Embryo transfer in mares the reality Clones Why
Embryo transfer in mares -the reality
Clones Why E. T. ? Continued competition of donor Donor unable to carry pregnancy & split embryos, cloning, zoo spp.
D. I. Y. Take embryo from one mare and put it into another mares at the same stage of the estrous cycle. Tranfer retards the embryo so a recipient uterus can be up to 3 days "younger" but better results w. better synch.
Superovulation? e. FSH often increases ovulations up to 3 or 4 but not always & Not available
Synchronizing estrous cycles: big bands of mares or P&E
Collection of embryos Day 6 (freezing/splitting) Day 6 - 8 for general purposes ET & shipping
The basic setup
Collection of embryos Day 6 (freezing/splitting) Day 6 or 7 for general purpose ET
Medium: Dulbeccos PBS & glucose & antibiotics = commercial flushing media
Checking system. .
Insert catheter & lock cranial to Cx with ~ 80 ml air
Instill 1 -2 l at body temp. Wait 3 -5 minutes & flush by gravity at least 3 times Chances of finding an embryo? 189 flushes 31% on first 3 flushes but 46% w. 4 flushes (oxytocin in last)
Instill 1 -2 l at body temp. Wait 3 -5 minutes & flush by gravity at least 3 times Chances of finding an embryo? 189 flushes 31% on first 3 flushes but 46% w. 4 flushes (oxytocin in last)
Between 9 to 30% of mare remain pregnant! Discuss termination of pregnancy w. owner
Of those retrieved Keep embryos wet 2 liters : 55% retrieval & 4 liters : 25% retrieval & 8 liters: 20 % retrieval
Washing & cleanliness is of great importance
Search for the embryo
Emphasize cleanliness!
Washing 10 x
Transfer through the Cx with great care. 7 day old embryo Use a triple guarded Cassou gun for transfer Altrenogest ? NSAIDs?
6 days after ET � � � Caveats � � Donors ~ as young as possible; 2 yrs old ~ embryos in 80% 15 yrs old ~ embryos < 20% � � �
The reality check Assume 50% embryo retrieval Assume 70% pregnancy after transfer Probability of a foal is ~ 35% with one attempt.
Attempt # Pregnant ? Yes (35%) 2 3 Total amount spent Chance of this happening in all attempts $2000. 00 35% $2000. 00 65% $2000. 00 12%* $4000. 00 42%* $2000. 00 4%* $6000. 00 27%* No (65%) Yes 1 Cost No Yes &Yes No & No $2000. 00 Yes, Yes & Yes No, No & No $2000. 00 * Similar probability to tossing a coin twice in a row. One multiplies the two probabilities to determine the probability of “heads” occurring twice in a row
The cost of one time ET ~ $3500. plus drug costs, PD. leasing fees, semen Dr E. Squires. CSU: “If the foal is not worth $10, 000 as a weanling, then you are probably not terribly justified (in doing ET) unless it is an emotional decision”
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