The stability of progesterone in feces of different wild animal species kept in a zoological garden

Methodical investigations were carried out to monitor especially in what respect external factors (dry mass of faeces, time point of freezing, duration of storage of the frozen samples, multiple defrosting of the samples) influence the progesterone concentration of the faeces of several wild animal species (Baringo giraffe, Black rhinoceros, Dama gazelle, Mountain goat) living in a zoological garden. With reference to one animal species the dry mass of the faeces showed only small variations. Therefore, it is possible to estimate comparable progesterone levels in several faecal samples of the same animal species without drying the samples. In all cases the progesterone concentration was increased after 24 and 48 hour storage of the faecal samples at room temperature compared with samples frozen directly (significant differences for giraffes and rhinoceroses). Samples of rhinoceroses and gazelles showed no significant changes of their progesterone concentration after a long time of storage (one and three months) in the freezing state (-20 degrees C). On the other hand, in faeces of giraffes with high progesterone levels a significant decrease of the initial level was pointed out. In comparison of single and multiple defrosting of the faecal samples, the latter caused a decrease of the progesterone concentration of the faeces of all animal species investigated (significant differences for rhinoceroses and gazelles).