Roles of predisposing factors and gonadal hormones in the buller syndrome of feedlot steers.
In a study of the role of predisposing factors and gonadal hormones in the buller syndrome, it was found that weather, amount of space available to each steer, and entry weights of the steers were not associated with increased occurrence of bulling; however, the type and timing of administration of the hormonal implant, the number of steers in a pen, and the manner in which the steers were grouped after arrival at the feedlot were found to influence the incidence of the syndrome. Serum concentrations of estradiol and testosterone in the buller steers were found to be lower during bulling than after a short period of isolation and apparent recovery from the syndrome. It was concluded that the occurrence of bulling is related to the use of hormonal implants and certain feedlot management procedures but that it is apparently not related to increased serum estrogen or testosterone concentrations.