Skip to main content
ARS Home » Research » Publications at this Location » Publication #119562
Title: PHENOTYPIC TRAITS AS RELIABLE INDICATORS OF FERTILITY IN MALE BROILER BREEDERS

Author
item MCGARY, S - UNIVERSITY OF MARYLAND
item ESTEVEZ, I - UNIVERSITY OF MARYLAND
item Bakst, Murray
item POLLOCK, D - PURDUE FARMS

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/29/2001
Publication Date: 12/31/2001
Citation: Mcgary, S., Estevez, I., Bakst, M.R., Pollock, D.L. Phenotypic traits as reliable indicators of fertility in male broiler breeders. Poultry Science. 81:102-111, 2002.

Interpretive Summary: Selective breeding for increasingly heavier meat-type broiler chickens has resulted in lowered reproductive efficiency. Using two commercial strains, we searched for behavioral and physical traits in male broiler breeders that were positively correlated with male fertility. After determining individual male fertility in each strain we measured comb area and testes weights. Strain differences were observed in fertility and physical traits. It was concluded that comb size can be positively correlated with male fertility in one line but not the other line of broilers examined. This information will be used as the basis for further research in establishing measureable physical traits which can be correlated with male fertility. The broiler industry will also benefit by having new selection criteria to select breeder males of high reproductive potential.

Technical Abstract: The genetic selection procedures applied to improve broiler performance can have a negative impact on the subsequent reproductive efficiency of breeders, particularly males. Identification of traits that reliably indicate individual male fertility would facilitate selection for reproduction. We hypothesized that physical traits (comb area, relative testicular weight, and testicular weight asymmetry) may correlate with fertility in two male-selected primary broiler breeder strains (A and B). Thirty males per strain, individually housed with an average of 10 females, were evaluated at 5 age periods within the 30 to 50-week breeding cycle. Candling fertility at day 19 of incubation and true fertility by visual assessment of the germinal disc were determined. Sperm penetration (SP) through the perivitelline layer was assessed. Comb area was evaluated by image analysis at 40 and 50 weeks, relative testicular weight was measured at 50 weeks. Strain A true and candling fertility (P < 0.001) and SP values (P < 0.0001) were significantly lower than Strain B. Both strains show significant decline of fertility and SP with age (P < 0.0001). Strain A comb area correlated with true fertility (P < 0.05), candling fertility (P < 0.05), and relative testicular weight (P < 0.01). Conversely, Strain B relative testicular weight correlated with true fertility (P < 0.0001) and candling fertility (P < 0.001). Correlations were not found between testicular weight asymmetry and other reproductive traits. Results suggest comb area may reliably indicate male fertility in Strain A.