Ringworm Identification and Control in Cattle

Ringworm, also known as dermatophytosis, is a highly contagious fungal skin infection that affects cattle and other livestock. Properly identifying ringworm infections and implementing control measures are essential for cattle health and farm biosecurity.

What is Ringworm?

Ringworm is caused by various fungi in the Trichophyton and Microsporum genera. These fungi feed on keratin, the key protein in skin, hair, and hooves. The name “ringworm” comes from the circular skin lesions that are the most obvious visible symptom.

According to the Merck Veterinary Manual, over 30 species of dermatophytes cause ringworm in domestic animals. Cattle are mainly affected by T. verrucosum. This fungus is very contagious but generally only spreads between cattle. Other common cattle ringworm fungi include M. nanum, M. equinum, and T. mentagrophytes.

Ringworm Symptoms in Cattle

The main ringworm symptom is round, raised skin patches that can be red and itchy. Hair loss occurs in the affected areas, often creating noticeably circular bald spots.

As the infection spreads skin can become thick, cracked and scabbed over. Lesions usually start small but expand up to several inches in diameter.

Cattle of all ages can develop ringworm but calves and young cattle seem most susceptible according to veterinary researchers. The disease can emerge anytime but is more common in winter.

Accurately Identifying Ringworm

Distinguishing ringworms from other skin conditions like mange, warts or photosensitivity can be challenging. The characteristic circular lesions provide a clue but definitive diagnosis requires laboratory culture.

Vets usually collect samples by brushing the edges of affected areas onto the culture medium. After 1-2 weeks fungal growth can be analyzed under a microscope to confirm infection.

PCR testing provides faster results than culture, detecting ringworm fungi in just 2-3 days. However, this molecular testing method is more expensive for cattle herds than routine fungal culture.

Controlling and Preventing Cattle Ringworm Infections

Once ringworm is confirmed in a cattle herd, prompt treatment and biosecurity measures are vital. Follow these tips to control and prevent outbreaks:

• Isolate infected cattle – Keep them separated from the main herd to minimize transmission.
• Groom/brush out lesions – Carefully groom infected areas to remove scabs and infectious fungal spores. Clean brushes and combs after each use.
• Apply antifungal washes – Topical treatments reduce infection severity and spread to other body areas. Common antifungals for livestock ringworm include lime sulfur, povidone iodine or miconazole.
• Administer oral antifungals – For heavy infections or valuable breeding cattle, vets may prescribe oral glandular antifungals like griseofulvin.
• Improve sanitation – Thoroughly clean and disinfect housing, feed equipment and other surfaces cattle contact. Hydrated lime is an affordable and effective ringworm-killing disinfectant suitable for barns .
• Modify facilities – Adjust ventilation, drainage and bedding to reduce environmental fungus and skin irritation.
• Examine the herd – Identify asymptomatic carrier cattle via culture testing. Cull chronic ringworm spreaders.
• Quarantine incoming/returning cattle – Isolate and screen any new additions or animals that leave the farm.
• Minimize stressors – Wean, transport, assemble groups and use handling systems judiciously to avoid immune suppression.

With vigilant monitoring and biosecurity, ringworm can usually be controlled and eliminated within a few months. Veterinary assistance is recommended for developing a targeted treatment strategy when faced with an outbreak.

FAQs:

1. How do cows get ringworm?

Cattle get ringworm from infected spores of fungal species like Trichophyton verrucosum. The spores come into contact with broken skin or mucous membranes and cause lesions that then shed more spores, spreading the infection.

2. What does ringworm look like on a cow?

Ringworm causes circular areas of hair loss and skin lesions on cattle. The lesions often look reddish, crusty, or scabbed with raised, roughened edges. As they expand, ringworm lesions leave the distinctive round, bald patches that give the disease its name.

3. How is ringworm transmitted between cattle?

Direct contact with the fungal spores transmitted from infected cattle causes ringworm to spread through a herd. Ringworm spores cling to surfaces like brushes, cloth, wood, feed buckets, bedding material, etc. Sharing any infected items also transmits the highly contagious disease.

4. How do you test cattle for ringworm?

To definitively diagnose ringworm, veterinarians collect skin scrapings or hair samples from the margins of suspicious lesions on cattle. These samples get cultured in a lab to allow any ringworm fungi present to grow for microscopic fungal identification.

5. How do you treat ringworm on cattle?

Treating cattle ringworm involves antifungal medications, frequent grooming of lesions, topical antiseptic baths and disinfecting the cattle’s environment. Oral antifungals may be prescribed for widespread infections. Isolating infected cattle is also important to control outbreaks.

6. What kills ringworm spores?

Hydrated lime, sodium hypochlorite (bleach), potassium peroxymonosulfate, quaternary ammonium compounds and some phenolic disinfectants can kill ringworm fungi and spores on surfaces and equipment cattle contact. Routine cleaning with these products is key for prevention.

7. How long does ringworm last in cattle?

With treatment, ringworm infections typically resolve within 2-4 months. However, spores can persist in the environment leading to new outbreaks. Strict biosecurity and isolation of infected animals is necessary to control ringworm in a cattle herd long-term.