Factors affecting piglets stillbirth in Large White sows

Abstract

This study considers signs of a sow that affect the stillborn piglets number in the nest and the likelihood of stillbirth. The animals that were used for this study were kept on the pig farm of «Tavriys’ki svyni» LLC, located in the Skadovsky district (Kherson region, Ukraine). The experimental materials used for this study consisted of 100 animals from productive parent sows of the Large White pig. The reproductive indicators of each animal included in this study were evaluated. The total number of piglets at birth (both live and dead), i.e. total litter size and and sow farrowing number were monitored for the first eight farrows during the period of eleven years (2007–2017). Stillborn piglets were observed in 63.3 ± 1.7% of litter, and their average proportion in the nest was 11.5 ± 0.4%. The proportion of piglets born dead of the total piglets at birth obtained in this study is within the range of 5 to 15%, which has been previously noted for commercial pig farms in other countries. With an increase in the age of the sow (the number of farrowing’s), there was a gradual decrease in the proportion of the litter in which no stillborn piglet was observed (χ2 = 51.35; P < 0.001), and, conversely, the proportion of nests in which 2–4 stillborn piglets were recorded gradually increased (χ2 = 46.32; P < 0.001). The number of stillborn piglets and the frequency of stillborn piglets in the litter tended to increase in sows that had a large litter size at birth (in both cases: P < 0.001).The binary logistic regression analyses indicated that the probability of a piglet being stillborn was significantly associated with the farrowing number of the sow and the total number of piglets in the litter (χ2 = 155.00; P < 0.001). This model predicted well the presence of at least one stillborn piglet per litter (in 86.6% of cases) and more or less adequately predicted its absence (in 42.9%). Our results indicate that there is a significant interaction between the number of farrowing and the total size of the litter when determining the estimate of the proportion of stillborn piglets in the litter. The same predicted estimates can be obtained for a small litter in an older sow, or, conversely, for a large litter in a first-farrowing sow.

Keywords

• stillborn piglets
• frequency of stillborn piglets
• litter size
• farrowing number
• binary logistic regression model