Effect of superovulation on performance of bovine embryo donors imported from temperate zone to tropical climate during the first two years of adaptation

The results of a multiple ovulation and embryo transfer (MOET) program, obtained in its first two years, were evaluated. The donor heifers were imported already pregnant from Hungary to the North-East area of Brazil. Comparisons of the results obtained in 1996 and 1997 with superovulation programs with AUSA-Superov (FSH) and Folligon (eCG) were made. The number of CL found on both ovaries was 5.3 (FSH) and 4.2 (eCG) in 1996, and 8.2 (FSH) and 9.6 (eCG) in 1997, while the number of degenerated eggs and embryos was 2.8 (FSH) and 3.8 (eCG) in 1996, and 6.5 (FSH) and 7.4 (eCG) in 1997. The number of good quality embryos was 1.9 (FSH) and 2.3 (eCG) in 1996, and 5.5 (FSH) and 4.0 (eCG) in 1997. The embryo collection efficiency was 40% (FSH) and 35% (eCG) in 1996, and 85% (FSH) and 83% (eCG) in 1997. Significant differences were found for all results obtained in 1996 and 1997 (P<0.05). Two new commercial products were used in 1997, Pluset and Folltropin-V, both with FSHp. With Pluset therapy the number of unfertilized eggs and degenerated embryos harvested was 11.7 per retrieval, while the number of good quality embryos was 5.1 per retrieval. With Folltropin therapy the number was 4.5 and 1.9, respectively, showing that better results were obtained with Pluset (P<0.05).

Cattle; Holstein-Friesian; heat stress; acclimatization; embryo; superovulation


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