About AI | Embryo Transfer

Embryo Transfer (ET)

The Society rules state that bloodtypes or DNA profiles must be submitted for both sire and dam used in ET programs.
Like AI, bovine Embryo Transfer is a technique for genetic enhancement. The standard procedure involves treating a donor female with hormones, which causes superovulation. She is then inseminated several times. The fertilised eggs are collected at 7 days and transferred to recipient cows, which were in oestrus at the same time as the donor. The recipient then carries the embryo till the calf is born. Fertilised eggs can also be successfully frozen for implantation at a later date.
ET can be a useful tool for a new breeder to get established by buying superior females and multiplying these rapidly. Importing and exporting of embryos also gives breeders worldwide access to a wider genetic pool and is a much cheaper and safer technique than International movements of live animals.
Donors can either be programmed and have embryos collected on farm by a recognised ET technician or most ET companies offer donor housing and flushing at a central facility, many of which are approved for export of embryos.

Selection of Donors
Embryo transfer is a valuable breeding tool to either rapidly multiply the offspring of valuable or superior females that have been recognised as such on genetic or economic merit. True genetic value is the most important long range consideration. Treatment of heifers under 15 months of age is not recommended. Success rates may decline when cows older then 12 years are used.
Cows that have been calved at least 45 days are suitable as donors and must have been checked by a veterinarian to ensure no reproductive abnormalities. Donor cows should be on a high energy ration during the program especially if lactating. Mineral and trace element balance on the property is important for successful ET results as with all reproduction.
The expectations for results are an average of 8 good embryos collected from each donor. The more donors programmed should give results near the average.

Selection of Recipients
Selecting animals for a recipient dam is a matter of striking a balance among standards of quality, economic feasibility and availability. The ideal recipient is a young, disease free cow with proven fertility and mothering ability. Recipients should be on a rising plane of nutrition during an ET program. If the calf she will carry is likely to be larger than she would usually deliver, she should be well grown and have a history of easy calving.
Old cows and wild cows should not be used. Another consideration is to use cull cows from the purebred herd as long as they are healthy, reproductively sound and can adequately rear a calf. This is because their EBV's can then be factored into the ET offspring's EBV's. If using other breeds, for performance recording purposes, it is better to use all the same breed of recipient. Results of 60% live calves from either fresh or frozen embryos implanted should be achievable.

Health
Rigid health tests should be conducted on all recipients before introducing them to your property. Consult the Association or progressive stud principals for suggestions of which Embryo Transplant company they recommend to conduct your embryo transfer program. Expertise of the technician is vital to the success of any program.

ET Programs
Donor programs can vary considerably but could look like the following.

Day 0 - Insert CIDR to Donor
Day 2 - Inject Donor 1 ml CIDIROL
Day 6,7,8,9 - Inject superovulation hormone twice daily. Inject PG day 8 and remove CIDR same day
Day 10 - Observe Oestrus in donor(s) and breed at least twice
Day 17 - Collect embryos and implant or freeze

Recipient Programs
Recipients need to be synchronised to be in oestrus the same day as the donor in order for the reproductive tract to be receptive to the implantation of the embryo. This can be achieved in several ways but following the same programs as above for AI will achieve good synchronisation of recipients except that they must not be bred or allowed anywhere near a bull.

The different ET companies all have several hormone programs to suit various individual situations so please consult with them.