Fewer piglet deaths during gestation and improved sow welfare. That is what researchers from Animal Breeding and Genomics of Wageningen University & Research (WUR) and Topigs Norsvin want to achieve. They identified the genes associated with stillbirth among pigs and published their findings in the BMC genomics journal. These findings will lead to more live-born piglets by avoiding matings between two carriers.
Reducing the number of stillborn piglets is one of the major goals in the pig breeding industry, as pig farmers benefit from successful farrowing. Moreover, prevention of stillbirth will contribute to the improvement of overall animal welfare.
Lethal genetic variation
To prevent or reduce the number of stillborn piglets, lethal genetic variation has to be identified first. This is the existence of mutations in DNA which cause death in embryos and foetuses that carry two copies of the mutation, one from each parent. When two carriers mate, a quarter of the litter is expected to die early. Lethal genetic variation is present in every population, but often difficult to identify due to its relative rarity and it can only be measured indirectly, via reduced fertility of the parent animals.
In this study, the researchers aimed to identify regions in pig DNA related to stillbirth. They used a method that scans all of the animals’ DNA for regions containing lethal variation, supported by a reduced number of live-born piglets for carrier animals. Three purebred pig breeds were examined and possible lethal variation was found in each of them. For one particular variant strong evidence was found that matings between two carriers cause stillborns.
The results from this study confirm the existence of lethal genetic variation in breeding pigs. Fortunately, all of the lethal variation found is breed specific and not expected to affect crossbred production animals. But more importantly, this study will help to avoid risk-matings between purebred pigs and consequently has a positive impact on their well-being and on animal welfare in general.