Responses to androgen in lines of chickens selected for mating behavior

Two experiments were designed to study the effects of and relationships between caponization and androgen therapy on the mating behavior of lines of chickens that have undergone bidirectional selection for number of completed matings. Males from the high (HM) and low (LM) selected lines and the Athens-Canadiań (AC) randombred control population were randomly assigned to groups. One-half was caponized and the other half was used as intact controls. Groups were administered 0 and 0.9 mg/day of testosterone propionate (TP) in.25 ml cottonseed oil for 14 consecutive days in the first experiment. In the second experiment the equivalent of 14 daily doses of 0, 0.4, 0.8, 1.6, and 3.2 mg/day of testosterone cypionate (TC) in cottonseed oil was injected as a single dose. Mating behavior was measured by placing individuals singly for 10 min into pens of females for 6 days and recording the number of courts, mounts, treads, and completed matings.