Rapid colour-change pregnancy test for rhinoceros using faeces

Pregnancy is routinely determined by monitoring faecal progestogen levels in black and white rhinoceros, Diceros bicornis and Ceratotherium simum, respectively. However, current labora- tory procedures are too slow and not practical in the field, and transporting samples to the laboratory may not be possible, may cause them to deteriorate, or result in delays such that events subsequent to sampling supersede the results. We modified current enzyme-immuno assays (EIA) methods to create a field test that is robust under field conditions, requires minimal technical equipment and expertise, and yields results on-site within 24 h. The field assay is a tri-colour test and pregnancy is determined visually. Faecal samples from 55 free-ranging white and 7 black rhinoceros were col- lected from the rectums of animals at capture and from fresh dung piles while the rhinoceros were temporarily housed in boma. The accuracy of the colour-change field test was confirmed by radio- immuno assay (RIA) of matched faeces and independent blood serum analyses for 23 pregnant and 39 non-pregnant rhinoceros. This field pregnancy test is likely to be appropriate for other animals, such as elephants, that have high and sustained levels of progestogen during pregnancy.