ADMINISTRATION OF LEPTIN HORMONE ON ESTRUS INTENSITY AND TIME OF ESTRUS POSTPARTUM IN NULIPARA OF BALI CATTLE

    The economic success of a cattle farm generally depends on the success of making an optimal calving interval, which is about one year. To be able to achieve optimal calving intervals, the postpartum anestrus period should not exceed 65 days. During postpartum experiencing a negative energy balance means that energy consumption is lower than the energy needed by the parent. Physiologically, a cow in a state of negative energy balance will cause a decrease in dry matter intake, changes in hormonal circulation and decreased immune system. Even though the negative energy balance only lasts up to 3 weeks after parturition, its effect on the physiological condition of the mother cow will cause the time of the emergence of the first postpartum estrus and an extended uterine involution process, a delay in the time of postpartum insemination, extended days open and calving intervals.

    Low food intake before and after birth will increase the interval from delivery to the emergence of the next estrous cycle. If there is a negative energy balance after childbirth will increase the mobilization of energy reserves stored in adipose tissue. Leptin is a hormone secreted by adipose tissue with a molecular weight of 16 kDa with 146 amino acids, plays a role in conveying metabolic information on the pituitary axis of the ovarian pituitary.

    By administration leptin in postpartum cows, especially in heifers, it is expected to increase beef cattle productivity by improving reproductive efficiency by achieving optimal calving intervals (one year) and increasing calf birth and also optimizing the management of artificial insemination programs (IB).

    This research is to prove that giving leptin can increase the intensity of estrus and the time of emergence of postpartum estrus and in virgin cows. This research is a true experimental study with a Randomized Pre Post Grop Control Design. Giving leptin, the observation of the emergence of estrus in Bali cattle was carried out at the symantry and the Bali Cattle Breeding Center in Sobangan Village, Mengwi District, Badung Regency, with the duration of the study carried out for 3 months.