Analysis of urinary progesterone metabolites with behavioral correlation in Guenther's dik-dik (Madoqua guentheri)

Urine samples and behavioral data were collected from nine adult female Guenther's dik-dik (Madoqua guentheri) from September 1989-November 1992. The durations of predefined individual behaviors were recorded during focal sampling periods and ad libitum. Immunoreactive pregnanediol-3-glucuronide (PdG) concentration in dik-dik urine was determined by radioimmunoassay. The immunoreactive PdG radioimmunoassay was validated for use with dik-dik by determining parallelism [F(alpha=0.05,1,4) = 0.04) between a serially diluted PdG standard and serially diluted dik-dik urine. Behavioral estrus was manifested by lordosis. Eighty-nine percent of the estrous behavior occurred during or within 2 days of the interluteal phase period, as delineated by immunoreactive PdG concentrations; thus, a high degree of correlation between hormone concentrations and behavioral data was observed. The mean (+/-SD) luteal phase, interluteal phase, and estrous cycle lengths were 14.4+/-5.5 days (range, 6-29 days; n = 50), 6.6+/-5.1 days (range, 2-33 days; n = 50), and 20.2+/-6.6 days (range, 10-43 days; n = 48), respectively. During the collection period, one animal conceived, with a gestation period of 170 days. Estrous cyclicity occurred throughout the year, with no evidence of seasonality. Cochromatography of pooled urine samples with radiolabeled PdG indicated that the major progesterone metabolite detected by the immunoreactive PdG antibody during luteal phase and pregnancy was not PdG. This is the first detailed description of female dik-dik reproductive endocrine activity.