[Superovulation and uterine lavage in relation to subsequent conception in donor cows]. / Superovulace a výplach delohy ve vztahu k následné koncepci krav-dárkyn.

On the Slusovice co-operative farm, embryo transfer has been practised since 1984 as a method of controlled reproduction of the heifer and cow herd. The effect of superovulation, embryo recovery and administration of 500 micrograms Oestrophan Spofa upon the donors' conception rate and upon their resuming a new reproduction cycle was studied on this farm. The effect of superovulation, induced by FSH-P (Folicotropin, Spofa), was evaluated in 162 cows, out of which 121 (74.69%) got in calf after three inseminations. Fifty-nine (48.76%) of the pregnant cows got in calf after the first insemination, 38 (31.40%) after the second insemination, and 24 (19.83%) after the third insemination. Having been subjected to embryo collection and luteolysis, the donors conceived within 67.6 days, on an average, and the animals superovulated within 60 days post partum conceived within 59.11 days. The average SP of the superovulated animals was about 148 days but in the donors from which the embryos had been recovered within 60 postpartal days the SP did not exceed 110 days. Hence the earlier postpartal superovulation of cycling cows speeds up the resumption of reproduction in the donors and increases the numbers of recovered embryos. Repeated superovulation had no influence on the fertility of the cows but adequately prolonged the service period.

[Use of a rapid method of cryopreservation of bovine embryos for non-surgical transfer in transplantation practice]. / Vyuzití rychlého zpusobu kryokonzervace embryí skotu pri nekravavém prenosu v transplantacní praxi.

The embryos were frozen and thawed in Cassou minipaillette by a rapid method. Embryos with cryoprotective agent (glycerol, 1.5 M) were placed directly into the freezing medium at the temperature of -6 to -7 degrees C, frozen after seedling at the temperature decrease by 0.3 to 0.5 degrees C per minute to the temperature of -32 degrees C and then transferred directly into liquid nitrogen. They were thawed in a bath warm 20 to 37 degrees C. After thawed the cryoprotective agent was evacuated in 1.1 M sucrose. The best-quality embryos were selected for freezing. Out of these 366 thawed so far, with average survival of 74.31%. The total of the 268 thawed embryos were transferred ipsilaterally, by a non-surgical method, to 190 synchronised heifers, out of which 105 (55.26%) got in calf. Rapid freezing method based on 1.5 M of glycerol and thawing at the presence of 1.1 M sucrose proved effective and suitable for practice, as not only sufficient reviviscence of embryos and their survival in womb are guaranteed, but also a substantial shortening of the freezing as well as thawing process.

Artificial induction of twinning in cattle by means of supplemental embryo transfer.

The induction of twins by surgical and nonsurgical transfer was performed 6 - 8 days after Artificial Insemination (A.I.) in a total of 142 cows. Of the 47 heifers, which received surgically transferred embryos, 32 (68%) became pregnant. Of the 95 cows, which received nonsurgically transferred embryos, 58 (61,6%) became pregnant. A total of 90 (63.5%) of the recipient animals became pregnant. Up to date 64 recipients have calved; twins have resulted in 40 and 48,2% resp, from surgical and nonsurgical inductions. Out of a total of 64 calvings 29 (45,3%) were twins, and of these 38% were males, 27% were females, and 34% were mixed births. Female - calves resulted in freemartinism. There was no increase in the incidence of either retained placenta or dystocia. The induction of twinning by means of embryo transfer can be regarded as a useful method for the increase in the reproductive performance cattle.