Evaluation of an oestrone sulphate dipstick immunoassay for pregnancy testing mares

J. STEWART AND K. HENDERSON

AgResearch Ltd., Reproductive Technologies Group, Wallaceville Animal Research Centre, PO Box 40063, Upper Hutt, New Zealand

E-Mail:

Proceedings of the New Zealand Society of Animal Production 2001. 61: 45-47

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.

Keywords: NZSAPAB; Oestrone sulphate; horse; serum; pregnancy; dipstick immunoassay

Last Updated 7/08/01