This work aimed to evaluate the effects of sire's and dam's biological type, dam's age class at calving and individual heterozygosis, and to estimate variance components for weaning weight adjusted to 210 days (WW210) in beef cattle of different breed groups. Records of 13 687 animals, obtained from 2000 to 2007, were used. Bulls from the biological types Zebu (N), Adapted (A), British (B), Continental (C) and ¼N|¼A|¼B|¼C were mated with purebred zebu (N) and crossbred females (½C|½N and ½B|½N). Dam age at calving was 3–12 years. The influence of several effects on WW210 was tested using the least square method. Variance component analysis was performed using a Bayesian approach. The model included contemporary group, dam's age class at calving, sire's and dam's biological types as systematic effects, animal's age and individual heterozygosis as linear covariates, and direct and maternal additive genetic, maternal permanent environmental and residual effects as random effects. The progeny of bulls from biological type B and the crossbred cows showed higher WW210 means. Cows at 6–7 years old weaned heavier calves. Direct and maternal heritability estimates for WW210 were 0.5 ± 0.04 and 0.1 ± 0.02, respectively. Calves with 100% individual heterozygosis weighed on average 25.98 kg more at weaning compared to progenies from pure breeds. Sire's and dam's biological types influence the WW210 of the crossed progenies. Crossbred cows produce heavier calves compared to biological type N cows. These results and the obtained direct and maternal heritabilities suggest it is possible to choose the lines of sires and dams that could be used to make the crosses to obtain progenies with better performance for WW210.

The present study examined the possibilities and consequences of selecting pigs for reduced aggression and desirable maternal behaviour. Data were recorded from 798 purebred Large White gilts, with an age of 217±17.7 (mean±SD) days, which were observed at mixing with unfamiliar conspecifics. The reaction of the sows towards separation from their litter was assessed for 2022 litters from 848 Large White sows. Sows’ performance during their time in the farrowing unit was scored based on the traits farrowing behaviour (i.e. need of birth assistance), rearing performance (i.e. litter quality at day 10 postpartum (pp)), usability (i.e. additional labour input during lactation period e.g. for treatments) and udder quality of the sow (i.e. udder attachment). For agonistic behaviour, traits heritabilities of h2=0.11±0.04 to h2=0.28±0.06 were estimated. For the sow’s reaction towards separation from her litter low heritabilities were found (h2=0.03±0.03 for separation test on day 1 pp and h2=0.02±0.03 for separation test on day 10 pp). Heritabilities for lactating sow’s performance (farrowing behaviour, rearing performance, usability of the sow and udder quality) in the farrowing unit ranged from h2=0.03±0.02 to h2=0.19±0.03. Due to these results it can be assumed that selection for these traits, for example, for udder quality or reduced aggression, is possible. Antagonistic associations were found between separation test on day 1 pp and different measures of aggressiveness (rg=−0.22±0.26 aggressive attack and rg=−0.41±0.33 reciprocal fighting). Future studies should determine economic as well as welfare-related values of these traits in order to decide whether selection for these traits will be reasonable.

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.