Abstract

Serum samples from 213 mares were received for routine pregnancy testing and analysed by a conventional oestrone sulphate (OS) enzymeimmunoassay (EIA) and a new OS dipstick immunoassay. OS concentrations, measured by EIA, in 122 of the samples were <10 ng/ml, indicating the mares were not pregnant. The same 122 samples also returned a `not pregnant` diagnosis when analysed by the dipstick immunoassay. The remaining 91 samples returned diagnoses of `pregnant` by the OS EIA, i.e., OS concentrations were >20 ng/ml. Of these, 89 also returned a `pregnant` diagnosis by the dipstick assay, but 2 returned a `not pregnant` diagnosis. Both these mares were found to be pregnant on follow up, indicating that the dipstick test had returned a false negative diagnosis in each instance. These results show that there is 100% agreement between the conventional OS EIA and the new dipstick assay in diagnosing `non pregnancy`. However, the dipstick assay may return a small proportion (2.2%) of false negative diagnoses relative to the EIA. Overall, the new dipstick immunoassay offers a practical alternative to the OS EIA for diagnosing pregnancy status in mares.

J, Stewart, and K Henderson

Proceedings of the New Zealand Society of Animal Production, Volume 61, Christchurch, 45-47, 2001