The influence of acute or repeated immobilization on plasma prolactin levels in the turkey (Meleagris gallopavo).

Three experiments were conducted to evaluate the effect of immobilization on plasma prolactin (PRL) levels in the immature turkey. Acute immobilization for 120 min resulted in elevated PRL levels (P less than 0.05) starting 15 min after the onset of immobilization. Release from immobilization caused PRL levels to return to those of the nonimmobilized controls by 120-180 min following replacement of the turkeys in cages. Repeated immobilization for 3 or 5 consecutive days diminished PRL response (P less than 0.05) to subsequent immobilization. It is suggested that the PRL controlling mechanism(s) of the young turkey is both susceptible and able to habituate to changes induced by immobilization stress.