Cow Hair Loss: Causes, When to Worry & What to Do

Hair loss in cows is a symptom, not a diagnosis. Common causes include lice, mange mites, ringworm, dermatophilosis, and nutrition-related skin disease. Merck notes that lice can cause itching, rubbing, rough hair coat, and hair loss, especially in stressed animals or during winter housing. Mange mites can cause intense itching, crusting, thickened skin, and alopecia. Ringworm in cattle often causes round, scaly patches with broken hairs and gray-white crusts, while dermatophilosis can create matted “paintbrush” tufts, scabs, and patchy to widespread hair loss.

External parasites are a very common reason for hair loss in cattle. Lice tend to be easier to spot by parting the hair along the face, neck, topline, dewlap, and tail base. Mange can be harder to confirm without skin scrapings. Some mite infestations are also zoonotic, meaning they can affect people, so it is smart to use gloves and limit close skin contact until your vet has evaluated the herd.

Infectious skin disease matters too. Dermatophytosis (ringworm) is a superficial fungal infection and is usually seen as focal hair loss with crusting and scaling. It can spread between cattle and to people. Dermatophilosis is more likely when skin stays wet or when lice and ticks damage the skin barrier. Youngstock, crowded housing, damp conditions, and shared equipment can all make outbreaks more likely.

Less obvious causes include trace mineral or nutritional imbalance, especially zinc-related skin disease in some cattle, plus chronic illness, poor body condition, or irritation from rubbing on fences and feeders. If hair loss comes with weight loss, diarrhea, pale gums, fever, or poor growth, your vet may need to look beyond the skin and check for a broader health or feeding problem.

A small, non-itchy patch of hair loss on an otherwise bright, eating cow may be reasonable to watch for a short time while you improve hygiene and monitor closely. Take photos every few days so you can tell whether the area is stable, shrinking, or spreading. If more than one animal develops similar lesions, that shifts the situation away from simple monitoring and toward a herd problem that deserves veterinary input.

Call your vet soon if the hair loss is spreading, the cow is itchy, the skin is crusted, thickened, bleeding, or oozing, or the animal seems uncomfortable. You should also contact your vet if the cow has reduced appetite, weight loss, fever, weakness, anemia, poor milk production, or poor growth. Severe lice infestations can contribute to unthriftiness and even anemia, and severe mange can lead to secondary infection and major production losses.

See your vet immediately if a calf is becoming weak, multiple animals are rapidly affected, there are deep wounds or heavy scabbing over large areas, or you are worried about a reportable or fast-spreading disease in your region. Hair loss by itself is often not an emergency, but hair loss plus systemic illness is a different situation.

Because ringworm and some mite problems can spread to people, it is wise to wear gloves, wash hands well, and avoid sharing halters, brushes, or clippers between affected and unaffected cattle until your vet advises you.

Your vet will start with a hands-on skin and coat exam and ask about the timeline, season, age group affected, housing, bedding, recent additions to the herd, nutrition, and whether the cow is itchy. They may part the hair in common lice locations, look for crusts and lesion patterns, and check body condition, temperature, and signs of broader illness.

To narrow the cause, your vet may collect skin scrapings for mites, hair and crust samples for fungal testing, or samples for cytology and culture if infection is suspected. Merck states that fungal culture is the definitive test for cattle ringworm, even though experienced clinicians may sometimes make a presumptive diagnosis from the lesion pattern. If nutrition or internal disease is on the list, your vet may recommend bloodwork, fecal testing, or a ration and mineral review.

If more than one animal is affected, your vet may approach this as a herd management problem, not just an individual skin case. That can include checking housing moisture, stocking density, parasite control timing, quarantine practices, and whether all in-contact cattle need treatment at the same time.

Typical costs vary by region and travel distance, but a large-animal farm call and exam often lands around $100-$250, with add-on diagnostics such as skin scraping, fungal culture, fecal testing, or biopsy increasing the total. University diagnostic lab fee schedules in 2025 show skin scraping commonly around $22-$38 and fungal culture around $30 before clinic markup and sample handling, so your final invoice through a practice is often higher.

Home care should focus on comfort, hygiene, and preventing spread while you work with your vet. Keep affected cattle in a clean, dry area if possible, and reduce prolonged wetting of the coat. Do not share brushes, halters, clippers, or blankets between affected and unaffected animals. If you handle lesions, wear gloves and wash thoroughly afterward.

Check the skin every few days for new patches, thicker crusts, drainage, or signs of self-trauma from rubbing. Taking clear photos can help your vet judge whether the lesions are improving. Also watch appetite, milk production, weight, and attitude. Hair loss that is staying localized is different from hair loss that is spreading across the face, neck, topline, or tail head.

Avoid applying random over-the-counter products, caustic disinfectants, or extra-label livestock medications without veterinary guidance. Some skin problems look alike but need very different treatment plans. For example, ringworm may be self-limiting but still contagious, while mange or severe lice infestation often needs herd-level parasite control.

If your vet suspects a nutrition component, follow the feeding and mineral plan carefully rather than adding multiple supplements on your own. Too little trace mineral can be a problem, but too much can also be harmful. Thoughtful, consistent management usually helps more than trying many products at once.