samples were selected, with a broad range in chemical composition and quality parameters. The samples were incubated in the rumen for 2, 4, 8, 16, 32, 72 and 336 h, using the nylon bag technique. Large range was found in the rumen degradable fractions of DM, OM, CP, starch and aNDFom because of the broad range in chemical composition and quality parameters. The new database with in situ rumen degradation characteristics of DM, OM, CP, starch and aNDFom of the maize silages was obtained under uniform experimental conditions; same cows, same incubation protocol and same chemical analysis procedures. Regression equations were developed with significant predictors (P<0.05) describing moderate and weak relationships between the chemical composition and the washout fraction, rumen undegradable fraction, potentially rumen degradable fraction, fractional degradation rate and effective rumen degradable fraction of DM, OM, CP, starch and aNDFom.

The chemical composition inclusive amino acids (AAs) and the energy and protein value of three wheat, three maize and seven blend (mainly wheat) dried distillers grains and solubles (DDGS) were determined. The net energy for lactation (NEL) was derived from digestion coefficients obtained with sheep. The digestible protein in the intestines (DVE) and the degraded protein balance (OEB) were determined by nylon bag incubations in the rumen and the intestines of cannulated cows. Additional chemical parameters like acid-detergent insoluble CP (ADICP), protein solubility in water, in borate-phosphate buffer and in pepsin-HCl, in vitro digestibility (cellulase, protease, rumen fluid) and colour scores (L*, a*, b*) were evaluated as potential predictors of the energy and protein value. Compared to wheat DDGS (WDDGS), maize DDGS (MDDGS) had a higher NEL-value (8.49 v. 7.38 MJ/kg DM), a higher DVE-content (216 v. 198 g/kg DM) and a lower OEB-value (14 v. 66 g/kg DM). The higher energy value of MDDGS was mainly due to the higher crude fat (CFA) content (145 v. 76 g/kg DM) and also to better digestible cell-walls, whereas the higher protein value was mainly due to the higher percentage of rumen bypass protein (RBP: 69.8 v. 55.6%). The NEL-value of blend DDGS (BDDGS) was in between that of the pure DDGS-types, whereas its DVE-value was similar to MDDGS. Although lower in CP and total AAs, MDDGS provided a similar amount of essential AAs as the other DDGS-types. Lysine content was most reduced in the production of WDDGS and cysteine in MDDGS. Fat content explained 68.6% of the variation in NEL, with hemicellulose and crude ash as extra explaining variables. The best predictor for RBP as well as for OEB was the protein solubility in pepsin-HCl (R 2=77.3% and 83.5%). Intestinal digestibility of RBP could best be predicted by ADF (R 3=73.6%) and the combination of CFA and NDF could explain 60.2% of the variation in the content of absorbable microbial protein. The availability of AAs could accurately be predicted from the rumen bypass and intestinal digestibility of CP.

Glucocorticoid receptor (GR) transcription is driven by alternative promoters to produce different exon 1 mRNA variants. CpG methylation on GR promoters profoundly affects GR transcription. GR in hippocampus is critical for energy homeostasis and stress responses, yet it remains unclear whether hippocampal expression of GR exon 1 mRNA variants and the methylation status of GR promoters differ between Large White (LW) and Erhualian (EHL) pigs showing distinct metabolic and stress-coping characteristics. EHL pigs had higher hippocampus weight relative to BW (P<0.01), which was associated with higher serum cortisol level compared with LW pigs. Hippocampal expression of brain-derived neurotrophic factor (P<0.05) was significantly higher, while Bax, a pro-apoptotic gene, was significantly lower in EHL pigs (P<0.05). Hippocampal expression of total GR did not differ between breeds, yet GR exon 1 to 11 mRNA was significantly higher (P<0.01) in EHL pigs, which was associated with a trend of increase (P=0.057) in GR protein content. No significant breed difference was detected for the methylation status across the whole region of the proximal GR promoter, while CpG334 and CpG266.267 were differentially methylated, in a reversed manner, between breeds. The methylation status of CpGs 248, 259, 260, 268 and 271 was negatively correlated (P<0.05) with GR exon 1 to 11 mRNA abundance. Our results provide fundamental information on the breed-specific characteristics of GR and its mRNA variants expression and the status of DNA methylation on the proximal GR promoter in the pig hippocampus.

This study aimed to investigate the effects and possible interactions of birth weight and n-3 polyunsaturated fatty acid (PUFA) supplementation of the maternal diet on the fatty acid status of different tissues of newborn piglets. These effects are of interest as both parameters have been associated with pre-weaning mortality. Sows were fed a palm oil diet or a diet containing 1% linseed, echium or fish oil from day 73 of gestation. As fish oil becomes a scarce resource, linseed and echium oil were supplemented as sustainable alternatives, adding precursor fatty acids for DHA to the diet. At birth, the lightest and heaviest male piglet per litter were killed and samples from liver, brain and muscle were taken for fatty acid analysis. Piglets that died pre-weaning had lower birth weights than piglets surviving lactation (1.27±0.04 v. 1.55±0.02 kg; P<0.001), but no effect of diet on mortality was found. Lower DHA concentrations were observed in the brain of the lighter piglets compared with their heavier littermates (9.46±0.05 v. 9.63±0.04 g DHA/100 g fatty acids; P=0.008), suggesting that the higher incidence of pre-weaning mortality in low birth weight piglets may be related to their lower brain DHA status. Adding n-3 PUFA to the sow diet could not significantly reduce this difference in DHA status, although numerically the difference in the brain DHA concentration between the piglet weight groups was smaller when fish oil was included in the sow diet. Independent of birth weight, echium or linseed oil in the sow diet increased the DHA concentration of the piglet tissues to the same extent, but the concentrations were not as high as when fish oil was fed.

MicroRNAs are endogenous ~22nt RNAs that negatively regulate gene expression at the posttranscriptional level via binding to the 3′-untranslated region (3′UTR) of target mRNAs. The microRNA miR-27a was reported to depress the expression of myostatin, a critical inhibitor of skeletal myogenesis, by binding to its 3′UTR in mouse. In this study, we cloned the full-length 3′UTR of porcine myostatin by rapid amplification of 3′-cDNA ends (3′-RACE) and demonstrated that the 3′UTR of porcine myostatin is targeted by miR-27a. The phenomenon that the level of myostatin inversely correlated with miR-27a was observed in fat and heart of pigs and also in proliferating porcine myoblasts. Besides, overexpression of miR-27a in porcine myoblasts promoted cell proliferation by reducing the expression of myostatin. Our data suggest that miR-27a positive regulates porcine myoblast proliferation via targeting myostatin.

There are important differences in terms of metabolic activity, energy utilization and capacity of protein and fat deposition when Iberian and modern pigs are compared. Primary culture of hepatocytes was used to evaluate hepatic function and sensitivity to hormones between breeds without the interference of circulating blood factors. Hepatocytes were isolated from pure Iberian (n=10) and Landrace (n=8) pigs of similar BW (24.5±12.1 and 32.9±6.1 kg BW, respectively), by collagenase perfusion. Monolayers were established in medium containing fetal bovine serum for 1 day and switched to serum-free medium for the remainder of the culture period. Hepatocytes were maintained in William’s E supplemented with β-mercaptoethanol (0.1 mM), glutamine (2 mM), antibiotics (gentamicin, penicillin, streptomycin and amphotericin B), dimethyl sulfoxide (1 µg/ml), dexamethasone (10−8 M), insulin (0.173 and 17.3 nM) and glucagon (0.287, 2.87 and 28.7 nM) for 24 to 48 h. Gluconeogenesis (GNG), glycogen degradation, triglycerides (TG) content and esterification, β-hydroxybutyrate (BHB) synthesis, IGF-1 synthesis, albumin and urea synthesis were determined. Iberian pigs had greater capacity of GNG than Landrace (24%, P<0.05), although no difference in glycogen degradation was found (P>0.10). TG content and esterification tended to be lower in hepatocytes from Iberian compared with Landrace pigs (12% and 31%, respectively; 0.10<P<0.05). Furthermore, addition of free fatty acids (CLA or linoleic acid, 0.2 mM) increased TG content (64%, P<0.001) although no difference between fatty acids was found. When free fatty acids were compared, a trend toward increased esterification (41%, P=0.078) was found for CLA. Although glucagon stimulated and insulin inhibited BHB synthesis, no difference between breeds was found (P>0.10). IGF-1 synthesis was diminished in hepatocytes from Iberian compared with Landrace pigs (16%, P<0.05). On the contrary, rate of albumin synthesis was greater in Iberian compared with Landrace pigs (58%, P<0.05). Finally, the capacity of urea synthesis was lower in hepatocytes of Iberian compared with Landrace pigs (37%, P<0.05). When ammonia was added to the media, urea concentration increased (648%, 1108% and 2791% when 0 mM was compared with 2.5, 5 and 10 mM, respectively). Urea synthesis increased on increasing ammonia content (55% and 325% when 0 mM was compared with 5 and 10 mM, respectively; P<0.0001). In conclusion, the genetic background accounts for important differences in protein and energy metabolism pathways found in primary culture of hepatocytes from lean and obese pigs.

Individual drinking patterns are a potential tool for disease monitoring in pigs. However, to date, individual pig drinking behaviour has not been described, and effects of external factors have not been examined. The aim of this study was to perform detailed quantification of drinking behaviour of growing pigs and to examine effects of period of day and effects of competition for access to the drinking nipple on the drinking behaviour, amount of water used and water wastage. In all, 52 cross-bred castrated male pigs (live weight 20.5±1.7 kg; mean±s.d.) maintained as either 3 (N3) or 10 (N10) pigs per pen and water nipple (four groups/treatment) were used. All pigs were fitted with a transponder ear tag. A radio frequency identification reader recorded and time stamped visits at the nipple. In each pen, water flow was logged every second. The drinking behaviour was recorded for 4 consecutive days and analysed using a linear mixed model. Overall, the pigs spent 594 s at the nipple during 24 h distributed among 44 visits. During this period, 5 l of water were used, of which >30% was wasted. Social competition did not affect the drinking behaviour over 24 h, except for the proportion of interrupted visits where pigs, kept with recommended nipple availability (N10), showed an increased proportion of interrupted drinking bouts compared with pigs kept at very low level of competition (N3) (0.18±0.01 v. 0.11±0.01; P<0.01). However, splitting data into 8-h periods (P1, P2, P3) starting from 0600 h revealed differences between treatments, showing that in N3, water use per visit was lower in P1 than P2 and P3 (110±10 v. 126±7 and 132±7 ml; P<0.05), whereas in N10, the water used per visit was higher during P3 than during the other periods (P1: 107±14 ml, P2: 112±10 ml v. P3: 151±10 ml; P<0.001). A similar pattern was found for visit duration. In N3, fewer nipple visits were observed in P2 than P1 (15.6±1.2 v. 22.0±1.2; P<0.001), whereas no difference was found between P1 and P2 in N10. The results demonstrate that growing pigs at the two levels of competition maintained a comparable level of 24 h water intake by changing behavioural variables involved in drinking. This dynamic characteristic of drinking behaviour means that if individual drinking patterns are to be used as disease monitoring tools, it is important to consider effects of external factors and include data on period level to allow rapid detection of behavioural changes.

Straw possesses many characteristics that make it attractive to pigs and can therefore be effective in preventing negative penmate-directed behaviours. However, straw is difficult to handle in current vacuum slurry systems under most commercial conditions and can therefore only be used in limited amounts. To occupy pigs effectively, straw must remain attractive to pigs throughout the whole day; hence, have a certain degree of novelty. We investigated the penmate-directed behaviour of liquid-fed growing pigs in a production herd, assigned to five experimental treatments: 1×25, 1×50, 1×100, 2×50 and 4×25 g of chopped straw/pig per day, with 20 replicates of each treatment (pen was regarded as experimental unit). Behaviour was observed at two different growth stages; ~40 and 80 kg live weight of the pigs. Activity and exploratory behaviour directed at penmates, straw, pen components and the slatted floor were registered continuously for 15 min of each hour during day time (0600 to 2200 h) by use of video observation of three focal pigs per pen. The pigs were active for about one-third of the day corresponding to ~5 h/day. Of the active time, an average of 7% (35 min) was spent on penmate-directed behaviour. The pigs were more active and increased their straw-directed behaviour when provided with 100 g straw/pig per day compared with 25 and 50 g (P<0.001). However, penmate-directed behaviour was not reduced with an increased amount of straw (P>0.05), and there was no effect on pigs’ behaviour when straw provision was increased per day (P>0.05). Pigs became less active and reduced their straw-directed activities when their weight increased from 40 to 80 kg live weight (P<0.001), but the amount of penmate-directed behaviour was similar (P>0.05). Further, the residual straw results indicated that perhaps a more frequent straw provision could help establish a more even level of fresh available straw during the day. However, the frequent straw provision did not occupy pigs more than one daily allocation did. In conclusion, there was no difference in penmate-directed behaviour of the pigs when given 25 or 50 g of straw/pig per day compared with 100 g of straw/pig per day, nor were there any difference when 100 g of straw/pig per day was provided more frequently.

The aim of the study was to assess the impact of selection for residual feed intake (RFI) on the behavioural activity of lines divergently selected for RFI during seven generations. In all, six successive batches from the seventh generation of selection were raised in collective pens equipped with a single-place electronic feeder (SEF) from 10 weeks of age to 100 kg BW. Each batch included four groups of 12 pigs: high RFI (RFI+) castrated males, RFI+ females, low RFI (RFI−) castrated males, RFI− females. At 17 weeks of age, health criteria were evaluated using a gradient scale for increased severity of lameness, body lesions, bursae and tail biting. Individual behavioural activities were recorded by 24-h video tape on the day after health evaluation. The investigative motivation towards unfamiliar objects was quantified at 18 weeks of age. The daily individual feeding patterns were computed from SEF records during the 4 weeks surrounding 12, 17 and 22 weeks of age. All pigs spent significantly most of their time lying in diurnal (80% of total scan) and nocturnal (>89%) periods. The RFI− pigs showed a lower proportion of health problems (P<0.01) than RFI+ pigs. The RFI− pigs used the SEF less than the RFI+ pigs, in diurnal (5.3% v. 6.4% of video scans, P<0.05) and nocturnal periods (3.6% v. 4.5% of video scans, P<0.05). This was confirmed by a significantly lower daily number and duration of visits to the SEF computed from the SEF data. The feeding activity measured from the video recording was significantly correlated (R>0.34; P<0.05) with feeding patterns computed from the SEF. The RFI− pigs spent less time standing over the 24-h period (9.7% v. 12.2% of scans, i.e. 35 min/day, P<0.05). In terms of energy costs, this amounted to 14% of the line difference in terms of daily metabolizable energy intake. The castrated males used the SEF more than females, especially at night (4.7% v. 3.4% of total scans, P<0.05), whereas females displayed greater investigation of their environment (7.7±0.3% v. 6.6±0.2% of total scans, P<0.05) and the novel objects (10.7% v. 4.9% of total scans, P<0.05). In conclusion, the lower physical activity associated with reduced energy expenditure in RFI− pigs compared with RFI+ pigs contributed significantly to their improved efficiency and was not related to worsened health scores.

In order to evaluate the influence of rearing system (free-ranging (FR) v. confinement (C)) on buffalo heifer efficiency to reach age of puberty and on behavioural and immune functions, two experiments were conducted from September 2010 to October 2011. In Experiment I, 32 subjects aged 8 to 9 months at the start of experiment were used. A total of 16 animals (group C) were group housed in an indoor slatted floor pen (4 m2/animal) with an outdoor paddock (4 m2/animal); 16 others grazed on a Mediterranean natural pasture of 40 ha (group FR). Behavioural data were collected and organic matter digestibility, blood metabolites and progesterone were determined. At the end of the experiment, a novel object test and a skin test were conducted, and the avoidance distance (AD) at the manger was measured. Free-ranging animals were able to express natural behaviours such as wallowing and grazing. C animals devoted more time to the novel object than FR animals, whereas AD at manger was lower in group FR than in group C (P<0.01). Cellular immune response was higher in FR heifers than in C animals (P<0.01). FR animals also showed a higher digestibility of organic matter (P<0.01). Heifers from group FR had higher plasma concentrations of non-esterified fatty acids (P<0.001) and lower concentrations of glucose than heifers from group C (P<0.001). C animals showed higher daily weight gains (P<0.01) and weight at the puberty (P<0.05), but there were no differences in terms of age of puberty between the two groups. The intakes of dry matter (DM), CP and energy to reach the age of puberty were similar in both groups. In order to verify whether the results obtained in Experiment I could be replicated in different rearing conditions (reduced pasture availability, different location and altitude), a second experiment was conducted on 26 animals, where only onset of age of puberty and metabolic profile were monitored. In Experiment II, 13 heifers grazed on a natural pasture of 5 ha, other 13 received the same space as indicated for Experiment I. Results from Experiment II generally confirmed those of Experiment I. Only the intakes of DM and energy to reach the age of puberty were higher in group C than in FR (P<0.001). A lower competition with human nutrition, reproductive performances similar to those shown by confined animals and the indications given by immune and behavioural variables, suggest that a free-range-based system may be conveniently used for buffalo heifer farming purposes.