Hormonal induction of incubation behavior in ovariectomized female turkeys (Meleagris gallopavo)

Two experiments were conducted to evaluate the effect of estradiol benzoate (EB), progesterone (P), ovine prolactin (oPrl), or their combinations on temporal patterns of serum luteinizing hormone (LH) and Prl and on nesting behavior in adult ovariectomized female turkeys. Levels of serum LH were initially reduced (p greater than 0.05) by the steroid treatments, while continuation of treatments induced surges of LH to levels comparable to pretreatment levels. Administration of steroid increased (p less than 0.05) levels of serum Prl, which persisted until termination of treatments. Administration of oPrl had no effect on levels of serum LH but blunted the steroid-induced release of Prl. Neither EB, P, nor oPrl treatments alone nor a combination of EB + P elicited nest occupation. Nest occupation was observed after administration of P only in turkeys pretreated with EB. Administration of oPrl maintained and advanced the P-induced nesting to persistent nesting behavior (incubation behavior). Once persistent nesting behavior was established, hormonal treatments were terminated, yet nesting behavior was maintained and serum samples showed increasing levels of Prl and decreasing levels of LH. It is suggested that incubation behavior in the female turkey is facilitated by the combined action of estradiol, P, and Prl.