The effect of embryo donors and fathers on the results of superovulation and embryo transfer

The objective of the paper was to evaluate the effect of donors (MOTHERS) a nd sires (FATHERS) on embryo recovery and quality after superovulation trea tment, and on survival after transfer of fresh and thawed embryos, i.e. on conception rates of donors. Heifers and first-calvers of Piemontese breed ( n = 75) were used us embryo donors; they were included in a superovulation schedule prostaglandin F-2alpha (Oestrophan) - FSH (Folicotropin Spofa) at a total dose of 560 i.u. FSH for cows and 400 i.u. far heifers. Donors were inseminated three times using a single semen dose in each case. Embryos we re collected on day 7 after the first insemination, and cultivated by commo n techniques. Embryo freezing took place in a medium containing 1.37M glyce rol (10% by volume) under a regime of 0.3 degrees C/min to reach a temperat ure of -35 degrees C before they were transferred to LN2. Embryo thawing la sted 7 seconds in the air and in 30 degrees C water bath. Three steps were taken to rinse glycerol away. Synchronization of heifers-recipients at the age and live weight after the first insemination included double applicatio n of prostaglandin F-2alpha (Oestrophan) in an Ii-day interval. Embryos wer e transferred to convenient recipients to the ipsilateral uterine horn onto an ovary with CL, using Worrlein instrument (Germany). Routine variation-s tatistical methods and multifactor analysis of variance were used for data processing. Differences in average numbers of recovered ova (from 4.40 +/- 3.81 in ZPI 168 /ZPI = sire register/ to 6.25 +/- 9.10 in ZPI 162 and ZPI 1 69, and 6.53 +/- 6.08 in ZPI 164) and transferable embryos (1.75 +/- 1.29 i n ZPI 173 to 4.63 +/- 3.46 in ZPI 169) were statistically insignificant (P > 0.05), probably due to high variability of results. Multifactor analysis of variance of the effects mother and father facilitated to determine highl y significant (P < 0.01) and significant (P < 0.05) effects of mothers and fathers on recovery of ova and transferable embryos and/or on their percent age and on recovery of unfertilized oocytes. But the inclusion of the effec t mother x father did not demonstrate ally significant effects of this fact or on any indicator under study. TI-ris indicates the effect of embryo moth ers and fathers an some parameters, but the effect is not inherent in a def inite parental combination mother x father. The effect of mated sires on em bryo survival after ET was evaluated for the total of 395 transfers in ten breeding bulls-embryo fathers of Piemontese breed. Insignificant difference s were determined in conception rates of recipients after fresh embryo tran sfer (P > 0.05) with respect to the sire used for insemination as well as a fter transfer of frozen embryos and embryos in total. Above-average concept ion rates were recorded in two sires after fresh embryo transfer. Basic sta tistical data on the set of 193 embryo recoveries from 75 donors inseminate d by 12 sires are presented. A total of 6.145 +/- 3.945 ova wale recovered on average: out of them 3.425 +/- 2.296 transferable embryos originated, wh ich is 49.619 +/- 32.931% of transferable embryos from the particular colle ctions.