Fertilization rate and embryonic survival in dairy cows in relation to transferrin and J antigen groupings of sires and dams.

Biochemical polymorphism has been widely discussed in connection with the function of many body systems (for review see Ogden, 1961). One expression of biochemical polymorphism which has been related to reproductive efficiency in cattle is the variation in serum transferrin type. Ashton (1959) considered that embryos differing in /?-globulin (transferrin) type from their dams were less compatible with their dams than those with the same type as their dams, and were therefore less likely to survive. Ashton & Fallón (1962) modified this theory in a report on data from five cow populations in Britain and Australia. It appeared that breeding efficiency was highest when mating took place between unlike homozygotes and was reduced progressively with mating between like homozygotes, homozygotes crossed with hétérozygotes and lowest with hétérozygotes crossed with hétérozygotes. They also considered that there was a different effect on fertilization and embryonic death in that matings between like homozygotes were considered more fertile than matings between unlike homozygotes while heterozygous embryos were considered more viable than homozygous ones. These hypotheses were based on field fertility data and blood grouping for bulls and cows. Gahne (1967) has summarized the results of these and other workers in a recent study of the influence of transferrin variation