Influence of GnRH and its timing of application on the fertility of artificially inseminated dairy cows synchronized with double doses of PGF2α”

• DOI: 10.22533/at.ed.973352326043

• Palavras-chave: Fertility, Gonadorelin, Prostaglandin F2Fα, Reproduction, Jersey cows.

• Keywords: Fertility, Gonadorelin, Prostaglandin F2Fα, Reproduction, Jersey cows.

• Abstract:

  The objective of this research was to analyze the effect of GnRH applied at the beginning of estrus or in artificial insemination, considering that low fertility problems in dairy herds is one of the factors that most affects production and profitability levels. 146 Jersey cows with 2.2 lactations, 40.2 days in milk and 2.8 of body condition were used, which were synchronized with two applications of prostaglandin F2α, at the beginning of estrus, they were randomly assigned to one of three treatments, T1: GnRH/I.A; n = 51, T2: GnRH/SD; n=49; and T3: Without GnRH, the pregnancy percentage was analyzed by logistic regression with the glm procedure with the R software. The percentage of pregnancies was not different between treatments, with values of 45, 59 and 46 respectively, possibly because in this exploitation, nutrition, management, health and heat detection are optimal. Therefore, it is concluded that in the conditions in which this research was carried out, GnRH did not improve fertility.