Effect of semen treatments and age of tom on fertility of unstored semen and semen held 18 hours.

Three experiments were conducted to determine the effects of semen dilution, semen extender, and age of tom on the fertility of unstored semen and semen stored for 18 h at 5 C. In Experiment 1, semen was diluted 2:1, 1:1, and 1:2 with Beltsville poultry semen extender (BPSE) #2. In Experiment 2, semen was diluted 1:1 with either Lake's extender, BPSE #2, or BPSE #1. In Experiment 3, the fertility of semen from males 30 to 45-wk-old (first reproductive cycle) was compared to semen from males 51 to 66-wk-old (second reproductive cycle). Identical experiments were conducted in the fall-winter (F-W) and in the spring-summer (S-S). All hens were inseminated with 250 million spermatozoa per dose three times prior to egg production, then weekly for 15 wk. Egg fertility was determined after 7 days of incubation. In all experiments there was a significant interaction between holding time and treatment (semen dilution ratio, semen extender, or age of tom). Fertility of stored semen diluted 1:2 in Experiment 1 was lower than stored semen diluted 2:1 or 1:1 regardless of time of year (season) the experiment was conducted. Fertility was affected by a significant interaction between season and semen dilution ratio. Fertility of semen from males in F-W was higher than semen from males in S-S (Experiment 1). Semen fertility was unaffected by season when comparisons were made between semen extenders (Experiment 2) or age of tom (Experiment 3). Fertility was affected by a significant interaction between season x holding time x age of tom.