Paternity efficiency in turkeys differs extensively after heterospermic insemination

All commercial turkey hens in the U.S. are bred by artificial insemination (AI). Since semen samples are pooled from 10 or more males (heterospermic i nseminations), paternity of the progeny is rarely known. Whereas it is know n that sperm competition exists, the degree to which any male's sperm ferti lizes ova relative to other male's remains unknown. In this work, we determ ined individual male fecundity relative to that of other males in the study and attempted to establish a relationship between male fecundity and semen characteristics in turkeys. Fingerprinting of genomic DNA from parents and offspring was used to determine parentage efficiency. This work demonstrat ed that relatively few toms sired a high percentage of the progeny. Of the 26 toms contributing to the pooled ejaculates, six (23%) sired more than 60 % of the 145 poults. Conversely, 14 toms (54%) sired three or fewer poults. We found that the semen parameters evaluated, some of which are used routi nely by the turkey industry, were not good at predicting paternity. Under t he conditions of this study, the majority of the progeny were derived from semen from one or two toms after heterospermic inseminations.