Researchers Develop Better Tools to Spot Equine Inflammation

Early Signs of Horse Inflammation Found with New Blood Ratios

Inflammation is the body’s built-in protective response, activating immune cells to address injury or illness and begin the healing process. But when this reaction becomes persistent or overly intense, it may contribute to further tissue damage and the development of long-term health issues.

In horses, identifying whether inflammation is short-term or chronic can be difficult. Veterinarians typically depend on physical exams, medical history, and routine bloodwork to make assessments, yet these tools do not always detect the early stages of inflammatory change.

Recognizing inflammation sooner is crucial for equine health. Early intervention can reduce discomfort, prevent chronic conditions from taking hold, and support improved performance. A commonly used diagnostic tool is the complete blood count (CBC), which measures different blood cell types. Although widely used, traditional CBC reference ranges were not designed with inflammation detection in mind.

To improve diagnostic accuracy, Penn State researchers have created new inflammatory indices—mathematical formulas that combine various CBC parameters to give a clearer picture of inflammatory activity. These indices incorporate information from several white blood cell groups and platelets, offering a more integrated assessment.

“A horse could have mild inflammation and still have ‘normal’ complete blood count values because the reference intervals - in other words, the normal CBC ranges - were created using horses that appeared healthy, even though some might have had early inflammation,” explained study first author Molly Friend, a doctoral candidate in the Intercollege Graduate Degree Program in Integrative and Biomedical Physiology.

“These industry standard reference intervals are not designed specifically to detect inflammation, so they can miss subtle inflammatory changes.”

Friend works under the supervision of Danielle Smarsh, associate professor of equine science and senior author of the study. Instead of analyzing CBC numbers individually, the research team evaluated ratios that reflect interactions among white blood cell subtypes.

This method highlights shifts between the body’s immediate immune defenses and its more specialized responses, helping veterinarians better interpret inflammatory patterns in horses.

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