Assessment of ovarian cycles in the African elephant (Loxodonta africana) by measurement of salivary progesterone metabolites.

Monitoring ovarian cycles through hormonal analysis is important in order to improve breeding management of captive elephants, and non-invasive collection techniques are particularly interesting for this purpose. However, there are some practical difficulties in collecting proper samples, and easier and more practical methods may be an advantage for some institutions and/or some animals. This study describes the development and validation of an enzymeimmunoassay (EIA) for progestins in salivary samples of African elephants, Loxodonta africana. Weekly urinary and salivary samples from five non-pregnant elephant cows aged 7-12 years were obtained for 28 weeks and analyzed using EIA. Both techniques correlated positively (r = 0.799; P < 0.001), and the cycle characteristics obtained were identical. The results clearly show that ovarian cycles can be monitored by measuring progestins from salivary samples in the African elephant. This is a simple and non-invasive method that may be a practical alternative to other sampling methods used in the species.