Relationship of fertility to day of insemination during the laying sequence.

Fertility among hens artificially inseminated (AI) at different stages of the laying sequence were compared in two experiments with broiler breed (Experiment 1) and egg-type hens (Experiment 2). The different stages of the laying sequence were prepause (PP)-oviposition without ovulation, pause (P)-no oviposition with or without ovulation, and nonpause (NP)-oviposition with ovulation. There were no significant differences among PP, P, and NP groups for duration or percent fertility in Experiment 1. Fertility and duration were significantly lower in PP than NP in Experiment 2. However, these differences were most likely caused by 36% of the PP hens ovipositing during the time of AI. Time of AI seems to be a more important factor in determining subsequent fertility than the day of AI during the laying sequence.