Exploring the Influence of Maternal Breeding Values on Sow Behaviour and Production Parameters in a Crated and Free Farrowing System

Poor maternal care of sows reduces piglet growth and survival, and comes at a high cost for producers. Therefore, management interventions have led to crating the sow during the peri-partum period and lactation. As a result, this management strategy clearly reduces pre-weaning mortality, but it also obscures the expression of maternal care. Since there is growing societal pressure to abolish these restrictive housing systems and give the sows more behavioral freedom, the quality of maternal care becomes increasingly important. The breeding company Topigs Norsvin uses an Estimated Breeding Value for Mothering Ability (EBV_MAB), for sows housed under restrictive conditions. This EBV_MAB might not reliably predict mothering abilities in free farrowing systems. Therefore, this study aims to validate this estimated breeding value for maternal care for free farrowing conditions. Thus, the interaction between EBV_MAB and housing condition (crated vs. free farrowing) was studied in relation to sow behavior and production parameters. Preliminary results showed that free farrowing sows had higher piglet mortality (12.0%) due to crushing compared to crated sows (1.2%). However, free farrowing sows with a higher EBV_MAB had lower piglet crushing rates compared to sows with a low EBV_MAB (5.9% vs. 16.0%). Additionally, there appear to be behavioral differences between high and low crushing sows. For example, high crushing sows seemed to show more sternal lying pre- and post-parturition compared to low crushing sows. Through this approach we gain a deeper insight in the phenotypic and genetic variation that is needed to improve EBVs for free farrowing conditions.