Studies on transferrins of blood serum as selection criteria for animals in breeding herds.

In three species of breeding animals: cattle, sheep and pigs the relationship between the polymorphic differentiation of blood serum transferrins and the most important utility traits have been observed. The investigation included 3343 cows of black-white and 1925 cows of red-white breeds, 657 Polish Merino sheep and 636 Polish Landrace pigs. Significant connections have been found for red-white cattle and sheep. In cattle they referred to: weight at birth, daily gain of weight, milk and fat yield during 305-day lactation, which resulted from the favorable influence of alleles TfA and TfE. In sheep the polymorphism of transferrins affected the weight at birth of lambs, and the most favorable configuration of alleles was genotype TfD/TfE. In pigs and black-white cattle no connections between the polymorphic differentiation of transferrins and utility traits have been found.