THE EFFECT OF POSTPARTAL PERIOD ON SUPEROVULATION AND QUALITY OF RECOVERED EMBRYOS

The objective of this study is to evaluate the position of superovulat ion with respect to its use in cattle breeding. The results were analy zed that were obtained in a set (n = 1,380) of donors (heifers, primip aras and cows of milk breeds) in order to determine the effect of dono r parity and the interval from calving to superovulation estrus on sti mulation level, nonsurgical recovery and embryo quality in dual-purpos e and milk breeds and their crossbreds. The sexual cycle of donors was synchronized by two applications of the analog prostaglandin F2 alpha (Oestrophan, Leciva Praha) within a 11-day interval. The preparation Folicotropin, Spofa Praha, was applied i.m. from the 9th to the 11th d ay of the sexual cycle in the morning and in the evening (7.00; 19.00 hours) for four days at doses of 2.3; 3.2; 1.1; 1.1 ampoules of the pr eparation (total dose of 14 ampoules, i.e. 560 i.u. FSH) to dairy cows and to heifers 2.2; 1.1; 1.1; 1.1 ampoules of the preparation (total dose of ten ampoules, i.e. 400 i.u. FSH). The analog prostaglandin F2 alpha (Oestrophan, Leciva Praha) was applied at a dose of 500 to 750 m icrograms in the morning on day 3 of superovulation treatment. Insemin ation and reinsemination were executed on days 5 and 6 of superovulati on treatment. Analyses of variance and covariance were used for statis tical data processing. In the set of 1,380 treated donors, 97 donors ( 7%) were without any CL production, 274 donors (19.8%) produced 1-2 CL and they were subjected to flushing, 170 donors (12.3%) produced 0 to 2 CL and no flushing followed, and 839 donors (60.8%) showed superovu lation responses (3 CL and more) at rectal checks before embryos were recovered. In total, 12.501 +/- 11.751 CL (nu = 4%) were determined in the set of 1,380 donors, ovum recovery showed the average value 8.831 +/- 10.08 ova (nu = 114.1%, the percentage in the CL number is 70.6%) , out of which 5.885 +/- 8.445 embryos were transferable ones (nu = 14 3.5%, the percentage of transferable embryos in the recovered ones mak es 66.6%). The best quality of embryo recovery was observed in donors treated within 60 to 100 days after calving while CL production as wel l as the number and quality of embryo recovery were somewhat lower in donors treated within 60 days. The best superovulation results were ac hieved in donors inseminated within 61 to 150 days after calving. Heif er superovulation was a little less successful. The best quality of em bryo recovery was observed in donors of the Czech Pied breed and its c rossbreds with Ayrshire breed.