  |
Management of Embryo RECIPIENT ANIMALS
The selection and management of the animals to be used as embryo recipients is critical to the success of the embryo transfer program. Unfortunately, producers, having already invested a considerable amount on the purchase and the transfer of the embryos, will often try to minimize expense on the purchase and care of recipients. That is a serious mistake which can seriously undermine the embryo program.
Selecting acceptable recipients
The following recommendations apply to choosing recipients:
 | dam-line sheep breeds preferred - ideally 25 % prolific breed with extended breeding season and good maternal traits |
| reproductively proven - ideally, one or two uncomplicated birthings |
| good udders |
| good body condition (score of 3/5) |
| on a rising plane of nutrition- primarily calorie based (grains) diet with little legume content |
| up-to-date with vaccinations (clostridial essential) and de-wormings |
| ideally maedi-visna/ CAE negative |
| weaned at least 6 weeks prior |
| properly tattooed or ear tagged |
| consider insuring for the value of the embryos |
Consider SRGenetic's high-health status recipients to use in your ET program.
PROGRAMMING RECIPIENT ANIMALS
Recipients are synchronized into estrus with the donor animals and embryos are transferred - normally 6 to 7 days following estrus.
Typical SHEEP OR GOAT RECIPIENT PROGRAM - number of days (duration of pessary) may vary between programs
DAY |
ACTION |
|
| 0 | progesterone (vaginal pessary) inserted remove fleece from abdominal region | |
| 10 | inject prostaglandin | |
| 12 | PM | pessary removed and give 500 iu PMSG intra muscularly |
| 13 | PM | IF AVAILABLE - teaser
ram introduced for 24 hrs OR - 50 ugm GnRH |
| 19 | FROM NOON | withhold food and water following AM feeding |
| 20 | embryo transfer day |
EMBRYO TRANSFER PROCEDURE AND NORMAL RATES OF SUCCESS
Embryos are transferred with the aid of a laparoscope. Normally, two good quality embryos are transferred to each recipient. If lesser quality embryos are present they may be added. In some cases up to four embryos are transferred. Normal rates of success for good quality embryos (those that survived the freezing well) in a well managed program are:
| EXPECTED PREGNANCY RATE PER WELL MANAGED RECIPIENT RECEIVING 2 TO 3 GOOD EMBRYOS | EXPECTED LAMBING RATE PER GOOD QUALITY EMBRYO TRANSFERRED | |
| FRESH EMBRYOS | 70% |
60-70% |
| FROZEN EMBRYOS | 60% |
50-60 % |
ET companies can not guarantee any level of success. The rates reported are typical of those experienced in our program and reported world-wide with good embryos in a well managed program. However, disappointment or even a complete failure is not uncommon. Clients must understand the uncertainty and those factors that can effect success. When good quality embryos are placed correctly, the factor that has the greatest influence on the success is the timing and management of the recipient ewe.
The client must also realize that embryo transfer is a surgical procedure with the normal risks that surgery implies. Animals must be vaccinated for clostridial disease and should be adequately insured against accidental death.
CLIENT RESPONSIBILITIES
1. PLAN TO USE ONE RECIPIENT FOR EVERY TWO EMBRYOS TO BE TRANSFERRED
2. PROVIDE TWO EXTRA RECIPIENTS FOR EVERY 10 PLANNED- PARTICULARLY DURING OUT-OF-SEASON PERIOD
3. INSURE THAT RECIPIENTS ARE NOT PREGNANT
4. INSURE CORRECT USE OF VAGINAL PESSARIES AND DRUGS
5. WITHHOLD ALL FOOD AND WATER THE NIGHT BEFORE SURGERY
6. HAVE EWES IN SHORT FLEECE TWO WEEKS PRIOR TO TRANSFER DATE
7. ARRIVE WITH THE ANIMALS IN CLEAN CONDITION - ADEQUATE BEDDING IN TRANSPORT
8. ARRIVE WITH A CLEAN TRUCK AND CLEAN BEDDING
9. ARRIVE WITH CLEAN BOOTS AND CLOTHING (CLEAN COVERALL PREFERABLY) AND BE PREPARED TO CLEAN BOOTS THOROUGHLY ON ARRIVAL
10. PROVIDE TWO PHYSICALLY CAPABLE PEOPLE TO DO ANIMAL HANDLING, INCLUDING LIFTING AND REMOVING RECIPIENTS FROM SURGICAL TABLES. We will all be busy with the embryos or the surgery.