Abstract

BASILE, João Roberto; CHEBEL, Roberto Jorge  and  BASILE, Leandro Francisco. Effect of season on embryo transfer in superovulated Holstein cows with PMSG. Braz. J. Vet. Res. Anim. Sci. [online]. 1998, vol.35, n.6, pp. 00-00. ISSN 1413-9596.  http://dx.doi.org/10.1590/S1413-95961998000600005.

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.

Keywords : Embryo transfer; PMSG; Seasons; Cattle.