Abstract
The copulation rate and the average number of normal embryos were examined after superovulatory treatment with 5iu PMSG and 5iu hCG given 48h apart in the adult femeals of 23 inbred and 3 mutant strains. Singnificant strain differences were observed in the copulation rate (15.8-84.2%) as well as in the rate of normal embryos among those recoverd (10.1-79.7%). Average number of normal embryos at the 8-16 cell stage, recoverd on Day 2 of pregnancy. varied from 3.5 to 31.3 among the strains.
