Skin diseases are rarely fatal, but they can cause significant discomfort to livestock and are often highly contagious.
Chloe Palmer speaks to veterinary surgeon, Anthony Wilkinson to find out more about their causes and treatment.
When animals are housed for the winter months, the incidence of skin conditions such as ringworm and lice often increases.
Although rarely critical, skin diseases can lead to production losses due to reduced or disrupted feeding caused by irritation or damaged skin. Many disorders are caused by ectoparasites or a fungal infection, but most can be prevented and treated successfully, according to Anthony Wilkinson of Friars Moor Livestock Health, Dorset.
He says: “Lice and mange are two of the most common skin problems. While there are usually quite low levels of both in herds, they frequently come onto farm on bought in cattle. Quarantining animals when they arrive and treating any symptoms immediately is essential to prevent further spread.”
Mr Wilkinson points to the use of treatments for lice such as those containing active ingredients from the avermectin group of M-L anthelmintics, which can either be applied as a pour-on or by injection.
Chorioptic mange, caused by infestation with Chorioptes bovis, is commonly seen in adult cattle towards the end of the winter housing.
Infestation causes serum exudation and thickening of the skin characteristically at the base of the tail, but infestation may spread to the udder, scrotum and limbs.
Poorly nourished calves and immune suppressed individuals, such as those suffering from persistent BVD infection, will be more susceptible to many skin diseases.
Ringworm also appears to favour weaker animals and is caused primarily by a spore forming fungus called Trichophyton verrucosum. Ringworm manifests itself as circular hairless lesions which may be raised and crusty and are more common on the head and neck, but may extend over much of the body.
Mr Wilkinson says: “Ringworm is seen more commonly in younger animals. They tend to recover from it, but it may take several months. It can spread rapidly through groups of animals and to humans, so great care must be taken when handling affected livestock.
“Historically, skin washes have been used to treat ringworm, but this does not always give good results. There is an effective vaccine which is given as two injections 10 days apart and will also help to speed the recovery of animals.”
Warts are another common finding on many cattle. In most cases they are a minor nuisance, but they can become troublesome.
“Warts on teats can cause difficulties when milking, and bulls can acquire penile warts which can be persistent. Elsewhere, they rarely cause a problem and no treatment is necessary as they will usually disappear in time.”
Digital dermatitis is an infectious skin disease caused by a group of bacteria called Treponemes and although usually considered as a cause of lameness, it can be the cause of serious lesions on the udder and teats.
Recovery from several common skin diseases can be aided by exposure to sunlight. Conversely, photosensitisation is triggered by sunshine and particularly affects non-pigmented skin. The skin often oozes serum and eventually will become dry and slough off.
Mr Wilkinson says: “Liver disease can predispose an animal to photosensitisation and can result in severe symptoms when the animal is exposed to sunlight. The ingestion of certain plant species such as St John’s wort can cause the liver damage.”
Mange: Causes oozing of liquid serum from the blood and thickening of the skin. Treatment is rarely necessary as lesions heal spontaneously when cattle are turned out to pasture in spring.
Lice: Infestations cause cattle to rub against fences and barriers, resulting in hair loss, most often over the neck and shoulders.
Inspection using a magnifying glass will identify adult louse populations and eggs adherent to hairs. A pour-on synthetic pyrethroid preparation such as deltamethrin will remove all lice.
Injectable group 3-ML anthelmintics (ivermectin, doramectin and eprinomectin) will remove all sucking lice and over 98 per cent of biting lice. All cattle in direct contact must be treated.
Ringworm: Lesions are greyish and slightly raised, clearly delineated and may extend up to 10cm in diameter and sometimes merge into large patches.
Although the disease is often described as ‘self-limiting’, treatment can be advisable if large numbers of animals are affected.
Topical enilconazole is commonly used, but may not be effective in all outbreaks, and repeat applications are necessary.
A vaccine can be used as prophylactic dose for active immunisation to reduce clinical signs of ringworm or as a therapeutic dose to shorten the recovery time of infected cattle showing clinical signs of ringworm.
Papillomatosis or warts: Warts are commonly seen on cattle particularly between 6 and 24 months of age. They occur most frequently on the head and dewlap. Papillomas may also affect the penis, vagina and teats.
The causal virus can be spread by physical contac or equipment such as halters or milking machines. Lesions vary from unobtrusive flat warts to cauliflower-like growths.
Extensive growths are sometimes seen in immune suppressed animals such as those with persistent BVD infection.
Warts are generally self limiting and most cases will resolve without treatment in one to 12 months, but as they are unsightly, some keepers may request treatment where animals are prepared for sale.