ABSTRACT
Reproductive performance was measured on Peliguey sheep managed primarily under pasture conditions near Aldama, Tamaulipas, Mexico, during 1974 and 1975. The study involved 40 ewes, 2 mature rams, and lambs born during the experimental period. The rams were kept with the ewes continuously. Constants related to reproductive performance were obtained from a study of ovulation phenomena in postpartum ewes. Laparotomies were performed, and the data from laparotomized ewes were recorded separately from those of intact ewes. Mean daily milk production was significantly higher for ewes nursing twins than for ewes nursing singles. Laparotomized ewes had longer lambing intervals, with longer anestrus after first lambings as compared to later lambings. Single lambs were heavier than twins for both sexes. Single males were heavier than single females and the combined weight of single and twin males was heavier than combined weight of single and twin females.
