Signs of Health Problems: How to Determine if Your Horse is Not Well

Author: Jenifer Nadeau
Jenifer.Nadeau@uconn.edu

Reviewer: Crystal Smith, Animal Science Extension Agent, Virginia Tech; Debra Hagstrom, Extension Specialist, Illinois Extension
Publication EXT134 | May 2025

DOI Pending

Introduction

Health problems in horses are not always easy to detect. If you know what is normal for your horse, then you may be able to tell right away when they are sick. 

Other signs than those presented here may also be associated with sickness or disease, so be sure to consult your veterinarian for assistance if you think something is not quite right. Better to be safe than sorry.

Common ailments and their symptoms in horses are listed below. This is not a comprehensive list. Be sure to consult your veterinarian when you notice something unusual. Of the ailments listed below, colic is one of the more serious. There are many signs that can indicate a horse has colic, try to familiarize yourself with them so that you can take immediate action. Influenza and strangles are both highly contagious, so you will also want to be sure that you can recognize them so that you can isolate your horse and prevent the spread of infection. Laminitis is not contagious but if not stopped in its early stages, may lead to founder, a more serious and long-term condition. 

Signs Colic Influenza Laminitia Strangles
Difficulty Defecating X (Impaction)
Depressed Appetite X
Dry Hard Coughing X
Enlarged Lymph Nodes - esp. between jaws close to the skin X
Getting up and down frequently X
Heel to toe movement when walking X
High Temperature (101 - 106 F) X
Increased Pulse Rate X
Kicking at Belly X
Looking at Sides X
Lying Down Frequently X
Pawing X
Pointing of front feet X
Reluctance to Move X
Restless X
Sawhorse Posture X X
Severe Pain X X
Watery Nasal Discharge X

These are some other common diseases. Luckily there is a vaccine available for all those listed below except Lyme Disease. It is definitely worth trying to prevent these diseases rather than hoping for a speedy recovery and the EEs can be fatal. None of the diseases listed below are contagious. EIA and EEE, WEE, and VEE are spread by insects so keeping insects under control and preventing water from pooling on your property is important. Lyme Disease is spread by ticks, and if riding outside, your fly spray may help to prevent their attachment. Potomac Horse Fever can arise from mayflies that are attracted to lights on outside at night, so turning lights off may be an important preventative.

Signs EIA** EEE, WEE, VEE* Lyme Disease Potomac Horse Fever
Abnormal Gait X
Anemia X
Changed Attitude X
Circling X
Colic X
Complete paralysis and death X
Depressed Appetite X X
Diarrhea X
Difficulty Defecating X
Difficulty Urinating X
Difficulty Walking X X
Drooping Ears X
Drooping Lower Lip x
Drowsiness X
Fever 104 - 108 Degrees F X sometimes X
Fever that may be above 106 Degrees F X
Head held low, food hanging from lips X
Hyprsensitivity to Sound X
Irritability X
Jaundice and edma of abdomen, sheath, scrotum and limbs X
Lameness, esp. larger joints X
Lameness shifting from limb to limb X
Laminitis X
Loss of Weight X
Mild Depression X
Overexcited for a time X
Paralysis X
Restlessness X
Severe Colic X
Severe Depression X
Stiffness X
Tongue Hanging Out X
Unwillingness to Work X
Weak X

*EEE = Eastern Equine Encephalomyelitis
*WEE = Western Equine Encephalomyelitis
*VEE = Venezuelan Equine Encephalomyelitis
**EIA = Equine Infectious Anemia

The diseases in our next table are also very serious and cause mainly neurological issues. Botulism, tetanus, and West Nile virus can be fatal. Horses with equine protozoal myeloencephalitis may have neurological signs that are so severe that they can no longer be ridden. Rabies requires euthanasia of the horse. Fortunately, there is a vaccine for Type B botulism which is often recommended for horses consuming round bales of hay. EPM is caused by horses ingesting secretions from animals such as opossums and may be harder to prevent for horses on pasture. No vaccine is available for EPM. Fortunately, there is a vaccine for rabies, tetanus and West Nile Virus. West Nile virus may present like EEE and EPM.

Signs Botulism EPM* Rabies Tetanus West Nile Virus
Changes in Eating Habits X
Circling X
Colic X
Death X X
Depressed Appetite X
Difficulty Breathing X
Difficulty Walking X X X
Drooling X
Drooping Tongue X
Facial Paralysis X X
Food Acummulation in Mouth X
Grinding of Teeth X
Head Tilt X
Hindleg Paralysis X
Incoordination X X
Jaw Spasms X
Lameness X
Muscle Atrophy X
Muscle Fasciculations X
Muscle paralysis of limbs, jaw, tongue and pharynx X
Prolapse of the third eyelid X
Recumbency X X
Seizures X
Viciousness X

*EPM = Equine Protozoal Myoencephalitis

Acknowldgements

I am grateful for the reviews by Crystal Smith, Animal Science Extension Agent, Warren County Cooperative Extension Service, Virginia and Dr. Debra Hagstrom of the University of Illinois, Horse Extension Specialist. 

The information in this document is for educational purposes only. The recommendations contained are based on the best available knowledge at the time of publication. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. UConn Extension does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available. The University of Connecticut, UConn Extension, College of Agriculture, Health and Natural Resources is an equal opportunity program provider and employer.