A status quo Survey on Artificial Insemination among Chickens and a Proposed Plan for Improvement of Fertility Rate

Abstract

A survey was conducted on a breeding poultry farm in Saitama Prefecture to find out any cause for the marked decrease in fertility rate there which had begun to be noticed about 3 months after the adoption of an artificial insemination program. As a result, it indicated that there were a number of breeding cocks there which produced spermatozoa with lowered activity.
Then the fertility rate was compared between two groups of cocks on that farm. One group had consisted of cocks producing spermatozoa with relatively high activity and the other group of those with low activity. The fertility rate of the first group was significantly higher than that of the second group, although it was much lower than about 85 per cent, or the rate generally regarded as standard one. An increase in amount of the semen injected was of no use for improvement of the fertility rate.
A slight modification of the conventional method for semen injection resulted in a conspicuous increase in fertility rate. It brought about a more remarkable effect than the injection of semen containing spermatozoa with better activity by the conventional method. It gave rise, however, to an increase in number of eggs in which embryos exhibited interrupted development and of dead-in-shell chicks. Accordingly, it was impossible to disregard the degree of activity of the spermatozoa to be injected.