NON-INVASIVE MONITORING OF OVARIAN-FUNCTION IN SEVERAL FELID SPECIES BY MEASUREMENT OF FECAL ESTRADIOL-17-BETA AND PROGESTINS

An extraction and assay procedure to measure fecal estradiol-17 beta a nd progestin concentrations in several cat species was developed and v alidated for use for noninvasive monitoring of ovarian function. Fecal samples were collected over a range of 3-20 months from female tigers (three), lions (three), snow leopards (three), cheetahs (two), caraca ls (two), and domestic cats (five). Samples were extracted with 90% me thanol, lipids removed with petroleum ether, and the estradiol and pro gestins in the methanol measured by radioimmunoassay (RIA). High Perfo rmance Liquid Chromatography (HPLC) fractionation and subsequent RIA o f the fractions indicated that the estradiol-17 beta antiserum cross-r eacted primarily with estradiol-17 beta in the feces of lions and tige rs and was assumed to be specific for estradiol-17 beta in the feces o f other species as well. However, there were several immunoreactive co mpounds, presumably progesterone metabolites, excreted in the feces wh ich varied both quantitatively and qualitatively among species. The be havior of tigers, lions, cheetahs, and caracals was visually monitored during the collection period and frequency of sexual behaviors was po sitively correlated with increases in fecal estradiol in all species o bserved. The mean fecal estradiol-17 beta peaks were as follows: tiger s, 128.0 +/- 13.1; lions, 186.0 +/- 14.8; snow leopards, 136.7 +/- 15. 9; cheetahs, 140.9 +/- 9.0; caracals, 24.5 +/- 4.0; and domestic cats 158.9 +/- 19.3 ng/gm. Fecal progestin concentrations rose significantl y (P < 0.001) only after breeding or during pregnancy and were as foll ows: tigers, 5.6 +/- 0.6; lions, 1.9 +/- 0.1; cheetahs, 8.4 +/- 1.1; a nd caracals, 2.4 +/- 0.4 mu g/gm. Fecal progestins were elevated for o ne-half to two-thirds of the gestation length during presumed pseudopr egnancy but remained elevated throughout successful pregnancies. These results suggest that ovarian function can be monitored noninvasively in the family Felidae by the measurement of fecal estradiol-17 beta an d progestin concentrations (C) 1995 Wiley-Liss, Inc.