In farmed salmonids the majority of consumed nitrogen is lost in metabolic waste products (mainly ammonia) and the faeces (Table 1). Any improvement in nitrogen retention, brought about by reductions in these components, would decrease environmental load. Inter-individual variation in retained nitrogen has been little investigated as a basis for selection of more efficient fish; this communication points to an experimental approach to measuring individual variation by concentrating on digestive efficiency and protein turnover as possible contributors to nitrogen retention. The utilization of dietary nitrogen was investigated in two species of farmed salmonid, the rainbow trout, Oncorhynchus mykiss and the Atlantic salmon, Salmo salar.

Recent studies have shown increased silage intake and improved milk fat concentration in dairy cows offered restricted compared to extensively fermented silages (Chamberlain et al., 1990; Mayne 1992). Changes in milk composition may be related to increased intake per se and/or alterations in rumen fermentation parameters. A study was therefore undertaken to examine the effects of silage fermentation type, dry matter intake and the addition of water soluble carbohydrate (WSC) or lactic acid on rumen fermentation parameters in dairy cows.

Two direct cut grass silages were prepared using either an inoculant (Ecosyl, 3 1/t, ICI. pic) or Maxgrass (BP Chemicals, 6 1/t). Five silage only treatments were offered to four ruminally fistulated dairy cows in a five period, partially balanced, changeover design experiment. Each period was of 4 weeks duration. Treatment 1: Inoculant treated silage (I), 2: Maxgrass silage (M), 3: Maxgrass ad-libitum (MAL), 4: Inoculant + sucrose (500 g/day) (IS), 5: Maxgrass + lactic acid (200 ml/day) (ML).

Field data were analysed in an attempt to identify factors contributing to differences between haemoglobin types n i the proportion of ewes lambing per ewe exposed to the ram in flocks grazing oestrogenic pastures. The number of ewes mated and the proportion of ewes failing to conceive to first service per ewe exposed to the ram were analysed. Neither was found to significantly differ between matings of different haemoglobin type. It is concluded that differences in reproductive performance between haemoglobin types could possibly result from differences in embryo survival.

One hundred and thirty crossbred gilts (Yorkshire × Duroc × Hampshire) were exposed to either natural (40 lux) or supplemental lighting (700 lux) beginning at 8 weeks of age. Gilts received supplemental lighting from 40-W flourescent bulbs from 05·15 to 09·00 h and 16·30 to 20·15 h from 9 September to 22 April. At 4 months of age, all gilts were exposed daily for 15 min to mature boars five times weekly. Twelve gilts from each group were slaughtered at 4, 5, 6 and 7 months of age. All gilts were bled from indwelling cannulas at 20-min intervals for 4 h the day preceding slaughter. In addition, blood samples were drawn weekly from 17 gilts in each group from 7 to 9 months of age and analysed for progesterone to determine age of puberty. Twelve of 17 gilts that received supplemental lighting reached puberty at 228 (s.e. 11) days of age whereas 11 of 16 gilts that received natural lighting reached puberty at 252 (s.e. 7) days of age (P = 0·07). No significant differences occurred in anterior pituitary gland weight or pituitary concentration of LH, mean concentrations of serum LH or number of LH secretory spikes between natural and supplemental-lighted gilts at each month (all P > 005). Concentration of oestradiol-17β and progesterone in follicular fluid was similar between treatment groups within months and follicular size (P > 0·05). Content of GnRH in the stalk-median eminence, preoptic area and hypothalamus proper were also similar between treatment groups (P > 0·05). In summary, supplemental lighting reduced the age of puberty in gilts without a detectable change in pituitary, hypothalamic or ovarian parameters.

Three different stages of pig antral follicles have been studied in a granulosa-cell transcriptome analysis on nylon microarrays (1152 clones). The data have been generated from seven RNA follicle pools and several technical replicates were made. The objective of this paper was to state the feasibility of a transcriptomic protocol for the study of folliculogenesis in the pig. A statistical analysis was chosen, relying on the linear mixed model (LMM) paradigm. Low variability within technical replicates was hence checked with a LMM. Relevant genes that might be involved in the studied process were then selected. For the most significant genes, statistical methods such as principal component analysis and unsupervised hierarchical clustering were applied to assess their relevance, and a random forest analysis proved their predictive value. The selection of genes was consistent with previous studies and also allowed the identification of new genes whose role in pig folliculogenesis will be further investigated.

The study was carried out on a continuously stocked grass/white clover pasture, which was maintained at two sward heights: 3·5 cm (low; LSH) and 6·5 cm (high; HSH). Three oesophageal-cannulated and three other rumen-cannulated Merino sheep were allocated to each of the plots (LSH and HSH) in order to study the effects of sward height and advancing grazing season on rumen fermentation in grazing sheep. Three grazing periods (13 days) were considered: mid June, late July and early October. During each grazing period and after a preliminary period (7 days), samples of the grazed herbage and of grass hay were incubated in nylon bags in the rumen of each sheep for 0, 3, 6, 12, 24, 48, 72 and 96 h. On days 10 and 12 rumen fluid was sampled at the incubation time (11.00 h) and at 3, 6 and 12 h afterwards and pH, ammonia-nitrogen and volatile fatty acids (VFA) concentrations were determined. Sward height did not affect (P > 0·05) the degradation rate of dry matter (DM) and neutral-detergent fibre (NDF) from grazed herbage in any of the considered periods. Animals grazing LSH presented higher (P < 0·05) DM and NDF effective degradabilities (DMED and NDFED, respectively) during October but no differences were found during June and July. HSH grazing animals presented lower (P < 0·05) degradation rates of DM and NDF from grass hay during June and July than those found for LSH grazing sheep, with no differences (P > 0·05) observed during October. Sward height did not affect (P > 0·05) grass hay DMED and NDFED during July but during June and October HSH grazing sheep presented higher (P < 0·05) values. In general, DMED and NDFED from grazed herbage increased with advancing season, the lowest (P < 0·05) value being observed during June. Rumen ammonia-nitrogen concentrations were higher during October than during June and July for both sward heights but values were higher than 200 mg/l at any sampling time during all grazing seasons. Rumen pH values were within the range considered adequate for maintaining a normal cellulolytic activity at most of the sampling times, with the exception of sheep grazing LSH during October. Rumen VFA concentrations were within the range reported for other grazing studies and only a few differences between sward heights were found. Differences in rumen parameters are discussed in relation to both chemical composition of grazed herbage and pattern of intake.

On pig farms, a high proportion of the cost of production comes from feed costs. However, the use of alternative ingredients such as legume seeds may help to reduce this cost. In fact, legume seeds are an important source of essential amino acids (EAA) and can therefore be an alternative to oilseed meals. However, the accurate use of these legume seeds requires a precise knowledge of the standardized ileal digestibility (SID) of EAA, which may vary depending on its botanical variety. A meta-analysis was performed on a database compiling data from 41 studies published between 1981 and 2013 and 178 dietary treatments. Models of prediction of the SID of EAA as well as the dietary concentration of digestible standardized EAA (dEAA) were obtained, based on the chemical composition of ingredients reported in the publications. The effect of the type of legume seeds (faba bean, lupin, pea and soya bean), surgical procedures (T-cannula, re-entrant cannulas, post valve T-cannulas and ileo-rectal anastomosis), and BW of pigs (BW⩽25 kg BW>25 kg) were also tested in each model. Results showed that dietary CP and crude fibre (CF) were, respectively, the best predictors of each EAA SID for faba bean, lupin and pea (R2=0.42 to 0.89) and soya bean (R2=0.32 to 0.77). For the dEAA content, the best prediction models included dietary CP and ADF for faba bean, lupin and pea and soya bean, respectively, with R2 ranging from 0.66 to 0.98. Models developed in this study allow predicting the digestibility of EAA in these alternatives feedstuffs.

The response of performance tested purebred Simmental heifers to various superovulatory treatments with ovine FSH was examined in two experiments. The heifers were 12 months old at embryo recovery, had average live weights of 468·4 kg (experiment 1) and 493·2 kg (experiment 2), and were fat (body condition score approx.4·0 to 4·5 units) at embryo recovery. In experiment 1, the effect of administering a total of 9·0 or 10·8 mg ovine FSH (Ovagen) administered as eight equal doses twice daily over 4 days was evaluated. In experiment 2, a total of 9·0 mg ovine FSH was administered either in equal doses in a level pattern or in declining doses twice daily over 4 days.

The response to the low, compared with the high, dose of ovine FSH in experiment 1 was 8·8 v. 10·5 ovulations (corpora lutea); 7·7 v. 7·7 totalova plus embryos recovered; 6·0 v. 4·1 viable embryos; 4·4 v. 3·1 grade 1 embryos (P > 0·05); and 1·7 v. 4·1 non-fertile ova(F < 0·01). In experiment 2, the response to the same total dose of ovine FSH administered in a level compared to a declining pattern was 8·5 v. 10·7 ovulations; 5·6 v. 9·6 total ova plus embryos; 3·1 v. 5·6 viable embryos; 2·5 v. 3·8 grade 1 embryos; and 1·7 v. 2·2 non-fertile ova. It was concluded that, although the differences between the treatments in the yields of viable and grade 1 embryos were not significantly different, there are practical and economic advantages to using a low rather than a high level of gonadotropin and there are no marked disadvantages in these areas to administering ovine FSH in a declining rather than a level pattern of doses.

Best Linear Unbiased Prediction (BLUP) is now the method of choice for the estimation of breeding values in dairy and beef populations. The advantages of this mixed model methodology over traditional methods are well documented and include the simultaneous estimation of fixed effects and prediction of random effects and the utilization of records from all relatives to predict an individuals breeding value. In addition, account is taken of genetic trend and of reduction in genetic variance due to selection. In Canada, BLUP is now used for breeding value estimation of pigs but the structure of the Canadian pig industry is one of many herds practising selection with the herds linked by a widespread use of artificial insemination. The advantages of BLUP have not been investigated for the situation of the UK pig industry where most selection is performed within closed nucleus herds.

The objectives of this study were to use computer simulation to determine rates of response, accuracy of prediction and accummulation of inbreeding for pigs in closed nucleus herds when selection decisions were based on estimated breeding values (EBVs) derived from BLUP compared to more traditional methods of phenotypic selection and index selection.

The objective of this study was to investigate genetic merit of return over feed (ROF), which is a herd profit index defined by CanWest Dairy Herd Improvement as a difference between milk income and feed cost. A multiple-trait (MT) model and random regression model (RRM) were used. The traits analyzed in MT were rearing cost and ROF of the first three lactations. In RRM, a cumulative ROF was fitted as function of age and rearing cost was treated as a correlated trait. Variance components were estimated within a Bayesian framework by Gibbs sampling using a subsample of data. Breeding values were then estimated for 3 041 078 animals using records of 1 951 893 cows. Estimates of heritability for rearing cost from MT and RRM were 0.23 and 0.22, respectively. ROF per lactation and cumulative ROF were negatively correlated with rearing cost. Estimates of heritability of ROF through the first, second and third lactation from MT were 0.27, 0.10 and 0.08, respectively. Estimates of heritability of ROF from RRM increased with age and ranged from 0.08 through 0.31. Estimated breeding values (EBVs) for ROF from MT and RRM were moderately correlated with official EBV for production traits and the Canadian selection index (Lifetime Profit Index). Herd life EBV had −0.07 and 0.19 correlations with EBVs for ROF from MT and RRM, respectively. From both MT and RRM, small favorable correlations were reported between EBVs for ROF and for bone quality and angularity, whereas low unfavorable correlations were reported with EBV for udder depth, front end and chest width. Majority of correlations between EBVs for ROF and for reproduction traits were near 0, with the exception of EBV for gestation length, calf size and calving ease, where small favorable correlations were reported. The ROF is a good indicator of cow profitability despite the fact that it is a simplified profit index that does not account for animal-specific health and reproductive cost. However, because ROF does not account for differences in heritabilities between components of profit, ROF is not recommended to be used for direct selection for profit.

Animal health issues are a problem on many dairy farms, and much is already known about clinical treatments and the behaviour of sick animals. Animal health issues can influence behaviour seen around the milking parlour, but less is known about the relationship between the number of previous medical treatments and the queuing to be milked, the ‘milking order’. Information was collected on five afternoon milking sessions, the individual cows’ age and the medical treatment history of each cow in a group of 100 cows. The question addressed was whether the age and the medical treatment history of each cow in the herd affected its milking order. In addition, milking order was tested day to day, and was found to be consistent. A significant positive correlation was found between medical treatment history and milking order rank, meaning that cows with a higher medical treatment history tended to enter the milking parlour later than cows with a lower medical treatment history. In contrast with this finding, it was found that older cows were more likely to enter the milking parlour early when compared to younger animals, a finding which is supported by previous studies. These somewhat contradictory effects of (a) age and (b) medical treatment history on milking order suggest that health disorders may have long-term measurable effects on the position of a cow in the milking order, even when the effect of age on milking order is accounted for.

Low levels of antibiotics have been used in animal diets since the 1950’s to improve growth rates by stabilising the gut flora. At higher levels antibiotics have also been used as prophylactics against enteric diseases.

As a result of growing public concern of the the indiscriminate use of antibiotics in the animal industry there are now strict controls on their use. An alternative approach to the use of antibiotics in the control of the gut flora is the use of what have become known as probiotics. Probiotics include viable lactobacillus bacteria cultures and fermentation products which actively colonise the gut wall, and suppress further colonisation by potential pathogens such as virulent E. coli organisms. At times of stress in an animal’s life, such as weaning or re-grouping, the oral application of probiotic agents could be beneficial by both preventing disease and minimising the clinical use of antibiotics.

Early-weaned artificially-reared piglets are particularly at risk to enteric disease and therefore the purpose of the present study was to assess the efficacy of a probiotic agent in pigs weaned at 6 hours of age.

Following an outbreak of highly pathogenic avian influenza virus (HPAIV) in a poultry house, control measures are put in place to prevent further spread. An essential part of the control measures based on the European Commission Avian Influenza Directive 2005/94/EC is the cleansing and disinfection (C&D) of infected premises. Cleansing and disinfection includes both preliminary and secondary C&D, and the dismantling of complex equipment during secondary C&D is also required, which is costly to the owner and also delays the secondary cleansing process, hence increasing the risk for onward spread. In this study, a quantitative risk assessment is presented to assess the risk of re-infection (recrudescence) occurring in an enriched colony-caged layer poultry house on restocking with chickens after different C&D scenarios. The risk is expressed as the number of restocked poultry houses expected before recrudescence occurs. Three C&D scenarios were considered, namely (i) preliminary C&D alone, (ii) preliminary C&D plus secondary C&D without dismantling and (iii) preliminary C&D plus secondary C&D with dismantling. The source-pathway-receptor framework was used to construct the model, and parameterisation was based on the three C&D scenarios. Two key operational variables in the model are (i) the time between depopulation of infected birds and restocking with new birds (TbDR) and (ii) the proportion of infected material that bypasses C&D, enabling virus to survive the process. Probability distributions were used to describe these two parameters for which there was recognised variability between premises in TbDR or uncertainty due to lack of information in the fraction of bypass. The risk assessment estimates that the median (95% credible intervals) number of repopulated poultry houses before recrudescence are 1.2 × 104 (50 to 2.8 × 106), 1.9 × 105 (780 to 5.7 × 107) and 1.1 × 106 (4.2 × 103 to 2.9 × 108) under C&D scenarios (i), (ii) and (iii), respectively. Thus for HPAIV in caged layers, undertaking secondary C&D without dismantling reduces the risk by 16-fold compared to preliminary C&D alone. Dismantling has an additional, although smaller, impact, reducing the risk by a further 6-fold and thus around 90-fold compared to preliminary C&D alone. On the basis of the 95% credible intervals, the model demonstrates the importance of secondary C&D (with or without dismantling) over preliminary C&D alone. However, the extra protection afforded by dismantling may not be cost beneficial in the context of reduced risk of onward spread.

The majority of lambs in the United States are born from late winter to early spring and pregnant ewes are generally sheared in the last third of pregnancy. Although there are benefits to shearing before parturition, shorn animals may be more vulnerable to the cold, highly variable climatic conditions associated with these seasons. The objective of this study was to determine if late gestation shearing induces differences in individual BW, dry matter intake (DMI) and plasma metabolite concentration of finewool ewes managed outdoors during winter. Thirty-six mature, pregnant Rambouillet ewes (3.8±0.45 years; 76.8±11.4 kg) were managed in a drylot with ad libitum access to pelleted alfalfa in bunks capable of measuring individual daily DMI. The treatment group consisted of ewes sheared at ~5 weeks before the estimated parturition date (shorn; n=18). Unshorn ewes (n=18) remained in full fleece throughout the experiment and were shorn on the last day of the experiment ~2 weeks before the estimated parturition date. Blood was collected on days 0 (before shearing shorn group), 7, 14 and 21 (before shearing unshorn group) of the trial, and plasma was isolated and analyzed for non-esterified fatty acid (NEFA), β-hydroxybutyrate (BHB) and glucose (GLU) concentrations. There was no effect of shearing on ewe DMI or BW during the trial (P⩾0.35). Plasma NEFA and GLU concentrations were similar (P⩾0.36) between shearing groups, though plasma BHB concentration was 103.7 μmol/l greater (24.1%; P<0.01) in unshorn ewes. Lamb BW at birth was not affected (P=0.30) by ewe shearing treatment. Under conditions of this study, no differences in economically important aspects of sheep production were observed between shorn and unshorn pregnant ewes.

Bovine placental lactogen (bPL) is structurally related to prolactin (PRL) and growth hormone (GH). In synergism with steroid and thyroid hormones, bPL is crucial in stimulating the development of the mammary gland, mammary cell differentiation and function. To further explore whether bPL gene is associated with milk production traits, we herein analyzed single-nucleotide polymorphisms (SNPs) within eight regions of bPL gene, which are potentially associated with five milk production traits on 1028 Chinese Holstein cows. Among these, two SNPs, NT7409(T–C) and Nt11246(G–A), were identified. The former is within exon 2; it induces an alteration of amino acid from Val to Ala. The later is within exon 4. It is a synonymous mutation. We found that there were significant associations between NT7409(T–C) and milk and protein yield. Cows of the AA genotype yielded less milk (P = 0.001) and less protein (P = 0.003) than those of genotypes AB and BB. However, on the NT11246(G–A) locus, no significant association was observed in the five milk production traits studied. In addition, bPL has been localized near markers RM185 and CC549051 with a distance of 23.2 cR on BTA 23. It is at the same position as the region including quantitative trait loci (QTLs) affecting milk and protein yields by previous linkage analysis. In summary, our findings demonstrated that the SNP within exon 2 of bPL (NT7409(T–C)) is associated with two milk production traits, and this provided further evidence that bPL could be a major gene-controlling milk production trait in Holstein dairy cattle.

The aim of this paper was to present an alternative multi-criteria evaluation model to assess animal welfare on farms based on the Welfare Quality® (WQ) project, using an example of welfare assessment of growing pigs. The WQ assessment protocol follows a three-step aggregation process. Measures are aggregated into criteria, criteria into principles and principles into an overall assessment. This study focussed on the first step of the aggregation. Multi-attribute utility theory (MAUT) was used to produce a value of welfare for each criterion. The utility functions and the aggregation function were constructed in two separated steps. The Measuring Attractiveness by a Categorical Based Evaluation Technique (MACBETH) method was used for utility function determination and the Choquet Integral (CI) was used as an aggregation operator. The WQ decision-makers’ preferences were fitted in order to construct the utility functions and to determine the CI parameters. The methods were tested with generated data sets for farms of growing pigs. Using the MAUT, similar results were obtained to the ones obtained applying the WQ protocol aggregation methods. It can be concluded that due to the use of an interactive approach such as MACBETH, this alternative methodology is more transparent and more flexible than the methodology proposed by WQ, which allows the possibility to modify the model according, for instance, to new scientific knowledge.