Administration of Leptin Increased Concentration of Estrogen and Accelerate the Emergence of Estrus in Post Partum Anestrus of Bali Cattle

Leptin is a hormone synthesized by adipose tissue with a molecular weight of 16 kDa with 146 amino acids that plays a pivotal role in the communication of nutritional status to centers that control reproduction. This study aimed to test the hypothesis that administration of exogenous leptin increased concentration of estrogen and accelerate the emergence of estrus in postpartum anestrus Bali cattle. Twenty seven postpartum anestrus Bali cattle were equally divided into three groups. Control ( n = 9 ), received s.c injections of saline. Treatment I ( n = 9 ) treated with 100 ?g/head of recombinant leptin via s.c injection. Treatment II(n = 9) received s.c injection of recombinant leptin 200 ?g/head. Exogenous leptinwas administered twice at 12 hours interval. Blood samples were collected via the jugular vein every 12 hours before the start of treatment until the appearance signs of estrus. The results showed that the average concentration of estrogen before treatment for control, treatment1, treatment2 were 54.4 ± 2.3 ng / L; 53.1 ± 2.74 ng / L; 55.8 ± 0.47 ng / L, respectively. After treatment, concentrations of estrogen were 54.1 ± 2.26 ng / L; 80.7 ± 0.58 ng / L and 80.8 ± 1.62 ng / L respectively. The timing of the estrus after treatment 1 and 2 were 57.33 ± 5.29 and 49.33 ± 4.00 hours respectively. While control showed no signs of the emergence of estrus until the end of the study. In conclusion, the administration of exogenous recombinant leptin increased concentration of estrogen and accelerated the emergence of estrus in postpartum anestrus. Key Words : Estrus, Leptin, Concentration of Estrogen, Postpartum Anestrus