Sperm-egg penetration in laying breeder flocks: a technique for the prediction of fertility.

1. An experiment was conducted to evaluate indices of fertility including the sperm penetration (SP) assay as a technique for the prediction of fertility. Forty-eight males consisting of White Leghorn (WL), New Hampshire (NH), Iraqi Brown (IBr) and Iraqi Barred (IBa) (12 males each) and 64 WL hens were divided at random into 4 groups of 4 replicates of 3 males and 4 females each. 2. At the beginning of each week semen was collected from males and pooled by breed of male. Hens in each breeding group were inseminated once weekly, by breeding group, for 4 consecutive weeks with pooled semen from WL, NH, IBr and IBa males (WLxWL, NHxWL, IBrxWL and IBaxWL). 3. The differences in percentage of dead sperm, acrosomal abnormalities, mass motility, individual motility and spermatocrit between the experimental breeds demonstrated the superiority of WL and NH males in all these quantitative characters of the semen. On the other hand, WL hens inseminated with spermatozoa from NH males had significantly more sperm-egg penetration (SP) holes than WL hens inseminated with spermatozoa from other breeds of males. The breed of males used for insemination affected fertility, hatchability and embryonic mortality. 4. The highest fertility and hatchability and lowest embryonic mortality were observed in eggs laid by hens inseminated with spermatozoa from WL and NH males in comparison with hens inseminated with spermatozoa from Iraqi males. 5. There was a strong positive correlation between SP values and fertility for WLxWL, NHxWL, IBrxWL and IBaxWL. The correlation for all breeds combined was also significant. In addition, SP was also positively correlated with hatchability and negatively correlated with embryonic mortality.