Vie CONG. INTERN. REPROD. ANIM. INSEM. ARTIF., FARIS, 1968, VOL. II

SEXUAL BEHAVIOR AND PROGESTERONE SECRETION
DURING THE MENSTRUAL CYCLE IN RHESUS AND
PIGTAIL MACAQUES

D.W. BULLOCK, C,A. PARIS, J.A. RESKO and R.W. GOY
Oregon Regional Primate Research Center,
Beaverton, Oregon, U.S.A.

Among the aspects of sexual behavior in monkeys we have studied
(1) has been the incidence of mating during the menstrual cycle and
its relation to the condition of the ovary and the secretion of
progesterone (P4). Conception rate is highest from matings occurring
around mid-cycle (2,3) and mounting of the female by the male is
most frequent at this time (4).

MATERTALS AND METHODS. Female Rhesus monkeys were paired for 10
minutes with each of 5 males on a given day of the menstrual cycle
and sexual behavior was observed. After testing, the female was
subjected to laparotomy when the ovaries were removed for histologi=
cal examination and blood was collected from the ovarian vein. P4
concentration of the blood was determined by gas chromatography.

Eight female Pigtail macaques (M. nemestrina) were studied for
sexual behavior when paired with the same male on alternate days of a
menstrual cycle. Blood samples were collected from a femoral vein
and P4 was determined by a competitive protein-binding method,

Daily measurements of the diameter of the sex skin were taken using
calipers. On a subsequent cycle, serial laparotomy was performed on
5 females for 6 days at about the time of maximum sex skin swelling
and the condition of the ovary was visually examined,

1. RHESUS MACAQUES. The number of males achieving ejaculation on a
given day varied with the stage of the female's menstrual cycle,
reaching a maximum between days 11 and 13. At laparotomy it was
determined that maximum probability of mating occurred when the

(1) Supported by grants NIH FR 00163 and MH 08634,

(2) C.G. HARTMAN, 1932. Contributions to Embryology No., 134,
Carnegie Inst., Washington, pp. 161.

(3) G. van WAGENEN, 1945. Endocrinology 8720 307=3127

(4) R.P. MICHAEL, G.S. SAAYMAN, D, ZUMPE, 1967. Nature 215: 554-556,

1657