Imputation of high-density genotypes from low- or medium-density platforms is a promising way to enhance the efficiency of whole-genome selection programs at low cost. In this study, we compared the efficiency of three widely used imputation algorithms (fastPHASE, BEAGLE and findhap) using Chinese Holstein cattle with Illumina BovineSNP50 genotypes. A total of 2108 cattle were randomly divided into a reference population and a test population to evaluate the influence of the reference population size. Three bovine chromosomes, BTA1, 16 and 28, were used to represent large, medium and small chromosome size, respectively. We simulated different scenarios by randomly masking 20%, 40%, 80% and 95% single-nucleotide polymorphisms (SNPs) on each chromosome in the test population to mimic different SNP density panels. Illumina Bovine3K and Illumina BovineLD (6909 SNPs) information was also used. We found that the three methods showed comparable accuracy when the proportion of masked SNPs was low. However, the difference became larger when more SNPs were masked. BEAGLE performed the best and was most robust with imputation accuracies >90% in almost all situations. fastPHASE was affected by the proportion of masked SNPs, especially when the masked SNP rate was high. findhap ran the fastest, whereas its accuracies were lower than those of BEAGLE but higher than those of fastPHASE. In addition, enlarging the reference population improved the imputation accuracy for BEAGLE and findhap, but did not affect fastPHASE. Considering imputation accuracy and computational requirements, BEAGLE has been found to be more reliable for imputing genotypes from low- to high-density genotyping platforms.

We investigated the diagnostic reliability of pregnancy detection using changes in interferon stimulated gene (ISG) messenger RNA (mRNA) levels in circulating immune cells in ewes. Two different groups of ewes (an experimental group, experiment 1 and a farm group, experiment 2) were oestrus-synchronized and blood sampled on day 14 (D0=day of insemination in control animals, experiment 1) and day 15 (experiment 2). Real-time PCR were performed to evaluate the abundance of different ISG mRNAs. In the experimental group, peripheral blood mononuclear cells of 29 ewes born and bred in experimental facilities were isolated using a Percoll gradient method. Gene expression for Chemokine (C-X-C motif) ligand 10 (CXCL10), Myxovirus (influenza virus) resistance 1 (MX1) and Signal transducer and activator of transcription 1 (STAT1) mRNA were, respectively, 8.3-fold, 6.1-fold and 2.7-fold higher (P<0.001) in pregnant compared with non-pregnant ewes. The receiver operating characteristic (ROC) curves generated from the real-time PCR data demonstrated that a reliable cut-off could be established for CXCL10, MX1 and STAT1. In the farm group of animals, peripheral blood leucocytes of 37 cross-bred multiparous ewes bought from several herds were isolated using the PAXgene® procedure. This blood sampling procedure is achievable in farms, whereas the Percoll method is not. No significant differences (P>0.10) in CXCL10, STAT1, MX1, Myxovirus (influenza virus) resistance 2 (MX2) and ISG15 ubiquitin-like modifier (ISG15) mRNA expression were found between pregnant and non-pregnant ewes. The ROC curves and the hierarchical classification generated from the real-time PCR data failed to discriminate between pregnant and non-pregnant animals. In this group of animals, our results show a strong variability in ISG expression patterns: 17% of animals identified as non-pregnant by the five tests were in fact pregnant, only 52% of pregnant animals had at least two positive results (two genes above threshold), whereas up to five positive results (five genes above threshold) were needed to avoid misclassification. In conclusion, this study illustrates the high variability in ISG expression levels in immune circulating cells during early pregnancy and, therefore, highlights the limits of using ISG expression levels in blood samples, collected on PAXgene® tubes on farms, for early pregnancy detection in sheep.

There is absence knowledge about the effects of lactation trimester and parity on eating behavior, production and efficiency of dairy cows. Objective of this study was to identify and characterize in 340 dairy cows, the 20% high efficient (HE), 20% low efficient (LE) and 60% mid efficient (ME) cows according to their individual residual feed intake (RFI) values, within and between lactation trimesters and between 1st and 2nd parities. Efficiency effect within each lactation trimester, was exhibited in daily dry matter intake (DMI), eating rate and meal size, that were the highest in LE cows, moderate in the ME cows and lowest in the HE group. Daily eating time, meal frequency, yields of milk and energy-corrected milk (ECM) and BW were similar in the three efficiency groups within each trimester. The lower efficiency of the LE cows in each trimester attributes to their larger metabolic energy intake, heat production and energy losses. In subgroup of 52 multiparous cows examined along their 1st and 2nd trimesters, milk and ECM production, DMI, eating behavior and efficiency traits were similar with high Pearson’s correlation (r=0.78 to 0.89) between trimesters. In another subgroup of 42 multiparous cows measured at their 2nd and 3rd trimesters, milk and ECM yield, DMI and eating time were reduced (P<0.01) at the 3rd trimester, but eating rate, meal frequency and meal size remained similar with high Pearson’s correlation (r=0.74 to 0.88) between trimesters. In subgroup of 26 cows measured in 1st and 2nd parities, DMI, BW, milk and ECM yield, and ECM/DMI increased in the 2nd lactation, but eating behavior and RFI traits were similar in both parities. These findings encourage accurate prediction of DMI based on a model that includes eating behavior parameters, together with individual measurement of ECM production. This can be further used to identify HE cows in commercial herd, a step necessary for potential genetic selection program aimed to improve herd efficiency.

The objective of this study was to determine the effects of varying forage particle length on chewing activity, sorting behavior, rumen pH and rumen fill in late lactation and dry dairy cattle, fed rations with similar physically effective NDF but different mean particle length. Treatments consisted of three diets differing only in geometric mean length of forage: hay (5.40, 8.96 and 77.90 mm, for short (S), medium (M) and long (L) diets, respectively) for Experiment 1 (E1), and straw (10.16, 24.68 and 80.37 mm) for S, M and L diets, respectively, for Experiment 2 (E2). Hay or straw comprised the sole source of forage (50% and 75% of ration dry matter (DM) for E1 and E2, respectively). Both experiments used three rumen cannulated Holstein dairy cows, in late lactation for E1 and dry in E2, with 3 × 3 Latin square designs with 14 day periods. In E1, DM intake (DMI; 18.3 ± 2.1 kg/day; mean ± s.e.), pH (6.4 ± 0.1), time spent eating (280 ± 22.5 min/day), time spent ruminating (487 ± 17 min/day), and total time spent chewing (767 ± 34 min/day) were not different, whereas eating minutes per kilogram of DMI and NDF intake (NDFI) tended to increase linearly as forage length increased. Rumen digesta volume (l; 113.3 S, 117.8 M and 114.4 L ± 17.1) had a quadratic response, and rumen digesta weight tended to respond quadratically; however, differences were numerically small. In E2, DMI (8.3 ± 1.3 kg/day), pH (6.7 ± 0.1), time spent eating (236 ± 23.5 min/day), time spent ruminating (468 ± 45.2 min/day), total time spent chewing (704 ± 67.7 min/day) and minutes per kilogram NDFI were not different, whereas minutes per kilogram of DMI had a trend for a quadratic effect. Rumen digesta volume (111 ± 18.8 l) and weight (103 ± 17.4 kg) were not different. In both experiments, cows sorted against longer particles as determined by a particle length selection index; this behavior increased linearly as particle length increased. Greater forage particle length increased sorting behavior, but had no effect on rumen fermentation or chewing behavior.

An evaluation of three automatic recording probes, the Fat-o-Meater (FOM), the Hennessy Grading Probe II (HGP) and the Destron PG-100 (DST) was carried out for use in the revised European Community (EC) Pig Grading Scheme. One hundred and forty-five pig carcasses were selected from four abattoirs covering the national fatness distribution. Two fat thickness depths, one at the head of the last rib (LR) and the other at the 3rd/4th from the last rib (3/4LR fat), and one muscle depth (3/4LR muscle) taken in the same operation for recording 34LR fat were studied as predictors of EC reference lean concentration. All measurements were taken 60 mm from the dorsal mid line. The corresponding cut surface measurements were also recorded and the carcasses were dissected. The prediction of cut surface fat depths from fat depth probes was better than the prediction of cut surface muscle depth from muscle depth taken with the probes. The DST fat measurement predicted more accurately the corresponding cut surface measurements and FOM muscle depth was more precise in predicting muscle cut surface depth. The DST was better in the prediction of EC reference lean concentration with 3/4LR fat and 3/4LR muscle as predictors (residual s.d. 23·1 g/kg). By adding LR as a third independent variable FOM predicted slightly better the lean concentration (residual s.d. 22·3). For Spain, the equations with these three independent variables were submitted to the Pig Management Committee of the EC. All the methods tested predicted EC reference lean concentration with a residual s.d. less than 25 g/kg and a correlation higher than 0·8.

Although the intensive production system of Lacaune dairy sheep is the only profitable method for producers outside of the French Roquefort area, little is known about this type of systems. This study evaluated yield records of 3677 Lacaune sheep under intensive management between 2005 and 2010 in order to describe the lactation curve of this breed and to investigate the suitability of different mathematical functions for modeling this curve. A total of 7873 complete lactations during a 40-week lactation period corresponding to 201 281 pieces of weekly yield data were used. First, five mathematical functions were evaluated on the basis of the residual mean square, determination coefficient, Durbin Watson and Runs Test values. The two better models were found to be Pollott Additive and fractional polynomial (FP). In the second part of the study, the milk yield, peak of milk yield, day of peak and persistency of the lactations were calculated with Pollot Additive and FP models and compared with the real data. The results indicate that both models gave an extremely accurate fit to Lacaune lactation curves in order to predict milk yields (P = 0.871), with the FP model being the best choice to provide a good fit to an extensive amount of real data and applicable on farm without specific statistical software. On the other hand, the interpretation of the parameters of the Pollott Additive function helps to understand the biology of the udder of the Lacaune sheep. The characteristics of the Lacaune lactation curve and milk yield are affected by lactation number and length. The lactation curves obtained in the present study allow the early identification of ewes with low milk yield potential, which will help to optimize farm profitability.

In total, 20 multiparous Holstein-Friesian dairy cows received one of four diets in each of four periods of 28-day duration in a Latin square design to test the hypothesis that the inclusion of lucerne in the ration of high-yielding dairy cows would improve animal performance and milk fatty acid (FA) composition. All dietary treatments contained 0.55 : 0.45 forage to concentrates (dry matter (DM) basis), and within the forage component the proportion of lucerne (Medicago sativa), grass (Lolium perenne) and maize silage (Zea mays) was varied (DM basis): control (C)=0.4 : 0.6 grass : maize silage; L20=0.2 : 0.2 : 0.6 lucerne : grass : maize silage; L40=0.4 : 0.6 lucerne : maize silage; and L60=0.6 : 0.4 lucerne : maize silage. Diets were formulated to contain a similar CP and metabolisable protein content, with the reduction of soya bean meal and feed grade urea with increasing content of lucerne. Intake averaged 24.3 kg DM/day and was lowest in cows when fed L60 (P<0.01), but there was no effect of treatment on milk yield, milk fat or protein content, or live weight change, which averaged 40.9 kg/day, 41.0, 30.9 g/kg and 0.16 kg/day, respectively. Milk fat content of 18:2 c9 c12 and 18:3 c9 c12 c15 was increased (P<0.05) with increasing proportion of lucerne in the ration. Milk fat content of total polyunsaturated fatty acids was increased by 0.26 g/100 g in L60 compared with C. Plasma urea and β-hydroxybutyrate concentrations averaged 3.54 and 0.52 mmol/l, respectively, and were highest (P<0.001) in cows when fed L60 and lowest in C, but plasma glucose and total protein was not affected (P>0.05) by dietary treatment. Digestibility of DM, organic matter, CP and fibre decreased (P<0.01) with increasing content of lucerne in the diet, although fibre digestibility was similar in L40 and L60. It is concluded that first cut grass silage can be replaced with first cut lucerne silage without any detrimental effect on performance and an improvement in the milk FA profile, although intake and digestibility was lowest and plasma urea concentrations highest in cows when fed the highest level of inclusion of lucerne.

Instrumental assessments and sensory tests were performed to evaluate the effects of diet and postmortem ageing time (1, 7 and 21 days) on beef quality. A total of 48 Friesian calves were randomly allocated to four dietary treatments: control, whole linseed (10% linseed), conjugated linoleic acid (CLA) (2% protected CLA), and whole linseed+CLA (10% linseed and 2% protected CLA). Animals were slaughtered at 458±16.6 kg live weight and 11 months of age. Ageing was more significant than diet on most instrumental parameters. Meat from linseed enriched diets had greater drip loss (P⩽0.001) and intramuscular fat (P⩽0.01) than meat from animals fed CLA. Beef aged for 7 and 21 days had lower cooking losses (P⩽0.01) and shear force (P⩽0.001) than beef aged for 1 day. Lightness was affected only by display time. The addition of CLA in the diet increased hue and yellowness, whereas the inclusion of linseed decreased these values, as well as increased redness. Linseed in the diet decreased fat odour (P⩽0.05), but increased beef (P⩽0.01) and liver (P⩽0.05) flavours. Meat aged for 21 days was significantly more rancid (P⩽0.001), even under vacuum storage. Several organoleptic properties were improved with the inclusion of linseed in the diet, whereas they remained unaffected by the inclusion of CLA.

1. Eight British Friesian and eight Jersey calves were fed fresh milk during the period from 3 days to 40 days of age, at two levels of feeding.

2. Energy and nitrogen balances were measured twice for each calf.

3. Fasting heat production (FHP) (MJ/day), which was measured on these occasions, was related to live weight (kg) by FHP = 0·435 W0·75. There was no significant difference in FHP/kg0·75 between the breeds but previous level of feeding and the duration of fast had significant effects.

4. The data for heat production, metabolizable energy (ME) intake and energy retention were interpreted to provide estimates of ‘true’ net energy required for maintenance of 0·23–0·27 MJ/kg0·75 daily.

5. Pooled values for ME required for maintenance and for the net efficiency of utilization of ME above maintenance were 0·39 or 0·42 MJ ME/kg0·75 daily, and 0·67 or 0·72 determined by simple or multiple regression techniques respectively; there were no significant differences between the breeds. Pooled values for the partial net efficiencies of utilization of ME for the synthesis of protein and fat were 0·54 and 0·79 respectively.

6. ME required above maintenance was estimated to be 11·3 and 13·6 MJ ME/kg of live-weight gain for the lower and higher rates of gain respectively.

7. A small experiment revealed no major differences between diets of milk alone or milk plus solid food, with regard to maintenance requirement or net efficiency of utilization of ME by calves.

Previous research has shown that piglets using the sow's more anterior teats tend to have greater average weight gains, but this difference is often slight in the first lactation and increases in subsequent lactations. In this study, 27 sows were used to determine whether this difference develops because of the piglets' preferential use of the anterior teats during the first lactation. In their first lactation, 14 sows had their anterior teats (pairs 1 to 3) and 13 sows had their posterior teats (pairs 4 to 7) covered so that the piglets could use only one end of the udder. In the second lactation, all the teats were left uncovered and the sucking positions and weight gains of the piglets were studied. Piglets in the second lactation showed the usual preference for anterior teats regardless of which teats had been used in the first lactation. Where the anterior teats had been covered in the first lactation, there was no difference in weight gain between anterior- and posterior-sucking piglets in the 1st week of the second lactation, but a degree of anterior superiority had developed by the 3rd week (P < 0·01). Where posterior teats had been covered in the first lactation, piglets using anterior teats showed substantially greater weight gains than those using posterior teats throughout the first 3 weeks of the second lactation (P < 0·001). Thus, non-use of a teat in the first lactation tended to reduce its productivity, at least in the early part of the next lactation. We conclude that previous non-use of posterior teats can contribute to their tendency for lower productivity, but the effect does not explain completely the greater piglet weight gains usually associated with using the anterior teats.

Pushing the testes of lambs 1 to 2 weeks old into the body cavity and applying a rubber ring to cause atrophy of the empty scrotum, did not prevent most testes growing in a subcutaneous position. A modified technique used in a second experiment, which caused ablation of the tunica vaginalis as well as the scrotum, impeded more effectively the descent and growth of the testicles.

In the two experiments growth rates of the induced cryptorchids were, respectively, 15·3% and 6·0% (non-significant) greater than those of castrated males, dressing percentages were about 2 units lower, and fat depth over the eye muscle of 13th rib chops was 2·6 compared with 2·9 mm (non-significant) and 1·9 compared with 4·1 mm. Chops from the cryptorchids had a visual appeal similar to those from castrated male and from female lambs; differences in flavour detected by taste panel had no significant effect on overall flavour acceptability.

Tenderness did not differ significantly between sex groups, but age and Warner-Bratzler shear values were significantly and positively correlated as were ultimate pH of the meat and age at slaughter. Cryptorchidism induced by the modified technique probably permits the production of heavier carcasses with lower fat cover than on castrated males and avoids practical disadvantages that may be encountered in raising entire male lambs.

Increasing the concentration of dietary lipid is a promising strategy for reducing methane (CH4) emissions from ruminants. This study investigated the effect of replacing grass silage with brewers’ grains on CH4 emissions of pregnant, non-lactating beef cows of two breeds. The experiment was a two×two factorial design comprising two breeds (LIMx, crossbred Limousin; and LUI, purebred Luing) and two diets consisting of (g/kg diet dry matter (DM)) barley straw (687) and grass silage (301, GS), or barley straw (763) and brewers’ grains (226, BG), which were offered ad libitum. Replacing GS with BG increased the acid-hydrolysed ether extract concentration from 21 to 37 g/kg diet DM. Cows (n=48) were group-housed in equal numbers of each breed across two pens and each diet was allocated to one pen. Before measurements of CH4, individual dry matter intake (DMI), weekly BW and weekly body condition score were measured for a minimum of 3 weeks, following a 4-week period to acclimatise to the diets. CH4 emissions were subsequently measured on one occasion from each cow using individual respiration chambers. Due to occasional equipment failures, CH4 measurements were run over 9 weeks giving 10 observations for each breed×treatment combination (total n=40). There were no differences between diets for daily DMI measured in the chambers (9.92 v. 9.86 kg/day for BG and GS, respectively; P>0.05). Cows offered the BG diet produced less daily CH4 than GS-fed cows (131 v. 156 g/day: P<0.01). When expressed either as g/kg DMI or kJ/MJ gross energy intake (GEI), BG-fed cows produced less CH4 than GS-fed cows (13.5 v. 16.4 g/kg DMI, P<0.05; 39.2 v. 48.6 kJ/MJ GEI, P<0.01). Breed did not affect daily DMI or CH4 expressed as g/day, g/kg DMI or kJ/MJ GEI (P>0.05). However, when expressed as a proportion of metabolic BW (BW0.75), LUI cows had greater DMI than LIMx cows (84.5 v. 75.7 g DMI/kg BW0.75, P<0.05) and produced more CH4 per kg BW0.75 than LIMx cows (1.30 v. 1.05 g CH4/kg BW0.75; P<0.01). Molar proportions of acetate were higher (P<0.001) and propionate and butyrate lower (P<0.01) in rumen fluid samples from BG-fed compared with GS-fed cows. This study demonstrated that replacing GS with BG in barley straw-based diets can effectively reduce CH4 emissions from beef cows, with no suppression of DMI.

Jugular and ovarian venous profiles of progesterone and endometrial progesterone concentrations were measured in pregnant and non-pregnant ewes. Mean jugular concentrations were not significantly different (3·12v.2·39 μg/l). The incidence of progesterone concentrations above a chosen threshold was significantly greater in the ovarian vein than in the jugular vein (P < 0·05) and was greater (P > 0·05) in the ovarian venous plasma of pregnant than of non-pregnant ewes. Mean endometrial progesterone concentrations were significantly higher in pregnant than in non-pregnant ewes (T < 0·05). It is suggested that the lower progesterone concentrations in the ovarian veins of non-pregnant ewes may have a rôle in pregnancy failure and that ovarian venous concentrations may influence endometrial progesterone concentrations.

Limited research has suggested that higher lambing densities increase interference from foreign ewes at lambing which disrupts the ewe-lamb bond and compromises lamb survival. This may be particularly evident in mobs of twin-bearing ewes compared to single-bearing ewes because a greater number of lambs are born per day. Therefore, we hypothesised that; (i) decreasing the mob size of ewes at lambing has a greater impact on the survival of twin-born lambs than single-born lambs; (ii) the relationship between mob size and lamb survival can be explained by differences in the rate of interaction with foreign ewes and lambs at lambing; and (iii) ewes will utilise a limited area of the paddock at lambing and thus lambing density will be defined by the distribution of ewes in the paddock rather than the paddock area. Merino ewes were allocated into a 2×2 factorial combination of ewe pregnancy status (single- or twin-bearing) and mob size (high (n=130 ewes) or low (n=50 ewes)) on day 140 from the start of joining. Each treatment had two replicates excepting the low mob size for twins which had a third replicate. Ewes lambed at a stocking rate of 11 ewes/ha. Feed-on-offer during lambing exceeded 2400 kg dry matter (DM)/ha. Ewe-lamb behaviour was observed and dead lambs were autopsied over 11 days during the peak of lambing. The distribution of ewes in each paddock was recorded every 2 h during daylight hours by counting the number of ewes occupying 2500 m2 grids. The proportion of ewes and their newborn progeny which interacted with foreign ewes at lambing did not differ between the high and low mob sizes for single- (24.9% v. 20.8%) or twin-bearing ewes (14.3% v. 19.6%; P=0.74). Similarly, interaction with foreign lambs did not differ between the high and low mob sizes for single- (14.5% v. 25.2%) and twin-bearing ewes (34.5% v. 26.4%; P=0.44). The distribution of ewes within the paddock did not differ between treatments (P=0.95). On average, single-bearing ewes which lambed at the high and low mob sizes occupied 34% and 36% of the paddock during daylight hours, and the corresponding values for twin-bearing ewes were 40% and 43%. Survival of twin-born lambs was lower than single-born lambs (75.3% v. 87.9%; P<0.01), however, lamb survival was not influenced by mob size regardless of birth type. These results suggest that higher mob sizes may not compromise lamb survival when feed-on-offer during lambing exceeds 2400 kg DM/ha.

The effect of vitamin A (retinol) on ovine stearoyl-CoA desaturase (SCD) mRNA levels and fatty acid composition was investigated. Sheep adipose tissue explants were maintained in culture for 24 h in the presence of all-trans retinoic acid (RA). Tissue SCD mRNA levels were increased with 25 μmol/l RA but the levels of SCD mRNA in tissue treated with 100 μmol/l RA were not different from control. The effect of vitamin A supplement on SCD mRNA levels in vivo was then characterized: growing lambs were given a concentrate diet (2 kg/day) containing 0, 0.225, 1.125 and 3.375 mg vitamin A per kg diet for 21 days. Treatment resulted in a concentration-dependent increase in adipose tissue and liver SCD mRNA levels, although the greatest effect was seen in the liver. SCD mRNA levels were highest in tissue from animals given 0.225 mg vitamin A per kg diet and further increases in vitamin A supplementation were not accompanied by corresponding increases in SCD gene expression. Fatty acid composition was also determined. Overall, tissue from animals given vitamin A had greater levels of both palmitoleic and oleic acid relative to their precursors. These data clearly show that SCD gene expression in adipose tissue and liver is regulated by retinoic acid and the liver appears to be most responsive. However, although significant, the change in the proportion of oleic acid was only small indicating that dietary manipulation with vitamin A is not a suitable method for increasing the unsaturated fat content of sheep meat.

The overall aim of the present study was to analyse and compare organic beef cattle farming in Spain with intensive and conventional systems. An on-farm study comparing farm management practices and animal health was carried out. The study also focussed on a slaughterhouse analysis by comparing impacts on the safety and quality of the cattle products. Twenty-four organic and 26 conventional farms were inspected, and farmers responded to a questionnaire that covered all basic data on their husbandry practices, farm management, veterinary treatments and reproductive performance during 2007. Furthermore, data on the hygiene and quality of 244, 2596 and 3021 carcasses of calves from organic, intensive and conventional farms, respectively, were retrieved from the official yearbook (2007) of a slaughterhouse. Differences found between organic and conventional farms across the farm analysis did not substantially reflect differences between both farm types in the predominant diseases that usually occur on beef cattle farms. However, calves reared organically presented fewer condemnations at slaughter compared with intensive and to a lesser extent with conventionally reared calves. Carcass performance also reflected differences between farm type and breed and was not necessarily better in organic farms.

1. Three isocaloric diets containing 170, 210 or 231 g crude protein per kg were given at two levels, and offered ad libitum to entire and castrated male pigs growing from 20 to 70 kg live weight.

2. Between 20 and 45 kg, growth rate improved with each increase in level of feeding (P < 005) and, on the ad libitum treatment the food intake and growth performance of both entire and castrated pigs were similar. On the restricted feeding treatments the growth performance of entire, but not of castrated pigs, improved when dietary protein was raised from 170 to 210g/kg (P < 005).

3. During the live-weight periods 45 to 70 and 20 to 70kg, raising food intake improved growth rate (P < 005) but increased the food conversion ratio and carcass fat measurements at 70 kg (P < 0·05). However, food conversion ratio and the majority of carcass characteristics of entire pigs fed ad libitum were equivalent to those of castrated pigs fed at the lowest level.

4. Dietary protein level had no significant effect on growth performance from 20 to 70 kg or on carcass fat measurements at the latter weight. However, each increase in dietary protein in the live-weight period 45 to 70 kg depressed the performance of castrated pigs (P < 0·05) while that of entire pigs was reduced when the protein level of the diet was raised from 210 to 231 g/kg.

This paper examines a paradox at the centre of efforts to improve livestock production in sub-Saharan Africa. For decades livestock nutrition and animal food have been identified as critical constraints, yet producers have shown little interest in improved food technologies. The main argument is that the analyses highlighting nutrition and food as critical constraints have focused primarily on biological productivity, and are thus at odds with livestock producers’ perceptions. The paper concludes by suggesting that livestock research in Africa must taker greater account of different systems, situations and producers, as well as key characteristics of technology such as reliability and management flexibility.

Oilseeds offer some protection to the access of ruminal microorganisms and may be an alternative to calcium salts of fatty acids (FA), which are not fully inert in the ruminal environment. This study aimed to evaluate the effects of different sources of FA supplementation on apparent total tract nutrient digestibility, milk yield and composition, and energy balance (EB) of cows during the transition period and early lactation. We compared diets rich in C18:2 and C18:3 FA. Multiparous Holstein cows were randomly assigned to receive one of the four diets: control (n=11); whole flaxseed (WF, n=10), 60 and 80 g/kg (diet dry matter (DM) basis) of WF during the prepartum and postpartum periods, respectively; whole raw soybeans (WS, n=10), 120 and 160 g/kg (diet DM basis) of WS during the prepartum and postpartum periods, respectively; and calcium salts of unsaturated fatty acids (CSFA, n=11), 24 and 32 g/kg (diet DM basis) of CSFA during the prepartum and postpartum periods, respectively. Dry cows fed WF had higher DM and net energy of lactation (NEL) intake than those fed WS or CSFA. The FA supplementation did not alter DM and NDF apparent total tract digestibility, dry cows fed WF exhibited greater NDF total tract digestion than cows fed WS or CSFA. Feeding WS instead of CSFA did not alter NEL intake and total tract digestion of nutrients, but increased milk fat yield and concentration. Calculated efficiency of milk yield was not altered by diets. FA supplementation increased EB during the postpartum period. Experimental diets increased long-chain FA (saturated and unsaturated FA) in milk. In addition, cows fed WS and CSFA had higher C18:1 trans-11 FA and C18:2 cis, and lower C18:3 FA in milk than those fed WF. Furthermore, cows fed CSFA had higher C18:1 trans-11 and cis-9, trans-11 FA than cows fed WS. Although supplemental C18:2 and C18:3 FA did not influence the milk yield of cows, they positively affected EB and increased unsaturated long-chain FA in milk fat.

Animals perceiving repeated aversive events can become chronically stressed. Chronic activation of the hypothalamic–pituitary–adrenal (HPA) axis can have deleterious consequences on physiological parameters (e.g. BW, blood chemistry) and behaviour (e.g. emotional reactivity, stereotypies, cognition). Environmental enrichment (EE) can be a mean to reduce animal stress and to improve welfare. The aim of this study was first, to assess the effects of EE in battery cages on the behaviour of young Japanese quail and second, to evaluate the impact of EE on quail exposed to chronic stress. The experiment involved quail housed in EE cages and submitted or not to a chronic stress procedure (CSP) (EE cages, control quail: n=16, CSP quail: n=14) and quail housed in standard cages and exposed or not to the CSP (standard non-EE cages, control quail: n=12, CSP quail: n=16). Our procedure consisted of repeated aversive events (e.g. ventilators, delaying access to food, physical restraint, noise) presented two to five times per 24 h, randomly, for 15 days. During CSP, EE improved quail’s welfare as their stereotypic pacing decreased and they rested more. CSP decreased exploration in all quail. After the end of CSP, quail presented increased emotional reactivity in emergence test. However, the effect of EE varied with test. Finally, chronic stress effects on comfort behaviours in the emergence test were alleviated by EE. These results indicate that EE can alleviate some aspects of behavioural alterations induced by CSP.