Negative Prediction Value of Pregnancy-associated Glycoprotein Contributes to Reduce the Days During Which Nonpregnant Holstein Cows are Subjected to Diverse Strategies of Hormonal Synchronization

The objective of the present study was to determine the accuracy and the negative prediction value of Pregnancy-Associated Glycoprotein (PAG) at 29 d post artificial insemination by ELISA. Blood serums of multiparous Holstein cows were used (n = 275). Pregnancy diagnosis was carried out by rectal palpation at 40 d and it was considered as reference test. Pregnancy results based on the PAG-ELISA and the pregnancy diagnosis at 40 d showed high concordance with a kappa value of 0.7. The accuracy test based on PAG-ELISA at 29 d post artificial insemination compared with pregnancy diagnosis by rectal palpation was 88%. The values of sensibility, specificity, positive prediction value, negative prediction value and positive and negative likelihood ratio were 96, 78, 83 and 95%, 4.5 and 0.0442, respectively. It is concluded that pregnancy diagnosis of PAG-ELISA is reliable and accurate at 29 d post artificial insemination. The PAG-ELISA's negative prediction value diminishes the number of days in subjecting cows diagnosed as nonpregnant to diverse strategies of hormonal synchronization protocols.