Comparative Studies of Different Methods for Early Diagnosis of Pregnancy Based on Determination of Progesterone Levels and PAG in Buffaloes of the Bulgarian Murra Breed

Abstract

The aim of the present study was to perform a comparative evaluation of the methods for early diagnosis of pregnancy in buffalo cows of the Bulgarian Murrah breed by determining the concentrations of progesterone in serum, the P4 Rapid test in milk and the proteins associated with pregnancy in serum and milk. Blood samples were obtained from 57 buffalo cows, as well as 55 milk samples on the 23rd (progesterone determination in serum and milk) and 28th day (PAG determination in serum and milk) after artificial insemination. We interpreted the results of the rapid P4 test according to the manufacturer's instructions. Determination of serum concentrations of progesterone was performed with an ELISA analyzer Huma Reader (HUMAN, Germany), with a Progesterone EIA 96 TEST kit (Linear Chemicals, Spain). Pregnancy-specific glycoproteins were determined by the ELISA method using the Alertys Bovine Pregnancy kit for blood and milk. A transrectal ultrasound examination for pregnancy was performed on day 35 after insemination. The obtained results for the parameters characterizing the effectiveness of the methods used were processed by a computer statistical program (Statistica 7, Microsoft Corp. 1984-2000 Inc.) by a non-parametric method of percentage comparison. The highest sensitivity was recorded in the method for determining progesterone in serum, and the lowest in determining PAG in milk. For PAG ELISA tests, 100% specificity was found, while the other two tests had low values of 71.1% and 72.5%). The accuracy of individual methods for early diagnosis of pregnancy is in the range of 80.0% – 98.2%. Rapid P4 tests and serum progesterone distribution can be used to identify non-pregnant animals after insemination. PAG ELISA tests have high efficiency and are preferable to other methods for diagnosing early pregnancy in buffalo cows.