Edward L. Squires, PhDProfessor Office: W121 ARBL Building, Foothills Campus Member Education Link to a PubMed listing of Dr. Squires's
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Teaching Activities
I am one of the instructors in our short course series offered to horse breeders and equine practitioners.
Research Interests -- Assisted Reproductive Technology in the
Equine
Improving reproductive efficiency of mares and stallions is the goal of my research program. Hormonal regimens are evaluated for their efficacy in controlling estrus and ovulation in mares. These synchronization schemes are becoming very important with increased use of cooled, transported and frozen semen.
A series of studies is being conducted to determine the cause of seasonal and postpartum anestrus. Low pituitary content and secretion of LH during winter anestrus and early postpartum appears to be due to diminished secretion of GnRH. Research currently is focused on development of methods for administering GnRH to mares and stallions.
Studies also continue on embryo preservation, culture, freezing and bisection. We developed techniques for embryo transfer. Now equine embryos can be maintained at 5°C for 24 hours without altering fertility. Efforts to obtain foals from older mares are being made by developing techniques for oocyte collection, maturation and in vitro fertilization and intracytoplasmic sperm injection.
Studies on preservation of stallion spermatozoa also are of interest, with current research on determining the most appropriate cooling rate for storage of liquid semen and evaluation of seminal extenders.
Lastly, emphasis is being placed on investigating causes of lowered fertility in older, barren mares, such as uterine infection, failure of fertilization and early embryonic death.
For additional information on current projects, consult the page on Reproductive Technology.
Representative Publications
Squires EL, McCue PM, Vanderwall DK. 1999. The current status of equine embryo transfer. Theriogenology 51:91-104.
Denniston DJ, Squires EL, Bruemmer JE, Brinsko SP, McCue PM, Graham JK. 2000. Effect of antioxidants on the motility and viability of cooled stallion spermatozoa. J Reprod Fert (Suppl) 56:121-126.
McCue PM, Fleury JJ, Denniston DJ, Graham JK, Squires EL. 2000. Oviductal insemination of mares. J Reprod Fert (Suppl) 56:499-502.
Schmid RL, Kato H, Herickhoff LA, Schenk JL, McCue PM, Chung YG, Squires EL. 2000. Effects of follicular fluid or progesterone on in vitro maturation of equine oocytes before intracytoplasmic sperm injection with non-sorted and sex-sorted spermatozoa. J Reprod Fert (Suppl) 56:519-525.
Carnevale EM, Maclellan LJ, Coutinho da Silva MA, Scott TJ, Squires EL. 2000. Comparison of culture and insemination techniques for equine oocyte transfer. Theriogenology 54:981-987.
Crockett EC, Graham JK, Bruemmer JE, Squires EL. 2001. Effect of cooling of equine spermatozoa before freezing on post-thaw motility: Preliminary results. Theriogenology 55:793-803.
Lindsey AC, Bruemmer JE, Squires EL. 2001. Low dose insemination of mares using non-sorted and sex-sorted sperm. Anim Reprod Sci 68:279-289.
Maclellan LJ, Carnevale EM, Coutinho da Silva MA, Scoggin CF, Bruemmer JE, Squires EL. 2002. Pregnancies from vitrified equine oocytes collected from super-stimulated and non-stimulated mares. Theriogenology 58:911-919.
Squires EL, Carnevale EM, McCue PM, Bruemmer JE. 2003. Embryo technologies in the horse. Theriogenology 59:151-170.
Li G-P, Seidel GE Jr, Squires EL. 2003. Intracytoplasmic sperm injection of bovine oocytes with stallion spermatozoa. Theriogenology 59:1143-1155.
Dr. Squires demonstrating his dish-washing skills.
