Barium chlorideassay of urine: A cost-effective method for early diagnosis of pregnancy in cow

Abstract

To reduce calving interval through an appropriate reproductive management program, the early detection of pregnancy at the 1st
trimester is essential to enable the prompt re-insemination of non-gravid cows. We aimed to re-evaluate the efficacy of barium chloride assay to detect early pregnancy in cross-bred cows. Urine and blood samples were collected from 72 and 65 artificially inseminated cows, respectively. Pregnancy status at 1^st(Day: 1-90)and 2^nd(Day: 91-180)trimesters were compared using two different methods: a bariumchloride assay from urine samples and a progesterone enzyme linked immune sorbent assay (P₄-ELISA) from blood samples, where rectal palpation was considered as gold-standard. We found that although the overall (combining both 1^st and 2^nd trimesters) true positive, negative predictive value (NPV) and accuracy of P₄-ELISA was better, the barium chloride assay performed equally well as the P₄-ELISA in terms of true positive percentage of pregnancy diagnosis (70.8% in barium chloride vs. 85.7% in P₄-ELISA; P>0.05) at the 1^st trimester. In addition, specificity of pregnancy diagnosis was higher inbarium chloride test than P₄-ELISA at the 1sttrimester (100% in barium chloride vs. 66.7% in P₄-ELISA). Therefore, barium chloride method could be a good choice under farm and field set up of early pregnancy diagnosis at the 1^st trimester in cows.