Oestrous cycle induction in a white rhinoceros (Ceratotherium simum simum) monitored by fecal progestagen analysis

Reproductive rate of white rhinoceroses (Ceratotherium simum simum and C. s. cottoni) in captivity is very poor. A recent study using faecal progestagen evaluations indicated missing or erratic luteal activity as a possible reason. Faecal progestagen evaluations in one white rhinoceros kept at Salzburg zoo failed to detect luteal activity for a period of > 2 years. Therefore we attempted to induce cyclic activity in this animal using CMA (Chlor Madinone Acetate, Synchrosin®) and hCG (Chorulon®). CMA was applied orally in 32 doses (35 mg each) in 35 hour intervals (45 days); hCG (8,400 IE) was given in a single intra muscular injection 5 days after the CMA application. Faecal progestagens were low before and during the application of CMA. They increased 10 days after hCG application and the duration of the induced luteal phase was about 20 days. Oestrous behavior was seen 70 days after the hCG application, but cyclic activity did not continue. In conclusion, monitoring of faecal progestagens demonstrated that luteal activity can be induced using a synthetic progesterone derivative, followed by an injection of hCG. Attempts to induce cyclicity in the white rhinoceros should be continued and monitored by faecal progestagen analysis in order to find optimal treatment protocols.