This document discusses fescue toxicosis in horses, which is caused by a fungus living symbiotically in tall fescue grass that produces ergot alkaloids like ergovaline. These alkaloids can disrupt mares' endocrine systems during pregnancy, causing issues like agalactia (lack of milk production). The document examines a study on agalactic mares in Japan that tested treating them with domperidone, a drug that blocks dopamine receptors and could counter the effects of the ergot alkaloids. The study compared hormone levels in treated versus untreated mares and found differences, suggesting domperidone therapy may help agalactic mares affected by fescue toxicosis

1. Fescue Toxicosis: Can Domperidone
Therapy Help Agalactic Mares in Japan?
Presented by: Chelsea Herron

2. Grass can harm a horse?
• Lynn Klimas Petr
– Founder of STAR (Therapeutic Riding Center)
– My riding instructor
• Fescue Toxicosis
– Endophyte
– 2ndary Metabolites
http://www.metropulse.com/stories/people-you-should-
know/lynn-klimas-petr-knoxvilles-therapeutic-riding-exp
What did
you say?
http://www.classichorse.com/classic-horse-clip-
art/classic-horse-cartoon-clip-art/confused-2/

3. Can I avoid it?
• 2011: Over 35 million acres in USA
– Primary forage for ≈700,000 horses
• Cut the Grass
• Try Replacing
• Highly Competitive

4. Symptoms of Fescue Toxicosis
I. Agalactia
II. Prolonged Gestation
III. Placental Wall Thickening
IV. Dystocia http://www.emcocala.com/Fetal%20
Malposture%20and%20Dystocia.html

5. What is an endophyte?
• Arbuscular Mycorrhiza
– Neotyphodium coenophialum
• Plant Friendly
– Efficient nutrient absorbance
– Defense against biotic & abiotic stress
http://planthealthproducts.com/category/mycorrhizae/

6. What’s the big deal with Alkaloids?
• Ergovaline
– Agonist
– D₂-Dopamine receptors
Ergot Alkaloid Ergovaline
Estrogen hormone

7. How much does it take?
• Negative Effect Level
– 0.05 mg/kg = Agalactia
• Plant Body
– 0.2-0.6mg/kg
• Seed Head
– > 1 mg/kg
The Endophyte Life Cycle

8. The Endocrine Disruptive Effects of Ergopeptine
Alkaloids on Pregnant Mares
Tim J. Evans
Published by Elsevier Inc. 2011

9. PRL & PRG Concentrations
Progesterone(ng/ml)

10. Domperidone
• Antagonist
– D₂-Dopamine receptors
– Pushes Bromocriptine Out
– Ergovaline Moves In

11. Domperidone Therapy

12. Changes in Serum Concentrations of Prolactin, Progestagens,
and Estradiol-17ß and Biochemical Parameters During
Peripartum in an Agalactic Mare
Kenji Korosue et al.
Published by Elsevier Inc. 2013

13. Agalactic Mares in Japan
• Could it be Fescue Toxicosis?
– Domperidone Therapy
– Compare Hormone Levels

14. PRL vs. PRG Concentrations in Agalactic Mare

15. What is the culprit?
• Lack of symptoms
• Different Pathology
• More Information Necessary
You got a
cure yet
Doc?
https://cometscorners.files.wordpress.com/2012/04/sick-horse.jpg

16. References
Evans, T. J. (2011). The Endocrine Disruptive Effects of Ergopeptine Alkaloids on
Pregnant Mares. Veterinary Clinics of North America: Equine Practice, 165-173.
Herron, C. (2015). Fescue Toxicosis: Disruption of Pregnant Mare Endocrine
Systems by Ergopeptine Alkaloids. Senior Honors Thesis.
Korosue, K., Murase, H., Sato, F., Ishimaru, M., Watanabe, G., Harada, T., . . .
Nmabo, Y. (2013). Changes in Serum Concentrations of Prolactin, Progestagens,
and Estradiol-17ß and Biochemical Parameters During Peripartum in an Agalactic
Mare. Journal of Equine Veterinary Science, 279-286.
Neotyphodium coenophialum. (2012, December 21). Retrieved March 23,
2015, from Microbe Wiki:
https://microbewiki.kenyon.edu/index.php/Neotyphodium_coenophialum
Nevala, R. (2001). Isoflavones. Effects of genistein and daidzein on arterial tone
and blood pressure in rats.

17. http://1.bp.blogspot.com/-IGnaVcnQjBs/Uh02h3RZ-1I/AAAAAAAAAVc/TSxm6gy9_Nk/s1600/pop+quiz.png