Bova-Tech Ltd.

Embryo Transplants

General Information > Donors


Selection of donors is very important.  Donors are usually selected on the basis of superior genetic merit compared with the rest of the herd.  Whether the criterion is performance records, show ring appeal, or both, consid­eration must be given to the potential dollar value of her calves.

 The potential donor cow should be reproductively sound to produce maximum results, some of the important criteria to look for in prospective donors are:

  • Normal postpartum history
  • Regular heat cycles (length of 18 to 24 days)
  • Body condition of 2.5 to 3.5-4 (skinny or fat animals tend to do poorly in most cases)
  • Heifers are more unpredictable than cows and usually produce fewer embryos. Heifers should be 350 kg or more, be cycling and have a well developed reproductive tract.
  • Young cows are usually preferred (3 to 8 years old). Embryo production in old cows varies greatly depending on their genetics, but in general the older the cow gets, the lower the chances of being a successful donor.


  1. Nutrition:
    1. Cows need to be under a good nutritional plan including mineral supplementation.
    2. Maintaining or increasing an acceptable body condition. Cows losing condition or over-conditioned have a lower reproductive activity.
  2. Reproductive tract examination:
    It is always recommended that cows are palpated and tested by ultrasound before entering into the ET program. When preparing donor cows to be done on-farm, your local veterinarian can examine your cows to determine the status of their reproductive tract.
    1. Normal uterus involution after calving.
    2. Discard the presence of pathological conditions including uterine infections, if there is a problem, it needs to be treated accordingly before a cow is place into an ET program.
    3. Ensure that the cows are open.
    1. Determine the presences and quality of normal ovarian structures. Cycling vs. non-cycling.
    2. Presence of abnormalities such as cystic ovaries, adhesions of scar tissue, etc.
  3. Health:
    1. Vaccinations should be up to date. Pay special attention when using modified live vaccines for BVD and IBR. If vaccinating, cows need to be done 40 days or more before starting the super-ovulation protocol.
    2. Do not dip the cows with pour on medications for at least 10 days before starting the super-ovulation protocol.
  4. Handling:
    1. Handle donors with calm and keep them under as low stress environment as possible.
    2. CIDR application and injections can be administered by the producer right on-farm as it is easy enough.
    3. How to apply CIDRs. It is recommended to rinse and disinfect your CIDR applicator between cows.
      Click here for printable EAZI-BREED CIDR instructions (English)
      Click here for printable EAZI-BREED CIDR instructions (Spanish)
    4. Ensure that all injections are administered intramuscularly (the neck region is preferred especially in over-conditioned cows).
    5. When giving injections, always check donors to ensure the CIDR is still in place.
    6. Typical super-ovulation protocol for donor cows.
      Description: C:\Users\Owner\Desktop\BTL Web Pics & Tex\Donor superov protocol.jpg Click to enlarge
  5. Insemination/Semen:
    1. Two inseminations are required and are performed 12 hours apart; the timing of the 1st breeding will depend on the super-ovulation protocol to be used.
    2. Use high quality semen, in general it is recommended to have three dosages of semen on hand in case one may explode or the cow shows an extended heat that will require a 3rd breeding. On some occasions and under specific circumstances a few more straws of semen will be recommended.
    3. If there is any doubt regarding the quality of the semen to be used, please let us know. We can evaluate frozen semen prior to use, increasing the chances for success by discarding potentially infertile or sub-fertile semen.
    4. Save all semen straws for us and attach them to the super-ovulation record.
  6. Flushing Day:
    1. It is recommended to have an indoor place to flush a cow since at certain times of the year the environmental conditions can be unpredictable. Donor cows cannot be flushed outdoors when is raining, too cold, or extremely windy.
    2. Have the super-ovulation record filled out and returned to us.
    3. Please check and let us know if the cow needs to be DNA tested.

NOTE: Keep us informed with the development of the program. In case of any problems or if you have any questions, please let us know so we can help with the situation before is too late. Make sure the instructions are understood and followed precisely, since these programs are very sensitive.