Ringworm (Dermatophytosis) in Cows

Ringworm, also called dermatophytosis, is a superficial fungal skin infection in cattle. It affects the hair and outer skin layers rather than deeper tissues. In cows, the most common organism is Trichophyton verrucosum. Despite the name, ringworm is not caused by a worm.

This condition often shows up as circular areas of hair loss, scaling, and crusting, especially on the face, around the eyes, ears, neck, and sometimes the body. Young cattle are affected more often, but adults can develop lesions too, especially during periods of crowding, stress, or close indoor housing.

Ringworm in cattle is often self-limiting, meaning lesions may eventually resolve without aggressive treatment. Still, that does not mean it should be ignored. The fungus is contagious to other cattle and to people, so your vet may recommend treatment and management steps to reduce spread through the herd and protect anyone handling the animals.

In cattle, ringworm is usually caused by the fungus Trichophyton verrucosum. Other dermatophyte fungi can occasionally be involved, but this is the classic cattle-associated organism. The fungus spreads by direct contact with an infected animal or by contact with contaminated equipment, halters, fences, grooming tools, bedding, or housing surfaces.

Spores can persist in the environment, which is one reason outbreaks can move through groups of calves or newly housed cattle. Crowding, damp housing, poor ventilation, winter confinement, transport stress, and skin trauma can all make spread more likely. Young animals are commonly affected because their immune systems and skin defenses are still developing.

Ringworm is also a zoonotic disease, which means people can catch it from infected cattle. Farm workers, family members, and anyone handling affected animals should use gloves, protective clothing, and good hand hygiene. Your vet can also help you think through herd-level risk factors so treatment and prevention fit your setup.

Your vet will often start with a physical exam and lesion pattern. In cattle, the combination of circular hair loss, crusting, and scaling in the right age group and housing situation can be strongly suggestive of ringworm. Even so, other skin problems can look similar, including lice, mange, dermatophilosis, trauma, photosensitization, and other fungal or bacterial conditions.

To confirm the diagnosis, your vet may collect hair, crusts, and skin scrapings for fungal culture. Culture is considered the definitive test in many cases, although results can take time. Some clinics or diagnostic labs may also use microscopic examination or additional testing depending on what else is on the list of possibilities.

Diagnosis matters because treatment plans can differ a lot depending on the cause. If the problem is ringworm, your vet can help you choose a practical plan for the individual animal, the herd, and the people caring for them.

Prevention starts with reducing exposure and improving herd hygiene. Avoid sharing grooming tools, halters, and equipment between affected and unaffected cattle unless they are cleaned first. If possible, handle healthy animals before affected ones, and wear gloves when touching suspicious skin lesions.

Housing also matters. Ringworm tends to spread more easily in crowded, poorly ventilated, damp, or dark conditions, especially during winter housing. Better airflow, lower stocking density, and cleaner resting areas can help reduce transmission pressure. Quarantining new arrivals and checking calves closely for early lesions can also make outbreaks easier to contain.

Because spores can persist in the environment, prevention is not only about the cow in front of you. It is also about the group, the barn, and the people. If ringworm keeps recurring, your vet can help you review housing, handling routines, and cleaning practices to build a prevention plan that works for your farm.