The objective of the study was to compare production and welfare of rabbit does and their kits housed in various types of cages. Female rabbits were randomly allocated to four groups with the following cage types: CN: common wire-mesh flat-deck cage, without footrest; CF: cage similar to the CN but with plastic footrest; ECWP: enlarged cage with wire-mesh platform; and ECPP: extra enlarged cage with plastic-mesh platform. All does were inseminated on the same day, 11 days after kindlings. Reproductive performance was evaluated during the first five consecutive kindlings. Severity of sore hocks was scored at each insemination. Location preference of the does and the platform usage of their kits were evaluated. Kindling rate, litter size (total born, born alive, alive at 21 and 35 days) and kit mortality were not significantly influenced by the cage types. The litter weight at 21 days was higher in ECWP and ECPP cages than in the CF group (3516, 3576 and 3291 g, respectively; P<0.001), and at 35 days the difference was only significant between the groups ECPP and CF (8712 and 8060 g, respectively, P<0.05). At 21 and 35 days of age, the kits were heavier in large (ECWP and ECPP) than in conventional cages (CF and CN) (P<0.001). At the fifth insemination, the percentage of rabbits with sore hocks’ score of 1 to 2 (0=intact foot pads; 1=no hairs, callus formed, <2.5 cm; 2=no hairs, callus formed, >2.5 cm) and 3 to 4 (3=callus opened, cracks present; 4=wounds) were 58%, 60%, 78% and 48%, and 0%, 5%, 0% and 48% in groups ECPP, ECWP, CF and CN, respectively. Higher number of daily nest visits was observed for CF does than for ECWP does (12.5 v. 5.9; P<0.05). The frequency of multiple nursing events (>2/day) was higher in the CF group than in the ECWP group (12.1 v. 3.2%; P<0.01). Within large cages, the does were observed on the platform more frequently in the ECPP cages compared with the ECWP cages (56.9% v. 31.7%; P<0.001). Similarly, 2.7% and 0.2% of kits at 21 days of age, and 33.2% and 5.2% of kits at 28 days of age, were found on the platforms of ECPP and ECWP cages, respectively. In conclusion, cages larger than the conventional ones improved kits’ weaning weight, plastic footrests and plastic-mesh platforms in conventional and/or large cages reduced sore hocks’ problems, plastic-mesh platforms were more used by both does and kits compared with the wire-mesh platforms.

Approximately 5% of pigs produced in Australia is believed to be traded at livestock sales. Interviews and focus group discussions were conducted with producers (106 and 30 producers, respectively), who traded pigs at livestock sales. The purpose of the study was to gather information on how producers identified their pigs in order to evaluate how these practices may impact the ability to trace pig movements in the event of an emergency animal disease outbreak or food safety hazard. Results were analyzed according to herd size (0 to 150 sows, 150+ sows) and location (peri-urban, regional) as prior studies suggested a higher biosecurity risk among smaller farms and due to perceptions that peri-urban farms pose additional risk. Most producers (91.5%) had less than 150 sows and a high proportion (70.8%) resided in regional areas compared with only 29.2% residing in peri-urban areas. A higher proportion of large-scale producers identified their pigs than small-scale producers. A third of small-scale producers reported not identifying breeding stock and most did not identify progeny. The most common forms of on-farm identification used were ear tags for breeding stock and ear notches for progeny. Producers identified breeding stock to assist with mating management and genetic improvement. Ear notches were used to determine the litter of origin of progeny. All large-scale producers owned a registered swine brand and used the official body tattoo for post-farm-gate identification. However, approximately 15% of small-scale producers did not own a registered swine brand, and an additional 8% did not identify their pigs post-farm-gate. Producers were satisfied with tattoos as a methodology for post-farm-gate identification of pigs and considered other methodologies cost-prohibitive. However, variations in the maintenance of the branding equipment, the type of ink used and the time of tattoo application in relation to the animal sale were highlighted during focus group discussions. These results suggest that there is a need for education and extension activities, especially among small-scale pig producers, regarding the benefits of identifying animals on-farm. In addition, increased awareness of the traceability legislation that exists in Australia to meet the National Performance Standards for Livestock Traceability in this country is required.

A trial was performed to investigate the interaction between energy and protein source for cows in negative energy balance. Six cows were assigned to each of four types of concentrate (metabolizable energy (ME) 12 MJ/kg dry matter (DM), crude protein (CP) 180 g/kg DM) with low or high fibre contents (LF or HF) and protein degradability (LD or HD). For groups HDLF, LDLF, HDHF and LDHF respectively, acid-detergent fibre contents (g/kg diet DM) were 69·2, 66·1, 117·5 and 113·3; protein degradability values were determined as 0·78, 0·61, 0·72 and 0·66. Low-fibre diets were given at the rate of 11 kg/day concentrates with 6 kg/day hay (ME 8 MJ/kg DM, CP 84·5 g/kg DM) and high-fibre diets at the rate of 10 kg/day concentrates with 7·5 kg/day hay from weeks 4 to 13 of lactation. Cows were given a standard diet over the first 3 weeks of lactation and performance in week 3 was used as a covariate.

Milk yield was not affected by treatment but the butterfat content of milk from cows given the high-fibre diets (44·9 g/kg) was higher than the low-fibre diets (36·4 g/kg; P < 0·01), which resulted in significant differences in fat-corrected milk yield (HDHF: 25·1, LDHF: 26·2, HDLF: 22·7, LDLF: 21·5, s.e.d. 1·5 kg/day). ME balance was lower for the LDHF group (−4·1 MJ/day) than for groups LDLF and HDLF (-15·4 and -16·8 MJ/day; P < 0·05) but was not significantly different from the HDHF group (-29·4 MJ/day). Undegradable protein (UDP) balances were 53·4, 93·8, -21·2 and 193·8 (s.e.d. 45, P < 005) g/day for groups HDLF, LDLF, HDHF and LDHF respectively. Differences from zero in ME and UDP balance were accounted for in all groups except LDHF by changes in live weight plus a systematic correction of approximately 10 MJ/day. It is considered that the cows given high-fibre diets responded to high UDP by increasing fat-corrected milk production but mobilization of body fat to support this increase was accompanied by retention of protein with associated water, resulting in very little change in live weight. It is also probable that the high UDP levels improved the digestion of fibre i n the rumen, but this is unlikely to have been sufficient to have accounted for all of the response.

The fatty acid composition of milk samples from Ayrshire twin cows was determined. The results were in general agreement with those reported by other workers. Comparisons between the variation within pairs of one and two-egg twins showed that the proportions of different fatty acids are subject to a high degree of genetic control.

Changes in the partitioning of both dissected and chemical fat were examined from birth to maturity, in rams and ewes from flocks of Merino sheep selected for high (weight-plus) and low (weight-minus) weaning weight and from a randomly bred control flock. The partitioning of fat between six dissected and 11 chemical fat partitions in the body was examined in 34 mature animals, and the maturing patterns for these fat partitions calculated relative to the weight of total body fat, using the mean values for the mature animals and individual data from 106 immature animals.

Strain had no effect on the partitioning of dissected fat in the mature animals, but did affect the partitioning of chemical fat in the bone and pelt partitions. Mature ewes had greater proportions of dissected subcutaneous and kidney fat, and lower proportions of dissected intermuscular and scrotal/udder fat, than the mature rams.

There were significant strain and sex effects on maturing patterns for dissected subcutaneous and intermuscular fat. Strain and sex effects were also significant for the maturing patterns of some chemical fat partitions.

Selection for high or low weaning weight had little effect on the partitioning of either dissected or chemical fat when compared at the same stage of maturity of total fat. There were large differences in the partitioning of both chemical and dissected fat between the rams and the ewes when compared at either the same weight of total fat, or the same stage of maturity of total fat in the body.

Data from 22, 28, 36 and 41 pregnant cows in weeks 4, 3, 2 and 1 before calving respectively and 51, 65, 56 and 36 cows in weeks 1 to 4, 5 to 8, 9 to 12 and 13 to 16 of lactation respectively were used in multiple regression analyses to study the feasibility of predicting the daily total and the roughage organic matter and digestible organic matter intakes of cows given known weights of concentrates plus roughage ad libitum. The digestibility of the total intake and of the roughage component, the weight of concentrates eaten per day, the proportion of roughage in the total intake, age, milk yield, fat-corrected milk yield, live-weight gain and the 1·0, 0·73 and 0·66 exponents of live weight were used as independent variables.

The accuracy of the models was assessed from the significance of the partial regression coefficients, the size of the residual standard errors, and the population tolerance limits about predicted values, and by applying selected models to a set of data not included in the study. The results indicated that the precision likely to be achieved in the prediction of intake for individual cows was of limited practical application, but the mean intakes of groups of 30 similar cows could be predicted with an acceptable level of accuracy for practical application. In general, weight of concentrates offered and the digestibility of the roughage were the most effective independent variables in all cows, together with milk yield in lactating cows. The application of the results to conventional feeding systems and to complete diets offered ad libitum is discussed.

British Friesian dairy female calves were offered once daily either 320 or 480 g of milk substitute reconstituted in warm water. Weaning took place when calves were consistently eating 400, 650 or 900 g/day of concentrates. The number of days taken to reach weaning was greater with calves offered 480 g than with calves offered 320 g of milk substitute per day. Calves with a high initial live weight achieved the required concentrate intake and were therefore weaned sooner than smaller calves. A fall in energy intake occurred immediately after weaning and this was greatest in calves previously offered 480 g/day of milk substitute. The treatments had no significant effect on the total intake of concentrates and hay over the 8 weeks of the experiment. Increasing the amount of milk substitute from 320 to 480 g/day increased total feed costs, and feed costs per kg live-weight gain. Increasing the required level of concentrate intake at weaning also increased total feed costs and feed costs/kg live-weight gain, but to a lesser extent. The results suggest that it is preferable to feed dairy replacement calves only 320 g of milk substitute in a once-daily feeding system. Weaning can be successfully under-taken when the calves are consistently eating 400 g/day of concentrates.

A maternal breeding goal for the UK beef industry is described and economic selection indexes are developed to assist in the selection of animals for the goal. The breeding objective is made up of general maternal ability traits, cow size, calving and carcass traits. The general maternal ability traits include calving interval, age at first calving, lifespan, maternal weaning weight and maternal calving difficulty. The calculations of economic values for the traits are outlined and discounted genetic expression coefficients are presented. Three selection indexes are illustrated. The first provides a general dualpurpose index for the selection of bulls to produce replacement heifers in most situations. The second, the hardy breed index, is designed to allow selection for improved maternal performance in extensive and hardy environments. The third, the fertile herd index, allows producers who do not have herd fertility problems to place more selection emphasis on objectives other than fertility. A sample of data from the Limousin breed was used to calculate estimated breeding values (EBVs) which were used to investigate response to the three indexes when the top 20% of sires were selected from either sires with 50 or more grand-maternal progeny or bulls with no recorded progeny. Approximately two thirds of the economic response seen in the selection of heavily used bulls was observed in bulls with no progeny for the hardy and dual-purpose indexes. Bulls were also selected using the existing UK terminal sire index and the resulting bulls assessed in the dual-purpose maternal index. There was found to be a negative economic response to the maternal aspect of the index, though a positive response was seen in the carcass objective. The indexes are presented as the sum of four subindexes emphasizing the contribution of maternal ability, cow size, calving and carcass, respectively to the total index. This further assists commercial producers in selection decisions.

Genetic parameters were estimated for traits recorded in a calving survey for beef sires used in commercial dairy herds in England and Wales. The five traits included in the survey were calving difficulty score, calf mortality to 48 h after birth, gestation length, and subjectively assessed calf size and conformation. The data file examined included over 88 000 records, on 323 sires of eight beef sire breeds, namely Aberdeen Angus, Belgian Blue, Blonde d'Aquitaine, Charolais, Hereford, Limousin, Piedmontese and Simmental.

Estimates of heritability and genetic and phenotypic correlations were obtained for all traits by REML procedures using a sire model. The effects of cow age, calf sex, year and season of the calving and sire breed were included in the model, together with interactions.

Heritability estimates were 0·09 (s.e. 0·01) for calving difficulty score, 0·32 (s.e. 0·03) for gestation length, 0·02 (s.e. 0·003) for mortality, 0·09 (s.e. 0·01) for calf size and 0·06 (s.e. 0·01) for calf conformation.

Heritability estimates for the scored categorical and binomial (mortality) traits were also obtained using threshold model analysis. As expected, these estimates were higher than the REML estimates; 0·16 (s.e. 0·01) for calving difficulty score, 0·08 (s.e. 0·01) for mortality, 0·14 (s.e. 0·01) for calf size and 0·09 (s.e. 0·01) for calf conformation. Calving difficulty score was strongly correlated genetically with calf size (-0·84), mortality (0·74) and calf conformation (-0·72), and moderately correlated with gestation length (0·26). Calf size and conformation were very highly correlated genetically (0·86), and both were also strongly correlated with mortality (-0·63 and -0·52 respectively). In all cases, the genetic correlations were stronger than the phenotypic correlations.

Sire genetic merit was predicted for all traits and the distribution of these predictions is described. Sire predictions of genetic merit for calving difficulty score on the underlying scale were backtransformed to predict the expected incidence of serious difficulties in future calvings and these predictions are illustrated for the major sire breeds.

A dynamic model for simulation of growth in pigs was extended by a module to describe protein turn-over in six body protein pools (muscle, connective tissue, liver, blood plasma, gastro-intestinal, and 'other' proteins). The model describes protein deposition in these pools following different growth curves and differential rates of turnover. Growth curve parameters and turn-over rates were obtained from the literature.

In growing animals, experimentally measured turn-over rates represent a combination of turn-over of already-present body protein and fractional (repeated) synthesis of newly deposited protein. An attempt was made to distinguish between these processes by varying the values of the fractional rate of synthesis of newly deposited protein (FRSdrp) and of the proportionof maintenance energy requirements not related to protein turn-over (FrcMEmaint), and comparing the simulated outputto the output from the original model without the protein turnover module.

The turn-over rate (TRpres)of already present connective tissue protein reached unrealistic values for FRSdep > 2·5 per day, which puts an upper limit on FRSdep.

The output from the extended and the original models showed similar patterns for certain combinations of FRSdefl and FrcMEmaint, dependent on the levels of model input variables. For FRSdcp 2·5 perday, these similar patterns have their optimum at FrcME^^ = 0·65, coinciding with FRSdep =2·0 per day. The corresponding TRpres values were 0·060, 0·019, 0·585, 1·492, 0·582, and 0·016 per day for the above mentioned pools.

Two experiments were carried out simultaneously in a temperate environment (T), at Sourches (west France), with 24 Landrace X Large White sows and in a tropical environment (TRO), in Guadeloupe, France (16° latitude N, 61° longitude W), with 18 Large White sows, to study the effect of incorporating fat into the lactation diet on sow and litter performance. In each environment, multiparous sows were divided into three groups and given either a control diet (C) containing 20 g fat per kg, or the same diet enriched with a 50 : 50 peanut-rapeseed oil mixture, so as to obtain a fat content of 80 g/kg (medium fat, MF) or 140 g/kg (high fat, HF). A restricted experimental diet was supplied to the sows from day 105 of gestation until farrowing and then ad libitum throughout the 28-day lactation period. The piglets all had ad libitum access to solid food from day 21 to day 70. Milk samples were collected 24 h post partum (colostrum) and at day 21 of lactation. Chemical composition of milk was determined and fatty acid composition was assessed by capillary gas chromatography. Compared with T, the TRO sows showed an increase (P < 0⋅001) in rectal temperature and respiration rate but a decrease in food intake (P < 0·01), milk yield (P < 0⋅001) and litter weight gain from birth to weaning (P < 0⋅05) as well as from weaning to day 70, reaching 25 to 30 kg live weight (P < 0⋅05). However, as dietary fat level increased, the T sows showed a linear decrease (P < 0⋅01) in food intake and no significant change in metabolizable energy (ME) intake during the lactation period. In TRO, the MF diet led to a 0⋅22 proportional increase (P < 0⋅01) in ME intake through a change in nycthemeral feeding behaviour. Both environment and increased dietary fat level significantly affected the fat level and fatty acid composition of colostrum as well as mature milk, particularly n-3 polyunsaturated fatty acid concentration in milk. In conclusion, the addition of fat to the lactating sow diet may be more beneficial under high ambient temperatures than in thermoneutral conditions.

The growth performance, carcass characteristics and meat quality measurements were evaluated on broiler chicks fed different dietary levels of whole inedible dates (WID). WID used in this study were consisted of date fruits (∼850 g/kg) and date pits (∼150 g/kg). Three hundred unsexed Lohman broiler chicks were randomly and equally distributed into six groups. Each was formed of 50 chicks (five replicates, 10 chicks per replicate), and was assigned to a dietary treatment. Six dietary treatments of WID (0, 30, 60, 90, 120 and 150 g/kg feed) were included in the formation of isocaloric (metabolizable energy of ∼3060 kcal/kg feed) and isonitrogenous (CP of ∼192 g/kg feed) broiler rations. The treated rations were fed to the group chicks between 15 and 42 days of age (the experimental period). A straight-run design was considered. At 42 days of age, five males from each treatment were randomly chosen and slaughtered to determine carcass characteristics, internal organs and meat quality measurements. Digestibility of nutrients was measured at the end of the experimental period using five caged-individual males per treatment. The inclusion of broiler rations on WID for up to 150 g/kg feed, over the experimental period, did not significantly influence body weight gain (1452 to 1521 g/chick), feed intake (3268 to 3621 g/chick), feed conversion ratio (2.26 to 2.36 kg/kg) and dressed carcass (63.4% to 67.3%). In addition, levels of WID for up to 150 g/kg feed did not significantly influence the digestibility of nutrients and meat quality measurements. Such results suggest the possible inclusion of broiler rations on WID for up to 150 g/kg feed, during the period of 15 to 42 days of age without adverse effects on growth performance and meat quality.

Linear measurements of six body dimensions were taken of Large White × Landrace pigs in the live-weight range of 1 kg to 286 kg. Logarithmic regression lines were fitted to the live-weight and measurement data. It was found that the body dimensions could be expressed as a function of live weight and that these equations agreed well with the simple allometric equation L = kW1/3, where linear dimension, W= live weight and k= an appropriate coefficient. It is suggested that these equations may provide a method of estimating the static space occupied by a pig and thus provide a basis for the development of space allocation recommendations in pig housing. It is also suggested that these principles may be applicable to other livestock.

A total of 50 mixed parity sows of a high-prolificacy genetic line were used to evaluate the impact of feed restriction during lactation on their production and reproductive performance and their performance in the subsequent lactation. From day 7 of lactation, sows were distributed according to a completely randomized experimental design into two treatments. In treatment 1, sows were fed 8.0 kg feed/day (control) and in treatment 2, sows were fed 4.0 kg/day. The same suckling pressure was maintained until weaning on day 28 of lactation. Average minimum and maximum temperatures measured during the experimental period were 32.1°C and 16.5°C, respectively. Control sows presented significantly higher feed intake (P<0.001) compared with the restricted sows (6.43 v. 4.14 kg/day, respectively). Treatments influenced BW and backfat thickness losses (P<0.001). Control sows lost less BW than the restricted-fed sows (7.8 v. 28.2 kg). Restricted-fed sows lost more backfat thickness than those in the control group (3.97 v. 2.07 mm; P<0.01). Restricted-fed sows tended (P<0.10) to be lighter at weaning compared with the control sows (211 v. 227 kg). The composition of BW loss was influenced by the treatments (P<0.001), as the restricted-fed sows lost more body protein, lipids and energy compared with the control sows (3.90 v. 0.98 kg, 11.78 v. 4.83 kg and 584 v. 224 MJ, respectively). Litter weight gain was greater (P<0.05) in control sows than in restricted-fed sows (2.70 v. 2.43 kg/day). Daily milk production was 19% higher (P<0.01) in the control sows compared with the restricted-fed sows (8.33 v. 6.99 kg/day). However, restricted-fed sows presented a higher (P<0.05) lactation efficiency than the sows of the control group (82.30% v. 72.93%). No differences were detected (P>0.10) in weaning-to-estrus interval and averaged 4.3 days. No effect of the treatment (P>0.10) was observed on any of the studied performance traits in the subsequent lactation, except for litter size at birth that tended (15.2 v. 14.1; P<0.10) to be lower for the restricted sows. In conclusion, the present study demonstrated that feed restriction during lactation leads to intense catabolism of the body tissues of sows, negatively affecting their milk production, and the litter weight gain and possibly number of piglets born in the next litter. On the other hand, restricted-fed sows are more efficient, producing more milk per amount of feed intake.

Artificial insemination has been a landmark procedure in improving animal agriculture over the past 150 years. The utility of artificial insemination has facilitated a rapid improvement in animal genetics across agricultural species, leading to improvements of growth, health and productivity in poultry, swine, equine and cattle species. The utility of artificial insemination, as with all assisted reproductive technologies side-steps thousands of years of evolution that has led to the development of physiological systems to ensure the transmission of genetics from generation to generation. The perceived manipulation of these physiological systems as a consequence of assisted reproduction are points of interest in which research could potentially improve the success of these technologies. Indeed, seminal fluid is either removed or substantially diluted when semen is prepared for artificial insemination in domestic species. Although seminal fluid is not a requirement for pregnancy, could the removal of seminal fluid from the ejaculate have negative consequences on reproductive outcomes that could be improved to further the economic benefit of artificial insemination? One such potential influence of seminal fluid on reproduction stems from the question; how does the allogeneic foetus survive gestation in the face of the maternal immune system? Observation of the maternal immune system during pregnancy has noted maternal immune tolerance to paternal-specific antigens; a mechanism by which the maternal immune system tolerates specific paternal antigens expressed on the foetus. In species like human or rodent, implantation occurs days after fertilisation and as such the mechanisms to establish antigen-specific tolerance must be initiated very early during pregnancy. We and others propose that these mechanisms are initiated at the time of insemination when paternal antigens are first introduced to the maternal immune system. It is unclear whether such mechanisms would also be involved in domestic species, such as cattle, where implantation occurs weeks later in gestation. A new paradigm detailing the importance of paternal–maternal communication at the time of insemination is becoming evident as it relates to maternal tolerance to foetal antigen and ultimately pregnancy success.

The objectives of the present study were to investigate the influence of yearling weight on the occurrence of early pregnancy and to determine differences between precocious and non-precocious heifers in terms of pre- and postnatal calf mortality, calf weight and height, mature cow weight, and stayability of the cow in the herd. Data from 26 977 females of a Nelore herd that participated in the breeding season between 1986 and 2004 were analyzed. The influence of yearling weight on sexual precocity and differences between precocious and non-precocious heifers in pre- and postnatal calf mortality and stayability were analyzed using the GENMOD procedure of the SAS program. Differences in the growth traits between precocious and non-precocious animals were estimated by contrast analysis. Three groups were analyzed for postnatal mortality: first calving of the heifers, calves born from the third calving and all offspring of the cow. In order to have a standardized calving to conception period for all females (precocious and non-precocious), calves born from the second calving were not included in the analysis. This was necessary because the first calving to conception period (days open) of precocious heifers was longer than for non-precocious due to farm reproductive management. No differences in postnatal mortality rates, from the third calving, were observed between the two groups of heifers studied. Analysis of all offspring of the dams showed a 9% higher probability of death of calves born to precocious heifers compared with calves born to non-precocious heifers. With respect to stayability, precocious heifers presented 33% greater odds to remain in the herd until 5 and 6 years of age and 28% greater odds to remain in the herd until 7 years when compared with non-precocious heifers. Precocious heifers weaned calves (205 days) significantly heavier than non-precocious ones, 1.410 and 0.797 kg considering the weaning weights of all offspring and of the third calving, respectively. With respect to sexual precocity, the results suggest that the probability of heifers to become pregnant at 16 months of age increases with increasing weight. However, heifers weighing more than 240 kg present practically the same pregnancy probability. Nevertheless, exposure of heifers during the early breeding season is recommended for beef cattle herds raised in tropical regions in view of the numerous benefits demonstrated here.

Nursing piglets are entirely dependent, for their micronutrient provisions, upon in utero, colostrum and milk transfers from the dam. An adequate maternal transfer of micronutrients is all the more important during these periods which, in fact, lasts for approximately half the life cycle (conception to slaughter) of modern pigs. The present study aimed to set up a simple approach to assess the maternal perinatal transfer of vitamins and trace elements in sows. Prenatal transfer (R-u) was estimated as limited, passive or active using the ratio between pre-colostral serum concentrations of a given micronutrient in newborn piglets and corresponding pre-farrowing values in sows. Efficiency of the postnatal transfer (R-c) was estimated from the ratio between serum concentrations of post- and pre-colostral micronutrients in piglets. Data from literature (12 studies) were used for vitamins A, D, E, C, folic acid and B12, whereas vitamins B2, B3, B6 and B8 as well as Zn, Fe, Cu and Se were generated from a trial where blood sera from 20 sows, and their litter were collected during the perinatal period. In sow trial, statistical t tests were used to determine if ratios differed from 1. Prenatal transfer was active and in favour of piglets (R-u > 1, P < 0.03) for Zn and vitamins B6 and B8 (sow trial) as well as for vitamins C and B12 (literature data). This transfer was limited (R-u < 1, P < 0.01) for vitamin B2, Fe, Cu and Se (sow trial) and for vitamins A, E, D and folic acid (literature data) whereas it was passive for vitamin B3 (R-u = 1, P > 0.37). After birth, the early postnatal transfer through colostrum was active towards piglets for most micronutrients but vitamins B6 and B8 (R-c < 1, P < 0.01). Globally, the perinatal transfer (combination of R-u and R-c) was favourable to the neonatal piglets for most micronutrients except for vitamins A and D as well as Fe, Cu and Se whereas there is apparently a barrier for prenatal transfer which is not compensated by the colostrum provision to neonatal piglets. Then, post-colostral concentrations of these micronutrients in piglets remain below prenatal levels of their dam. Neonatal strategies of micronutrient provision are known for Fe (intramuscular injection) and Se (sow milk enrichment). Further studies are needed to assess the importance of the unfavourable perinatal transfer for Cu and vitamins A and D for piglet robustness later in life.

Genetic improvement in production efficiency traits can also drive reduction in greenhouse gas emissions. This study used international ‘best-practice’ methodology to quantify the improvements in system-wide CO2 equivalent emissions per unit of genetic progress in the Irish Maternal Replacement (MR) and Terminal (T) beef cattle indexes. Effects of each index trait on system gross emissions (GE) and system emissions intensity (EI) were modelled by estimating effects of trait changes on per-animal feed consumption and associated methane production, per-animal meat production and numbers of animals in the system. Trait responses to index selection were predicted from linear regression of individual bull estimated breeding values for each index trait on their MR or T index value, and the resulting regression coefficients were used to calculate trait-wise responses in GE and EI from index selection. Summed over all trait responses, the MR index was predicted to reduce system GE by 0.810 kg CO2e/breeding cow per year per € index and system EI by 0.009 kg CO2e/kg meat per breeding cow per year per € index. These reductions were mainly driven by improvements in cow survival, reduced mature cow maintenance feed requirements, shorter calving interval and reduced offspring mortality. The T index was predicted to reduce system EI by 0.021 kg CO2e/kg meat per breeding cow per year per € index, driven by increased meat production from improvements in carcass weight, conformation and fat. Implications for incorporating an EI reduction index to the current production indexes and long-term projections for national breeding programs are discussed.

The systematic use of the same genotype in several different environments provides information that can be used to estimate genotype by environment interaction (G ✕ E) variances and parameters. Data from the UK Suffolk Sire Referencing Scheme Ltd were used to investigate a range of sire and dam by environment interactions in lamb weight (at 8 weeks and scanning) and body composition traits (muscle and fat depth). These interactions were calculated in a DFREML mixed model containing direct additive, maternal additive, maternal environmental random variance components and the covariance between direct and maternal additive effects. Sire interactions with year, flock and flock-year and dam effects within and between litters were investigated. The addition of all G ✕ E (co)variance components resulted in an improved fit of the model for all traits. Sire interactions accounted for between 2 and 3% of the phenotypic variance in all traits, usually at the expense of both additive effects. Maternal litter environmental variance components ranged from 10% (fat depth and muscle depth) to 20% (8-week weight) of phenotypic variance. Most of this variation was found in the residual component of variance when the term was omitted from the model. When fitting sire G✕ E components in a model the covariance between direct and maternal additive genetic effects, as a proportion of phenotypic variance, was reduced to a low level (from –0·36 to –0·08 for 8-week weight). Genotype by environment interactions form a significant source of variation in lamb growth and composition traits and reduce the high negative correlation between additive effects found previously in these traits.

The efficacy of an enzyme preparation added to barley and rye-based diets given to broiler chickens and containing both β-glucanase and arabinoxylanase activities, was investigated and compared with a well characterized commercial enzyme preparation containing predominantly P-glucanase activity.

Both enzyme preparations significantly improved body weight, cumulative food intake and food conversion efficiency for chickens given both barley- and rye-based diets. For the barley-fed chickens, on average a notable increase in body weight of 171 g at day 13 and 477 g at day 24 was noted, for both enzyme preparations. However, the preparation containing high amounts of both β-glucanase and arabinoxylanase activities was more effective in reducing the incidence of sticky droppings for rye-fed chickens, and, in comparison with previously published data, gave an optimal response at a lower supplementation rate. The results indicate that it is possible to reduce the protein content in enzyme-supplemented broiler chicken diets.