Testicular weights, ductus deferens semen volumes, and sperm concentration of turkeys with high and low ejaculate volumes.

Studies were conducted to determine if high and low ejaculate volumes were associated with differences in testicular weight and ductus (d.) deferens semen volumes. Mature male breeder turkeys were classified as low (less than or equal to .22 ml) or high (greater than .30 ml) semen producers. One week after or immediately after the last semen collection the turkeys were killed, testes weighed, and d. deferens and ejaculate semen volumes and sperm concentrations determined. Comparisons of low (LSP) and high (HSP) semen producers showed no differences in testes weights and sperm concentration in d. deferens. However, LSP turkeys had a lower volume of semen in the d. deferens and ejaculated a lower percentage of that volume than did HSP turkeys (P less than .05). Although the sperm concentrations of HSP and LSP were the same, the total number of sperm in the ejaculate of LSP was less than the HSP and was also less when calculated as a percentage of the sperm in the ejaculate plus d. deferens. These studies indicate that both a decreased reservoir of semen in the d. deferens and a lower efficiency of removal of semen from the d. deferens contribute to the decreased ejaculate volume of LSP.