Development of techniques for freezing equine embryos
Although we were able to show, in the mid 1980's, that equine embryos
could be frozen and thawed and result in live foals, this required
the collection of Day-6 embryos that were less than 300 microns in
size. Recent studies have focused on developing vitrification techniques
for rapid freezing of small embryos.
Refining techniques for freezing semen
Currently, equine sperm do not survive the freezing and thawing process
nearly as well as bull sperm. Therefore, studies are ongoing to evaluate
various cryoprotectants added to extenders in order to enhance the viability
of frozen-thawed sperm. These include substitution of amides for glycerol,
as well as addition of various sugars to the freezing extenders.
Assessing sperm damage after cooling and freezing
With the use of several new staining techniques, damage to sperm can
be assessed using the flow cytometer. This machine can evaluate whether
or not the sperm plasma membrane has been damaged or whether or not
the acrosome or mitochondria has incurred damage during the freezing
and thawing process.
Oocyte collection and maturation
Techniques have been developed for collecting oocytes from live mares using
transvaginal, ultrasound-guided aspiration. One can either collect in vivo-matured
equine oocytes by this technique or collect immature oocytes and subsequently
mature the oocytes in the laboratory. Once the oocytes mature they may be
transferred into the oviduct of a recipient mare (gamete intrafallopian
tube transfer) and the mare inseminated. This allows the oocyte to be fertilized
in vivo.
Another option is fertilization in vitro (test tube fertilization). Although we are working hard to perfect the techniques of in vitro fertilization, this work has proven unsuccessful except for sperm injection. Recently we were successful in producing the first test tube horse by intracytoplasmic sperm injection. Simply, this means that one sperm was injected into one egg.
Oocyte transfer
Oocyte transfer (OT) has been developed at CSU as a method to obtain foals
from mares that would otherwise be considered infertile because of problems
of their reproductive tract. For OT, oocytes (eggs) can be collected from
the ovarian follicles of mares and transferred into a recipient's oviduct
(fallopian tube). By using OT, we bypass any problems with the donor mare's
reproductive tract, such as uterine infections or a damaged cervix.
Intracytoplasmic sperm injection
Intracytoplasmic sperm injections (ICSI) have been used for many years for
human assisted reproduction. During ICSI, a single sperm can be microscopically
injected into the egg of a mare. CSU produced the first foal using ICSI
in 1996. Currently, research is being conducted at CSU to increase the success
of ICSI in the horse. CSU has used ICSI to produce foals from valuable stallions
with poor quality or limited sperm.
Development of techniques for inducing multiple ovulation
in mares
Embryo transfer is an extremely expensive procedure because of the low recovery
rate of embryos from mares. One possible way of decreasing the cost of embryo
transfer is to induce multiple ovulation in the mare, thus assuring recovery
of an embryo each time the mare's uterus is flushed. Studies are ongoing
to assess the use of equine FSH for induction of multiple ovulation in mares.
This procedure also will be helpful in enhancing the number of oocytes that
can be collected from mares by transvaginal, ultrasound-guided aspiration.
Most recently, the Laboratory has focused on the preservation of equine sperm, eggs and embryos. This area of research is primarily funded by private benefactors from the horse industry under a program entitled Preservation of Equine Genetics.
Clinical Services in Equine ReproductionA range of Equine Commercial Reproductive Services are offered by Colorado State University, including:
Graduate Studies in Equine ReproductionEquine reproduction graduate studies at Colorado State University offer opportunities for both Master of Science and Ph.D. degrees. For more information on the graduate program, please click here.
Contact Us
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Click on the map below
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From US Interstate 25, take exit 269B (also known as Hwy 14 or Mulberry St). Turn left to go west (toward the mountains).
Continue west on Mulberry until it dead-ends onto Overland Trail. Turn left to go south on Overland Trail. Drive up a short hill, then turn right onto Rampart Road. Drive 2-tenths of a mile west on Rampart Road. You will see the large hay barns on the right and the ARBL Equine Unit (Equine Reproduction Lab) on the left. Pull into the Equine Reproduction Lab's double brown gates. Park beside the runs on the right or pull around the barn to your right. The driveway is horseshoe-shaped, and you can park on the west side of the barn, as well as exit out of the gates on the west side of the barn.
