Equine Intracytoplasmic Sperm Injection Program
Purpose of the Intracytoplasmic Sperm Injection Program
The intracytoplasmic sperm injection (ICSI) program is offered at Texas A&M as a means of establishing pregnancies from oocytes (eggs) recovered from donor mares. Using ICSI, oocytes are injected with individual sperm from a donor stallion, and the resulting embryos are allowed to develop in the laboratory for approximately one week. Developed embryos are then shipped to a private embryo transfer facility for transfer to a recipient mare, as for standard embryo transfer.
This advanced reproductive technology is appropriate for mares that are unable to become pregnant themselves (i.e., mares with chronic uterine disease, cervical lacerations, or other damage to the reproductive tract that prohibit the mare from conceiving or supporting an embryo in the uterus for any length of time). The procedure can also be performed when pregnancies are sought from limited sperm supplies.
We recommend that the ICSI procedure only be used on mares that are not suitable candidates for routine embryo transfer (i.e., mares in which viable embryos are seldom recovered from standard uterine flushing), or, if done to obtain foals from a given stallion, for sperm that cannot be utilized effectively with standard insemination techniques. Because of the expense of the technology involved and the amount of labor associated with ICSI, foals produced from this program should be valuable enough to justify the increased effort and expense to produce offspring. Before participating in the ICSI program, it is important for each owner/lessee to know the regulations of their breed registry regarding the possibility of registering any resulting foals.
Overview of the procedure
Intracytoplasmic sperm injection is a technique in which oocytes (eggs) of a valuable broodmare (donor mare) are fertilized in the laboratory. The oocytes are recovered from the mare’s ovarian follicles, and then cultured to induce maturation, mimicking the developmental changes that would occur in an oocyte during the day or so immediately before ovulation. This maturation process generally takes 12 to 30 hours, depending upon the stage of maturation of the recovered oocytes.
Matured oocytes are injected with individual sperm from the desired stallion. For this procedure, one sperm is injected into the cytoplasm of each oocyte under a high-power microscope. The resulting fertilized oocytes are cultured in the laboratory for 7 to 10 days, to allow development into blastocysts, that is, embryos suitable for transfer to a recipient mare. Embryos will be shipped to a private embryo transfer facility for transfer to recipient mares.
The donor mare’s oocytes are typically removed from all follicles on the ovary once every two weeks, using a transvaginal ultrasound-guided technique with the mares under sedation. This procedure is performed at the Large Animal Clinic of Texas A&M University (TAMU), or can be performed by a referring veterinarian who then will ship the oocytes to the Equine Embryo Laboratory. Multiple oocytes are generally obtained during each session.
Alternatively, only the one large follicle preparing to ovulate may be aspirated, to recover a maturing oocyte; again, this may be performed approximately once every 2 weeks.
The attached contract with the Equine Embryo Laboratory includes processing of received oocytes, fertilization, embryo culture and shipment or vitrification of resulting embryos.
All charges related to the transfer of resulting embryos to recipient mares will be billed to you, the client, by the embryo transfer facility performing the transfer and are not included in our contract.
When transvaginal aspiration of all follicles is performed, at the Large Animal Clinic at A&M we typically recover oocytes from 50% of the follicles aspirated. For a Quarter-type mare with an average number of follicles, this means that around seven oocytes are typically recovered per aspiration. About 65% of these oocytes are expected to mature in the laboratory, giving an average of four to five mature oocytes to be injected with sperm. We anticipate a 20% rate of blastocyst development if the sperm is from a fertile stallion, thus about 1 blastocyst on average per aspiration. Our expected rate of ongoing pregnancies after embryo transfer is currently 65%.
Costs for the program are given in our fee schedule; please see the links at the top of this page.
For questions about laboratory procedures (oocyte maturation, intracytoplasmic sperm injection, embryo culture and shipment) or to schedule a mare for clinical aspiration, contact:
Ms. Kindra Rader | Equine Embryo Laboratory
Department of Veterinary Physiology & Pharmacology
Texas A&M College of Veterinary Medicine & Biomedical Sciences
4466 TAMU | College Station, Texas 77843-4466
Tel: 979.458.3894 (lab) | 979.219.7543 (business cell)