Conception rate of dairy cows submitted to fixed time artificial insemination at different seasons of the year [Taxa de concepção de vacas leiteiras submetidas à inseminação artificial em tempo fixo em diferentes épocas do ano]
Silva N.C.,Instituto Federal Of Educacao Ciencia E Tecnologia Goiano Ifg |
Leao K.M.,Instituto Federal Of Educacao Ciencia E Tecnologia Goiano Ifg |
Marques T.C.,Instituto Federal Of Educacao Ciencia E Tecnologia Goiano Ifg |
Rodrigues M.C.,Instituto Federal Of Educacao Ciencia E Tecnologia Goiano Ifg |
And 2 more authors.
Bioscience Journal | Year: 2014
The objective of the present study was to assess the influence of season of the year on conception rate of different categories of milking cows submitted to fixed time artificial insemination (FTAI). The cows were divided into the following categories: high production multiparous (MA), low production multiparous (MB) and high production primiparous cows (PA). The conception rate was compared between the cows inseminated in the period with mild temperatures (TA) and in the period with higher temperatures (TE), within each animal category. The following FTAI protocol was used for all the animals: D0 - progesterone implant, 2 mg of estradiol benzoate, D8 - progesterone implant removal, 0.15 mg of cloprostenol sodium, 300 UI of equine chorionic gonadotropin, 1 mg of estradiol cypionate; D10 - 0.004 mg of buserelin acetate and artificial insemination 48 hours after removing the implant. Pregnancy was diagnosed at 30 and 60 days after FTAI and the data was analyzed by the Exact Fisher test. There was no statistical difference in the conception rate of the cows inseminated at different seasons of the year in any categories analyzed. The season of the year did not interfere in the conception rate of high production multiparous cows, low production multiparous cows and high production primiparous cows.