Risk Factors Affecting the Drop of Litter Size at Second Parity in Sows in La Piedad Michoacan, Mexico

Abstract

A problem attributed to first parity sows is the second litter syndrome (the number of piglets of the second litter is lower or similar to the first litter). The objectives of this study were to estimate the frequency of sows showing the second litter syndrome and to determine the effect of some risk factors on the drop of the litter size of second parity sows in a commercial farm in La Piedad Michoacan, Mexico. Data on 6809 sows were used. The data were analyzed by a binomial logistic regression model. The model included the fixed effect of year and season of farrowing, breed group, weaning to service interval and pigs born alive at first parity. 48.1% of the sows showed the syndrome. Year of farrowing, weaning to service interval and pigs born alive had effect (P<0.05) on the second-litter syndrome. Sows with more than 17 days weaning to service interval had lower odds, and sows with large litters born alive at first parity had higher odds of a drop in litter size at second parity. Therefore, greater attention should be given to first parity sows with large litters at first parity.

Keywords

• breed
• litter size
• parity
• pigs
• risk factors