engleski

The efficacy of milk ejection induced by luteal oxytocin as a method of early pregnancy diagnostics in cows

The aim of research was to determine the accuracy and reliability of the early diagnosis of pregnancy in cows using PGF2α analogue. Namely in case of corpus luteum (CL) presence, the release of luteal oxytocin is induced by intravenous administration of a non luteolytic dose of PGF2α. The research was performed in 30 lactating cows, 18-22 days after insemination, and three hours prior to the evening milking. A teat cannula is placed in the left fore-teat. When the cisternal milk flow ceased, a Dinoprost (256μg Dinolytic) was injected in v. jugularis. If CL was present, the alveolar milk flow (559.4±83.7 ml) started 189±18 s later and early pregnancy could be presumed. If CL was no longer functional, the milk flow did not start again and the cow was considered not pregnant. Seventeen out of 30 cows was confirmed pregnant 35 days after insemination by ultrasound and 13 were not found pregnant. The accuracy of positive results is 100% and is identical to that obtained by ELISA of milk progesterone used as a reference method. The accuracy of negative results was lower (46.1% vs. 84.6%) (P<0.05), because seven non pregnant cows out of 13 which has responded to milk ejection test. In spite of this disadvantage, the test approved as being inexpensive, rapid, and easy to interpret and is therefore very applicable, especially under field conditions. It can be applied i.e. 20 days after insemination. Progesterone rapid test from milk or by milk ejection test can be used with similar accuracy.

cow; luteal oxytocin; milk progesterone; pregnancy diagnosis

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