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

2017; UNIVERSIDADE FEDERAL DE GOIÁS; Volume: 18; Linguagem: Inglês

10.1590/1089-6891v18e-37643

1809-6891

Priscila Assis Ferraz, Marcus Vinícius Galvão Loiola, Alexandra Soares Rodrigues, Marcos Chalhoub Coelho Lima, Thereza Cristina Bório dos Santos Calmon Bittencourt, Antônio de Lisboa Ribeiro Filho,

Effects of Environmental Stressors on Livestock

Abstract 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.