Risk factors associated with stillbirth of piglets in Ukrainian Meat breed sows

Stillbirths often result in significant piglet losses shortly before or during the farrowing process. This issue leads to a high level of stillbirths, causing substantial losses in the swine industry and requiring immediate attention. The purpose of this study is to evaluate farrowing order, the total number of piglets born, the year and season of farrowing, the breed of the boar, and the average piglet weight in the litter at birth as risk factors for stillbirths in sows of the Ukrainian Meat breed. Experimental data obtained from 262 sows of the Ukrainian Meat breed in the main herd of LLC “Tavriyski Svyni” (Skadovsk district, Kherson region, Ukraine) were used for the study. The proportion of litters containing at least one stillborn piglet, the number and proportion of stillborn piglets in the litter were investigated over 11 years. At least one stillborn piglet was observed in 56.9% of litters, with an average number and proportion of stillborn piglets in the litter of 1.2 and 10.5%, respectively. The results indicate a highly significant impact of the farrowing year on the proportion of litters containing at least one stillborn piglet, the number, and proportion of stillborn piglets in the litter (in all cases: P<0.001). There was a decrease in estimates of stillbirths during 2007-2013, with a gradual increase until 2017. The farrowing season had a certain (P<0.05) influence on estimates of stillbirth rates, since the proportion of stillbirth piglets in litters born in summer was 9.5%, and in litters born in autumn – 12.0%. The proportion of stillborn piglets in litters sired by Duroc boars (15.0%) was significantly higher (P<0.001) than in litters sired by Ukrainian Meat breed, Large White, or Landrace boars (10.1-10.0%). From the first to the 10th farrowing, stillbirth rates gradually increased (in all cases: P<0.001). The number and proportion of stillborn piglets in the litter tended to increase among sows with larger litter sizes at birth (in both cases: P<0.001). Binary logistic regression results suggested that the probability of having at least one stillborn piglet in the litter was significantly associated with the average live weight of piglets at birth