Reproductive efficiency and serum progesterone concentration on dairy cattle based on blood urea nitrogen (BUN) concentrations

The objective of this study was to identify the levels of Blood Urea Nitrogen (BUN) and its relation to the reproductiveefficiency and serum progesterone concentration in lactating Holstein Friesian dairy cattle. Data were obtained by stratifiedrandom sampling from population to get 18 dairy cows, which divided into three groups. The first, second, and third groupseach with milk yield of less than 17, between 17-21, and over 21 liters/day, and with calving interval of less than 365, between365-450 and more than 450 days. Blood was collected from the coccygeal vein at the time of insemination (D0), 7 day (D+7)and 22 days (D+22) after insemination. BUN and progesterone concentration were measured. Data analysis showed nosignificant difference (P 0.05) on the observed parameters. Data regrouping based on BUN concentration showed that themean of services per conception (S/C) was lower and conception rate (CR) was higher (P 0.05) in dairy cattle havingBUN 18 than those of with BUN 18 mg/dL. The mean of progesterone concentration at D+22 was higher (P 0.05) than thoseat D0 and D+7 in pregnant dairy cows and with BUN 18 mg/dL, as well as those at D+22 in non-pregnant dairy cows withBUN 18 and BUN 18 mg/dL. This study concluded that high BUN concentration affect the reproductive efficiency of dairycows by decreasing CR and increasing progesterone serum concentration.