Recovery rate and quality of embryos produced by superovulated donors-beef cows.
Charolais, Blonde dAquitaine, Aberdeen-Angus (AA), Limousin, Simmental, Piedmont and Hereford heifers/cows (3-60 per group) were superovulated with FSH, injected twice daily over a 4-day period, the total dose amounting to 560 IU in cows and 400 IU in heifers. In the 7 groups respectively, the number of transferable embryos recovered per donor cow averaged 4.34, 5.0, 4.0, 4.97, 8.33, 9.61 and 0, the number of degenerated embryos 6.16, 3.0, 3.68, 3.50, 1.25, 2.89 and 2.17, and the number of unfertilized oocytes 1.65, 0.53, 0.39, 1.75, 0.58, 1.50 and 0.16. Similar data are give for the heifers. Fewer transferable embryos were recovered from heifers than from cows. Figures are also given for embryo recovery from donor heifers and cows that were F1 crossbreds of the above breeds (except for Hereford and Simmental) with Czech Pieds. The average number of transferable embryos per donor ranged from 2.3 (Piedmont crossbreds) to 8.75 (AA crossbreds) in cows, and from 2.20 (Piedmont crossbreds) to 5.40 (Charolais crossbreds) in heifers.