The Effect of Long Non-Reproductive Periods on the Genital Health in Captive Female White Rhinoceros
This study examined 48 southern and six northern white rhinoceros (Ceratotherium simum simum, C.s. cottoni) using ultrasound and fecal hormone analysis to elucidate causes for female reproductive failure and to determine whether long non-reproductive periods have a detrimental impact on genital health. Results showed that 76% of the nulliparous females had never been bred. Fifty-six percent of the studied population had reproductive pathology. The stages of the lesions in nulliparous females correlated with age. Due to the severity of the lesions, 28% of the study population was considered post reproductive. The reproductive lifespan in some individuals was 10–20 years short. However, in parous females the incidence of pathologic lesions was significantly lower.1 Seventy-eight percent of females studied had erratic or absent luteal activity. The hormone data corresponded with two ultrasonographic levels of ovarian activity, active and inactive, occurring within an age range of 3–19 y and 15–38 y, respectively. This suggests the lack of ovarian activity by reproductive mid-life in non-reproducing females. Our data suggest that the development of reproductive pathology and ovarian inactivity in white rhinoceros is an age-related consequence of long non-reproductive periods. This asymmetric ageing process it seems can be prevented with one pregnancy.
The International Rhino Foundation and SOS Rhino funded this work. The authors are grateful for financial support by the African Lion Safari, Cambridge, Canada; Burgers’ Zoo, Arnhem, Netherlands; La Palmyre Zoo, France; Wild Animal Park, Escondido, CA, USA. Our team pays tribute to the tremendous support and work of all our American and European colleagues in this study.
1. Hermes R., T.B. Hildebrandt, C. Walzer, F. Goeritz, M.L. Patton, S. Silinski, C.E. Reid, G. Wibbelt, K. Tomasova, and F. Schwarzenberger. 2005 The effect of long non-reproductive periods on the genital health in captive female white rhinoceroses (Ceratotherium simum simum, C.s. cottoni). Theriogenol. 65:1492–1515.