Occurrence of Estrus in Sows Following Parturition

Abstract

The occurrence and fertility of estrus during a 21-day period following parturition were studied in an experiment on 29 sows in which one group suckled their pigs for two days and were allowed to eat the afterbirth, and another group had their pigs removed at birth and were not allowed to eat the afterbirth. None of the post-partum heats (all occurring between the first and third day after farrowing) expressed by 17 sows were fertile—probably none of the sows ovulated. Twenty-two exhibited heat between day-8 and -16 and 21 ovulated with a fertilization rate on 197 eggs of 92.5 percent. The data suggest that neither suckling nor the post-partum heat had an over-all effect on the number of corpora lutea produced at the latter heats. However, six sows that neither suckled nor had post-partum heats had either inactive or cystic ovaries with few or no corpora lutea in five cases. Copyright © . .