Banca de QUALIFICAÇÃO: ISABELLA DE OLIVEIRA BÊTA

FOLLICULAR DYNAMICS AND PROGESTERONE AND ESTROGEN PROFILE IN PREPUBERENT NELORE AND MURRAH HEIFERS SUBJECTED TO FIXED-TIME ARTIFICIAL INSEMINATION (TAI)

biotechnology, reproduction, hormones, heifers, buffalo.

The objective of this research will be to evaluate the follicular dynamics and the profile of the hormones progesterone (P4) and estradiol (E2) in prepubertal Nelore heifers and prepubertal Murrah heifers, using fixed-time artificial insemination biotechnology. Six Nellore heifers and six Murrah heifers will be used for this experiment. The FTAI protocol that will be used consists of an intravaginal implant with 0.5mg of progesterone, for 8 days, and application of 2mg of estradiol benzoate (EB). When removing the implant, 0.4 ml of estradiol cypionate (EC), 2.5 ml of prostaglandin, and

1.5      ml (300Ul) of equine chorionic gonadotropin (eCG) will be administered intramuscularly (IM), will also be performed marking of the animals in the sacral-caudal region with a marker stick to determine the expression of estrus. All females will be inseminated 48 to 54 hours after the removal of the intravaginal device, during the period of application of the protocol, ultrasound will be performed to evaluate the follicular dynamics during D8 (dominant follicle), D10 (ovulatory follicle), in Nellore heifers, and in D9 (dominant follicle), D11 (ovulatory follicle) in Murrah heifers, after insemination, ultrasound will be performed every 12 hours until ovulation, blood will also be collected to estimate the dosage of progesterone and estradiol during the days of D8 and D10 in Nelore heifers and during the days of D9, D11 in Murrah heifers. From the data obtained, the follicular dynamics in prepubertal Nelores and Murrah heifers and the profile of progesterone and estradiol will be evaluated. During the IATF protocol, Nelores and Murrah heifers will undergo blood collection for hormonal measurement of progesterone and estradiol. In Nelores heifers the collection will be carried out on D8 and D10 by puncture of the jugular vein, and in Murrah heifers the collection will be carried out on D9 and D12 by puncture of the jugular vein. During the insemination protocol, an assessment of the follicular dynamics of the heifers will also be carried out, which will consist of monitoring through ultrasound to analyze the development of the follicles and determine the time at which ovulation will occur, which will be established as the time of the examination, at which ovulation will occur. disappearance of the ovulatory follicle (ovulation).