Recognizing and Managing Common Health Problems of Horses

F.C. Faries, Jr., DVM, MSTexas AgriLife Extension Service

Texas A&M SystemCollege Station, Texas

Cutaneous (Skin) Problems

Rain Gall Fungus (Dermatophilus)

Summer Itch Face-neck allergy

Gnats (Culicoides, Simulium) Skin Worms (Onchocerca)

Mane-tail allergy Gnats (Culicoides)

Summer Sores Stomach worms (Habronema) Skin wounds Mucous membranes

Proud Flesh Wounds (irritation)

Rain Gall, Dew Poisoning (Cutaneous Dermatophilosis, Streptotrichosis)

Agent – fungus (Dermatophilus) Actinomycete

Transmission – mechanical Vector – stablefly Vehicles – instruments

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)

Diagnosis – paint brush lesions Culture

Management Dry conditions Bathe (remove lesions) Drying solution

Summer Itch (Gnat Allergy)

Agent – gnats (Culicoides, Simulium) (Eggs, larvae, pupae – water, mud, decayed vegetation)

Season – April – October (Summer)

Effects – allergic dermatitis

Hair loss Inflammation – papules, vesicles, pustules,

scabs Pruritus – self trauma Face, neck, chest, armpits, ventral midline,

flanks

Ears Mane, tail Reaction to saliva (Hypersensitive Horses)

Recovery – November – March (Winter)(recurs annually)

Diagnosis Skin biopsy

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

Summer Itch (Cutaneous Onchocercosis) Agent – Onchocerca microfilariae

(Adults – ligamentous tissues – withers, legs, spleens – nonpathogenic)

Vector – common gnat (Culicoides) Season – April – October (Summer)

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)

Recovery – November – March (Winter) (Recurs annually)

Diagnosis Skin biopsy

Management Reduce gnat exposure

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)

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)

Recovery – noncomplete healing in winter, reinfection in summer

Diagnosis Biopsy

Management Control flies

Digestive Problems

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

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

Infectious Disease Problems

Sleeping sickness – Encephalomyelitis EIA – Equine Infectious Anemia Rhinopneumonitis Influenza Lockjaw – Tetanus

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

West Nile Encephalitis

In U. S. A reportable disease

Viral Bird Disease – >100 Species Blue jays, crows, hawks Encephalitis death

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

Incubation Period 3 to15 Days

Horse WNE – Rabies Symptoms

Virus in brain Stumbling, staggering wobbling Leg weakness – falling Difficult rising – dog sitting Muscle twitching

Horse WNE Diagnosis Blood, postmortem brain

Horse WNE Vaccination Innovator® WNE killed vaccine (Ft Dodge) Recombitex® WNE recombinant vaccine

(Merial)

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®)

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

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

Hereditary Problems

HYPP Hyperkalemic Periodic Paralysis

(Gene Defect)

Horse Health Management Practices

Shelter Management Adequate housing

Open sheds Stalls (12’ x 12’)

Proper ventilation Protect against heat and cold Adequate exercise

Environmental Management Prevent overcrowdedness Maintain cleanliness Maintain dryness Utilize composts

Stall bedding disposal Manure disposal Hay waste disposal

Reduce dust Proper ventilation Protect against heat and cold

Nutritional Management Adequate forages

Grass and/or hay Required supplements

Concentrates (grains) Protein supplements

Free choice salt Clean water Proper hay/grain storage

Dry and rodent free

Insect Management (horseflies, deerflies, stableflies, houseflies, mosquitos, gnats) Utilize composts

Stall bedding disposal Manure disposal Hay waste disposal

Proper drainage Maintain dryness Routine insecticide applications

Premise chemicals (sprays, baits) Animal chemicals (sprays, dusts, repellents)

Worm Management (strongyles, roundworms, pinworms) Prevent overcrowdedness Maintain cleanliness Utilize composts

Stall bedding disposal Manure disposal

Maintain dryness Proper drainage Separate age groups Routine deworming (1 to 12 times per year or

continuous)

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

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.)

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)

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

Identify sources Horses Other animals Environment Vehicles Vectors

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

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