THE EFFECT OF THE INTENSITY OF ESTRUS EXPRESSION ON THE FOLLICULAR DIAMETER AND FERTILITY OF NELLORE COWS MANAGED UNDER A FTAI PROGRAM

• Main Authors: Priscila Assis Ferraz, Marcus Vinicius Galvão Loiola, Alexandra Soares Rodrigues, Marcos Chalhoub Coelho Lima, Thereza Cristina Borio dos Santos Calmon de Bittencourt, Antonio de Lisboa Ribeiro Filho
• Format: Article
• Language: English
• Published: Universidade Federal de Goiás 2017-03-01
• Series: Ciência Animal Brasileira
• Subjects: Animal Reproduction
• Online Access: https://www.revistas.ufg.br/vet/article/view/37643

The aim of this study was to determine the relationship between the intensity of estrus expression on the ovulatory follicle diameter (OFD) and its effect on the conception rate in zebu females managed under a FTAI program. On a random day of the estrous cycle, day 0, 308 Nellore females received an intravaginal progesterone device and 2.0 mg of estradiol benzoate were administered intramuscularly (IM). On day 8, the progesterone device was removed, and 300 IU of equine chorionic gonadotropin, 150 μg of d-cloprostenol, and 1.0 mg of estradiol cypionate were administered IM. The animals were then painted with animal marker spray between the sacral tuberosity and the tailhead. On day 10, the animals were categorized into three groups: no estrus expression (n = 78), low intensity of estrus expression (n = 66) and high intensity of estrus expression (n = 164). The OFD was then measured, and artificial insemination (AI) was performed. The results suggest that determining the intensity of estrus expression is a good parameter to identify females with greater follicular diameter and increased fertility in Nellore cows submitted to a FTAI protocol. Keywords: artificial insemination; estrus detection; Nellore.