Bad Breath (Halitosis) in Horses

Key Takeaways

Halitosis is the term used to describe bad breath. Horses’ breath usually smells musky and sweet, like hay or grass.

• Bad breath in horses usually smells like rotten flesh or vegetation, urine, or sour

• Horses with halitosis require prompt veterinary attention

• Halitosis is typically indicates there is an issue with oral health in horses

• Associated symptoms include quidding, tilting the head while eating, excessive drooling, weight loss, and discharge from one nostril

• In rarer cases, halitosis can indicate an intestinal obstruction, kidney failure, or tumor in the stomach

• Diagnostic tools include physical and dental examination, bloodwork, urinalysis, and X-rays

• Treatment depends on the root cause and may include dental work, anti-inflammatories, antibiotics, or specific treatment of underlying internal conditions

A Closer Look: What is Halitosis in Horses?

A horse’s breath is usually pleasant. It generally smells like the food they eat: oats, pellets, grass, or hay. It is sweet and musky. Horses with breath that smells bad, either sour-smelling, like rotting meat or vegetation, or like urine, require prompt veterinary attention.

Possible Causes

Typically, bad breath is caused by dental issues in horses. These include:

• Wounds on the lips, gums, cheeks, throat, or trachea

• Abscesses in the mouth

• Abscessed, broken, or loose teeth

• Ulcers on the cheeks

Retained caps (baby teeth that haven’t fallen out)

• Sharp enamel points causing tissue damage

• Oral tumors

• Foreign objects stuck in the mouth, such as sticks

In rarer cases, the cause of bad breath is further inside the body, including:

Intestinal obstructions

• Tumors in the stomach

• Kidney disease

Risk Factors

The severity of halitosis depends on the underlying cause. Bad breath from abscesses, infections, retained caps, or other soft tissue damage typically smell like rotten flesh. Intestinal obstructions usually make the breath smell sour, or like rotten vegetation. Kidney disease typically makes the breath smell like urine.

Testing and Diagnosis

Horses with bad breath require prompt veterinary attention. Diagnostic tools include:

• Physical examination

• Oral examination

• X-rays or ultrasounds

• Bloodwork

• Urinalysis

• Nasogastric intubation 

• Gastroscopy 

Note: nasogastric intubation should only be performed by a veterinarian. There is no safe way to intubate a horse at home. 

Treatment depends on the diagnosis.

In the case of a confirmed diagnosis related to dental or oral health, dental work is necessary. Antibiotics and anti-inflammatories may be needed depending on the dental issue identified. 

Treatments for internal conditions such as intestinal obstruction or kidney failure may include:

• IV fluids

• Surgical intervention

• Antibiotics

• Laxatives

Similar symptoms

Halitosis in horses is generally unmistakable. Taking care to ensure that the smell is coming from the mouth allows for easy diagnosis.

Associated Symptoms

Halitosis is most commonly associated with dental issues.  Other symptoms of dental pain include:

Quidding (dropping feed) 

Lack of appetite

• Tilting the head while eating

• Excessive salivation

• Weight loss

Discharge from one nostril

• Discomfort with the bridle

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