Introduction to MOET (Multiple Ovulation Embryo Transfer)
MOET is also referred to as flushing or just ET. It has been used for over 30 years and is the main method used internationally to produce multiple pregnancies from elite donors.
A brief outline
Donors are treated to make them produce multiple ovulations rather than the single egg that is normally released.
- Donors are artificially inseminated.
- Embryos are “flushed” non-surgically a week later. Flushing is a good word to describe the process as the inside of the uterus is washed with a special media which is then passed through a filter to collect the embryos.
- The embryos produced are approximately 0.1 mm (100 microns) in diameter and are located using a microscope.
- The embryos are then graded and can be implanted into recipients or frozen for later implanting.
All of the programming is carried out on farm by the farmer under the supervision of their vet and the embryo company. It is simply a matter of following instructions and giving injections at milking time. Cows are flushed on-farm and embryology is carried out on-farm in a mobile laboratory. Embryos are collected and transferred on the same day.
A flow chart of the process can be found here.
- Q. How many embryos do you get per flush? A.This depends on many factors. Friesian dairy cows average five embryos per flush, Jerseys average six and beef cows average higher than this.
- Q. Do any donors fail to produce embryos? A. Overall, 20% of donors will fail to produce embryos for an individual flush.
- Q. What percentage of embryos develop into pregnancies? A. We work on 66% with fresh embryos and 55% for frozen embryos. However, results do vary depending on environmental effects, recipient type and embryo quality.
- Q. What happens when embryos are frozen? A. They are stored in liquid Nitrogen at -196 Celcius. In this state they can be kept indefinitely and can be transported (and exported) easily.
- Q. How quickly will donors get back in calf? A. Donors will generally cycle within ten days of embryo collection. This heat will have reduced fertility compared to usual. The following heat is of normal fertility.
- Q. What cows are suitable to use as donors? A. In general, any empty cow who is cycling and has no known reproductive problems is suitable. Results from yearlings are lower than from mature cows.