Determining the reproductive status of two female southern white rhinoceroses (Ceratotherium simum simum) in Khao Kheow Open Zoo in Thailand by measuring fecal progesterone

Abstract

Breeding performance in captive southern white rhinoceroses is disappointing. The same applies to the two female southern white rhinoceroses in the Khao Kheow Open Zoo in Thailand. Since these females have never produced offspring, the reproductive status is examined in this study. With the use of non-invasive monitoring, by measuring fecal progesterone and by observing behavior related to the estrous, one could make some assumptions about their reproductive cyclicity. The peaks and nadirs in the progesterone profiles, indicate that both females are cyclic, with cycle lengths of respectively 30,5 days and 36 days. Furthermore, both females showed mating behavior, which occurred on the day progesterone concentrations were at a nadir (taking in account the gastrointestinal transit time), underlining that they were in estrous. However, the timespan of this study and the regularity of sample collection were not sufficient to draw firm conclusions. A long-term study with a more regular sample collection would give more comprehensive hormone profiles. Simultaneously performing ultrasonographic examination would provide valuable data to gain more knowledge about the failure in reproducing of the two female southern white rhinoceroses.