| Title |
Investigators | Department | Objectives | Approach Keywords | Progress Reports | Impact Statements | Publications | |
Project * COL00619 | |
| Title | Identification of Factors and Development of Technologies to Improve Efficiency of Assisted Reproductive Technologies in the Horse |
| Investigator(s) | Bruemmer, JE; Denniston, D; |
| Department | Animal Science |
| Objectives | 1. Identify nutrient, physical and/or biochemical attributes associated with viability and fertility of stallion spermatozoa following refrigeration and/or cryopreservation. 2. Identify dietary strategies to enhance viability of equine spermatozoa following refrigeration and/or cryopreservation based on factor(s) identified in objective 1. 3. Development of techniques and/or protocols designed to alter viability of stallion spermatozoa based on the outcome of objectives 1 and 2. 4. Identify factors associated with follicular development and subsequent formation of corpus luteum and the potential mechanism by which maternal recognition occurs uniquely in the mare. 5. Development of techniques and/or protocols designed to enhance fertility of the mare by incorporating the findings associated with objectives 3 and 4. 6. Disseminate the information generated through scientific, technical and industry publications, meetings and workshops for use by veterinarians and other equine professionals. |
| Approach | Stallion semen investigation: Use stallions currently housed at the Equine Reproduction Laboratory. We will investigate the difference in spermatozoa characteristics and associated fertility in this population of horses. Vitamin E and Omega-3 fatty acid will be fed and parameters related to sperm membrane and fertility will be investigated in neat, cooled and frozen-thawed samples. Maternal Recognition: Up to 24 mares will be used in a cross-over design where each animal will serve as her own control. Endometrial biopsies, CL biopsies, blood samples (and on pregnant cycles- embryos) will be collected from pregnant and non-pregnant cycles. Microarray analysis will be employed in an attempt to identify signaling pathways associated with the recognition of pregnancy as early as 12 d post-ovulation. |
| Keywords | equine, spermatozoa, maternal recognition |
| Progress Reports | |
| 1993 | Several studies were conducted to develop techniques to hasten the onset of estrus, superovulation, collection and maturation of oocytes in vitro along with studies of various techniques for cooling and handling of spermatozoa. Like humans, mares also experience reproductive tract pathology, resulting in infertility and failure to conceive. Studies conducted in horses help with the understanding of reproduction in other species. Two studies were conducted using GnRH implants to hasten ovulation. In both studies, a subcutaneous implant of GnRH analog induced ovulation within 48 h of injection with doses no higher than 2 .2 mg/mare. In another study, mares were superovulated with 40 mg of equine pituitary extract (EPE). Embryo recovery was less than expected, fertilization rates and embryo development were similar between superovulated and control mares. Studies were conducted to develop the technique of gamete intrafallopian tube transfer (GIFT) in mares using oocytes obtained by transvaginal ultrasound guided follicular aspiration. GIFT resulted in 2 out of 8 mares confirmed pregnant. Studies were conducted evaluating the effects of 4 extenders and 2 cooling rates on stallion spermatozoa. Samples from each treatment were cooled from 20 to 5 C at -0.05 or -.5 C/min. There was no overall effect of cooling rate on the treatments. Egg yolk and glycerol were detrimental to fertilizing ability of sperm cooled in a non-fat dried skimmed milk based extender. |
| 1994 | Several studies were conducted to develop techniques to hasten the onset of estrus, superovulation, collection and maturation of oocytes in vitro along with studies of various techniques for cooling and handling of spermatozoa. Like humans, mares also experience reproductive tract pathology, resulting in infertility and failure to conceive. Studies conducted in horses help with the understanding of reproduction in other species. Mares were superovulated with 40 mg of equine pituitary extract (EPE). Embryo recovery was less than expected, fertilization rates and embryo development were similar between superovulated and control mares. Studies were conducted to develop the technique of gamete intrafallopian tube transfer (GIFT) in mares using oocytes obtained by transvaginal ultrasound guided follicular aspiration. GIFT resulted in 2 out of 8 mares confirmed pregnant. Identification of embryonic signals necessary for suppression of PGF2-alpha and progesterone continued secretion is also being studied. Environmental quality and animal well-being is being tested in a stable bedding material comparisons and animal preference trial. Behavior trials on breeding stallions and saddle horses are being conducted. |
| 1995 | Several studies were conducted to develop techniques to hasten the onset of estrus, superovulation, collection and maturation of oocytes in vitro, along with studies of various techniques for cooling and handling of spermatozoa. Studies relating thyroid hormone with ovulation rate in GnRH treated mares were completed. Environmental quality and animal well-being is being tested in a stable bedding material comparisons and animal preference trial. Physiological effects of recycled phone book paper was compared with sawdust bedding. Behavior trials relating location of hair whorl patterns and agitation during restraint were completed. |
| 1996 | The first in vitro fertilization (test-tube foal) was born this year through the use of instructoplasmic sperm injection (ICSI) producing a 10 cell embryo for transplant. It was produced by injecting a single sperm into a single egg in vitro with ICSI sperm that is damaged can still be used to fertilize an egg as long as the sperm contains genetic material. On-going studies were conducted on fertility trial on techniques for cooling-freezing and handling of spermatozoa. Techniques for freezing semen by adding liposomes to extenders are being investigated. Cryptosporidium parvum, a parasite that can cause cryptosporidiosis in humans, has been investigated in adult horses used on trails. The study showed that .03% of the population was found to be positive by Merifluorcrypto/Giardia test kit. Our results show that horses used on Colorado trails are no threat to water supplies used for human consumption . Physiological and environmental effects of recycled paper were compared with other bedding materials showing paper to be as acceptable in a horses environment as other bedding sources. |
| 1997 | Several studies were conducted to investigate techniques for gamete preservation and factors affecting gamete preservation in the horse. Other studies were conducted to develop methods for, and to understand factors that influence reproductive efficiency of the mare and stallion . In addition, one study was conducted to determine whether oxidative stress within the equine joint is exacerbated during a diseased state. |
| 1998 | Several studies were conducted to investigate techniques for gamete preservation and factors affecting gamete preservation in the horse. Additional studies were conducted to develop methods and to understand factors influencing reproductive efficiency of the mare and stallion . Other studies were conducted exploring non-invasive techniques for use in monitoring bone growth and metabolism in the horse as well as the effect of nutrition on bone growth and metabolism in the horse. |
| 1999 | The use of cooled shipped semen for breeding mares has several advantages for mare owners. It eliminates the cost and complexities associated with shipping mares to stallions. One disadvantage of this technique is that the viability of sperm cells rapidly declines over time in cooled shipped semen. Therefore, shipment must be accurately timed with mare's ovulation for conception to occur, which is often difficult due to a relatively large degree of variation in predicting time of ovulation in the mare. Oxidative stress is thought to be a contributing factor to the decrease in the viability of sperm cells in cool shipped semen. An experiment was conducted to evaluate the effect of the addition of antioxidants to semen extenders on improving sperm viability in cooled shipped semen. As a result of this experiment , pyruvate was identified as a compound that can be added to stallion semen extenders and increase both motility and fertility of shipped cool semen thereby increasing the period of time that it can be used effectively for breeding mares. |
| 2000 | Joint disease is a significant health problem in equine athletes. Reactive oxygen species are compounds produced by the body that are capable of damaging all classes of biomolecules and have been implicated in the pathogenesis of joint disease in horses. However, evidence that reactive oxygen species are present in diseased joints of horses has not been reported. A study was conducted to determine if markers of reactive oxygen species are present in diseased joints at greater levels than in clinically normal joints. The results of this study suggest that reactive oxygen species are present at greater levels in diseased joints than in clinically normal joints. |
| 2001 | Statement of Problem: The use of cooled shipped semen for breeding mares has several advantages for mare owners. It eliminates the cost and complexities associated with shipping mares to stallions. One disadvantage of this technique is that the viability of sperm cells rapidly declines over time in cooled shipped semen. Therefore, shipment must be accurately timed with the mare's ovulation for conception to occur, which is often difficult due to a relatively large degree of variation in predicting time of ovulation in the mare. Oxidative stress is thought to be a contributing factor to the decrease in sperm cell viability in cooled shipped semen. Glutathione peroxidase is a selenium-containing enzyme that is an important antioxidant defense found in cells. In addition glutathione peroxidase activity with in cells can be influenced by dietary selenium. Description of the Study: Twelve stallions housed at the Colorado State University Equine Reproduction Laboratory are currently being used to determine if a relationship exists between spermatozoa viability and glutathione peroxidase activity in spermatozoa and seminal plasma. Spermatozoa viability is assessed by measuring motility. The motility of the spermatozoa, following cooling at 5o C for 48 h, varies considerably in these twelve stallions, ranging from 44 to 2%; and therefore provide a population to evaluate the relationship between post-cooling spermatozoa motility and spermatozoa- and seminal plasma-glutathione peroxidase activity. Following collection, a portion of the semen is processed for cooling. Spermatozoa motility is determined and recorded immediately prior to cooling at 5o C and following cooling for 24 and 48 h. The remaining portion of semen is separated into spermatozoa and seminal plasma, and analyzed for glutathione peroxidase activity. The correlation between spermatozoa motility and glutathione peroxidase activity of spermatozoa and seminal plasma is to be determined. If a positive relationship exists, then future studies will be conducted to determine whether glutathione peroxidase activity of spermatozoa and seminal plasma can be manipulated by dietary selenium, and subsequently used to improve spermatozoa viability following cooling to 5o C and storage for 48 h. |
| 2002 | Oxidative stress results from the production of reactive oxygen species generated in freeze/thaw cycles associated with the cryopreservation of equine spermatozoa, and is a significant factor influencing the ability of spermatozoa to successfully fertilize an egg. Spermatozoa contain several lines of antioxidant defense mechanisms protecting them from oxidative stress. One of which is glutathione peroxidase. Glutathione peroxidase is a selenium dependent enzyme that metabolizes hydrogen peroxide (a potential oxidative stressor) into water, and therefore is an important antioxidant defense mechanism for cells such as spermatozoa. Glutathione peroxidase activity is influenced by dietary selenium concentration. Therefore if a relationship exists between glutathione peroxidase activity and spermatozoa viability, post-cryopreservation, then dietary Se may be a useful tool for enhancing viability of spermatozoa following cryopreservation. We conducted an experiment to determine if a relationship existed between glutathione peroxidase activity (found in spermatozoa, seminal plasma, and blood plasma), and the viability of spermatozoa post-cooling at 5 degrees Celsius. Based on the outcome of this experiment we determined that there was a moderate relationship between blood plasma glutathione peroxidase activity and spermatozoa viability following cooling at 5 degrees Celsius. This finding does not imply a cause and effect relationship; however it does provide evidence for the justification of future experiments aimed at manipulating dietary selenium and the subsequent effect on spermatozoa viability following cryopreservation. |
| 2003 | Currently, cooling and shipping equine spermatozoa is a routine procedure at breeding farms, but freezing stallion spermatozoa requires a facility with additional cryopreservation capabilities that most breeding farms do not have. It is possible to ship cooled semen from a breeding farm to a facility capable of freezing semen; however the effect of cooling and transporting the semen, prior to freezing, on spermatozoa viability is unknown. Therefore a study was conducted to determine the effect of cooling to 5 degrees C for 0 (control), 6, or 18 hours prior to freezing on motion characteristics, viability, and acrosome membrane status, as well as, pregnancy rates in mares inseminated with cooled-frozen equine spermatozoa. Based on these experiments stallion spermatozoa can be effectively cooled and stored at 5 degrees C for 18 hours prior to cryopreservation without a significant decrease in motion characteristics and viability compared to the current cryopreservation protocol. However, 18-hour cooled-frozen spermatozoa has a lower percentage of live unacrosome reacted spermatozoa which may lead to a reduction in pregnancy rates compared to controls, but was unable to be detected in the current study. |
| 2004 | The use of frozen semen in breeding mares is widely practiced by horse breeding operations. Although frozen semen has several benefits (e.g. preservation of desirable genetics, greater accessibility to superior genetics), difficulties associated with its use in breeding mares exist. When stallion spermatozoa are frozen and thawed, seminal characteristics including fertilization rates are further impaired. Alteration of spermatozoa membrane structure during freezing is thought to be a major factor contributing to reduced fertilization rates achieved with frozen semen. Attempts to improve fertilization rates have been made by adding various compounds that confer a protective effect on spermatozoa membranes. The success of these compounds has varied. As a result new compounds are continually being investigated for their ability to protect spermatozoa during the freezing process and improve their viability upon thawing and insemination. Sodium hyaluronate is a compound found in cell membranes. Sodium hyaluronate addition to human and boar semen improves spermatozoa viability following a freeze-thaw cycle. A recent experiment conducted at Colorado State University Equine Reproduction Laboratory evaluated the effect of sodium hyaluronate addition to equine semen following a freeze-thaw cycle on post thaw spermatozoa characteristics. The study results indicate addition of 200 micrograms sodium hyaluronate/ml to freezing media slightly increased post thaw motility, but differences were not statistically significant. Addition of sodium hayluronate at a much greater concentration (1,000 micrograms sodium hyaluronate/ml) was detrimental to post-thaw motility. |
| 2005 | Oxidative stress results from the production of reactive oxygen species generated in freeze/thaw cycles associated with the cryopreservation of equine spermatozoa, and is a significant factor influencing the ability of spermatozoa to successfully fertilize an egg. Spermatozoa contain several antioxidant defenses protecting them from oxidative stress. One of which is glutathione peroxidase. Glutathione peroxidase activity depends upon the trace mineral selenium, and metabolizes hydrogen peroxide (a potential oxidative stressor) into water. Therefore, glutathione peroxidase is an important antioxidant defense mechanism for cells such as spermatozoa, and selenium is a dietary essential. Supplemental dietary selenium is available in two primary forms: inorganic and organic. Sodium selenite is the most common inorganic supplemental selenium form used in feeding horses. Selenomethionine is an organic selenium form that has recently been approved for use in livestock species other than horses, but little is known regarding its use for supplementing horses. Results from experiments conducted in species other than horses suggest that sodium selenite and selenomethionine are metabolized differently relative to their function in glutathione peroxidase. The effect of these two supplemental selenium sources on glutathione peroxidase activity in horses is unknown.We conducted a short term experiment (i.e., 56 d) to determine the effect of either sodium selenite or selenomethionine on the glutathione peroxidase activities in plasma, erythrocytes, and skeletal muscle. The results of our study indicated no clear difference between dietary selenium source on the glutathione peroxidase activities in plasma, erythrocytes and skeletal muscle. |
| 2006 | In order to maximize the efficiency (or fertility) or cooled and/or frozen semen, two parameters can and were investigated. The first involves the sperm cells themselves. During the past few years studies were conducted to investigate the effects of cryopreservation on the sperm cells. Both freeze rate and type of cryoprotecant were evaluated. These studies suggest that stallion semen is rather tolerant of osmotic changes prior to cryopreservation and that glycerol remains the better cryoprotectant. As a follow up we investigated the possibility of protecting the cells following the freeze-thaw cycle by enhancing membrane fluidity with cholesterol (as has been demonstrated in the bull). We found that semen motility parameters were increased. These data suggest that a fertility trial is in order. The second factor effecting fertility of the semen is the mare. We investigated the possibility of enhancing fertility by both increasing the chances of fertilization by increasing the number of oocytes available each cycle and by minimizing the sperm used through a more synchronous ovulation. We discovered that by "coasting" treatment of FSH mares were more responsive and produced more follicles. We were less successful in manipulating ovulation through the suppression of LH. |
| Impact | |
| 1999 | The addition of pyruvate to stallion semen extenders improves the efficiency of using cooled shipped semen. More efficient use of cooled shipped semen opens up new markets for stallion owners as well as reduces costs and risks assumed by mare owners associated with shipping mares to stallions. |
| 2000 | This finding should stimulate more research, aimed at investigating the actual role of the reactive oxygen species in joint disease and developing means of intervention to minimize their effect. |
| 2001 | If glutathione peroxidase activity is related to spermatozoa viability following the 48 hr incubation at 5oC, then experiments will be designed to determine if glutathione peroxidase activity can be manipulated via dietary selenium. Therefore the results of this experiment will impact the direction of future experiments aimed at providing horse breeders with techniques to make breeding mares with cooled semen a more efficient process. |
| 2002 | The finding that blood plasma glutathione peroxidase activity is moderately associated with spermatozoa viability following cooling at 5 degrees Celsius provides justification for future experiments aimed at manipulating dietary selenium and the subsequent effect on spermatozoa viability following cryopreservation. |
| 2003 | These findings provide an alternative to traditional practices for freezing stallion semen allowing breeding farms that do not have facilities for freezing stallion semen to use frozen semen as a means of cryopreservation. |
| 2004 | The results of this study provide a starting point for future study on the effect of sodium hyaluronate on post-thaw characteristics of frozen stallion spermatozoa in hopes of improving its viability and subsequent efficiency for use in breeding mares. |
| 2005 | Both sodium selenite and selenomethionine appear to have similar effects at maintaining glutathione peroxidase activity of plasma, erthrocytes and skeletal muscle over a short period of supplementation (i.e., 56 d). The long term effect of these two supplemental selenium sources on glutathione peroxidase activity has not been determined for horses, nor has their effect on spermatozoa glutathione peroxidase activity. Future experiments are being designed to evaluate the effect of organic versus inorganic supplemental selenium source on a longer term basis and measuring glutathione peroxidase activity in spermatozoa. |
| 2006 | We developed a procedure by which cholesterol can be added to the sperm membrane and aid in maintenance of post thaw motility (and presumably fertility). Additionally, we have enhanced fertility by increasing the chance of fertilization by stimulating the mare to produce more oocytes each cycle. Together these procedures should make the use of processed semen more effective. |
| Publications | |
| 1993 |
ALLEN, N.T. 1993. The effects of mediolateral balance on equine hoofs. M.S. Thesis, Colorado State University, Ft. Collins, 97 p. COOK, N.L., E.L. SQUIRES, B.S. RAY AND D.J. JASKO. 1993. Transvaginal ultrasonically guided follicular aspiration of equine oocytes. Equine Vet. J. 15:71-74. FARLIN, M.E., D.E. JASKO, J.K. GRAHAM AND E.L. SQUIRES. 1993. Heparin-induced capacitation: a comparison between the bull and stallion. Equine Vet. J. 15:71-74. JASKO, D.J., M.E. FARLIN, H. HUTCHINSON, D.M. MORAN, E.L. SQUIRES AND P.J. BURNS. 1993. Progesterone and estradiol in biodegradable microspheres for control of estrus and ovulation in mares. Theriogenology 40:465-478. KNOWLES, J.E. ET AL. 1993. Relationship of progesterone to early pregnancy loss in mares. J. Equine Vet. Sci. 13(9):528-533. LONG, P.L. ET AL. 1993. Identification of immature germ cells in semen of stallions. Equine Prac. 15(5):29-33. LONG, P.L. ET AL. 1993. Relationship between morphologic and seminal characteristics of equine spermatozoa. J. Equine Vet. Sci. 13(3):143-149. SQUIRES, E.L. 1993. Use of progestins in open and pregnant mares. Anim. Rep. Sci. 33:183-193. SWINKER, A.M. ET AL. 1993. Effect of body weight and body condition score on follicular development and ovulation in mares treated with GnRH analogue. J. Equine Vet. Sci. 13(9):519-520. TARR ET AL. 1993. Successful treatment of a horse with chronic, severe flexural deformity of the distal interphalangeal joint. J. Equine Vet. Sci. 13(12):9-12. |
| 1994 |
CHAMBERLAIN, R. and E.L. SQUIRES. 1994. Pointing the finger: Preparing stallions for breeding season. The Quarter Racing Journal, Dec. 1994, pp. 44-47. COOK, N. 1994. Transvaginal ultrasound-guided follicular aspiration of equine oocytes: Aspects of technique and effect in cycling mares. M.S. Thesis. Colo. State Univ. -- DIPPERT, K.D. 1994. Follicular development and superovulation in the mare. Ph.D. Diss. Colo. State Univ. DIPPERT, K.D., B.S. RAY and E.L. SQUIRES. 1994. Maximizing ultrasound-guided retrieval of equine oocytes. Proc. Int. Embryo Transfer Soc., Australia (Theriogenology) 41:190. DIPPERT, K.D., D.J. JASKO, G.E. SEIDEL, Jr. and E.L. SQUIRES. 1994. Fertilization rates in superovulated and spontaneously ovulating mares. Theriogenology 41:1411-1423. DISCAFANI, C. Functional state of primary and secondary corpora lutea during mid-gestation in the pregnant mare. M.S. Thesis. Colorado State University, Ft. Collins. DISCAFANI, C.M., E.L. SQUIRES and G.D. NISWENDER. 1994. Functional state of primary and secondary corpora lutea in pregnant mares. Sixth Int. Equine Reprod. Symp., Caxambu, Brazil. HEITLAND, A. 1994. Effects of seminal extenders on motion characteristics and fertility of cooled and frozen stallion spermatozoa and an evaluation of procedures for cryopreservation of stallion spermatozoa. M.S. Thesis. CSU. HEITLAND, A.V., D.J. JASKO, J.K. GRAHAM, R.P. AMANN and E.L. SQUIRES. 1994. Motility and fertility of stallion spermatozoa cooled and frozen in modified skim milk extender containing egg yolk and liposomes. Sixth Int. Equine Reprod. Symp., Caxambu, Brazil. JASKO, D.J., S.J. BEDFORD, N.L. COOK, E.L. MUMFORD et al. 1994. Effect of antibiotics on motion characteristics of cooled stallion spermatozoa. Theriogenology 40:885-893. MUMFORD, E. 1994. Applications for exogenous gonadotropin- releasing hormone treatment in the mare. M.S. Thesis. Colorado State University, Ft. Collins. MUMFORD, E.L. et al. 1994. Use of gonadotropin-releasing hormone estrogen, or a combination to increase releasable pituitary luteinizing hormone in early transitional mares. J.Anim.Sci. 72:174-177. MUMFORD, E.L., E.L. SQUIRES, K.D. PETERSON, T.M. NETT et al. 1994. Effect of various doses of GnRH analogue on induction of ovulation in anestrous mares. J.Anim.Sci. 72:178-183. PFAFF, R., G.E. SEIDEL, Jr. and E.L. SQUIRES. 1994. Effects of glycerol and ethylene glycol on survival of equine embryos. J. Anim. Sci. 72(Suppl. 1):82. RAY, B.S., E.L. SQUIRES, N.L. COOK, S.F. TARR, D.J. JASKO and K.L. HOSSNER. 1994. Pregnancy following gamete intrafallopian transfer in the mare. J. Equine Vet.Sci. 14:27-30. SISSENER, T., E.L. SQUIRES and C.M. CLAY. 1994. Early developmental equine embryo suppression of endometrial PGF2-alpha. Sixth Int. Equine Reprod. Symp., Caxambu, Brazil. SQUIRES, E.L. 1994. Comings and goings. Equine Sciences Newsletter, Spring, Vol. 12, No. 4, p. 7. SQUIRES, E.L. 1994. Equine embryo transfer. Equine Sciences Newsletter, Winter, Vol. 12, No. 3 , p. 1. SQUIRES, E.L., D.M. MORAN, M.E. FARLIN, D.J. JASKO, T.J. KEEFE, S.A. MEYERS, et al. 1994. Effect of dose of GnRH analog on ovulation in mares. Theriogenology 41:757-769. SQUIRES, E.L., S.F. TARR, R.K. SHIDELER et al. 1994. Use of transvaginal ultrasound-guided puncture for elimination of equine pregnancies during days 50 to 65. J. Equine Vet.Sci. 14:203-206. SWINKER, A.M. 1994. Animal warning issued on blister beetles in Hay. The Horseman's Voice. Vol . XIII, No. 5, May, pp. 14-16. SWINKER, A.M. 1994. Arabian horses donated to Colorado 4-H members. Equine Science Newsletter. Vol. 12, No. 3, p. 2. SWINKER, A.M. 1994. Blister beetle spotted in 1993 hay supplies. Rocky Mountain Quarter Horse. January,k pp. 91-92. SWINKER, A.M. 1994. Blister beetles. Equine Practice. Vol 16, No. 2, February, p. 28. SWINKER, A.M. 1994. Colorado Horse Expo features Equine Science staff. Equine Science Newsletter. Vol. 12, No. 3, p. 6. SWINKER, A.M. 1994. Colorado ranks 4th in nation. The Maverick Press. Vol. 1, Issue 7, April, pp. 1-21. SWINKER, A.M. 1994. Colorado State's horse industry update. Colorado Agri-Business Roundup. SWINKER, A.M. 1994. Don't get bugged this summer. The Maverick Press, Vol. 1, Issue 9, June, pp. 8-9. SWINKER, A.M. 1994. Don't let horses develop vices -- an ounce of prevention is worth a pound of cure. The Maverick Press. Vol. 1, Issue 5, January, p. 4. SWINKER, A.M. 1994. Drought -- reason for selenium toxicity in horses. The Maverick Press. September, p. 5. SWINKER, A.M. 1994. Focus on Rocky Mountain Horse Expo. The Record Stockman. No. 14, 105th, April, pp. 21-22. SWINKER, A.M. 1994. Horse Expo stallion row filling fast. The Maverick Press. Vol. 1, Issue 5, January, p. 7. SWINKER, A.M. 1994. Horse Expo to feature trade show. The Maverick Press. Vol. 1, Issue 5, January, p. 15. SWINKER, A.M. 1994. Horse Expo. Equine Practice. Vol. 2, No. 2, February, p. 28. SWINKER, A.M. 1994. Humane treatment of 4-H animals. Horse section, Extension publication. SWINKER, A.M. 1994. Plan Rocky Mountain Horse Expo in April. The Horseman's Voice. February, p . 30 SWINKER, A.M. 1994. Rocky Mountain Horse Expo focuses on horse industry. The Maverick Press. Vol. 1, Issue 6, February, p. 6. SWINKER, A.M. 1994. Rocky Mountain Horse Expo to feature educational programs. The Maverick Press. Vol. 1, Issue 7, April, p. 10 SWINKER, A.M. 1994. Rocky Mountain Horse Expo. Equine Sciences Newsletter. Vol. 12, No. 4, Spring, p. 10. SWINKER, A.M. 1994. State FFA Horse Judging Contest held in new Adams-Atkinson Arena. Equine Sciences Newsletter. Vol. 12, No. 4, Spring, p. 11. SWINKER, A.M. 1994. The perfect match. How genetics can improve your breeding program. International Arabian Horse. November, pp. 26-31. SWINKER, A.M. 1994. The Rocky Mountain Horse Expo. Equine Veterinary Data. Vol. 1.15, No. 2, p . 18 SWINKER, A.M. 1994. Transported semen. Colorado Horse News. April. SWINKER, A.M. 1994. Volunteers key to Rocky Mountain Expo. The Maverick Press. Vol. 1, Issue 5 , January, p. 5. SWINKER, A.M. and D.E. JOHNSON. 1994. Equine industries manure disposal practices, variations and magnitude. Great Plains Animal Waste Conference on Confined Animal Production and Water Quality Proceedings. GPAC No. 151 SWINKER, A.M. and J. HEIRD. 1994. Trends, opportunities and issues in the horse industry. In: Encyclopedia of Agricultural Science. Academic Press, San Diego, CA SWINKER, A.M., E.L. SQUIRES and E.L. MUMFORD. 1994. Correlation of thyroid hormone levels to ovulation in anestrous mares treated with varying doses of GnRH analogue. 14th Equine Nutr. and Physio. Soc. Symp. SWINKER, A.M., M.J. DEESING, M. TANNER and T. GRANDIN. 1994. Observation of normal and abnormal hair work patterning on the equine forehead. ADSA/ASAS proceedings WILHELM, K. 1994. The motility, cell viability, and acrosomal status of fresh and cryopreserved stallion spermatozoa. M.S. Thesis. Colorado State University, Ft. Collins. WILHELM, K.M., J.K. GRAHAM and E.L. SQUIRES. 1994. Motility and fertility of cryopreserved stallion spermatozoa in three extenders. Sixth Int. Equine Reprod. Symp., Caxambu, Brazil. |
| 1995 |
DIPPERT, K.D. 1995. Follicular development and superovulation in the mare. Ph.D. Dissertation, Colo State Univ., Fort Collins. -- GRANDIN, T., DEESING, M.J., STRUTHERS, J.J. and SWINKER, A.M. 1995. Cattle with hair whorl patterns above the eyes are more behaviorally agitated during restraint. Appl. Anim. Behav. Sci. 638 SWINKER, A.M. and JOHNSON, D.E. 1995. Equine industry manure disposal practices, variation and magnitude. ARPAS, Vol. 12, No. 4 SWINKER, A.M., SQUIRES, E.L. and MUNFORD, E.L. 1995. Correlation of thyroid hormone levels to ovulation in anestrous mares treated with varying doses of GnRH analogue. 14th ENPS Proc. p. 292-297 TANNER, M.K., SWINKER, A.M., ET AL. 1995. Physiological effects of recycled phone book paper vs sawdust bedding on the equine respiratory tract. Amer. Soc. Anim. Sci. 106:321 (Abstr.) |
| 1996 |
ANDERSON, T.M., B.W. PICKETT, J.C. HEIRD, and E.L. SQUIRES. 1996. Effect of blocking vision and olfaction on sexual responses of haltered or loose stallions. J. Eq. Vet. Sci. 16:254-261 BRUBAKER, J. 1996. Effect of Sperm Number and Frequency of Insemination on Fertility of Mares Bred with Cooled Semen. Master's Thesis, Colorado State University, Fort Collins, CO DIPPERT, K.D., B.S. RAY and E.L. SQUIRES. 1996. Aspiration of the dominant follicle and its effect on subsequent follicular development in mares 3 and 6 days later. Anim. Reprod. Sci. 40:77-88. -- HEITLAND, A.V., D.J. JASKO, E.L. SQUIRES, J.K. GRAHAM, B.W. PICKETT, and C. HAMILTON. 1996. Factors affectnig motion characteristics of frozen-thawed stallion spermatozoa. Eq. Vet. J. 28:47-53. -- LEHR, T and A. SWINKER. On Top in the Land Down Under, Western Horseman, September 1996, p. 112 LEIPOLD, S. 1996. Effect of Concentration and Sperm Number on Fertility of Frozen Equine Semen . Master's Thesis, Colorado State University, Fort Collins, CO McGRAGER, S., A. SWINKER, D. MARTIN, G. RUSK, and D. LAMM. 1996. A Survey of youth horse team participation in competitions. Master Thesis, Colorado State Univ MCGREGOR, M.S., SWINKER, A.M., LAMM, W.D., MARTIN, D.H. and RASK, G. 1995. A survey of youth horse team participation in compeitions. Am. Soc. An. Sci. 125:137 (Abstr. PICKETT, B.W., S.L. BADZINSKI and E.L. SQUIRES. 1996. Effects of altrenogest on stallion seminal characteristics, sexual behavior and total scrotal width. 2nd Int. Symp. on Stallion Semen, The Netherlands RAY, B. 1996. Transvaginal Ultrasound-Guided Follicular Aspiration, In Vitro Maturation and Transfer of Equine Oocyts. Master's Thesis, Colorado State University, Fort Collins, CO SICILIANO, P.D., PARKER, A.L. and LAWRENCE. 1996. Effect of dietary vitamin E supplementation on the integrity of skeletal muscle in the exercising horse. Am. Soc. An. Sci. 342:192 (Abstr. SISSENER, T.R., E.L. SQURE, and C.M. CLAY. 1996. Differential suppression of endometrial prostaglandin F2a by the equine conceptus. Theriogenology 45:541-546 SQUIRES, E.L. 1996. Early Embryonic Death. Equine Diagnostic Ultrasonography, A.O. McKinnon and N.W. Rantanen (eds.) In Press SQUIRES, E.L. 1996. Maturation and Fertilization of Equine Oocytes. Veterinary Clinics of North America: Equine Practice on Diagnostic Techniques and Assisted Reproductive Techniques. E.L. Squires (ed) 12:31-45 SQUIRES, E.L. 1996. Ultrasound-Guided Follicular Aspiration. Equine Diagnostic Ultrasonography , A.O. McKinon and N.W. Rantanen (eds). In Press SQUIRES, E.L. 1996. use of Transvaginal Ultrasound-Guided Puncture for Elimination of Equine Pregnancies. 1996. Veterinary Clinics of North America: Equine Practice on Diagnostic Techniques and Assisted Reproductive Techniques, E.L. Squires (ed) 12:161-168 SQUIRES, E.L. and N.L. COOK. 1996. Veterinary Clinics of North America: Equine Practice on Diagnostic Techniques and Assisted Reproductive Techniques, E.L. Squire (ed) 12:13-29 SQUIRES, E.L., BRUBAKER, J.E. and P.M. MCCUE. 1996. Sperm number and frequency of insemination on fertility of mares bred with cooled semen. Am. Soc. An. Sci. 524:238 SQUIRES, E.L., J.K. BRUBAKER and P.M. McCUE. 1996. Sperm number and frequency of insemination on fertility of mares bred with cooled semen. Proc. Western Section Am. Soc. Anim. Sci SQUIRES, E.L., J.M. WILSON, H. KATO and A. BLASCZYK. 1996. A pregnancy after intracytoplasmic sperm injecton into equine oocytes matured in vitro. Theriogenology 45:306 SQUIRES, E.L., S.D. LEIPOLD and J.K. Graham. 1996. The effect of sperm concentration and total motile sperm numbers on pregnancy rates of mares inseminated with frozen-thawed stallion spermatozoa. 2nd Int. Symp. on Stallion Semen, The Netherlands STIFFLER, L., SWINKER, A.M., and PEAIRS, F. 1996. Equine industry forageutilization practices, variations and magnitude. Am. Soc. An. Sci. 381:202 (Abstr. SWINKER, A and N. BROWN. History of the Rocky Mountain Horse Expo, Horse West News, March 1996 , p. 9 SWINKER, A. 1996. Being Prepared for the Worst: Develop a health care plan for your horse. Colorado Horse Council. Leadline, October 1996 SWINKER, A. 1996. Colorado State Equine Science Students Honored at Rocky Mountain Horse Expo, Equine Sci. Newsletter, Vol. 14, No. 2, p. 6 SWINKER, A. 1996. Horse Care on Small Acreages in Colorado, Part II, Horse West News, July 1996, p. 11-16 SWINKER, A. 4-H Youth Program Judges Training Clinic. CSU Equine Sci. Newsletter, Vol. 14, No. 1, P. 8 SWINKER, A. and N. BROWN. Welcome to Rocky Mountain Horse Expo, 1996. Horse West News, April 1996, p. 8 SWINKER, A., CSU Students Honored at Rocky Mountain Horse Expo, 1996 Maverick Press, p. 24 SWINKER, A.M. 1996. Determining horse temperament and its relationship to hair whorl patterns. 1996 Am. Youth Horse Council (Proc. TANNER, M.K. 1996. Recycled phonebook paper as bedding for horses: Physiological effect on the equine respiratory tract, effect on stall air quality and evaluation of decomposition and disposal, MS Thesis. Colo State Univ, p. 103 WILHELLM, K.M., J.K. GRAHAM, and E.L. SQUIRES. 1996. Effect of phosphatidylserine and cholesterol liposomes on the viability, motility and acrosomal integrity of stallion spermatozoa prior to and after cryopreservation. Cryobiology 33:320-329 WILHELM, K.M., J.K. GRAHAM, and E.L. SQUIERS. 1996. Comparison of the fertility of cryopreserved stallion spermatozoa with sperm motion analyses, flow cytometric evaluation and zona-free hamster oocyte penetration. Theriogenology 46:559-579 YOUNG, C. 1996. Cryopreservation of Day 7-7.5 Equine Embryos, Master's Thesis, Colorado State University, Fort Collins, CO |
| 1997 |
DENNISTON, D.J., E.L. SQUIRES, J.K. GRAHAM and S.P. BRINSKO. 1997. The effect of liposomes on fertility rates using frozen-thawed equine spermatozoa. Proc. 15th Equine Nutrn. Physiol. Soc. Symp KATO, H., G.E. SEIDEL, JR, and E.L. SQUIRES. 1997. In vitro fertilization after maturation of equine oocytes with epidermal growth factor or removal of cumulus cells. Proc. IV. Int. Symp. Equine Embryo Transfer, Reims, France, pp. 21-22 MCCUE, P.M., D.K. VANDERWALL and E.L. SQUIRES. 1997. Fetal mummification in a mare. J. Equine Vet. Sci. 17:267-269 MCCUE, P.M., S.S. LEMONS, E.L. SQUIRES, and D.K. VANDERWALL. 1997. Efficacy of Synovex-S(R) implants in suppression of estrus in the mare. J. Equine Vet. Sci. 17:327-329 NICKERSON, K.C., P.M. MCCUE and E.L. SQUIRES. 1997. Comparison of two dosage regimens of the GnRH agonist deslorelin acetate on reducing ovulation in seasonally anestrous mares. Proc. 15th Equine Nutr. Physiol. Soc. Symp SQUIRES, E.L., H. KATO, J.M. WILSON and G.E. SEIDEL, JR. 1997. Effect of activation of equine oocytes with A23187 after intracytoplasmic sperm injection. Proc. IV Int. Symp. Equine Embryo Transfer, Reims, France, p. 20 SQUIRES, E.L., S.D. LEIPOLD, J.K. GRAHAM and B.W. PICKETT. 1997. The effect of sperm concentration and total motile sperm numbers on pregnancy rates of mares inseminated with frozen-thawed stallion spermatozoa. Proc. 15th Equine Nutrn. Physiol. Soc. Symp SQUIRES, E.L., S.L. BADZINSKI, R.P. AMANN, P.M. MCCUE and T.M. NETT. 1997. Effects of atrenogest on total scrotal width, seminal characteristics, concentrations of LH and testosterone and sexual behavior of stallions. Theriogenology 48:313-328 YOUNG, C., E.L. SQUIRES and G.E. SEIDEL, JR. 1997. Effects of three methods of cryopreservation on survival of large equine blastocysts. Proc. IV Int. Symp. Equine Embryo Transfer, Reims, France, p. 32 YOUNG, C., E.L. SQUIRES and G.E. SEIDEL, JR. 1997. Effects of three methods of cryopreservation on survival of large equine blastocysts. Theriogenology 47:395 |
| 1998 |
Brinsko, S.P., Squires, E.L., Pickett, B.W., and Nett, T.M. 1998. Gonadal and pituitary responsiveness of stallions is not down-regulated by prolonged pulsatile administration of GnRH. J. Androl. 19:100-109 Brubaker, J.K., Squires, E.L., McCue, P.M., and Pickett, B.W. 1998. Effect of sperm number and frequency of insemination on fertility of mares inseminated with cooled semen. Theriogenology 49:743-749 Franz, L.C., Landon, J.C., Lopes L.A., Marinho, L.A., Sarma, C., Bruemmer, J.E., and Squires, E.L. 1998. Oral intravenous immunoglobulin therapy in neonatal foals. J. Equine Vet. Sci. 18:742-748 Leipold, S.D., Graham, J.K, Squires, E.L., McCue, P.M., Brinsko, S.P., and Vanderwall, D.K. 1998. Effect of spermatozoal concentration and number on fertility of frozen equine semen. Theriogenology 49:1537-1543 McCue, P.M., Thayer, J., Squires, E.L., Brinsko, S.P., and Vanderwall, D.K. 1998. Twin pregnancies following transfer of single embryos in three mares: A case report. J. Equine Vet. Sci. 18:832-834 Nickerson, K., McCue, P.M., Squires, E.L., and Nett, T.M. 1998. Comparison of two dosage regimens of the GnRH agonist deslorelin acetate on inducing ovulation in seasonally anestrous mares. J. Equine Vet. Sci. 18:121-124 |
| 1999 |
Brisko, S.P., Crockett, E.C. and Squires, E.L. 1999. Effect of centrifugation and seminal plasma removal on equine spermatozoal motility after cooling and storage. Proc. Equine Nutrn. Physiol. Soc. Symp., pp. 54-57 Bruemmer, J.E., Coy, R.C., Olson, A. and Squires, E.L. 1999. Efficacy of altrenogest administration to postpone ovulation and subsequent fertility in mares. Proc. 16th Equine Nutr . Physiol. Soc. Symp., pp. 336-337 Bruemmer, J.E., McCue, P.M. and Squires, E.L. 1999. Follicular stimulation of postpartum mares using equine pituitary extract. Proc. Equine Nutr. Physiol. Soc. Symp., pp. 200-201 Buchanan, B.R., McCue, P.M., Squires, E.L., Seidel, Jr., G.E. and Fleury, J.J. 1999. Pregnancy rates in mares folowing a single insemination with a low number of spermatozoa into the tip of the uterine horn. Theriogenology 51:395 Burns, P.J., Betschart, R., Fleury, J., Squires, E.., Nett, T.M., Gibson, J., Sullivan, S. and Tipton, A. 1999. Evaluation of the SABER-TM delivery system for the controlled release of the GnRH analogue deslorelin for advancing ovulation in mares: Effect of gamma radiation. Proc. Equine Nutr. Physiol. Soc. Symp., pp. 338-342 Burns, P.J., Squires, E.L., Sissener, T., Heitland, A., Wilhelm, K., Farlin, M., Foss, R. and Woods, J. 1999. Evaluation control of estrus and ovulation in mares using progesterone and estradiol biodegradable microspheres in a multicenter clinical trial. Proc. Equine Nutr. Physiol. Soc. Symp., pp. 194-199 Carnevale, E.M., Alvarenga, M.A. and Squires, E.L. 1999. Use of oocyte transfer in a commercial breeding program to obtain pregnancies from mares with reproductive pathologies. Proc. 45th Ann. AAEP Conv., pp. 200-202 Choi, Y.H., Chung, Y.G., Landim-Alvarenga, F.C., Seidel, Jr., G.E. and Squires, E.L. 1999. Development of equine oocytes matured in vitro and fertilized after partial zona removal (PZR) . Biol. Reprod. (Suppl. 1):176 Choi, Y.H., Landim-Alvarenga, F.C., carnevale, E., Seidel, Jr., G.E. and Squires, E.L. 1999. Penetration by stallion sperm of zone-free bovine oocytes matured in equine prevoulatory follicular fluid. Theriogenology 51:316 Coy, R.E., McCue, P.M., Bruemmer, J.E. and Squires, E.L. 1999. Follicular response of mares in deep or transitional anestrus to equine pituitary extract. Proc. Equine Nutrn. Physiol. Soc. Symp., pp. 65-68 Crockett, E.C., Graham, J.K., Bruemmer, J.E. and Squires, E.L. 1999. Effects of centrifugation and cooling prior to freezing on post-thaw motility of equine spermatozoa. Proc. Equine Nutr. Physiol. Soc. Symp. Pp. 192-193 Fleury, J.J., Betschart, R., Squires, E.L., Nett, T.M., Gibson, J., Sullivan, S.A., Tipton, A .J. and Burns, P.J. 1999. Evaluation of the SABER-TM delivery system for the controlled release of the GnRH analogue deslorelin for advancing ovulation in mares: Effect of dose and formulation. Proc. Equine Nutrn. Physiol. Soc. Symp., pp. 343-348 Hoyt, S. and Siliciano, P.D. 1999. A comparison of ELISA and RIA techniques for detection of serum osteocalcin in horses. Proceedings of the 15th Equine Nutrition and Physiology Symposium , Raleigh, NC p. 351-352 Hoyt, S., and Siciliano, P.D. 1999. Evaluation of precision and accuracy of commercially available enzyme linked immunoassays of bone-specific alkaline phosphatase and C-terminal propeptide of type I collagen for use in horses Proceedings of the 15th Equine Nutrition and Physiology Symposium, Raleigh, NC, p. 349-350 Hurtt, A.E., Seidel, Jr., G.E. and Squires, E.L. 1999. Vitrification of equine and bovine oocytes in an ethylene glycol, Ficoll and sucrose solution using open pulled straws. Theriogenology 51:166 Keith, S.L., Squires, E.L., Graham, J.K. and Brinsko, S.P. 1999. Evaluation of cryoprotectants for the preservation of equine spermatozoa. Proc. Equine Nutr. Physiol. Soc. Symp., pp. 268-269 Landim-Alvarenga, F., Alvarenga, M., Carnevale, E., Boyazoglu, S., Ramirez, R., Seidel, Jr., G .E. and Squires, E.L. 1999. Transfer of equine gametes to rabbit oviducts: An approach to produce equine embryos. Biol. Reprod. (Suppl. 1):176 McCue, P.M., Buchanan, B.R., Farquehar, V.J., Squires, E.L. and Cross, D.L. 1999. Efficacy of domperidone on induction of ovulation in anestrous and transitional mares. Proc. 45th Ann. AAEP Conv., pp. 217-218 McCue, P.M., Vanderwall, D.K., Keith, S.L. and Squires, E.L. 1999. Equine embryo transfer: Influence of endogenous progesterone concentration in recipients of pregnancy outcome. Theriogenology 51:267 Squires, E.L., Crockett, E.C., Graham, J.K. and Bruemmer, J.E. 1999. Effect of centrifugation and cooling prior to freezing on post-thaw motility of equine spermatozoa. Proc. 45th Ann. AAEP Conv., pp. 219-220 Squires, E.L., McCue, P.M., and Vanderwall, D.K. 1999. The current status of equine embryo transfer. Theriogenology 51:91-104 Vanderwall, D.K., Betschart, R.W. and Squires, E.L. 1999. Effect of prostaglandin F2a and 13, 14 dihydro-15-keto-prostaglandin F2a on corpora luteal function in nonpregnant mares. Proc. Equine Nutr. Physiol. Soc. Symp., pp. 204-205 |
| 2000 |
Dimock, A.N., Siciliano,P.D., and McIlwraith, C.W. 2000. Evidence supporting an increased presence of reactive oxygen species in the diseased equine joint. Equine vet. J. 32(5)439-443. |
| 2001 |
Bruemmer, J.E., Brady, H.A., and Blanchard, T.L. 2001. The use on one or two doses of progesterone and estradiol to postpone the first postpartum ovulation. Theriogenology July 19, 2001 Bruemmer,J.E., Coy, R.C., Graham, J.K., and Squires, E.L. 2001. Effect of pyruvate on the function of stallion spermatozoa stored for up to 48 hours. J. Anim. Sci. August, 2001 Burns, P.D., Nelson, S.E., Bruemmer, J.E., Escudero, J.M., and Clay, C.C. 2001. Regulation of cyclooxygenase-2 gene expression in bovine endometrial cells. Proc. 34th Ann Society for the Study of Reproduction. Crockett, E.C., Graham, J.K., Bruemmer, J.E., and Squires, E.L. 2001. Effects of centrifugation and storage at 5C on motility of frozen/thawed equine semen. Theriogenology 55:793-803. Foster H., Whittier, J.C., Burns, P.D., Bruemmer, J.E., Field, T., and Geary, T.W. 2001. Half dose GnRH does not affect pregnancy rates with the CO-Synch synchronization protocol. Proc. 2001 ASAS Western Section Ann. Mtg. Foster H., Whittier, J.C., Burns, P.D., Bruemmer, J.E., Baker, D., Engle, T., Field, T., Wailes, W.R., Geary, T.W., Anderson, D.C., and Boss, D.L. 2001. Use of bovine somatotropin in conjunction with CO-Synch and Select Synch protocols for synchronizing estrus and ovulation in beef cows. Proc. 2001 ASAS Western Section Ann. Mtg. Lindsey, A.C., Bruemmer, J.E., and Squires. E.L. 2001. Low dose Insemination of Mares. Animal Reproduction Sciences. 68:279-289. Lindsey, A.C., Bruemmer, J.E., Sondergard, R.L., Squires, E.L. 2001. Insemination of mares with 18h stored, sex-sorted spermatozoa. Society of Theriogenology. Vancouver, BC, Canada Lindsey, A.C., Morris, L.H.A., Allen, W.R., Schenk, J.L., Squires, E.L., and Bruemmer, J.E. 2001. Hysteroscopic insemination of mares with low numbers of non-sorted or flow-sorted spermatozoa. Equine Vet. J. July 19, 2001 Lindsey, A.C., Schenk, J.L., Graham, J.K., Bruemmer, J.E., and Squires, E.L. 2001. Hysteroscopic insemination of low numbers of flow-sorted frozen/thawed stallion spermatozoa. Equine Vet. J. July 19, 2001 Oberstein, N. O'Donovan, M.K., Bruemmer, J.E., Seidel Jr., G.E., Caravale, E.M., and Squires, E.L. 2001 Cryopreservation of equine embryos by open-pulled straw, cryoloop or conventional slow cooling method. Theriogenology 55:607-613. Squires, E.L., Carnevale, E.M., Bruemmer, J.E., and McCue, P.M. 2001. Advanced reproductive technologies in the horse. European Association of Animal Production. Budapest, Hungary. Squires, E.L., Lindsey, A.C., and Bruemmer, J.E. 2001. Sex selection of stallion spermatozoa. From Epididymis to Embryo and Beyond. Havermeyer Foundation Workshop. New Orleans, LA. |
| 2003 |
Hardy, Quinn. 2003. Effects of cooling prior to cryopreservation of stallion spermatozoa and pregnancy rates in mares, Master's Thesis. |
| 2006 |
Denniston, D.J., Crabb, J.J., Bruemmer, J.E., Squires, E.L. 2006. Effects of gonadotropin-releasing hormone antagonist and altrenogest on luteinizing hormone concentration and ovulatin in the mare. J. Equine Vet Sci 26:95-101. Moore, A.I., Squires, E.L., Bruemmer, J.E., Graham, J.K. 2006. Effect of freeze rate and cryoprotectant on the cryosurvival of equine spermatozoa. J. Equine Vet. Sci 26:215-218. Spizziri, B.E., Bruemmer, J.E., Squires, E.L., and Graham, J.K. 2006. Cryopreservation of cholesterol-loaded cyclodextrin-treated stallion sperm. Abstr. Proc. Soc. Thereiogenology Ann. Mtg. Welch, S.A., Denniston, D.J., Hudson, J.J., Bruemmer, J.E., McCue, P.M., Squires. E.L. 2006. Exogenous eFSH follicle coasting and hCG as a novel superovulation regimen in mares. J. Equine Vet. Sci. 26:262-270. |