Determination of male fertility in thirteen commercial lines of broiler parents.

Male reproductive capacity evaluated as percent fertility, hatchability, and duration of fertility was assessed for cockerels of 13 commercial broiler lines at 39 and 59 weeks of age using White Leghorn females. For each age the eggs were collected for 21 days following a second insemination of females with .05 ml of undiluted semen. With the exception of duration of fertility the differences among strains were not significant, suggesting that the differences among males within a strain were greater than those among strains for fertility and hatchability. The average percent fertility for a 4-day and 7-day postinsemination interval was 92.1% and 89.9% for Age I and 87.7% and 84.3% for the respective fertilities for Age II. The differences due to age were not significant. However, age had a significant effect on hatchability of settable eggs during 4 days (85.5% vs. 78.2%) and 7 days (83.2% vs. 74.9%) following artificial insemination (AI). The percentage of hatched chicks decreased progressively after day 7 following AI due to the greater incidence of infertile eggs and gradual increase in early embryonic mortality. The duration of fertility among broiler lines ranged between 9.7 to 13.9 days. The significant interaction between strain and age for duration of fertility reflected the changes in ranking among various broiler strains.