INFLUENCE OF THE PRE-OVULATORY FOLLICLE DIAMETER ON THE PREGNANCY RATE OF COWS SUBMITTED TO FTAI

Abstract

Fixed-time artificial insemination (FTAI) is a reproductive biotechnology used to improve the performance of herds through hormonal protocols. The use of this technique allows to induce cow cyclicity, besides eliminating the estrus observation, which has been a great differential for the growth of FTAI. An important point in the conception rate of cows is the size of the pre ovulatory follicle. The objective of this study is to confirm the existence of correlation between follicular diameter and gestation rate of cows. Thirty cows of three different breeds were used, among them Nelore, Purunã and crossbreed, and the measurement of the follicular diameter was performed by transrectal ultrasonography before FTAI. The animals were divided into two groups (G1= <10 mm e G2= <10 mm).  Thirty days after FTAI, the diagnosis of gestation was performed by rectal palpation and transrectal ultrasonography. The conception rate was 53.33% (16/30), among this 13,33% for the G1 and 40% for G2, besides that there was no influence of the follicular diameter (p= 0,056). This study suggests further resarch about the subject.