Medycyna Wet. 67 (8), 555-559, 2011
Jarczyk A., Milewska W., Drągowski D.
Most important breeding causes of stillborn piglets
The aim of the paper was to define the most important causes leading to the birth of stillborn and mummified piglets. The influence of the following factors was analyzed: the effect of the boar’s and sow’s breed, successive litters, the season of mating, as well as the sex and weight of piglets. 334 litters born in the years 2002-2005 were analyzed. Numerous aspects were examined: the total number of piglets, number of the live births, the number of dead and mummified piglets in the litter, as well as the body weight of the live and dead piglets. The number of stillborn piglets in the litter was on average 0.65. It depended on: the successive litter (p≤0.01), the size of litter (p≤0.01), the breed of sows (p≤0.05) and the boars (p≤0.01). Sows of PL x PLW gave a larger litter size by about 0.6 piglets than other groups of sows. This could be the result of heterosis effect. However, these sows had the largest number of stillborn piglets too. This was also observed in the successive litters (p≤0.05). Body weight of the stillborn piglets – and particularly newborn boars which originated from PL x PLW mothers – was also the largest (P≤0.05), which quite certainly can explain the phenomenon of high number of stillborn piglets by crossed sows. The coefficient of the correlation (r) between the number of stillborn piglets at the moment of birth and the total litter size, together with the body weight of the stillborn piglets amounted respectively: r = 0.297 (P≤ 0.05) as well as the r = -0.579 (P≤0.001). The chief portion of stillborn piglets were noticed among the lightest and heaviest ones. In the first case, the young piglets developed in the remote parts of the uterus horns, where they received less nourishment and oxygen. In the case of the heaviest piglets (>2 kg), mortality could have been the result of a protracted delivery action. Mummified piglets constituted about 33% of all stillborn pigs.
Key words: stillborn and mummified piglets, litter size, piglets body weight, seasons , correlations