Relationship between Milk Production in Donor Cows and the Yield and Quality of Embryos

The relationship between milk production in donor cows and the yield and quality of embryos and oocytes was examined. No significant differences in the yield of embryos among cows with low (group 1), medium (group 2), and high milk production (Group 3) were found. In group 1, there was the higher number of embryos per one donor. A significantly higher percentage of transferable embryos were recorded in the cows in group 1 with low milk production in comparison with group 3 with high milk yield (P<0.01). A slightly negative correlation (r = -0.35) was recorded, i.e. the number of embryos suitable for transfer decreased in cows with higher milk production. Also, a significant higher frequency of occurrence of degenerated embryos was recorded in the donors in group 3 with high milk production (P<0.01) in comparison with the other two groups, while the number of degenerated embryos increased positively in correlation to donors with higher milk production (r = 0.58). No differences emerged in the percentage of yielded oocytes among the groups.