Genomic regions under high selective pressure present specific runs of homozygosity (ROH), which provide valuable information on the genetic mechanisms underlying the adaptation to environment imposed challenges. In broiler chickens, the adaptation to conventional production systems in tropical environments lead the animals with favorable genotypes to be naturally selected, increasing the frequency of these alleles in the next generations. In this study, ~1400 chickens from a paternal broiler line were genotyped with the 600 K Affymetrix® Axiom® high-density (HD) genotyping array for estimation of linkage disequilibrium (LD), effective population size (Ne), inbreeding and ROH. The average LD between adjacent single nucleotide polymorphisms (SNPs) in all autosomes was 0.37, and the LD decay was higher in microchromosomes followed by intermediate and macrochromosomes. The Ne of the ancestral population was high and declined over time maintaining a sufficient number of animals to keep the inbreeding coefficient of this population at low levels. The ROH analysis revealed genomic regions that harbor genes associated with homeostasis maintenance and immune system mechanisms, which may have been selected in response to heat stress. Our results give a comprehensive insight into the relationship between shared ROH regions and putative regions related to survival and production traits in a paternal broiler line selected for over 20 years. These findings contribute to the understanding of the effects of environmental and artificial selection in shaping the distribution of functional variants in the chicken genome.

The aim of the present work was (1) to study the relationship between cross-sectional computed tomography (CT) images obtained in live growing pigs of different genotypes and dissection measurements and (2) to estimate carcass composition and cut composition from CT measurements. Sixty gilts from three genotypes (Duroc×(Landrace×Large White), Pietrain×(Landrace×Large White), and Landrace×Large White) were CT scanned and slaughtered at 30 kg (n=15), 70 kg (n=15), 100 kg (n=12) or 120 kg (n=18). Carcasses were cut and the four main cuts were dissected. The distribution of density volumes on the Hounsfield scale (HU) were obtained from CT images and classified into fat (HU between −149 and −1), muscle (HU between 0 and 140) or bone (HU between 141 and 1400). Moreover, physical measurements were obtained on an image of the loin and an image of the ham. Four different regression approaches were studied to predict carcass and cut composition: linear regression, quadratic regression and allometric equations using volumes as predictors, and linear regression using volumes and physical measurements as predictors. Results show that measurements from whole animal taken in vivo with CT allow accurate estimation of carcass and cut composition. The prediction accuracy varied across genotypes, BW and variable to be predicted. In general, linear models, allometric models and linear models, which included also physical measurements at the loin and the ham, produced the lowest prediction errors.

In farm animals, salivary cortisol has become a widely used parameter for measuring stress responses. However, only few studies have dealt with basal levels of concentration of cortisol in pigs and its circadian rhythm. The aim of this study was to examine the effects of ambient temperature and thermoregulatory behaviour on the circadian rhythm of salivary cortisol levels in fattening pigs. Subjects were 30 fattening pigs of different weight (60 to 100 kg), kept in six groups in an uninsulated building in pens with partly slatted floors. Saliva samples were taken every 2 h over periods of 24 h at different ambient temperatures at two times in winter and four times in summer. Thermoregulatory behaviour was recorded in the same 24-h time periods. The effect of time of day, body weight, ambient temperature and behaviour on the cortisol level was analysed using a mixed-effects model. Two peaks of cortisol levels per day were found. This circadian pattern became more pronounced with increasing weight and on days where thermoregulatory behaviour was shown. Mean cortisol levels per day were affected by weight but not by thermoregulatory behaviour. From our data, we conclude that long-term variations in cortisol concentration may be influenced by increasing age and weight more than by the respective experimental situation. In assessing animal welfare, it seems more reliable to consider the circadian pattern of cortisol concentration instead of only one value per day.

A simple expression relating the standardized selection differential (i) to the intensity of selection (p) is given by

i≏0·8+0·41 ln (R−1)

where R equals 1/p. This linear expression may allow simpler solutions to some optimization problems in selection than does the conventional formula for selection differential on truncation of the normal curve.

Using the expression, formulae for the maximum immediate response and optimum selection intensity in mass selection have been developed, taking account of the loss in performance through inbreeding. These formulae were used to study the effect on response of the total number of animals tested. The maximum response over a specified period of time, allowing for the loss in genetic variance from inbreeding, has also been considered. The optimum intensity of selection may then be well below that necessary for the maximum immediate response.

In the current intensive production system, ruminants are often fed high-grain (HG) diets. However, this feeding pattern often causes rumen metabolic disorders and may further trigger laminitis, the exact mechanism is not clear. This study investigated the effect of HG diet feeding on fermentative and microbial changes in the rumen and on the expression of pro-inflammatory cytokines and matrix metalloproteinases (MMPs) in the lamellar tissue. In all, 12 male goats were fed a hay diet (0% grain; n=6) or an HG diet (56.5% grain; n=6). On day 50 of treatment, samples of blood, rumen content, and lamellar tissue of hooves of goats were collected. The data showed that compared with the hay group, HG-fed goats had lower (P<0.05) rumen pH but higher (P<0.05) total volatile fatty acids and lactate in the rumen and higher (P<0.05) lipopolysaccharide (LPS) levels in the rumen and blood. HG diet feeding altered the composition of rumen bacterial community, and correspondingly, the results suggested that their functions in the HG group were also altered. HG diet feeding increased (P<0.05) the expression of interleukin-1β, interleukin-6, tumour necrosis factor-α and MMP-2 mRNA in the lamellar tissues compared with the hay group. Correlation analysis indicated that the expression of pro-inflammatory cytokines were positively correlated with MMP-2 expression in lamellar tissues. Overall, these results revealed that HG feeding altered the patterns of rumen fermentation and the composition and functions of rumen bacterial community, and lead to higher levels of LPS in the peripheral blood, and further activated the inflammatory response in lamellar tissues, which may progress to the level of laminar damage.

Conformation scores can account for more than 20% of cattle price variation at Australian livestock sales. However, there are limited available references which define genetic factors relating objective live developmental traits to carcass composition. Weaning and post-weaning weight, height, length, girth, muscle (ratio of stifle to hip width) and fat depth of 1202 progeny from mature Hereford cows (637) mated to seven sire breeds (Jersey, Wagyu, Angus, Hereford, South Devon, Limousin and Belgian Blue) were examined for growth and development across ages. Crossbred Wagyu and Jersey were both lighter in weight and smaller in size (height, length and girth) than purebred Hereford and crossbred Angus, South Devon, Limousin and Belgian Blue. Within the five larger crossbreds, there were significant changes in relative weight from weaning to 600 days. Sire breeds differed in fat depth, with Angus being the fattest (9% on average fatter than Hereford and Wagyu), and Jersey 5% less fat than Hereford, followed by South Devon and Limousin (19% lower than Hereford) and Belgian Blue (39% lower than Hereford). Direct heritability ranged from 19 to 42% and was higher than the proportion of total phenotypic variance accounted for by maternal effects (which ranged from 0 to 17%) for most body measurement traits except for weight (38 v. 18%) and girth (36 v. 9%) traits at weaning, an indication of maternal effect on some body conformation traits at early ages. Muscularity (19 to 44%) and fat depth (26 to 43%) were moderately to highly heritable across ages. There were large differences for growth and the objective measures of body development between crossbreds with a degree of overlap among the progeny of the seven sire breeds. The variation between genetic (positive) and environmental (negative) correlations for dry versus wet season average daily gains in weight and fat, suggested the potential use of live-animal conformation traits for within breed selection of genetically superior animal in these traits across seasons.

The carcass composition of Hereford × Friesian (HE), Friesian (FR) and Charolais × Friesian (CH) steers finished on diets of high (H) and medium (M) dietary metabolizable energy (ME) concentrations and slaughtered at low (L), normal (N) and heavy (W) carcass weights was examined in a 3 × 2 × 3 (no. = 9 per individual treatment) factorial experiment. A pre-finishing slaughter group of nine animals of each breed type was also included, giving a total 189 animals in 21 experimental groups. ME concentrations of the H and M diets which were offered ad libitum were 12·6 and 10·4 MJ/kg dry matter. Target carcass weights for L, N and W were 260, 300 and 340 kg for HE and FR and 260, 320 and 380 kg for CH.

Carcass side weights (before tissue separation) of the HE, FR and CH pre-finishing slaughter groups were 90·8, 970 and 101·0 (s.e.d. 3·9) kg. Corresponding tissue proportions were 188, 199 and 200 (s.e.d. 4·3) g/kg bone, 663, 686 and 690 (s.e.d. 5·3) g/kg muscle and 135, 99 and 96 (s.e.d. 5·7) g/kg fat. Main effect side weights of the finished groups were 152·3, 151·4 and 162·2 (s.e.d. 1·4) kg for HE, FR and CH. 158·5 and 152·2 (s.e.d. 1·1) kg for H and M and 131·2, 155·2 and 179·6 (s.e.d. 1·4) kg for L, N and W, respectively. Tissue proportions in the same order were 146, 160 and 157 (s.e.d. 2·0), 149 and 159 (s.e.d. 1·6) and 163, 154 and 146 (s.e.d. 2·0) g/kg bone, 579, 601 and 635 (s.e.d. 5·5), 600 and 610 (s.e.d. 4·5) and 637, 599 and 574 (s.e.d. 5·5) g/kg muscle and 264, 228 and 195 (s.e.d. 6·4), 240 and 219 (s.e.d. 5·2) and 188, 235 and 264 (s.e.d. 6·4) g/kg fat. CH had more (P < 0·001) of their muscle in the pelvic limb and less (P < 0001) in the thorax than HE and FR. HE had more (P < 0·001) of their carcass fat in the subcutaneous depot and less (P < 0·001) in the intermuscular depot than FR and CH. The allometric regression coefficients for the main joint and tissue weights on side weight were <1·0 for both limbs, loin, bone and muscle. Coefficients were >1·0 for the thorax, ribs, flank and fat. The regression coefficients for the main muscles of the pelvic limb and loin and total thoracic limb muscle on total side muscle were <l·0, while the coefficients for the flank, ribs and thorax muscles were >1·0. Similarly the regression coefficients for the bones of the two limbs on total side bone were <10, while the coefficients for the loin, ribs and thorax bones were >10. It was calculated (for the H diet) that at a carcass weight of 300 kg, HE, FR and CH would have carcass tissue proportions of 576, 600 and 642 g/kg muscle and 261, 227 and 180 g/kg fat. The three breed types would have similar carcass fat contents at carcass weights of 264, 300 and 376 kg for HE, FR and CH, respectively.

It was reasoned that, if we used a large sample of pigs, we could demonstrate that total and differential numbers of leukocytes, expression levels of swine leukocyte antigens (SLA) I and II, and serum concentrations of IgG and haptoglobin show additive genetic variation and are, therefore, potentially useful as criteria to improve selection of pigs for resistance to clinical and subclinical disease. We tested this premise by assessing 4204 male pigs from the Duroc, Landrace, and Yorkshire breeds for total and differential numbers of leukocytes and serum concentrations of IgG and haptoglobin; 1217 of the Duroc and Landrace pigs were also assessed for expression levels of SLA I and II. We estimated the amount of additive genetic variation by fitting linear animal models to the total and differential numbers of leukocytes and serum concentrations of IgG and haptoglobin. We fitted linear sire models to the expression levels of SLA I and II. We detected additive genetic variation for each group of traits. Total and differential numbers of leukocytes were moderately heritable (h2=0·22 to 0·30), expression levels of SLA I and II were moderate-to-highly heritable (h2=0·46 to 1·23), while serum concentrations of IgG and haptoglobin were lowly heritable (h2=0·14 to 0·16). The additive genetic variation shown for the immunological traits is encouraging for pig breeders. It indicates that these traits are potentially useful as criteria to improve selection of pigs for resistance to clinical and subclinical disease.

The aim of this study was to evaluate the sulphur hexafluoride (SF6) tracer technique for methane (CH4) emission measurement in sheep. Ten cryptorchid Romney sheep were involved in two indoor trials (T1 and T2), where daily CH4 emissions were individually measured both by the SF6 tracer (‘tracer CH4’) and by the indirect calorimetry chamber (‘chamber CH4’) techniques while fed on lucerne hay at 1.2 times maintenance requirements. Separate sets of permeation tubes with pre-calibrated permeation rates (‘pre-calibrated PRs’) were used in the two trials (for tracer CH4) and at the time of T1 and T2 these tubes had been deployed in the rumen for 250 and 30 days, respectively. The tracer CH4 measurements were carried out for 2 (T1) and 5 (T2) days in digestibility crates housed within a building (T1) or a well-ventilated covered yard (T2). Sheep were transferred to calorimetry chambers for 3 days acclimatisation, followed by measurement of CH4 emission for 7 (T1) and 3 (T2) days. In T1 samples from the chamber, outflow and inflow (collected over ∼22 h) were analysed for CH4 and SF6 concentrations using the tracer protocol. Thus, PRs of SF6 at the time of the trials (‘calculated PRs’) could be inferred and the corresponding CH4 emissions are then calculated using either the pre-calibrated PR or calculated PR. Permeation tubes were recovered at the end of the animal trials and their ‘post-recovery PR’ determined. In trial T1, the tracer CH4 estimates (based on the pre-calibrated PR) were much higher and more variable than the chamber CH4 values. In this trial, the calculated PR and the post-recovery PR were similar from each other but smaller than the pre-calibrated PR, and when the calculated PR was used in place of the pre-calibrated PR the CH4 emission estimates agreed well with the chamber CH4 values. This suggested that the discrepancy was due to a declining PR during the long deployment time of the tubes in T1, an observation reported elsewhere. When the long intra-ruminal deployment was avoided in T2, good agreement between the techniques for CH4 emission measurement was observed.

To evaluate the effect of crop maturity on digestion of maize silage in the rumen and post-ruminal digestive tract, four multiparous Holstein-Friesian cows fitted with a simple cannula in the proximal duodenum and a rumen cannula were offered four diets in a 4 ✕ 4 Latin-square design. Forage maize (cv. Hudson) was harvested and ensiled at target dry matter (DM) contents of 230, 280, 330 and 380 g per kg fresh weight (FW) to provide a range of starch contents. The mean values for volatile-corrected DM (VCDM) and starch content of the four maize silages as given were 221, 277, 308 and 372 g/kg FW and 173, 257, 328 and 382 g/kg VCDM respectively. Grass silage (GS) containing 250 g VCDM per kg FW was produced from the primary growth of a perennial ryegrass sward. The diets were 8·7 kg DM per day of a dairy concentrate supplement with one of four forage treatments offered ad libitum. The forage treatments were a 3 : 1 DM ratio of maize silage with GS, designated as T23, T28, T33 and T38. Each period lasted 6 weeks with rumen and duodenal samples being taken over 3 days in week 4 and faeces being collected in respiration chambers over 6 days in either week 5 or 6. Milk yield tended to increase with advancing maturity (30·5, 31·8, 32·5 and 32·3 kg/day) but individual treatment differences were not significant. DM intake increased from 19·62 to 21·30 kg/day (P < 0·05) but there were no significant effects on digestibility in the rumen, post-ruminal tract or total tract. Digestibility of neutral detergent fibre in the rumen declined with increasing starch content in the maize silage (P < 0·05) but total digestibility was not significantly affected. Starch intake increased from 3·11 to 5·04 kg/day (P < 0·001), duodenal flow from 0·40 to 0·89 kg/day (P < 0·01) and the amounts digested in the rumen and post-ruminal tract respectively from 2·72 and 0·34 kg/day to 4·16 and 0·71 kg/ day (P < 0·01). However the only significant effect on starch digestibility was a small fall in total digestibility from a mean of 0·981 for T23, T28 and T33 to 0·966 for T38. There were no treatment effects on nitrogen digestion. The molar proportions of acetic acid and n-caproic acid decreased and that of n-butyric acid increased with advancing maturity. It is concluded that the changes in composition of maize silage with increasing maturity result in large increases in the contribution of starch to DM digested in the rumen but only small differences in rumen fermentation. Post-ruminal starch digestion doubles but this is due to the increased starch concentration of the silage rather than major changes in digestion and the amount is small compared with that likely to result from feeding maize grain.

Genotype with nutrition interactions in carcass composition and meat quality traits were examined by testing pigs from four selection lines and a control line on isoenergetic diets, which differed in lysine: energy content. The selected lines resulted from seven generations of selection for high daily food intake, lean food conversion ratio (LFC) and lean growth rate on ad-libitum or restricted (LGS) feeding regimes in a Large White population. There were 128 pigs in the study, with 24 pigs per selection line and 32 pigs from a control line. During performance test, 30 to 90 kg, pigs were offered one of three isoenergetic diets, 14·0 MJ digestible energy (DE) per kg dry matter, which differed in ileal digestible lysine: digestible energy (A: 0·40 , C: 0·76 and E: 1·12 g lysine per MJ DE) on ad-libitum or restricted (0.75 g/g ad-libitum daily food intake) feeding regimes.

For the majority of performance test, carcass composition and meat quality traits there was no evidence of a genotype with diet or genotype with feeding regime interaction. The selection line with feeding regime interactions for average daily gain, daily food intake and rates of lean and subcutaneous fat deposition were primarily due to no feeding regime effect for the LFC selection line. Selection for high LFC had reduced ad-libitum daily food intake to such an extent that it was not significantly different from daily food intake on a restricted feeding regime, unlike other selection lines in the study. A selection line with feeding regime interaction was detected for muscle рH24h and muscle reflectance, which resulted from the LGS selection line. LGS pigs offered food ad libitum had higher muscle рH24h and lower muscle reflectance than LGS pigs given food at a restricted level, while there was no effect of feeding regime for the other selection lines.

The general absence of genotype with nutrition interactions for traits measured in the study indicated that the ranking of genotypes for performance test traits, carcass composition and meat quality traits will not be dependent on diet or feeding regime. Genotype specific nutritional inputs will also not be required for identification of pigs of high genetic merit, within a genotype. However, diet and feeding regime had significant effects on carcass composition and meat quality traits, such that the estimated mean value of a genotype will be dependent on the diet or feeding regime used to evaluate the genotype.

1. The heat production of four sows, approximately 17 months old at the start of the experiment, was measured at five ambient temperatures from 23° to 6°C. Food intake was controlled at different levels for different sows; one sow conceived during the experiment.

2. Heat production increased consistently as temperature decreased from 23° to 6°C; the relative effect on heat production of exposure to low temperatures was greater the lower the level of feeding.

3. Estimated values for whole body conductance decreased as ambient temperature decreased to minimum values of 73 to 77 kcal/m2. day. °C for three sows and 87 kcal/m2. day.°C for the fourth sow, which had a considerably thinner backfat than the others.

4. Estimated values for lower critical temperature varied from 10° to 20°C, with the lower values associated generally with the higher levels of feeding; nevertheless heat production was consistently lower at 23°C than at 18°C.

5. Differences in level of feeding were generally associated with differences in live weight, and it was difficult to obtain reliable estimates of metabolizable energy requirements for maintenance and of net efficiency of utilization of metabolizable energy above maintenance; however analysis on the basis of live weight0·75 produced values of 92 kcal/kg0·75 per day at 23°C and 106 kcal/kg0·75 per day at 18°C for maintenance and between 67 and 75% for the efficiency of utilization above maintenance.

Eleven sire breeds were evaluated in New Zealand from the performance of their calves at two sites using Aberdeen-Angus cows, and at a third site using Angus and Hereford cows. The experiment was carried out over 5 years, generating a total of 4519 calves by 161 different sires. There were seven recently imported sire breeds, Blonde d'Aquitaine, Charolais, Chianina, Limousin, Maine Anjou, Simmental (including strains from four countries) and South Devon, and four local breeds, Angus, Friesian, Hereford and Jersey. Overall, 92% of calves survived at birth and through to weaning, with a range from 86% for the Charolais sire breed to 96% for the Friesian and Jersey breeds. The proportion of calves (from cows aged 3 years and over) experiencing birth difficulty averaged 8·6% and ranged from 17·7% for the Charolais, 15·1% for the Chianina and 13·7% for the Maine Anjou, to 2·3% for the Hereford and 0·9% for the Jersey. Birth weights by sire breed had a range of 7·2 kg, proportionally 0·23 of the mean for the Hereford × Angus cross. The birth weights of calves by imported sire breds were greater than those of calves sired by local breeds by 4·7 kg. Sire breeds were ranked in approximately the same order for the weights of calves at weaning (5 months of age) and at 13 months of age. As a proportion of the mean for the Hereford × Angus crosses, there was a range due to sire breed of 0×17 for weaning weight and 013 for 13-month weight. As a group, the imported sire breeds had calves with 13-month weights 11·5 kg heavier than Hereford × Angus or 250kg heavier than straightbred Angus calves; proportionally these advantages in weight were 005 and 011, respectively. There was no evidence of any major interaction between sire breed and location. The heritability estimates ranged from 0·01 to 0·05 for calving difficulty and survival traits, from 0·13 to 0·33 for live weights and from 0·06 to 0·12 for pre-weaning live-weight gains. For gestation length the estimate was 0·48.

Sixty crossbred (Large White × Landrace × Duroc) pigs were used to compare the growth performance, carcass and pork quality characteristics of entire, surgically castrated and immunologically castrated male pigs from two Western Australian commercial genotypes (genotype A : ‘lean’ genotype and genotype B : propensity for increased subcutaneous fat deposition). Pigs from genotype B had a higher average daily gain and a superior food conversion ratio compared with pigs from genotype A. Entire males had lower backfat compared with surgically and immunologically castrated male pigs. Pork from entire males was drier, tougher and had lower overall acceptability scores compared with surgically or immunologically castrated male pigs. Pork from genotype A pigs had a lower m. longissimus thoracis (LT) ultimate pH and higher drip loss compared with pork from genotype B pigs. However, consumer taste panel assessment indicated that pork from genotype A pigs was more tender, had higher juiciness and overall acceptability scores compared with pork from genotype B pigs. Within genotype A, the consumer taste panel preferred pork from surgically castrated pigs compared with either entire or immunologically castrated pigs. Within genotype B, the consumer taste panel preferred pork from immunologically castrated pigs compared with either entire or surgically castrated male pigs. These results indicate that interactions between genotype and castration method can significantly influence eating quality of pork.

Data from 274 Dutch herds recording clinical mastitis (CM) over an 18-month period were used to quantify the genetic variation for overall and pathogen-specific CM. Analysed pathogens were Staphylococcus aureus, coagulase negative staphylococci (CNS), Escherichia coli, Streptococcus dysgalactiae, Streptococcus uberis and other streptococci. The data set contained 47 563 lactations of 28 695 cows of different parities. Cases of overall and pathogen-specific CM were treated as all-or-none traits. Variance components for the sire, maternal grandsire and permanent environmental effect were estimated using generalized linear mixed models with a logit link function for the binary traits. Average number of days at risk and in milk on trial was 198 days. The estimated heritability for overall CM was 0·04, and similar heritabilities for the pathogen-specific CM were estimated. Repeatability across lactations was low for overall and pathogen-specific CM (0·10 to 0·14). Genetic correlations with milk yield and somatic cell score (SCS) differed according to pathogen. For instance, the incidence rate of clinical E. coli mastitis was slightly unfavourably correlated with milk yield at 150 days (0·13) but stronger with SCS (0·74). Whereas, the genetic correlations with clinical Str. dysgalactiae mastitis were 0·70 and 0·16, respectively. The expected correlated responses showed that current selection practices (using milk yield and SCS) will be effective in reducing the incidence of E. coli and CNS but less effective in reducing the incidence of S. aureus and Str. dysgalactiae, even with a large relative weight for SCS in the selection index.

Cow longevity and lifetime performance traits are good indicators of breeding effectiveness and animal welfare. They are also interrelated with the economics of dairy herd. Unfortunately, a high milk yield is often associated with deteriorated cow health and fertility and, consequently, with an increased culling rate. This situation, observed also in the Polish population of Holstein-Friesian cattle, inspired us to undertake a study on the associations between some factors and lifetime performance characteristics. The data set consisted of the records on 135 496 cows, including 131 526 of the Black and White strain (BW), and 3970 of the Red and White strain (RW) covered by performance recording and culled in 2012. It was found that cows of the BW strain and those from the largest herds (>100 cows) reached higher lifetime and mean daily energy-corrected milk (ECM) yields than cows of the RW strain and those from smaller herds culled at a similar age. Cows youngest at first calving (<2.0 years) were characterised by the highest lifetime ECM yield. It indicates that heifers can be bred even when they are younger than 15 to 16 months with no significant negative effect on their later performance. Infertility and reproduction problems (39.6%) and udder diseases (15.5%) constituted the most frequent reasons for cow culling. Cow longevity and lifetime productivity were considerably affected by the interactions between the studied factors.

Three diets were formulated according to the nature of the fibrous components: a concentrate low fibre diet enriched in starch (diet S, neutral-detergent fibre (NDF) proportionately 0·078 of dry matter (DM)) and two high-fibre diets enriched in either sugar-beet pulp (diet BP, NDF = 0·219 of DM) or wheat bran (diet WB, NDF = 0·187 of DM). In a first experiment, the digestibility of nutrients in these diets were determined using dry sows. In a second experiment, 24 multiparous Large White sows were offered the experimental diets in a 3 x 3 Latin-square design during three 21-day periods over pregnancy in order to evaluate physiological and behavioural effects over the nycthemeral period. On the basis of the first experiment, the daily food supply was adjusted to 2·44, 2·74 and 2-90 kg/day for diets S, BP and WB, respectively, to provide the same amount of metabolizable energy to each treatment. In the hour prior to the meal, the diet effect was nil on plasma levels of glucose, insulin, glucagon and non-esterified fatty acid and limited on cortisol plasma level. After the food delivery, the peak responses of glucose and insulin to the meal were delayed in sows given the BP diet, while their level showed a higher increase for S than for WB and BP diets. Sows offered diet BP spent less time standing than sows offered diet S. The occurrence of non-feeding oral activities over the 45 min following food distribution was significantly reduced with fibrous diets. But no difference appeared during the 45-min period following the end of each meal. It was concluded that the incorporation of beet pulp in the diet was more effective than wheat bran in extending the feeding activity and the absorption of nutrients. The diet effect was limited to the 2 h after the food delivery for these sows given a restricted amount of food.

The aim of the study was to analyse the genetic background of different traits to characterise the maternal behaviour of sows and to evaluate the relationship to different causes of piglet losses – increasing piglet survival due to higher maternal abilities of the sow. A total of 1538 purebred litters from 943 German Landrace sows in the year 2004 were available for data analysis. Around 13 971 individually earmarked piglets were included in the analyses. Maternal abilities were characterised through the sow’s reaction to the separation from her litter during the first 24 h after farrowing, and on day 21 of lactation, the reaction towards the playback of a piglet’s distress call and the reaction towards an unknown noise (music). In 1220 of these litters, the sows were also scored for aggressiveness in the group when regrouped before entering the farrowing crates. To describe fertility, the number of piglets born alive, stillborn piglets, number of piglets born in total and the individual birth weight were utilised. Different causes of piglet losses were evaluated as binary traits of the dam with survival rate, different definitions for crushing by the sow, being underweight and runts. The heritability for being aggressive in the group was h2 = 0.32 and for the behaviour traits during lactation, the heritabilities ranged from h2 = 0.06 to 0.14. The genetic correlations showed that more-reactive sows had fewer piglet losses.

In a feeding trial with 24 sheep, we used the alkanes, long-chain alcohols (LCOH) or both of these plant wax markers, to estimate the diet composition of animals offered diets comprising alkane-labelled cottonseed meal (CSM) together with up to four forages. The diets used were: Diet 1 subterranean clover (Trifolium subterraneum); Diet 2 subterranean clover + phalaris (Phalaris aquatica); Diet 3 subterranean clover, phalaris + annual ryegrass (Lolium rigidum); and Diet 4 subterranean clover, phalaris, annual ryegrass + wheat straw (Triticum aestivum). Estimates of diet composition were made following correction of faecal alkane or LCOH concentrations for incomplete faecal recovery, using recovery estimates derived from individual animals, mean recoveries for a given dietary treatment or grand mean recoveries. Estimated dietary proportions of CSM and known intakes of CSM were used to estimate forage intake. The LCOH concentrations of the diet components were much higher than their alkane concentrations, especially for phalaris. Multivariate analyses showed that the discriminatory information provided by the LCOH was additional to that provided by the alkanes, and that a combination of (LCOH + alkanes) discriminated better between diet components than either class of marker alone. Faecal recoveries of LCOH increased with increasing carbon-chain length; there were no differences in recovery attributable to diet. The most accurate estimates of diet composition were obtained with the combination of (LCOH + alkanes). Estimates of diet composition based on LCOH alone were not as good as alkanes alone, due to the high correlation between the LCOH profiles of phalaris and ryegrass. Total grass content of the diet was very accurately estimated using LCOH. Diet composition estimates provided estimates of whole-diet digestibility, which did not differ from the measured values. Trends in the accuracy of forage intake estimates reflected those found with diet composition and almost two-thirds of estimates based on (LCOH + alkanes) had lower error than those found with alkanes alone. The results confirm that supplements labelled with plant wax components can be used to estimate forage intake, and also show that the LCOH are useful markers for estimating diet composition. Intakes were also computed using a combination of natural LCOH concentrations in the diet and the daily dose rate of even-chain alkanes administered by intra-ruminal device. Differences between intakes so estimated and the measured intakes were closely related to the difference in faecal recovery between the LCOH/alkane pair used to estimate intake, by an amount close to that expected on theoretical grounds. It is concluded that the use of plant wax LCOH, especially in combination with alkanes, will result in improved estimates of diet composition and intake in grazing animals.

Heritabilities (h2) and genetic correlations (rc) involving body weights, measures of testes size and ewe lamb reproduction were calculated using 953 spring-born lambs produced during formation of a three-breed composite population containing 0·50 Dorset, 0·25 Rambouillet and 0·25 Finnish Landrace breeding. The h2 of body weight ranged from 0·2 to 0·3 between 45 and 150 days of age, but increased to 0·41 at the start of breeding of ewe lambs at about 6 months of age. Additive maternal effects were not important, perhaps because intensive housing encouraged cross-suckling. Testes size was measured as scrotal circumference (SC), SC with linear adjustment for weight (SCW) and SC divided by the one-third power of body weight (RSC). The h2 of SC traits was highest at 90 days (0·52 for SC, 0·62 for RSC and 0·57 for SCW), and h2 for age at maximum SC growth rate (i.e. TI, the inflexion point of a logistic SC growth curve) was 0·49. The h2 of ewe lamb fertility in autumn was 0·09 but the h2 for frequency of remating the following spring was 0·41. The h2 for ewe lamb litter size in these data was zero. At 90 days, rc between alternative measures of testes size exceeded 0·86; rG with body weight were 0·67 for SC, 0·53 for RSC and –0·74 for TI. The rG with ewe lamb fertility for 90-day weight, SC, RSC and SCW and for TI were –0·25, 0·20, 0·25, 0·38 and –0·32, respectively. The rc for these traits with spring remating were 0·34, 0·34, 0·26, 0·10 and –0·48, respectively.