Estrus Characteristics and Reproductive Hormone Production in Boran and Boran×Friesian Dairy Cows at Bishoftu Agricultural Research Center, Ethiopia

A study was carried out at the Bishoftu Agricultural Research Center to determine the blood hormone level and estrus behavior exhibited by purebred Boran and crossbred dairy cows from October 2019 to June 2020. Twenty multiparous dairy cows were purposively selected after gynecological and obstetrical examination, and blood samples were collected on days zero, 7, and 11 to measure serum concentrations of estradiol and P4. In addition, visual observation was carried out three times per day for the detection of estrous behavior. The result revealed that 35% and 30%, 10% and 25%, and 15% and 30% of the crossbred and Boran showed quiet acceptance to be mounted, disoriented mounts, and attempts or rejection to mount, respectively, during the study period. The mean estradiol level was 19.38 2.46 pg/ml on day zero, 16.08 2.16 pg/ml on day 7, and 15.46 2.09 pg/ml on day 11 (P<0.0001).The mean progesterone level was 0.310.08ng/ml on day zero, 1.120.32ng/ml on day 7, and 1.190.19ng/ml on day 7 (p 1.19±0.19ng/ml on day (p<0.05).The mean estradiol levels were 19.153.19 pg/ml, 16.211.49 pg/ml, and 15.42.14 pg/ml for good, medium, and poor BCS animals, respectively. where the progesterone levels were 1.1200.31ng/ml, 1.070.26ng/ml, and 0.6660.21ng/ml, respectively. Boranhad had significantly (P< 0.0001) higher (13.051.63 pg/ml) circulating estradiol concentrations than crossbred cows (20.891.75 pg/ml). The progesterone profile of Boran was significantly (p 0.0001) higher (1.120.23 ng/ml) than that of crossbred crossbred cows (0.99±0.26ng/ml).This difference is most likely due to the differences in metabolism and metabolic hormone concentration between Boran and crossbred cows. It is recommended that detailed research be done on the all-inclusive hormonal profile and the effect of the season and other management systems of the farm on the efficiency of reproduction. Keywords: Boran, Boran× Holstein, Estradiol, Progesterone, Reproductive physiology