Breeding robust pigs

Past developments in livestock breeding have led to considerable genetic change in production traits, but the follow-up of nutrition and management is often incomplete. The pig production sector is moving to hotter climates, and to more intensive and limiting conditions. This increases demands for animal robustness. Robustness can be implemented as a breeding objective trait just like production traits. Breeding for robustness is feasible, but requires substantial investment in data and technology. As for all low-heritability traits with complicated data recording, DNA markers provide a useful tool to support selection; this requires good association studies and ongoing multiple marker development. Breeding for increased robustness must be implemented in balance with breeding for increased production. It is therefore useful to define robustness in terms of performance-relevant issues. A convenient approach is through the environmental sensitivity of the expression of genetic production potential. Environmental sensitivity illustrates loss of flexibility to deal with intensive or limiting conditions, due to unbalanced resource allocation. It can be quantified for individual animals in terms of reaction norm parameters, which can be used as estimated breeding values to support selection. The challenges of implementing such a system will be (i) the set-up of proper data collection in a wide range of environmental settings; (ii) the development of proper data processing tools; (iii) the design of suitable breeding objectives and selection criteria, including MAS; and (iv) the successful integration of the first 3 objectives.