PLASMA AND FECAL PROGESTAGEN EVALUATIONS DURING AND AFTER THE BREEDING-SEASON OF THE FEMALE VICUNA (VICUNA-VICUNA)

Plasma and fecal progestagen patterns of female (n = 10) vicunas (Vicu na vicuna) were determined about 1 to 2 mo before and until 4 mo after breeding. The vicunas were caught wild and were penned at the Lauca N ational Park (Chile, 4470 m above sea level) for 7 mo (December to Jun e). Plasma and fecal samples before and during the mating period (Janu ary to March) were collected 4 to 5 times weekly, and once or twice we ekly thereafter. The samples were analyzed by enzymeimmunoassays (EIA) using antibodies against progesterone and 20 alpha-dihydroprogesteron e. High performance liquid chromatography (HPLC) separations confirmed that progesterone and 20 alpha-dihydroprogesterone predominated in th e plasma, whereas in the feces several unconjugated, immunoreactive pr ogestagen metabolites containing either a 20-oxo- or a 20 alpha-OH-gro up occurred. The coefficients of correlation (n = 409; P < 0.01) betwe en matched plasma and fecal samples were 0.39 and 0.53 for 20-oxo- and 20 alpha-progestagens, respectively. Elevated (5 to 6 d) plasma and c orresponding fecal progestagens after mating indicated cyclic corpus l uteum activity in 5 of the animals. After the mating period (23.2 +/- 3.3 d), corpus luteum function in these 5 animals persisted, as it did in 3 other animals that were not observed to be mating. The persistin g corpus luteum function was demonstrated by increased mean plasma and fecal progestagen concentrations (>1 ng/ml and >100 ng/g, respectivel y). Mean plasma 20 alpha-dihydroprogesterone concentrations exceeded t hat of progesterone by about 1 ng/ml (P < 0.01). The results demonstra ted that in addition to plasma progesterone, plasma 20 alpha-dihydropr ogesterone and noninvasive fecal progestagen evaluations are useful, v alid tools for determining corpus luteum function in vicunas.