The behavioral responses in ovariectomized cattle to either estradiol,testosterone, androstenedione,or dihydrotestosterone

Steroid hormone effects on sexual behavior were measured in 15 sexually mature nulliparous cattle which were bilaterally ovariectomized. They were alloted at random to five groups of three animals each (sesame oil vehicle control, estradiol, testosterone, androstenedione, and dihydrotestosterone) in the fall of the year and reassigned at random to replicate the study the following spring. Each experiment was divided into three weekly trials. Animals within treated groups were reassigned each week to receive in random order one of three levels of a particular hormone (200, 400, and 800 μg of estradiol and up to 1000 times these doses of androgens).Estradiol, and to a lesser extent, testosterone were capable of increasing the frequencies of occurrence of most behavioral parameters studied. These were: (1) elicitation of vulval interest; (2) vulval sniffing; (3) agonistic interactions; (4) giving chin rests; (5) receiving chin rests; (6) attempted mounts; (7) successful mounts; and (8) standing when mounted. The mean interval from treatment to first standing to be mounted was 25.4 ± 0.8 and 33.3 ± 5.2 hr for the estradiol-treated and testosterone-treated heifers, respectively. Peak activity generally occurred the second day after initiation of hormone treatment and rapidly declined after the third day. Flehmen lip curl and bellowing were not stimulated by either hormone. Neither androstenedione nor dihydrotestosterone was capable of stimulating sexual behavior in these heifers, as measured by any of the parameters studied.