RECOVERY RATE AND QUALITY OF EMBRYOS PRODUCED BY SUPEROVULATED DONORS- BEEF BOVINE FEMALES

Evaluation of superovulation stimulation (classification of recovery r ate and embryo quality) applied in beef cows and heifers and F-1 cross es of Czech Pied cattle with bovine beef breeds was the principal obje ctive of the study. Superovulation was stimulated in the mid-estral ph ase of the sexual cycle (from Day 9 to Day 11 of the cycle) with FSH-p (Folicotropin, Spofa Prague) administered for 4 days in the morning a nd the evening in total dose amounting to 560 I.U. (cows) and to 400 I .U (heifers). Insemination and repeated insemination were done in two successive days with three frozen semen doses. On Day 7 after the 1(st ) insemination ova were collected and classified by routine procedures . Obtained results illustrate large variability of recovery rates (as much as 100%) and embryo quality (quantity and rate of transferable em bryos) in cows and heifers. Mean values of controlled parameters were lower in heifers compared to cows. it is evident that embryo recovery rate and quality are satisfactory in almost all studied beef breeds an d F-1 crosses. Very low rates were found in cows unconceived in one (L imousine) or two (Hereford) reproductive seasons. Superovulation of th ese females and their utilization as embryo donors are ineffective.