Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/24/2002
Publication Date: 5/1/2003
Citation: Mcgary, S., Estevez, I., Bakst, M.R. Potential relationships between physical traits and male broiler breeder fertility. Poultry Science. 82:328-37, 2003.
Interpretive Summary: The meat type chicken (broilers) are subjected to internse genetic selection for feed consumption (weight gain) and broad breast conformation. The success in this slection process has resulted in much heavier birds which grow at a faster rate than then did 20 years ago. A consequence of this rapid growth and large size is a lower reproductive efficiency. In this study we looked at the impact of genetic selection on bone measurements and lengths with emphasis on the pelvic region. We observed a significant relationship between increased width of the pelvis and lower fertility. Since there broiler naturally copulate to produce fertilie its, it is assumed that an increased pelvic width decreases the the likelihood of successful sperm transfer at copulation. This is of interest to scientists involved in investigating reproductive efficiency in poultry and in commercial broiler companies interested in maintaining a high rate of reproductive efficiency.
Technical Abstract: Genetic selection in primary broiler breeders may modify skeletal structure possibly impeding semen transfer, and could alter the size and degree of fluctuating asymmetry (FA) of bilateral traits associated with fertility. Hence, we hypothesized specific morphometric traits could predict differential fertility. Sixty primary broiler breeder males from Strains A and B (n=30/strain) were individually housed with an average of 10 females per male. Male fertility and sperm penetration (SP) through the perivitelline layer were estimated on fresh eggs. At 50 wks, body weight (BW), keel length (KL), posterior pelvic width and length (PPW, PPL), dorsal pelvic width and length (DPW, DPL), tarsometatarsal length and width (TL, TW), comb length and width (CL, CW), and wattle length, width, and area (WL, WW, WA) were measured. Results indicated that Strain A had smaller BW (P<0.01), KL, WL, WW, WA, CL, and CW (P<0.001 for all), PPL (P<0.01), DPL (P<0.01), and DPW (P<0.001). A higher degree of FA was found in Strain A TL and WL (P<0.05), yet DPW FA was greater for Strain B (P<0.001). In addition, DPW FA negatively correlated with Strain B fertility (r = -0.369; P<0.01), other FA measurements did not correlate with estimated fertility or SP. Strain A WL correlated with SP (r = 0.383; P<0.01) and fertility (r = 0.346; P<0.01). Results indicate DPW alteration may impact semen transfer upon copulation, as Strain A fertility negatively correlated with DPW (r = -0.298; P<0.05). This research provides evidence that morphometric traits might be useful to predict fertility in broiler breeders.