Effect of season on embryo transfer in superovulated Holstein cows with PMSG

Abstract

The authors tried to evaluate the effect of environmental factors on the embryo transfer of 21 Holstein cows, in a 30 months period, submitted to 37 superovulatory treatments with 3.000 I.U. of PMSG. The results were analyzed considering two seasons: wet period (October to March) with an average maximum temperature = 30.0 ± 0.8ºC and an average absolute precipitation = 153.1 ± 78.8 mm³ and dry period (April to September) with an average maximum temperature = 26.5 ± 1.6ºC and an average absolute precipitation = 59.2 ± 53.8 mm³. Climatic differences between seasons were demonstrated (P<0.05), but there were no significant differences between seasons in the average number of structures per superovulation: 5.4 ± 2.63 and 4.3 ± 4.00; in the viable embryos percentage: 50.0% and 57.6% and the pregnancy rates in the recipients: 44.4% and 35.2%, respectively. Then, the climatic variations between wet and dry periods did not appear to adversely affect the embryo transfer performance in superovulated Holstein cows with PMSG.