Use of phenotypic traits to predict cocks fertility: 1- the secondary sexual traits and the skeletal conformation [electronic resouce].

Includes references.

Genetic selection procedures applied to improve breeder performance may modify phenotypic traits which depress male fertility. Identification of traits that reliably indicate individual male fertility would facilitate selection for reproduction. It is hypothesized that male fertility might correlate with comb and wattle measurements, skeletal conformation, and degree of fluctuating asymmetry (FA) of bilateral traits. A total of thirty six Bandarah strain cockerels were classified into two groups according to the secondary sexual traits. Males with large comb and wattle (GL), and males with small comb and wattle (GS). Eighteen males per group, individually housed with 10 females per male, fertility was evaluated at five periods of cock's age (31-34 wk), (35-38 wk), (39-42wk), (43-46 wk), and (47-50wk). At 50 wk, comb area, length and width (CA, CL, CW), wattle area, length and width (WA, WL, WW), keel length (KL), posterior pelvic width and length (PPW, PPL), dorsal pelvic width and length (DPW, DPL), and tarsometatarsal length and width (TL, TW) were measured. Results of the overall means showed that GL males revealed a higher fertility (p < 0.01) than GS, however, the differences were significant (P<0.05) only at the 4th and 5th periods. GL males had a larger (P<0.01) comb and wattle measurements compared to GS males, also, there was a significant, strong positive correlation between comb area and fertility. Although no significant differences in skeletal structure were found, there was a significant positive correlation between fertility and TW within either groups. Further analysis revealed that within GS, males with greater WW FA and DPW FA tended to have lower fertility (P<0.05). This research provide evidence that phenotypic traits is a useful indicator to predict males fertility in Bandarah local strain.

Summary in Arabic.

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