Sire line of pigs affects weaning weight, growth performance, and carcass characteristics of offspring.

Today, early weaning is more frequently applied by the modern pig breeder to obtain more litters per year. In addition, more and more European pig breeders apply a batch management system, which allows weaning to occur at fixed time points but entails that the offspring are treated at the litter level and not as individuals. Both evolutions might result in weaning lightweight piglets, which can cause, e.g., growth retardation of the offspring. Hence, the objective of this research was to improve the weaning weight of piglets of the same age by breeding with a highly conformed sire line. Therefore, a total of 23 sows were inseminated, 10 sows with semen of a well-conformed sire line (sire line B) and 13 sows with semen of a less conformed boar (sire line A). In total, 299 offspring were observed to monitor behavior, growth performance, and carcass characteristics. Subsequently, linear mixed models were developed to analyze the growth performance and carcass characteristics wherein only variables classified as significant ( < 0.05) were introduced as fixed factors. Results indicate that no significantly increased weaning weight could be accomplished by breeding with semen of sire line B. This could be due to the significant ( < 0.05) shorter gestation length of sows inseminated with semen of sire line B. However, the offspring of sire line B was defined by better carcass classification characteristics. Furthermore, this study presents that the mean birth weight of each piglet was significantly lower if a bigger litter size was recorded. When considering behavior, it was observed that piglets that did not seclude themselves from the litter had a significantly greater daily weight gain from birth to weaning compared to piglets that showed signs of isolation from the litter. A significantly greater daily gain from birth to slaughter was established for piglets with a greater birth weight. Also, results indicate that barrows had a significantly greater daily growth from weaning to slaughter than gilts. To conclude, this research determines that breeding with highly conformed sire lines does not improve the weaning weight of the offspring and thus cannot serve as a solution for early weaning. However, more research is required by performing more experiments with a greater number of boars and sows to confirm this result. In general, this study allows researchers to continue to improve and standardize the weaning weight of piglets of the same age.