· PDF fileChristoffersen, M., et al., Inflammatory responses to induced infectious...
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UCDAVIS VETERINARY MEDICINE Randomized Comparative Trial of Methods to Clear Intrauterine Fluid in Mares Laura Swift, MPH, Ghislaine Dujovne, DVM MS, Mollie Samocha, MS, Bruce Christensen, DVM MS Department of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616 Background Results • Post breeding endometritis is a leading cause of early embryonic loss in the mare. 1,2 • An acute inflammatory response to semen and other debris resulting in uterine fluid is a normal physiological response and provides a mechanism for the uterus to clear contaminants. 1-7 • The vast majority of mares clear intrauterine fluid by 24 hours. 2-5,8,9 • 15% of mares are susceptible to continued pooling of fluid and inflammatory products 24-48 hours after breeding that can eventually threaten the viability of an embryo. 1-9 • Risk factors for susceptibility: poor perineal conformation, a pendulous uterus, failure of the cervix to relax during estrus, fluid retention in diestrus, advanced age, increased intraluminal nitric oxide, reduced myometrial contractility, poor lymphatic drainage, and underlying defects in innate immunity. 1-10 • Failure of embryonic survival results in considerable economic loss to the equine industry and poses a clinical challenge to veterinarians. 1-9 Study Objectives Routine therapy for persistent mating-induced endometritis is directed at removing fluid that has accumulated in the uterine lumen. Uterine ecbolics that promote smooth muscle contraction are well studied, however acupuncture and exercise are commonly prescribed yet their efficacy is unknown. • Aim 1: Determine if exercise is an effective method to reduce intrauterine fluid • Aim 2: Determine if acupuncture is an effective method to reduce intrauterine fluid • Aim 3: Compare the efficacy of exercise and acupuncture to well-established treatments of oxytocin and prostaglandin Materials and Methods Selection of mares Twenty mares were screened for susceptibility to persistent post breeding endometritis. Twelve susceptible mares were enrolled into the study based on response to insemination with freeze-killed stallion semen. Mares were considered susceptible if post breeding uterine fluid accumulation measured greater than 2cm at 48 hours based on the average of the long axis and the width of the greatest perpendicular column of fluid. 3,12 Study design, randomization, and treatment The study is following twelve mares through six estrous cycles with a randomized crossover design that uses both positive and negative controls. Each mare is challenged by all six treatment groups using a Latin Square: Prostaglandin Stall Rest Oxytocin Oxytocin & Exercise Exercise Discussion Sequence of events proposed by Woodward and Troedsson that occur after breeding in susceptible and resistant mares. Yellow text refers to resistant mares, orange text to susceptible mares, and white text to both. 7 Susceptible Not Susceptible Figure 1. Uterine Fluid Measurements by Treatment Group at 4, 24, and 48 Hours Post Breeding 4 Hours 24 Hours 48 Hours • Since only 23 of 72 treatments have been completed to date, enough data has not been compiled to analyze the efficacy of acupuncture and exercise. However, results from positive and negative controls are turning out as predicted, which lends confidence that study findings will have merit. • Acupuncture, one of the primary treatment groups of interest, has been difficult to study as some mares have refused to accept electro-acupuncture treatment. In clinical practice, mares that receive acupuncture for post breeding endometritis have already received acupuncture for other ailments and are accustomed to the treatment. • Mares selected for enrollment into the study conformed to many of the risk factors for susceptibility identified in the literature. References: Group 1: Acupuncture Group 2: Exercise Group 3: Exercise & oxytocin Group 4: Oxytocin (positive control) Group 5: Prostaglandin (positive control) Group 6: Stall rest (negative control) • Mares were bred with 500 x 10 6 dead sperm resuspended in 50 mL of milk based semen extender • Uterine fluid measurements were obtained by transrectal ultrasound at 0, 4, 24, 48, 72, and 96 hours • In most treatment groups, mares received treatment at intervals of 6, 12, 24, 36, and 48 hours Statistics • Associations between treatment efficacy and fluid clearance are being investigated using a random-effects logistic regression model • Time to fluid clearance is being investigated with a Kaplan-Meir Survival Analysis Conclusions • In future acupuncture studies mares should be screened for acceptability of acupuncture as a criteria for enrollment into the study • Based on ongoing results from positive and negative control groups, the study is well positioned to evaluate the efficacy of acupuncture and exercise as treatments to clear intrauterine fluid. • The results presented are preliminary and the final results can vary substantially. A special thank you for the generous financial and research support provided by the STAR Program and the Center for Equine Health. 1. Vanderwall, D.K., Early Embryonic Loss in the Mare. Journal of Equine Veterinary Science, 2008. 28(11): p. 691-702. 2. Maischberger, E., et al., Equine post-breeding endometritis: A review. Ir Vet J, 2008. 61(3): p. 163-8. 3. Brinsko, S.P., et al., A practical method for recognizing mares susceptible to post-breeding endometritis. 2003, American Association of Equine Practitioners (AAEP): Lexington. p. 363-365. 4. Christoffersen, M., et al., Inflammatory responses to induced infectious endometritis in mares resistant or susceptible to persistent endometritis. BMC Veterinary Research, 2012. 8(1): p. 1-14. 5. Troedsson, M.H. and E.M. Woodward, Our current understanding of the pathophysiology of equine endometritis with an emphasis on breeding-induced endometritis. Reprod Biol, 2016. 16(1): p. 8-12. 6. Troedsson, M.H.T., Problems After Breeding. Journal of Equine Veterinary Science, 2008. 28(11): p. 635-639. 7. Woodward, E.M. and M.H. Troedsson, Equine Breeding-Induced Endometritis: A Review. Journal of Equine Veterinary Science, 2013. 33(9): p. 673-682. 8. Liu, I.K. and M.H. Troedsson, The diagnosis and treatment of endometritis in the mare: yesterday and today. Theriogenology, 2008. 70(3): p. 415-20. 9. McCue, P.M., The Problem Mare: Management Philosophy, Diagnostic Procedures, and Therapeutic Options. Journal of Equine Veterinary Science, 2008. 28(11): p. 619-626. 10. Troedsson, M.H.T., A.M. Alghamdi, and J. Matissen, Proceedings of the 8th International Equine Reproduction Symposium. Equine seminal plasma protects the fertility of spermatozoa in an inflamed uterine environment. Theriogenology, 2002. 58(2): p. 453-456. 11. Blanchard, T.L., et al., Effects of ecbolic agents on measurements of uterine involution in the mare. Theriogenology, 1991. 36(4): p. 559-571. 12. Mesa, A.M., et al., l-Arginine supplementation 0.5% of diet during the last 90 days of gestation and 14 days postpartum reduced uterine fluid accumulation in the broodmare. Animal Reproduction Science, 2015. 159: p. 46-51.
Transcript of · PDF fileChristoffersen, M., et al., Inflammatory responses to induced infectious...
UCDAVIS VETERINARY MEDICINE
8
Randomized Comparative Trial of Methods to Clear Intrauterine Fluid in Mares
Laura Swift, MPH, Ghislaine Dujovne, DVM MS, Mollie Samocha, MS, Bruce Christensen, DVM MSDepartment of Population Health and Reproduction, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616
Background
Results
• Post breeding endometritis is a leading cause of early embryonic loss in the mare.1,2• An acute inflammatory response to semen and other debris resulting in uterine fluid is a normal
physiological response and provides a mechanism for the uterus to clear contaminants.1-7• The vast majority of mares clear intrauterine fluid by 24 hours.2-5,8,9• 15% of mares are susceptible to continued pooling of fluid and inflammatory products 24-48 hours after
breeding that can eventually threaten the viability of an embryo.1-9• Risk factors for susceptibility: poor perineal conformation, a pendulous uterus, failure of the cervix to
relax during estrus, fluid retention in diestrus, advanced age, increased intraluminal nitric oxide, reduced myometrial contractility, poor lymphatic drainage, and underlying defects in innate immunity.1-10
• Failure of embryonic survival results in considerable economic loss to the equine industry and poses a clinical challenge to veterinarians.1-9
Study ObjectivesRoutine therapy for persistent mating-induced endometritis is directed at removing fluid that has accumulated in the uterine lumen. Uterine ecbolics that promote smooth muscle contraction are well studied, however acupuncture and exercise are commonly prescribed yet their efficacy is unknown.
• Aim 1: Determine if exercise is an effective method to reduce intrauterine fluid• Aim 2: Determine if acupuncture is an effective method to reduce intrauterine fluid• Aim 3: Compare the efficacy of exercise and acupuncture to well-established treatments of oxytocin and
prostaglandin
Materials and MethodsSelection of maresTwenty mares were screened for susceptibility to persistent post breeding endometritis. Twelve susceptible mares were enrolled into the study based on response to insemination with freeze-killed stallion semen. Mares were considered susceptible if post breeding uterine fluid accumulation measured greater than 2cm at 48 hours based on the average of the long axis and the width of the greatest perpendicular column of fluid.3,12
Study design, randomization, and treatmentThe study is following twelve mares through six estrous cycles with a randomized crossover design that uses both positive and negative controls. Each mare is challenged by all six treatment groups using a Latin Square:
Prostaglandin
Stall Rest
Oxytocin
Oxytocin & Exercise
Exercise
DiscussionSequence of events proposed by Woodward
and Troedsson that occur after breeding in
susceptible and resistant mares. Yellow text refers to resistant mares, orange text to susceptible mares, and white text to both.7
Susceptible Not Susceptible
Figure 1. Uterine Fluid Measurements by Treatment Group at 4, 24, and 48 Hours Post Breeding
4 Hours 24 Hours 48 Hours
• Since only 23 of 72 treatments have been completed to date, enough data has not been compiled to analyze the efficacy of acupuncture and exercise. However, results from positive and negative controls are turning out as predicted, which lends confidence that study findings will have merit.
• Acupuncture, one of the primary treatment groups of interest, has been difficult to study as some mares have refused to accept electro-acupuncture treatment. In clinical practice, mares that receive acupuncture for post breeding endometritis have already received acupuncture for other ailments and are accustomed to the treatment.
• Mares selected for enrollment into the study conformed to many of the risk factors for susceptibility identified in the literature.
References:
Group 1: AcupunctureGroup 2: ExerciseGroup 3: Exercise & oxytocinGroup 4: Oxytocin (positive control) Group 5: Prostaglandin (positive control) Group 6: Stall rest (negative control)
• Mares were bred with 500 x 106 dead sperm resuspended in 50 mL of milk based semen extender• Uterine fluid measurements were obtained by transrectal ultrasound at 0, 4, 24, 48, 72, and 96 hours• In most treatment groups, mares received treatment at intervals of 6, 12, 24, 36, and 48 hours
Statistics• Associations between treatment efficacy and fluid clearance are being investigated using a random-effects
logistic regression model• Time to fluid clearance is being investigated with a Kaplan-Meir Survival Analysis
Conclusions
• In future acupuncture studies mares should be screened for acceptability of acupuncture as a criteria for enrollment into the study
• Based on ongoing results from positive and negative control groups, the study is well positioned to evaluate the efficacy of acupuncture and exercise as treatments to clear intrauterine fluid.
• The results presented are preliminary and the final results can vary substantially.
A special thank you for the generous financial and research support provided by the STAR Program and the Center for Equine Health.
1. Vanderwall, D.K., Early Embryonic Loss in the Mare. Journal of Equine Veterinary Science, 2008. 28(11): p. 691-702.2. Maischberger, E., et al., Equine post-breeding endometritis: A review. Ir Vet J, 2008. 61(3): p. 163-8.3. Brinsko, S.P., et al., A practical method for recognizing mares susceptible to post-breeding endometritis. 2003, American Association of Equine Practitioners (AAEP): Lexington. p. 363-365.4. Christoffersen, M., et al., Inflammatory responses to induced infectious endometritis in mares resistant or susceptible to persistent endometritis. BMC Veterinary Research, 2012. 8(1): p. 1-14.5. Troedsson, M.H. and E.M. Woodward, Our current understanding of the pathophysiology of equine endometritis with an emphasis on breeding-induced endometritis. Reprod Biol, 2016. 16(1): p. 8-12.6. Troedsson, M.H.T., Problems After Breeding. Journal of Equine Veterinary Science, 2008. 28(11): p. 635-639.7. Woodward, E.M. and M.H. Troedsson, Equine Breeding-Induced Endometritis: A Review. Journal of Equine Veterinary Science, 2013. 33(9): p. 673-682.8. Liu, I.K. and M.H. Troedsson, The diagnosis and treatment of endometritis in the mare: yesterday and today. Theriogenology, 2008. 70(3): p. 415-20.9. McCue, P.M., The Problem Mare: Management Philosophy, Diagnostic Procedures, and Therapeutic Options. Journal of Equine Veterinary Science, 2008. 28(11): p. 619-626.10. Troedsson, M.H.T., A.M. Alghamdi, and J. Matissen, Proceedings of the 8th International Equine Reproduction Symposium. Equine seminal plasma protects the fertility of spermatozoa in an inflamed uterine environment. Theriogenology, 2002. 58(2): p. 453-456.11. Blanchard, T.L., et al., Effects of ecbolic agents on measurements of uterine involution in the mare. Theriogenology, 1991. 36(4): p. 559-571.12. Mesa, A.M., et al., l-Arginine supplementation 0.5% of diet during the last 90 days of gestation and 14 days postpartum reduced uterine fluid accumulation in the broodmare. Animal Reproduction Science, 2015. 159: p. 46-51.
