Effect of using ecg in the fixed-time artificial insemination protocol in mixed-race dairy cows
Keywords:
Pregnancy, Artificial insemination, Synchronization of estrusAbstract
In Brazil, about 5% of the cattle herd reproduces through artificial insemination (AI) biotechnology. The success of AI depends on factors inherent to the female, inherent to the semen and the inseminator's ability. Among the factors inherent to the female are: body score, health status, reproductive status and hormonal protocol used. The literature reports different results among the various hormonal protocols. Therefore, the objective of this study was to verify the efficacy of eCG in fixed-time artificial insemination (IATF) protocols in cattle. Girolando crossbred cows (n=4886), with an average weight of 500 kg, were divided into two groups, IATF 1 (n=2.535) and IATF 2 (n=2.351). The data of the samples were collected from the Milk Producing Units (UPLs) - Campo Grande, Colmalândia, Ouro Branco and Ouro Verde - that are part of Fazenda dairy complex. Cows were divided into two groups, IATF 1 and IATF 2 each quarter. Both IATF protocols were performed over a ten day period. On day 0, the progesterone-impregnated intrauterine implant (1g) was administered, which remained for eight days and administered 2 mL of Estradiol Benzoate intramuscular. After removal of the implant in the D8, 2 mL of prostaglandin F2α (PGF2α) were administered intramuscularly together with 1 mL of Estradiol Cypionate. It was concluded that the use of eCG increased fertilization rates in cows with smaller follicles, but was unnecessary for females that presented normal uterine conditions.
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