Title: Effect of Semen Treatments and Age of Tom on Fertility of Unstored Semen and Semen Held 18 Hours
Abstract: 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 × holding time × age of tom.