Biceps femoris (BF) and masseter muscle (MM) are the mixture of slow oxidative and fast-twitch fibres. Compared with MM, BF had the significantly higher expression of myosin heavy chain (MyHC) fast IIx and IIb isoforms (MyHCIIx and MyHCIIb), but lower expression of MyHC slow isoform (MyHCI) and fast IIa isoform (MyHCIIa). The objective of this study was to investigate the expression pattern of troponin I (TnI) slow-twitch isoform (TNNI1) and fast-twitch isoform (TNNI2) in BF and MM of Yorkshire and Meishan pigs which differed significantly in the growth rate. The expression of the TNNI1 and TNNI2 peaked at the postnatal 35 days in Yorkshire pigs and postnatal 60 days in Meishan pigs. The expression of TNNI1 and TNNI2 in Meishan pigs was significantly higher than that in Yorkshire pigs at the foetal 60 days, while the opposite occurred at postnatal 35 days. The expression ratio of TNNI1 relative to TNNI2 favoured TNNI2 expression in BF and MM regardless of Yorkshire and Meishan pigs. TNNI1 expression in MM was significantly higher than that in BF at 60, 120 and 180 days in Meishan pigs and at 120 and 180 days in Yorkshire pigs. On the contrary, no significant difference of TNNI2 expression in BF and MM was found except for Yorkshire pigs of 180 days. This study provided the foundation for future research on TnI isoforms as the model gene to study mechanisms of muscle fibre-specific gene regulation in pigs.

Impracticality and cost of existing pain management strategies during surgical castration of beef cattle have limited their widespread implementation on-farm. A farmer-applied topical anaesthetic formulation, originally developed and used commercially to mitigate the pain of mulesing in lambs, was investigated for its potential use for managing pain in surgically castrated calves. This formulation contained lidocaine, bupivacaine, adrenalin and cetrimide. In this study, 24 Angus bull calves were randomly allocated to (1) surgical castration (C, n=8), (2) surgical castration with the post-operative application of topical anaesthetic (CTA, n=8) and (3) sham castration/control (CON, n=8). The experiment was conducted over 2 days, with treatment groups evenly represented across each day. Calves were habituated to handling before the experiment and blood samples were collected for plasma cortisol measurement at defined time periods before, at and post treatment, (at −0.5, 0 h, then +0.5, 1, 1.5, 2, 4 and 6 h). There was a significant effect of time on cortisol concentrations across all treatment groups (P<0.01), with lowest concentrations at −0.5 and 6 h and peak concentration at 0.5 h being significantly higher than the cortisol response at 0 h. The effect of treatment was not significant (P=0.077), however, there was a trend for CON calves to display lower cortisol concentrations than C and CTA calves and CTA calves to display lower cortisol concentrations than C calves. The mean area under the curve (AUC) of CON calves was significantly lower than those of C and CTA calves (P=0.04), however, there was no significant difference between the AUCs of CTA and C calves. Immediate application of topical anaesthetic after surgical castration did not significantly reduce plasma cortisol concentrations. However, the trend for CTA calves to display lower cortisol concentrations than C calves warrants further investigation into the use of TA for pain relief of surgically castrated beef calves.

Semi-purified diets incorporating 495·4 g/kg crude protein and 72·0 g/kg oil, were used to identify the qualitative requirement of Spams aurata juveniles for thiamin, riboflavin, pyridoxine, niacin and pantothenic acid. Deficiency of these vitamins was associated with poor performance in terms of growth, food efficiency and apparent net protein utilization. All dietary vitamin deficiencies resulted in elevated moisture and a lowering of the lipid content of the carcass. In addition to increased mortality among the fish fed deficient diets, a small number of externally visible changes were observed including food refusal, anorexia and changes of skin colour. At the haematological level, all cases of vitamin deficiency were associated with significant reductions in haematocrit. In general, histological examination revealed that the pancreas of vitamin-deficient animals became atrophic with an accumulation of pigmented granules around this organ while additionally, the normal homogeneity of the liver parenchyma was lost.

Feeding dairy cows diets rich in grain often leads to subacute rumen acidosis (SARA), which might affect their responsiveness to immunogenic stimuli such as exogenous lipopolysaccharide (LPS), and can lead to metabolic alterations. The main objective of this study was to investigate if SARA affects the stress and metabolic health responses resulting from an intramammary LPS challenge. Before the intramammary LPS challenge, the SARA cows showed higher blood glucose and a tendency for higher lactate and aspartate aminotransferase as well as a trend toward lower β-hydroxybutyrate (BHBA) and γ-glutamyltransferase compared with control cows. After the LPS challenge, the serum cortisol concentration markedly increased and the calcium concentration decreased both in SARA and control cows. In SARA-LPS cows, however, the lactate concentration increased due to the LPS infusion, whereas it remained unchanged in the control cows. A lower serum BHBA concentration was found in SARA-LPS compared with control-LPS cows. Higher non-esterified fatty acid concentrations were found in control-LPS cows shortly before the LPS challenge compared with SARA cows, challenged or not with LPS, whereas it did not differ from SARA-LPS cows thereafter. In conclusion, the results suggest that intramammary LPS challenge induced stress and lowered calcium concentration in all dairy cows, whereby this challenge showed lower BHBA and higher lactate levels in cows with SARA conditions.

Haryana and crossbred (Holstein × local Haryana) bullocks were subjected to work under heavy loads in summer. During the work, bullocks exhibited distress symptoms. After work, rectal temperature, respiration rate, heart rate and minute volume increased significantly, the average pO2 content increased, muscle lactic acid increased and creatine phosphate level declined. From the results it was evident that oxygen availability in blood improved during work. Despite the enhanced oxygenation of blood, there was accumulation of lactic acid in muscle. This indicated a certain degree of tissue hypoxia, which probably brought about fatigue earlier.

In this study, breeding structures and commercial sow lines were evaluated by economic and genetic simulation studies for their suitability to provide the Dutch organic pig sector with replacement gilts. Sow and litter performance from over 2000 crossbred sows from 2006 to 2007 were collected on 11 to 14 Dutch organic pig herds, respectively, and compared with conventional herds. Results showed that organic herds had lower farrowing rates (3.6% to 7.5%), more live born piglets per litter (0.4% to 1.2%) and higher preweaning mortality rates (7% to 13%) compared to conventional herds. These results were used to simulate economic performance of various combinations of breeding structures and sow lines under organic conditions, under the assumption of absence of genotype–environment interactions. Sow and litter performance data under organic conditions (total piglets born/litter, stillborn piglets/litter, mortality until weaning, lactation length, interval weaning-oestrus and sow culling rate) and the costprice calculation for the Dutch organic pig sector were used as input for the economic simulation studies. The expected genetic progress was simulated for three potential breeding structures of the organic sector: organic breeding herds producing F1 gilts (OrgBS), a flower breeding system (FlowerBS) and a two-line rotation breeding system (RotBS). In FlowerBS, an organic purebred sow line is bred, using on-farm gilt replacement. The OrgBS with a Yorkshire × Landrace cross had the highest margin per sow place (€779), followed by RotBS with Yorkshire × Landrace cross (€706) and FlowerBS with Yorkshire sow line (€677). In case that an organic purebred sow population of 5000 sows would be available, FlowerBS gave the highest genetic progress in terms of cost price reduction (€3.72/slaughter pig per generation), followed by RotBS and OrgBS (€3.60/slaughter pig per generation). For FlowerBS, additional costs will be involved for maintaining a dedicated breeding programme. In conclusion, OrgBS using conventional genetics is economically the most viable option for the organic pig sector. However, this structure has clear disadvantages in terms of risks with regard to disease transmission and market demand. FlowerBS using a dedicated purebred organic line will only be cost-effective if sow population size is sufficiently large. RotBS might be a viable alternative, especially in combination with artificial insemination (AI) boars that are ranked according to an organic selection index. Regardless of breeding structure, the Yorkshire sow line gave the highest prolificacy and the highest economic returns on organic herds.

Proxies have the potential to accelerate feed efficiency (residual feed intake (RFI); kg dry matter/day) improvement, assisting with the reduction of beef cattle feed costs and environmental impact. Heart rate (HR) (beats per minute (BPM)) is associated with feed efficiency and influenced by autonomic activity and peripheral metabolism, suggesting HR could be used as a proxy for feed efficiency. Objectives were to assess associations between overnight HR, lying patterns and RFI, and between acute stress HR and RFI. Heifer calves (n=107; 408±28 days of age, 341±42.2 kg) and yearling heifers (n=36; 604±92 days of age, 539±52.2 kg) were exposed to a performance test to determine productive performance. Overnight HR (electrode based) and lying patterns (accelerometer based) were monitored on a subgroup of heifer calves (n=40; 20 lowest RFI; 20 highest RFI). In the 10-min acute stress assessment, all heifers were individually exposed to the opening and closing of an umbrella and HR before (HRBEF), in response to (HRMAX), after (HRAFT) and change (HRCHG; HRAFT−HRBEF) as a result of exposure were determined. Using polynomial regression, rate of HR decrease pre-exposure (β1) and rates of HR increase (β2) and decrease (β3, β4) post-exposure were determined. Heifer calves in the overnight assessment were classified into equal RFI groups (low RFI; high RFI) and HR means were treated as repeated measures and compared using multiple regression. In the acute stress assessment, heifers were classified within cattle category into equal RFI groups (low RFI; high RFI) and means and polynomial regression parameters were compared using multiple regression. Low-RFI heifer calves had a lower overnight HR (69.2 v. 72.6 BPM), similar HR change from lying to standing intervals (8.9 v. 9.2 BPM) and similar time lying (61.1% v. 64.5%) compared with high-RFI heifer calves. Low-RFI heifer calves had a higher absolute HRMAX (162.9 v. 145.7 BPM) and β2 (−0.34 v. −0.20) than high-RFI heifer calves. Low-RFI yearling heifers had similar acute stress HR means and a lower β1 (0.003 v. 0.006) than high-RFI yearling heifers. Overnight HR and acute stress HR are potential indicators of RFI in heifer calves. However, acute stress HR results varied in yearling heifers, suggesting previous handling experience and/or age influence stress response. Pending further development (predictive ability, repeatability), the acute stress assessment could have potential for on-farm application as a feed efficiency proxy in young heifers with minimal handling experience.

The effects of (i) medium and high feed value (MFV and HFV) maize silages and (ii) MFV and HFV grass silages, each in combination with a range of concentrate feed levels, on the performance of finishing lambs were evaluated using 280 Suffolk-X lambs (initial live weight 36.1 kg). The MFV and HFV maize silages represented crops with dry matter (DM) concentrations of 185 and 250 g/kg, respectively, at harvest, and had starch and metabolisable energy (ME) concentrations of 33 and 277 g/kg DM and 9.6 and 11.0 MJ/kg, respectively. HFV and MFV grass silages had DM and ME concentrations of 216 and 294 g/kg and 11.0 and 11.5 MJ/kg DM, respectively. A total of 13 treatments were involved. The four silages were offered ad libitum with daily concentrate supplements of 0.2, 0.5 or 0.8 kg per lamb. A final treatment consisted of concentrate offered ad libitum with 0.5 kg of the HFV grass silage daily. Increasing the feed value of grass silage increased (P < 0.001) forage intake, daily carcass and live weight gains, final live weight and carcass weight. Increasing maize silage feed value tended to increase (P = 0.07) daily carcass gain. Increasing concentrate feed level increased total food and ME intakes, and live weight and carcass gains. There was a significant interaction between silage feed value and the response to concentrate feed level. Relative to the HFV grass silage, the positive linear response to increasing concentrate feed level was greater with lambs offered the MFV grass silage for daily live weight gain (P < 0.001), daily carcass gain (P < 0.01) and final carcass weight (P < 0.01). Relative to the HFV maize silage, there was a greater response to increasing concentrate feed level from lambs offered the MFV maize silage in terms of daily carcass gain (P < 0.05) and daily live weight gain (P = 0.06). Forage type had no significant effect on the response to increased concentrate feed level. Relative to the MFV grass silage supplemented with 0.2 kg concentrate, the potential concentrate-sparing effect of the HFV grass silage, and the MFV and HFV maize silages was 0.41, 0.09 and 0.25 kg daily per lamb, respectively. It is concluded that increasing forage feed value increased forage intake and animal performance, and maize silage can replace MFV grass silage in the diet of finishing lambs as performance was equal to or better (depending on maturity of maize at harvest) than that for MFV grass silage.

A 26-day trial with 18 Pietrain×(Landrace×Duroc) pigs was conducted to investigate the effect of two dose levels of a specifically selected Bacillus spp. direct-fed microbial (DFM) product, on the emission of environmentally harmful gasses (methane, ammonia and hydrogen sulphide) from manure. Pigs were assigned to one of three treatments in a randomized complete block design according to their sex and initial BW. Each treatment contained three replications with two pigs per pen. The test treatments included a Bacillus spp. DFM containing 3×108 colony-forming unit/g, added at a low (250 mg/kg) and high (500 mg/kg) dose to an antibiotic free high fibre-based diet, and a non-supplemented control diet. Manure from pigs fed with the supplemented diets emitted lower amounts of atmospheric contaminants. The most significant reduction was observed with low DFM supplementation, in which methane and ammonia volatilization decreased (P<0.05) by >40% and 50%, respectively, on fresh weight basis in relation to the control. Microbiome analysis of manure by high through put sequencing techniques on eubacterial and archaeal 16S rRNA genes highlighted the complex interactions between indigenous gut microflora and inoculated Bacillus spp. The tested Bacillus DFM could be considered as a best available technique in reducing the environmental impacts of growing pigs fed with high fibre-based diets.

Pudong White (PW) pigs are distributed in the Taihu region of China and are characterized by their completely white coats. A heated debate concerning this genetic resource and its relationship to Taihu and western pig breeds has arisen, due to the white coat of the animals. To determine whether PW is a unique genetic resource, we performed a detailed assessment of the genetic relationships among PW, six breeds from the Taihu population and three western pig breeds, based on whole-genome single nucleotide polymorphism (SNP) data. A total of 68 102 SNPs were identified in the genomes of the tested populations by next-generation sequencing technology, of which, 64 were determined as the potentially specific to PW breed. The genetic distance between PW pigs and the Taihu population was shorter than that between PW and western breeds. The genetic distance within the PW population was small and neighbour-joining tree analysis revealed that all PW individuals clustered into a separated group, indicating a close genetic relationship among PW individuals which may result from a small effective population size (Ne) and inbreeding. The results of both principal component analysis and evaluation using fastSTRUCTURE demonstrated that PW was clearly differentiated from other breeds. Together, these results indicate that PW is a distinctive genetic resource with a unique genetic structure separate from other Taihu and western pig breeds. Furthermore, this genome-wide comprehensive survey of the relationships among PW, Taihu and western pig breeds, demonstrates the rationality of the current breed classification of PW. The results also provide evidence about the unique genetic resource of PW, based on genome-wide genetic markers. These data will improve our understanding of the genetic structure and current state of PW breed, and facilitate the development of a national project for the conservation and utilization of these pigs.

A total of 45 continental bulls (1/2 Blonde d'Aquitaine/3/8 Charolais) were used in a continuous design randomized-block experiment, to examine the effects of the ratio of silage to concentrates in the diet on growth and carcass parameters. The proportions of concentrates in the five diets were 0·26, 0·40, 0·55, 0·68 and 0·75 (DM basis). The basal diet was grass silage with D value 730 g/kg and ammonia nitrogen per unit total nitrogen 86 g/kg. The mean initial and final live weights were 467 and 651 kg respectively, with a mean carcass weight of 384 kg. The digestibility of energy was not affected by the proportion of concentrates in the diet. The rates of live weight, carcass and separable lean tissue gain tended to reach a plateau at the higher concentrate proportions, while the rate of separable fat tissue gain increased linearly with increase in concentrate proportion. The separable lean content of the carcass was linearly and negatively related to the proportion of concentrates, with a predicted decrease of’10 g/kg for an increase in concentrate proportion of 0·16. Separable fat content was also linearly related to the proportion of concentrates, with a predicted increase of 10 g/kg for each 0·196 increase in proportion of concentrates. The absence of any effect of concentrate proportion on the content of saleable meat in the carcass was considered to reflect the high growth potential of the animals. An important conclusion was that 0·99 of the asymptote value for lean tissue gain was attained at a concentrate proportion of 0·52 and that 0·95 of the maximum rate of gain was obtained at the relatively low concentrate proportion of 0·39, therefore indicating that finishing bulls of this type can perform to a high level on diets which are predominately based on grass silage.

Twelve mature ewes were used to study the effect of forage: concentrate ratio in complete diets on voluntary intake and some digestive characteristics. Diets consisted of four combinations of chopped lucerne hay and a concentrate (390 g cracked barley grains, 440 g cracked maize grains and 170 g soya-bean meal per kg of concentrate) in the following proportions (fresh matter basis): 0·8:0·2 (C20), 0·6:0·4 (C40), 0·4:0·6 (C60) and 0·2:0·8 (C80). Diets were offered over two 42-day periods and, in each of them, three sheep received one of the four diets, with the restriction that no animal received the same diet in both periods. Chromium Ill-mordanted fibre was used as a marker to estimate passage rate of digest a and microbial nitrogen supply (MNS) was estimated from the urinary excretion of purine derivatives. The increase in the proportion of concentrate affected linearly (P < 0·05) the voluntary intake of food, the mean values being 36·8, 37·9, 36·3 and 30·0 g dry matter (DM) per kg live weight per day for C20, C40, C60 and C80 diets, respectively. Apparent digestibility of DM, organic matter (OM) and crude protein increased linearly (P < 0·01) with the proportion of concentrate in the diet, whereas that of cellulose evolved auadratically (P < 0·05), reaching a minimum value in the C80 diet. Digestible OM intake was unaffected (P > 0·05) by the proportion of concentrate in the diet. Both particulate passage rate from the rumen and through the caecum and proximal colon decreased linearly (P < 0·05) as concentrate proportion in the diet increased. MNS (g/day) was not affected (P > 0·05) by the diet, whereas its efficiency (g/kg digestible OM intake) tended (P < 0·10) to increase with the proportion of concentrate in the diet.

The effect of castration on fat partitioning in mature animals and on the maturing patterns for fat depots relative to total body fat was examined using slaughter and dissection data from 20 Dorset Horn rams and 20 Dorset Horn wethers. Animals were slaughtered at 6 kg intervals from 18 kg live weight to maturity. Five rams and eight wethers were classified as mature.

In the mature animals the partitioning of fat differed for the rams and wethers in that the rams had a lower proportion of subcutaneous fat, and higher proportion of intermuscular and mesenteric fat than the wethers. However, the proportions of total carcass dissectible fat (i.e. subcutaneous plus intermuscular fat) and of the total non-carcass depots (i.e. kidney plus channel fat, omental, scrotal and thoracic fat) did not significantly differ between rams and wethers.

The maturity coefficients of individual fat depots of rams and wethers were not significantly different and six of the nine depots were average maturing relative to total body fat. The intermuscular and thoracic fat depots were early maturing (maturity coeffient q= 1·19, 2·26 respectively), and the omental depot was late maturing (q= 0·52).

Comparison of the partitioning of fat in rams and wethers reflected the differences in the mature animals when made at either the mean weight or at the mean stage of maturity, as the maturing patterns of most depots were not greatly different from that of total fat.

The backtest response of a pig gives an indication of its coping style, that is, its preferred strategy to cope with stressful situations, which may in turn be related to production traits. The objective of this study was therefore to estimate the heritability of the backtest response and estimate genetic correlations with production traits (birth weight, growth, fat depth and loin depth). The backtest was performed by placing the piglet on its back for 60 s and the number of struggles (NrS) and vocalizations (NrV), and the latency to struggle and vocalize (LV) was recorded. In total, 992 piglets were subjected to the backtest. Heritability estimates for backtest traits were statistically moderate (although high for behavioral traits), with LV having the highest heritability estimate (0.56±0.10, P<0.001) and NrS having the lowest estimate (0.37±0.09, P<0.001). Backtest traits also had high genetic correlations with each other, with vocalization traits (NrV and LV) having the highest (−0.94±0.03, P<0.001), and NrS with NrV the lowest correlation (0.70±0.09, P<0.001). No significant correlations were found between backtest traits and production traits, but correlations between NrS and birth weight (−0.38±0.25), and NrV and loin depth (−0.28±0.19) approached significance (P=0.07). More research into genotype-by-environment interactions may be needed to assess possible connections between backtest traits and production traits, as this may depend on the circumstances (environment, experiences, etc.). In conclusion, heritability estimates of backtest traits are high and it would therefore be possible to select for them. The high genetic correlations between backtest traits indicate that it may be possible to only consider one or two traits for characterization and selection purposes. There were no significant genetic correlations found between backtest traits and production traits, although some of the correlations approached significance and hence warrant further research.

One hundred and twenty spring-born steers comprised of 40 Friesians (FR), 40 Canadian Hereford × Friesians (HF) and 40 Simmental × Friesians (SM) were reared together from shortly after birth to slaughter after a mean period of 740 days. During the finishing winter there was a 3 (breed types) × 2 (3 and 6 kg supplementary concentrates per head daily with grass silage ad libitum) × 2 (222- and 225-day finishing periods) factorial arrangement of treatments. One side from each of 96 carcasses (eight per treatment) was completely separated into bone, muscle, intermuscular fat and subcutaneous fat and a 10th rib sample of m. longissimus was chemically analysed.

Carcass weights per day of age and carcass weights were 404, 433 and 449 (s.e. 4·6) g and 301, 320 and 330 (s.e. 3·4) kg for FR, HF and SM, respectively. Corresponding proportions of carcass muscle were 602, 577 and 628 (s.e. 4·8) g/kg. FR and HF had similar proportions of their total muscle in the hindquarter, whereas SM had more of their muscle in the hindquarter. M. longissimus lipid concentrations for FR, HF and SM were 36, 39 and 26 (s.e. 1·96) g/kg. Increasing supplementary concentrate level from 3 to 6 kg/day increased side weight by 7 kg, of which proportionately 0·48 was fat. Extending the finishing period from 121 to 225 days increased side weight by 22 kg of which proportionately 0·45 was fat. Both the higher concentrate level and the longer finishing period reduced carcass muscle and bone proportions, and increased carcass fat proportion. Allometric regression coefficients for side muscle, bone and fat weights on side weight were 0·75, 0·51 and 2·13, respectively. It was calculated that FR, HF and SM would have similar carcass fat proportions at approximate carcass weights of 320, 290 and 380 kg, respectively.

Milk production and food intake records were available on individual animals from a high-yielding Holstein-Friesian herd in which selection had been practised on fat plus protein yield using nationally available artificial insemination sires. The relationship between sires and maternal grandsires' transmitting ability (ICC), expressed as a pedigree index (sire ICC + 0·5 maternal grandsire ICC), and offspring performance for milk production traits, food intake, and gross efficiency (milk energy (MJ)/total energy intake (MJ)) was investigated. The data comprised 475 26-week (data set 1) and 293 38-week (data set 2, a subset of 1) records, and for each data set analyses were conducted on heifers, cows and pooled lactations. Regressions of fat plus protein yield, fat yield, protein yield, and milk yield on their corresponding pedigree index were not far from the theoretical expectation (for a full lactation) of 1, for heifers (0·71 (s.e. 0·20), 0·72 (s.e. 0·20), 0·74 (s.e. 0·21) and 0·75 (s.e. 0·19), respectively), but slightly lower for the pooled lactations (0·57 (s.e. 0·20), 0·55 (s.e. 0·20), 0·67 (s.e. 0·19) and 0·64 (s.e. 0·15)) in data set 1. Regressions of fat plus protein yield, food intake and gross efficiency on pedigree index for fat plus protein yield, each trait expressed as a ratio of herd mean, were 1·31 (s.e. 0·37), 0·38 (s.e. 0·19) and 1·04 (s.e. 0·35) for heifers and 0·89 (s.e. 0·31), 0·48 (s.e. 0·18) and 0·59 (s.e. 0·26) respectively, for pooled lactations, in data set 1. Regressions for cow lactations were lower. Similar results were obtained with data set 2. In this study, a genetic increase of proportionately 0·1 in fat plus protein yield of daughters of sires of high genetic merit for fat plus protein yield, was accompanied by a proportional genetic increase of 0·029 in food intake and a 0·079 proportional genetic increase in efficiency.

The influence of a diet of either pasture or hay on the development of lactic acidosis in sheep was investigated using a grain challenge approach. Twenty-four Merino wethers with a mean live weight of 36·7 (s.e.3·6) kg were used; 12 were adapted to grass pasture and 12 to hay (lucerne and oaten hay, 60: 40) for 4 weeks before being given 1 kg of crushed barley via stomach tube. Six sheep in each group were also given virginiamycin (VM; 50 mg/kg barley) with the grain to test the efficacy of this antibiotic in controlling the bacteria responsible for the development of acidosis. Changes in volatile fatty acid (VFA), pH, lactate and bacterial count in the rumen and faecal pH and dry matter (DM) were measured for a 24-h period following administration of the barley. Daily intakes of hay were measured for a 10-day period following grain engorgement. Total ruminal VFA increased (P < 0·01) over time and tended (P = 0·08) to be higher in sheep adapted to hay than in those adapted to pasture (67·5 v. 59·8 mmol/l). The molar proportions of VFA changed (P < 0·01) over time in favour of propionate in both groups. Ruminal pH was higher (P < 0·001) in pasture-adapted sheep, but declined (P < 0·001) in both groups over time following the introduction of barley. This decline in pH was associated with increases in ruminal concentration of VFA in pasture-adapted sheep and VFA and lactate in hay-adapted sheep. The addition of VM resulted in a higher (P < 0·001) proportion of propionate and a trend towards higher (P = 0·24) faecal pH and DM content. Faecal pH and DM content declined (P < 0·001) over time and was lower for the pasture-adapted sheep. The introduction of either barley alone or barley with VM from both hay and pasture diets increased (P < 0·05) the viable counts of total bacteria, Streptococcus bovis and lactic acid bacteria. Bacterial isolates were purified and identified by complete sequencing of the 16S rRNA gene to determine the predominant bacteria during the overfeeding of grain. Isolates from medium selective for S. bovis were all identified as this species when VM was not given. VM had no effect on counts of viable bacteria, but inhibited the growth of S. bovis.

This study has shown that sheep given hay are more susceptible to lactic acidosis, the signs of which can be reduced by VM.

A sward of perennial ryegrass was either directly ensiled at 181 g dry matter (DM) per kg fresh weight with formic acid applied at 3·6 1/t fresh material or wilted for 65 h to achieve a DM concentration of 407 g DM per kg. Physical and respiration loss were measured in the field and losses during ensiling were estimated from buried bags. The silages were offered to 58 British Friesian steers, initially 3 months of age and 101 kg live weight (LW). Ten steers were allocated to an initial slaughter group and the remainder were offered the two silages either ad libitum or at two restricted levels of feeding. These animals were slaughtered after a mean period of 112 days to estimate the increments in the components of the body.

Loss of DM in the field increased from 4·3 to 86·6 g/kg on wilting and proportionately 0·75 of this additional loss was due to respiration. The fermentation characteristics of the silages were broadly similar except that the concentration of ethanol was higher in the unwilted than in the wilted silage (57·6 v. 5·6 g/kg DM). Losses of DM during ensiling were slightly higher with the unwilted (104·4 g/kg ensiled) than with the wilted (80·1 g/kg) material. Losses of nitrogen were relatively higher and energy losses lower than was the loss of DM.

Wilting significantly depressed the digestibility of gross energy from 0·651 to 0·631 (P < 0·001) and at the ad libitum level steers ate proportionately 006 more wilted silage (P > 0·05) resulting in similar intakes of digestible energy. At the ad libitum level of feeding steers given wilted silage gained more LW (+55 g/day) and empty-body weight (+64 g/day) than those given unwilted silage (P < 0·05). However, steers given wilted silage contained less fat and energy in the empty body at slaughter than those given unwilted silage. Thus, wilting did not influence the efficiency of utilization of digestible energy for energy retention nor the efficiency of utilization of dietary protein for protein gain. Since efficiencies by the animal were similar and also the increased field loss on wilting was partly compensated for by a reduced silo loss, it is concluded that the proportion of energy and protein in the standing crop retained by the steers is unaffected by wilting (65 and 64 kJ/MJ and 125 and 138 g/kg N for unwilted and wilted systems respectively). Further work is needed to establish the effect of wilting for a shorter period than in the current trial by increasing the drying rate of herbage.

Several studies have shown that computation of genomic estimated breeding values (GEBV) with accuracies significantly greater than parent average (PA) estimated breeding values (EBVs) requires genotyping of at least several thousand progeny-tested bulls. For all published analyses, GEBV computed from the selected samples of markers have lower or equal accuracy than GEBV derived on the basis of all valid single nucleotide polymorphisms (SNPs). In the current study, we report on four new methods for selection of markers. Milk, fat, protein, somatic cell score, fertility, persistency, herd life and the Israeli selection index were analyzed. The 972 Israeli Holstein bulls genotyped with EBV for milk production traits computed from daughter records in 2012 were assigned into a training set of 844 bulls with progeny test EBV in 2008, and a validation set of 128 young bulls. Numbers of bulls in the two sets varied slightly among the nonproduction traits. In EFF12, SNPs were first selected for each trait based on the effects of each marker on the bulls’ 2012 EBV corrected for effective relationships, as determined by the SNP matrix. EFF08 was the same as EFF12, except that the SNPs were selected on the basis of the 2008 EBV. In DIFmax, the SNPs with the greatest differences in allelic frequency between the bulls in the training and validation sets were selected, whereas in DIFmin the SNPs with the smallest differences were selected. For all methods, the numbers of SNPs retained varied over the range of 300 to 6000. For each trait, except fertility, an optimum number of markers between 800 and 5000 was obtained for EFF12, based on the correlation between the GEBV and current EBV of the validation bulls. For all traits, the difference between the correlation of GEBV and current EBV and the correlation of the PA and current EBV was >0.25. EFF08 was inferior to EFF12, and was generally no better than PA EBV. DIFmax always outperformed DIFmin and generally outperformed EFF08 and PA. Furthermore, GEBV based on DIFmax were generally less biased than PA. It is likely that other methods of SNP selection could improve upon these results.

To simulate the consequences of management in dairy herds, the use of individual-based herd models is very useful and has become common. Reproduction is a key driver of milk production and herd dynamics, whose influence has been magnified by the decrease in reproductive performance over the last decades. Moreover, feeding management influences milk yield (MY) and body reserves, which in turn influence reproductive performance. Therefore, our objective was to build an up-to-date animal reproduction model sensitive to both MY and body condition score (BCS). A dynamic and stochastic individual reproduction model was built mainly from data of a single recent long-term experiment. This model covers the whole reproductive process and is composed of a succession of discrete stochastic events, mainly calving, ovulations, conception and embryonic loss. Each reproductive step is sensitive to MY or BCS levels or changes. The model takes into account recent evolutions of reproductive performance, particularly concerning calving-to-first ovulation interval, cyclicity (normal cycle length, prevalence of prolonged luteal phase), oestrus expression and pregnancy (conception, early and late embryonic loss). A sensitivity analysis of the model to MY and BCS at calving was performed. The simulated performance was compared with observed data from the database used to build the model and from the bibliography to validate the model. Despite comprising a whole series of reproductive steps, the model made it possible to simulate realistic global reproduction outputs. It was able to well simulate the overall reproductive performance observed in farms in terms of both success rate (recalving rate) and reproduction delays (calving interval). This model has the purpose to be integrated in herd simulation models to usefully test the impact of management strategies on herd reproductive performance, and thus on calving patterns and culling rates.