Assessment of the Diagnostic Accuracy of a Pregnancy‐Associated Glycoproteins Test for Early Pregnancy Diagnosis in Dairy Heifers

This study aimed to assess the diagnostic accuracy of a PAG test (Idexx rapid visual pregnancy test, RVPT) for the diagnosis of early pregnancy in dairy heifers. The study material comprised 58 healthy dairy heifers, aged 13-15 months, with a body condition score ranging between 3.0 and 3.5, and raised under the same corporate management and feeding regimen on a dairy farm. The heifers exhibited spontaneous estrus and were inseminated upon detection of heat by visual observation. On days 24, 26, 28 and 32 following artificial insemination (AI), blood sampling was performed by coccygeal venipuncture. Immediately after the extraction of blood serum within approximately 2 h at room temperature, the RVPT was performed. On day 32 post-AI, pregnancy diagnosis was made by transrectal ultrasonography (TRUS) as the gold standard. The sensitivity and specificity, positive and negative predictive values and diagnostic accuracy of the RVPT on days 24, 26 and 28 post-AI were 96.2%, 78.1%, 78.1%, 96.2% and 86.2%, respectively. On day 32 after AI, the same parameters were 96.2%, 96.9%, 96.2%, 96.9% and 96.6%, respectively. Based on the area under the receiver operating characteristics (ROC) curve (AUC), the RVPT provided high accuracy in distinguishing between pregnant and open heifers. In conclusion, open heifers can be safely detected using the RVPT as of day 24 post-AI, whereas heifers diagnosed as being pregnant with the RVPT should be confirmed later.