Cattle Transferrins and Their Relation to Fertility and Milk Production1

Abstract

Transferrin types of 473 Holstein-Friesian cattle of two herds were determined. The observed and expected distribution of transferrin types closely agreed in one herd, whereas in the other there was a nonsignificant excess of heterozygotes. Normal segregation ratios were observed among offspring from 212 matings, except for a nearly significant excess of A/A offspring from matings of one A/A bull to A/D dams. We do not know the explanation for this discrepancy. Analysis of first lactation production records of 215 cows did not show an association between transferrins and either milk yield or percent butterfat. However, there was a definite tendency for Tf^D/Tf^D cows to have a slightly higher average milk yield than cows of the other genotypes. The results of 686 inseminations were randomly distributed among matings involving the various transferrin groups, suggesting that the transferrin locus does not affect fertility.