Evaluation of patterns of removal and associations among culling because of lameness and sow productivity traits in swine breeding herds

Objective - To characterize pattens of removal and evaluate the associations among culling because of lameness and sow productivity traits among culled gilts and sows. Design - Cross-sectional study. Sample Population - Data from a convenience sample of 11 farms pertaining to the removal of 51,795 gilts and sows from January 1991 to December 2002. Mean culling and mortality (death and euthanasia) rates for all inventoried gilts and sows ranged from 23% to 50% and 4.7% to 9.5%, respectively. Procedure - An analysis of categories of removal (cull, death, or euthanasia) and reasons for removal of gilts and sows was performed. Multivariate logistic regression was used to determine associations among culling because of lameness and sow productivity traits among culled gilts and sows. Results - Among sows that were removed, the proportion of parity ≥ 1 sows that died (both death and euthanasia) was > 3 times the proportion of parity ≥ 1 sows that were culled within 20 days after farrowing. Among lame sows that were removed, the proportion of parity ≥ 1 sows that died (death and euthanasia) was higher than the proportion of parity ≥ 1 sows that were culled within 20 days after farrowing. Among sows that were removed, the proportion of sows that died (deaths and euthanasia) was higher during lactation than nonlactation. This was also observed among lame sows that were removed. Conclusions and Clinical Relevance - The proportion of death among removed sows, especially lame sows, was higher during lactation than nonlactation. Results indicated that risk of death is not the same for sows throughout their lifetime.