Recognizing and Managing Common Health Problems of Horses

1. Recognizing and Managing Common Health Problems of Horses F.C. Faries, Jr., DVM, MS Texas AgriLife Extension Service Texas A&M System College Station, Texas

2. Cutaneous (Skin) Problems • Rain Gall • Fungus (Dermatophilus) • Summer Itch • Face-neck allergy • Gnats (Culicoides, Simulium) • Skin Worms (Onchocerca) • Mane-tail allergy • Gnats (Culicoides)

3. Summer Sores • Stomach worms (Habronema) • Skin wounds • Mucous membranes • Proud Flesh • Wounds (irritation)

4. Rain Gall, Dew Poisoning (Cutaneous Dermatophilosis, Streptotrichosis) • Agent – fungus (Dermatophilus) • Actinomycete • Transmission – mechanical • Vector – stablefly • Vehicles – instruments

5. Season – April – October (Summer) (rain, hot, high humidity, sweat, dew) Effects – Serum Dermatitis • Inflammation – crusts (paint brushes) • Lower legs, thighs, croup, poll (areas sweat, areas wet + fly bite) • Recovery – suppression November – March (Winter) (activates annually)

6. Diagnosis – paint brush lesions • Culture • Management • Dry conditions • Bathe (remove lesions) • Drying solution

7. Summer Itch (Gnat Allergy) • Agent – gnats (Culicoides, Simulium) (Eggs, larvae, pupae – water, mud, decayed vegetation) • Season – April – October (Summer)

8. Effects – allergic dermatitis • Hair loss • Inflammation – papules, vesicles, pustules, scabs • Pruritus – self trauma • Face, neck, chest, armpits, ventral midline, flanks

9. Ears • Mane, tail • Reaction to saliva (Hypersensitive Horses) • Recovery – November – March (Winter) (recurs annually) • Diagnosis • Skin biopsy

10. Management • Reduce gnat exposure • Stall – Daylight to 10am –4pm to dark • Fans, smoke, screens • Skin oil – prevents biting, promotes healing (petroleum jelly, glycerin) • Insecticides, repellents

11. Summer Itch (Cutaneous Onchocercosis) • Agent – Onchocerca microfilariae (Adults – ligamentous tissues – withers, legs, spleens – nonpathogenic) • Vector – common gnat (Culicoides) • Season – April – October (Summer)

12. Effects – allergic dermatitis • Hair loss • Inflammation – papules, vesicles, pustules, scabs • Pruritus – self trauma • Bilateral symmetrical – face, neck, chest, armpits, ventral midline, flanks • Reaction to dead microfilariae in only hypersensitive horses (universal infections)

13. Recovery – November – March (Winter) (Recurs annually) • Diagnosis • Skin biopsy • Management • Reduce gnat exposure

14. Summer Sores (Cutaneous Habronemiasis) • Agent – stomach worm larvae (Draschia, Habronema) • Adults – stomach • Vector – common housefly, stablefly (Eggs, larvae, pupae manure, stall bedding, hay waste, decayed vegetation) • Season – April – October (Summer)

15. Effects – granulomatous lesions • Skin wounds • Wet tender irritated skin • Conjunctiva, prepuce, penis, vagina • Proud flesh – hypergranulation of tissue • Aberrant larvae – irritates tissue • Worsens • rubbing (pruritus) • irritation (flies, gnats, grass, tail)

16. Recovery – noncomplete healing in winter, reinfection in summer • Diagnosis • Biopsy • Management • Control flies

17. Digestive Problems • Foot founder (Bahia grass) • Colic (cold front) • Tying-up (oats feed) • Chronic diarrhea (low roughage) • Foal diarrhea (Strongyloides)

18. Stumpsucker (boredom) (low roughage) • Cribber (boredom) (low roughage) • Bark chewing (hypervitaminosis) • Ankle swelling (sodium imbalance)

19. Infectious Disease Problems • Sleeping sickness – Encephalomyelitis • EIA – Equine Infectious Anemia • Rhinopneumonitis • Influenza • Lockjaw – Tetanus

20. Strangles (Streptococcus) • Salmonellosis (Salmonella) • PHF – Potomac Horse Fever (Ehrlichia) • EPM – Equine Protozoal Myeloencephalitis

21. West Nile Encephalitis • In U. S. • A reportable disease • Viral Bird Disease – >100 Species • Blue jays, crows, hawks • Encephalitis death

22. Transmissions • Virus in bird blood • Mosquito (>75 species) bite bird • Virus in 1% mosquito salivary glands – 10 to 14 days later • Mosquito bite bird - virus in blood (carrier) • Mosquito bite mammal – virus not in blood (dead end) • 1% horses and people – encephalitis (death or recovery) • 30% encephalitis horses – death (2 wks to 6 mos) • 6% encephalitis people – death

23. Incubation Period • 3 to15 Days

24. Horse WNE – Rabies Symptoms • Virus in brain • Stumbling, staggering wobbling • Leg weakness – falling • Difficult rising – dog sitting • Muscle twitching

25. Horse WNE Diagnosis • Blood, postmortem brain

26. Horse WNE Vaccination • Innovator® WNE killed vaccine (Ft Dodge) • Recombitex® WNE recombinant vaccine (Merial)

27. Attack Mosquito Breeding Sites – Standing, Stagnant Water • Attack mosquito breeding sites • Standing, stagnant water • Eliminate junk (cans, jars, buckets, tubs, pots, tires) • Treat troughs, bird baths, low areas (Bt Mosquito Dunks®)

28. Swamp Fever (Equine Infectious Anemia) (EIA) • Agent – virus (Lentivirus) • Transmission – mechanical • Vector – horsefly, deerfly • Vehicles – needles, instruments • Season • Peracute, acute – summer • Chronic – year around • Inapparent – year around

29. Effects – anemia • Peracute, acute – death • Chronic – emaciation • Inapparent – possible fever attacks • Recovery • Lifetime infections (chronic, inapparent) • Diagnosis • AGID (Coggins), CELISA serology • Management • Reportable to TAHC • Disposal or quarantine

30. Hereditary Problems • HYPP • Hyperkalemic Periodic Paralysis (Gene Defect)

31. Horse Health Management Practices • Shelter Management • Adequate housing • Open sheds • Stalls (12’ x 12’) • Proper ventilation • Protect against heat and cold • Adequate exercise

32. Environmental Management • Prevent overcrowdedness • Maintain cleanliness • Maintain dryness • Utilize composts • Stall bedding disposal • Manure disposal • Hay waste disposal

33. Reduce dust • Proper ventilation • Protect against heat and cold

34. Nutritional Management • Adequate forages • Grass and/or hay • Required supplements • Concentrates (grains) • Protein supplements

35. Free choice salt • Clean water • Proper hay/grain storage • Dry and rodent free

36. Insect Management (horseflies, deerflies, stableflies, houseflies, mosquitos, gnats) • Utilize composts • Stall bedding disposal • Manure disposal • Hay waste disposal

37. Proper drainage • Maintain dryness • Routine insecticide applications • Premise chemicals (sprays, baits) • Animal chemicals (sprays, dusts, repellents)

38. Worm Management (strongyles, roundworms, pinworms) • Prevent overcrowdedness • Maintain cleanliness • Utilize composts • Stall bedding disposal • Manure disposal

39. Maintain dryness • Proper drainage • Separate age groups • Routine deworming (1 to 12 times per year or continuous)

40. Infectious Disease Management • Avoid exposures • Isolate sick • Diagnose and treat • Diagnose and dispose • Quarantine exposed (2 to 8 wks.) • Adjacent premise buffer zone • Separate needles for injections • Disinfect instruments (tattoo, bits, floats, twitch) • Insect management • Rodent management • Separate feed-water utensils in travel

41. Separate age groups • Provide immunizations • WNV (1 to 2 times per yr.) • VEWT (1 time per yr.) • Flu (1 to 6 times per yr.) • Rhino – respiratory/live (1 to 6 times per yr.) • Rhino – abortion/killed (5, 7, 9 mo. pregnancy) • Strangles – high risk (1 time per yr.)

42. Care for new entry • Prior to entry (3 to 6 wks.) • Pre-purchase exam • Tests (EIA) • Immunizations • Deworm • After entry (immediately) • Post-purchase exam • Tests (EIA) • Isolate (2 wk. minimum)

43. Annual physical examinations • Tests (EIA) (1 to 4 times per yr.) • Dental care (1 to 2 times per yr.) • Foot care (1 to 6 times per yr.) • Integrated management practices • Shelter • Environmental • Nutritional • Insect • Worm • Infectious disease

44. Identify sources • Horses • Other animals • Environment • Vehicles • Vectors

45. Normal Vital Signs • Respiratory Rate 8 – 24 • Heart Rate 36 – 48 • RR:HR Ratio 1:4 – 1:2 • Hydration 1 • Capillary Refill 1 • Mucous Membrane Color Pink • Sweating None – Slight • Strength Strong • Temperature 99 – 100

46. Stress Vital Signs • Respiratory Rate >40 • Heart Rate >72 • RR:HR Ratio 1:1 – 2:1 • Hydration >3 • Capillary Refill >3 • Mucous Membrane Color Pale-Blue • Sweating Excess • Strength Weak • Temperature >105