An index or criterion for predicting  the  future reproductive performance of yearling ewes could be most useful  in  developing a more efficient sheep industry. It has long been assumed  that  there  is an  important  relationship  between ovulation rate and lamb production, but the repeatability of ovulation rate within a breeding season  and  between breeding seasons  is unknown.

Until recently, surgical procedures have been time-consuming and have discouraged the study of  these relationships.  However, use of the laparotomy cradle as developed by Lamond (1963) and use of local  anesthesia have made practical the examination of reproductive organs in large numbers of live animals.

The objective of this study was to determine the relationship between two ovulation rates measured at a 35-day interval during the peak of the breeding season and the relationship between the mean of these ovulations and  previous lifetime lamb production. The relationship between the number of corpora lutea (CL) at the first and second observation periods to the number of embryos resulting from matings at the second observation period was also studied.