12 December 2008
ET - Embryo Transper -Terraweena Stud
Transfer of embryos
With the exception of the freeze-thaw cycle indicated above, the transfer of fresh or frozen embryos is essentially the same. Most embryo transfers are performed using the laparoscope, in a fashion similar to that used for AI. As transfers can be made quite quickly, local anesthesia and sedation are often sufficient. Once the animal is placed on the tilt table, the abdomen is prepared routinely and infiltrated with local anesthetic. The laparoscope is placed through the abdominal wall and the ovaries inspected for evidence of one or more CL's. A CL (corpus luteum) is a progesterone producing body on the ovary where an ovulation occurred. Usually in sheep and goat recipients more than one CL is observed. If a normal CL is identified, a small incision is made on the midline of the abdomen, forward of the udder. The tip of the uterine horn corresponding to the ovary bearing the CL is pulled out. A fine catheter is used to transfer the embryos into the uterine horn. The uterine horn is allowed to return to the abdomen and the small incisions are closed. In most cases, two embryos are transferred into each suitable recipient although this may range from one to three. Pregnancy rates are usually higher with fresh embryos than frozen embryos of a similar developmental stage. The steps involved in freezing can result in the destruction of some cells of the embryo and may reduce the ability of the embryo to develop normally.
An injection of long acting penicillin or tetracycline is given and depending upon the operator, anti-inflammatory products may be recommended. In the majority of cases, post-operative recovery is rapid. Donors and recipients should be monitored for at least a week for signs of illness and treatment begun immediately if deemed appropriate.