BackgroundSows’ ability to produce an excessive amount of piglets has shaped modern piglet production and there has been a steady increase in litter size during the last decades. This development has caused some negative side-effects, such as an increase in the proportion of stillborn piglets, a decrease in the proportion of weaned piglets and a larger variation in quality of piglets. Swedish commercial piglet producing herds have, like other countries with high production levels, high piglet mortality and high annual removal rate of gilts and sow. These problems seem to have increased during the same period that litter sizes have increased. Therefore present study aim to investigate whether there is an association between litter sizes and sow stayability.ResultsThe probability to produce ≥4 litters during a lifetime was significantly lower for sows giving birth to ≤8, 15 and ≥17 piglets in total in their first parity litter compared to sows giving birth to 13 piglets. Except for the group of sows having a small (≤11 piglets born in total) first parity litter size in combination with a medium (12–14 piglets born in total) second parity litter size, all other groups were significantly associated with an impaired ability to stay ≥4 litters compared to sows having a medium both first and second parity litter size. There were differences in removal reason between sows having small, medium or large first parities litter sizes.ConclusionsAssociations between litter sizes in low parities and sow stayability were found. Our results indicate that aiming for keeping sows giving birth to a medium-sized litter, with approximately 12–14 piglets born in total may improve sows stayability and decrease the risk of unplanned removal. This should be considered when planning breeding strategy and annual removal in Swedish commercial piglets producing herds.

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms may be insufficient to achieve legislation compliance, 2) knowledge on risk factors for tail 32 biting and 3) recognition of when routine tail docking was occurring.

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.

No abstract

No abstract