The effect of tamoxifen on semen fertilization capacity in White Leghorn male chicks.

Tamoxifen (TAM) is an antiestrogen that advances sexual puberty in cockerels, turkey toms, and Muscovy drakes. The effect of TAM on semen-fertilization capacity in White Leghorn (WL) male chicks was assayed in the present study. Sixty, 2-wk-old, male chicks were divided into two equal groups. The chicks from one group were injected im with 1 mg of TAM per kg of BW every other day; those from the second group were vehicle-treated (with corn oil) and served as controls. Each chick was paired with a virgin, WL laying hen. When semen was produced, the paired female was inseminated twice a week. The results revealed that TAM administration caused the early production of fertile semen, which resulted in the first normal descendants as early as 8 wk of age and brought about 100% of parenthood by the age of 88 days.