Fecal progestagen evaluations to monitor the estrous cycle and pregnancy in the okapi (Okapia johnstoni)

Abstract

The present study was conducted to establish a noninvasive method of reproductive monitoring in the okapi (Okapia johnstmi). Fecal samples were collected three times a week from nonpregnant okapis (n = 3) for periods of 2, 9, and 23 months, respectively, and for 2 months each from pregnant okapis (n = 4) at different stages of gestation. Samples were analyzed with an enzyme-immunoassay (EIA), using an antibody against pregnanediol, and the results are considered as measurements of unconjugated total immunoreactive progestagens (Pd-Pgs). Mean values of Pd-Pgs during the follicular (FP) and the luteal phases (LP) of the estrous cycles were 0.6 * 0.1 Kg/g and 6.1 * 0.3 Kg/g feces, respectively.Matings occurred at the terminations of the LP. By dividing the number of entire LPs into the time over which samples were available, average estrous cycle lengths in two okapis were estimated to be 15.5 (n = 11 LP) and 15.8 (n = 36 LP) days, respectively. In three animals, gestation lengths of 423, 424, and 431 days were calculated by observed matings. During days -280 to -220 before parturition, the fecal Pd-Pgs constantly increased from about 20-60 pg/g feces. Values were 100-350 pg/g during the last third of gestation. Values decreased in the week before parturition, and a continuous decline to FP values was observed within 3-4 days postpartum. During the 2 months postpartum investigated in one animal, the Pd-Pgs were in the FP range except one LP 3 weeks postpartum. It was concluded that fecal Pd-Pgs in female okapis are present in a ratio of -1 : lo:> 100 during FP, LP, and late pregnancy, respectively. Their measurement by EIA enables noninvasive monitoring of the estrous cycle and pregnancy diagnosis.

Excretion Patterns of Fecal Progestagens, Androgen and Estrogens During Pregnancy, Parturition and Postpartum in Okapi (Okapia johnstoni)

“…In okapi, monitoring of the estrous cycle, pregnancy, parturition, and postpartum has been successful using the PdG assay with feces [14][15][16]. However, there are few reports on the use of the P 4 assay in okapi.…”

“…Endocrinological observations on reproductive physiology in female okapi have mainly been reported by the groups of Loskutoff [10][11][12][13] and Schwarzenberger [14][15][16][17]. Both groups have attempted to monitor luteal activity and diagnose pregnancy by assays of hormone metabolites in excreta.…”

“…Both groups have attempted to monitor luteal activity and diagnose pregnancy by assays of hormone metabolites in excreta. The estrous cycle of the okapi was determined to be approximately 15 days based on changes in the concentrations of pregnanediol glucuronide (PdG) in urine [11,13] and feces [14]. Urinary levels of estrogens have been reported to increase sharply 1-2 days after complete luteal regression [12].…”

“…Since mating occurs during pregnancy in some cases [1], routine hormone monitoring is more useful for determining the time of conception. Urinary PdG and 20α-dihydroprogesterone [11] and fecal PdG [14][15][16] have been reported to be excreted in significantly higher levels in pregnant versus non-fertile okapi. Thus, assays of these hormones have enabled pregnancy to be diagnosed non-invasively.…”

Okapi (Okapia johnstoni) : stratégie et revue du statut de conservation

“…Le temps de génération chez l'okapi a été estimé à 10 ans à partir d'une analyse des populations captives européenne et nord-américaine (Leus & Hofman 2012 ;Hofman & Leus, 2015). La gestation dure en moyenne 426 jours chez les femelles en captivité, et celles-ci donnent normalement naissance à un seul petit pesant environ 22 kg (Schwarzenberger et al 1993). Les jeunes peuvent généralement se tenir sur leurs pattes au bout de 30 minutes, mais durant les premiers mois de leur vie ils passent la majorité de la journée à se cacher pendant que leurs mères s'alimentent dans les fourrés (Bodmer & Rabb 1992).…”