Sperm competition greatly decreases the time interval when breeder hens are artificially inseminated by different cockerels

When hens are inseminated by different types of roosters, natural elimination of the influence of insemination by a previous rooster may require some time, reducing the breeding activity of the hens. Two separate experiments were conducted to determine the effects of sperm competition between 2 breeder males on reducing the time interval which eliminated the influence of previous artificial insemination (AI). At the conclusion of the experiments, sperm retained their activity even after 20 d in a noncompetitive situation. When females were artificially inseminated by different types of roosters, if the time interval between AI was less than 12 d, 14 d were required to eliminate the influence of the previous AI in the sperm competition even if the females were repeatedly inseminated by the second type of breeder males. However, if the duration between AI was more than 12 d, AI once by a different type of breeder males was sufficient to prevent the spermatization of the previous male. In summary, the current study suggests that maintaining a time interval of 12 d between inseminations and repeatedly inseminating females by a different type of breeder male every 4 d allowed the elimination of the influence of the previous AI within 14 d. This duration was 7 d less than that required for the natural elimination of the influence of the previous AI, and such a situation could be easily manipulated.