Associations between litter size and medical treatment of sows during farrowing and lactation

ABSTRACT Sow litter sizes have increased recently, and there is a lack of data on the effect of litter size on sow health and sow medical treatment. This study investigated associations between litter size and medical treatment of sows, using data for a 10-year period from one Swedish research farm. The data comprised 1947 litters from 655 Yorkshire sows. Association between litter size and medical treatment of sows during farrowing and lactation investigated using a multivariable multilevel logistic regression model. We found that odds of medical treatment of sows decreased for each additional piglet born up to five piglets (odds ratio 0.50, p = .002). For litter sizes ≥5, the odds for each additional piglet born (odds ratio 1.11, p < .001). Problems with milk let-down in early lactation were the main reason for treatment. Results imply that sows with very small or very large litters may be less profitable.