Efeito da indução de puberdade em novilhas nelore no desempenho reprodutivo na estação de monta.

Abstract

ABSTRACT

Brazil stands out as a country with great productive potential in livestock, with the largest commercial cattle herd in the world and the largest in beef exports. All this potential, however, is not fully exploited, which is evidenced by the success rate of the Brazilian herds. One of the greatest difficulties of Brazilian bovine production is the lack of sexual precocity of the animals, associated to the profile of Nelore cattle, which historically is not selected for sexual prehistory, becoming a phase of creation of a low profitability activity, limiting the sector. The use of technologies is of the utmost importance for animals to be early, current or early, giving the producer greater power during their productive life. With the use of hormonal structures, it is possible to cause a greater pulsation of LH, culminating in the first ovulation of the animal, followed by a progesterone phase with the maintenance of a functional corpus luteum. The objective of this work was to evaluate the use of a hormonal induction protocol for cyclicity in new pre-puberty Nelore with infant variance from 22 to 26 months. Twenty-three pre-pubertal Nellore heifers (CL) were treated with the following cycling induction protocol. No day zero (D0) as heifers up to a 27-day intravenous progesterone device (CIDR) for 12 days and a final application of 0.4 ml estradiol cypionate (ECP) on the day of device withdrawal. The period of examination for ultrasound for inducing the cycle of induction of the cycle of the evaluation of the cycle of evaluation of ultrasound for indetermination of cyclicity. They were cyclic constructs like heifers that sound CL. Then all heifers were submitted to ovulation synchronization protocol based on progesterone and 2 ml estradiol. The response rate to the induction protocol was 73.9% (17/23). In heifers that responded to induction of developmental rate in the first artificial insemination (AI) was 64.71% (11/17), in the animals that did not respond to induction, 50.00% (3/6) were observed. Sixty days after the end of the mating season the final diagnosis of gestation was performed and the results obtained for the animals submitted to an induction protocol were 76.47% (13/17) and the animals that were not answered with the command 50% breeding rate of reproductive management.

Key words: Conception, Reproductive Efficiency, IATF