Identifying and Treating Septicemia in Horses

An injured foal receiving first aid.
An injured foal receiving first aid. Keith Bowers

Newsdate: Thursday, October 02, 2025 - 11:00 am
Location: GILROY, California

Septicemia also known as sepsis is defined as an exaggerated, systemic inflammatory response to infection and is a common condition in horses. Once septicemia develops, the infection spreads to other organs, bones, joints, and the central nervous system causing a critical illness that calls for immediate treatment by a veterinarian.

Owners treating and disinfecting a bleeding wound on a horse's leg.

Owners treating and disinfecting a bleeding wound on a horse's leg.

Preventing septicemia in horses requires maintaining good hygiene in all areas where a horse injury could lead to systemic blood poisoning compromising the horse's immune system.
© 2017 by Mark Sellers New window.

In foals, septicemia resulting from exposure to bacteria in the environment usually occurs within three or four days of delivery. If septicemia occurs in-utero from passage of bacteria across the placenta, the foal may be delivered in a weakened or comatose state.

Clinical signs are often generalized and subtle and, therefore, are not usually recognized until the foal is critically ill. The survival rate for foals with septicemia runs between thirty and seventy-five percent.

In older horses, inflammatory bowel disease or GI obstruction that disturbs the intestinal barrier, allowing bacteria to move to intestinal lymphoid tissue, where inflammatory cells can be activated can lead to septicemia resulting in multiple organ failure and gut damage, and the cycle is then ongoing.

Signs of sepsis include general weakness, lethargy, diarrhea, excessive sleeping or resting, fever, labored breathing, colic-like symptoms, and swollen and painful joints . A diagnosis is based on a physical examination, plus laboratory tests and a blood culture to identify the causative bacteria, which helps the veterinarian prescribe appropriate antibiotics.

Preventing septicemia in horses requires maintaining good hygiene in all areas where a horse might be injured or contract a condition that could lead to systemic blood poisoning thereby compromising the horse's immune system.

In foals, preventing septicemia requires maintaining good hygiene during the mare's pregnancy and in the foaling environment. The mare should be placed in the foaling stall several weeks before foaling to allow her to produce antibodies against pathogens common to the foaling environment.

Foaling stalls should be disinfected before they are used, and cleaned daily. The mare should be washed daily to reduce bacterial buildup from the environment. These proactive measures will help reduce the risk of septicemia in the foal.

Attention to proper disinfection of the umbilical stump immediately following delivery is extremely important in preventing infection. Before the foal is allowed to nurse, the mare's udder, perineum, and rear quarters should be completely washed to remove any fecal material and other sources of bacteria.

Making sure that the foal receives adequate high-quality colostrum is critically important. Potential risk factors predisposing foals to septicemia are previous abortions in the dam or problems with previous foals.

Prematurity or being small at birth may impair a foal's immunity. Foals that are stained with meconium or that require resuscitation are at greater risk of septicemia. .

Working with a veterinarian prior to and during foaling is of paramount importance in preventing septicemia and other threatening complications.

If a veterinarian is not present at foaling, any signs of septicemia or a less-than-healthy foal call for immediate contact with the veterinarian. Antibiotics help reduce the spread of septicemia pending definite diagnosis through laboratory tests and a blood culture.

Although in the past, veterinarians avoided treating older horses with antimicrobial drugs in cases of septicemia, is is now considered a sound medical approach, requiring frequent and thorough patient monitoring, aggressive fluid therapy, cardiovascular support, appropriate antimicrobial drugs, and nutritional support, regardless of the animal's age.

Anti-endotoxin therapy remains important in cases of GI disturbances and other severe illnesses, such as retained placenta and metritis (uterine inflammation).

Many cases of septicemia are best treated in an equine hospital or clinic because of the need for around-the-clock care, the lengthy treatment with antibiotics and supportive drugs that is required, and the serious nature of the infection.

About the Author

Flossie Sellers

Author picture

As an animal lover since childhood, Flossie was delighted when Mark, the CEO and developer of EquiMed asked her to join his team of contributors.

She enrolled in My Horse University at Michigan State and completed a number of courses in everything related to horse health, nutrition, diseases and conditions, medications, hoof and dental care, barn safety, and first aid.

Staying up-to-date on the latest developments in horse care and equine health is now a habit, and she enjoys sharing a wealth of information with horse owners everywhere.

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