A survey of bone integrity from cull sows in Ireland

Changes in modern pig reproduction have led to increased numbers of pigs born throughout a sow's lifetime [16]. Such improvements necessarily increase metabolic demands on the reproducing sow. To date there has been no monitoring of how the sows' skeleton has reacted to these changes in Irish conditions. Furthermore, there is no information on how these changes in productivity have affected bone integrity of breeding sows under Irish conditions despite average culling rates of 11% for locomotory problems [2]. The purpose of this study was:1. To examine differences in physical characteristics of metacarpals among sows of varying parities from commercial farms; and,2. To compare the articular surfaces in the bones of cull sows in different housing systems and to examine any associations with lameness.There are numerous reports in the literature citing lameness as a significant cause of premature culling. However, the reason for lameness and any association with housing type remains unclear. High culling rates due to a potentially painful condition may indicate compromised welfare for the animals involved and warrants further detailed examination.The animals used in this survey were those being routinely culled and sent to the abattoir from the herds for commercial reasons. All of the farms commenced routine removal of breeding sows once their eighth parity was reached unless it was removed prematurely for health or economic reasons. No sow was kept beyond their ninth parity. Ill or severely injured sows were not included in the study as they were not transported to the abattoir but were humanely destroyed on the farm of origin.Four of the farms had an on-farm milling system in place and none of the commercial farms used phytase. Most of the farms fed a wet diet to the breeding sows.Prior to slaughter, sows were observed walking and trotting freely on concrete and lameness scored using the system (0 to 5) of Main et al. [18]. Joint surfaces were grossly examined post m