Vet Lisa Whitfield gives a rundown on the skin conditions farmers and their staff may encounter on their cows.

Actinobacillosis

More commonly referred to as ‘woody tongue’, Actinobacillosis a well-known condition affecting cattle. From the classic presentation of a drooling cow with a rigid, swollen tongue, this infection less commonly presents as unsightly, granulomatous masses bulging from under the skin

The causative bacteria is Actinobacillus lignieresi. This bacteria is a normal inhabitant of the mouth of cattle, but will take advantage to colonise areas beyond this location when trauma of any surface allows the bacteria to gain entry through the mucous membranes or skin, particularly when an inoculating dose is introduced through exposure to cattle saliva. The cheeks, neck and flank are areas where masses may erupt from. Treatment is with either antibiotics, sodium iodide (given in the vein) or potassium iodide (given orally).

PROGNOSIS: Excellent, particularly if detected and treated early.

Bug Allergy

Bites from insects can result in unsightly rashes of lumps and scabs on the skin. Frequently complicated by self-trauma from scratching on whatever is handy, insect bites can turn into extensive, scabby, infected areas of skin. The most common sites are under the neck and either side of the tail – areas where self-trauma is easy to achieve. Chemical control of biting insects such as sandflies, biting flies and ticks are useful preventative measures in the herd. Once bites become traumatised and infected, it may be necessary to treat individuals with antibiotics, anti-inflammatories and antihistamine to stop the itch-scratch cycle.

PROGNOSIS: Good – it is unlikely to kill an animal but it is a painful condition as it progresses with serious self-trauma.

Cancer

Skin cancers are the most common type of cancer in cattle. Melanoma and squamous cell carcinoma (cancer eye) are the two types regularly encountered in New Zealand. Skin cancers are aggressive and capable of spreading to other locations on the body, as well as to internal organs. Treatment is best attempted early – deal with cancerous lesions while they are small, and chance of cure is much greater. While not necessarily obvious, tumors are painful and they are also prone to being damaged in the day-to-day activities of cows. Surgical removal is the only practical option in most cases. Wide margins are necessary, hence why treatment attempts should be made while masses are small.

PROGNOSIS: Fair to poor – if skin cancers are not detected and dealt with early, the prognosis is poor.

Dermatophilosis

This skin infection is caused by the bacteria Dermatophilus congolensis. Typically, infected areas form on the back and are usually noted for having a thick crusting scab interspersed around the hair coat. As the scabs and hair come away, moist, pink, infected tissue becomes apparent underneath. Calves appear to be most commonly affected.

Treatment with antibiotics is required to clear the infection. Thick crusts can take some time to break down and occasionally an iodine wash may be required. Skin in affected areas will be tender, so consider giving pain relief as well.

PROGNOSIS: Good – treatment with a long course of penicillin-based antibiotics usually clears up the infection.

Ringworm

Ringworm is a fungal infection of the skin of cattle, usually caused by Trichophyton fungi. It presents as grey, hairless circles, most often on the head and neck. Generally this disease is considered harmless. It is rare for this disease to require intervention and treatment, however, it is a zoonotic disease so take care to cover your own skin when handling affected animals. Outbreaks typically occur in young stock. Occasionally a herd outbreak will occur in mature cows when heifers return from grazing.

Very occasionally, an individual may not be able to mount sufficient immune response to clear the fungus, and she will become overrun with plaques of disease all over her body.

PROGNOSIS: Excellent: after about six weeks affected animals usually clear the infection without any intervention.

Warts

Also known as papillomas, warts are caused by a viral infection with Papillomavirus. The disease presents with dry, fleshy masses erupting over the surface of the skin. Intervention is rarely required as animals will mount an immune response to the virus and clear the infection themselves. Occasionally, if the immune system of the cow fails to react strongly enough to the virus, papillomas can become chronic and may continue to grow and interfere with normal functions. Masses around the eyes are particularly troublesome if they rub on the surface of the eye.

PROGNOSIS: Excellent: generally self-resolving in six weeks in most cattle once an immune response develops to the virus.

• Lisa Whitfield is a Manawatu-based production animal veterinarian.