Mange usually appears as a skin condition associated with irritation and scratching that leads to inflammation, exudation and crusts and scabs forming on the skin. Untreated mange leads to thickening of the skin and loss of condition of the animal.
The disease is often seen in animals in generally poor condition and during the winter season. The condition sometimes causes welfare problems in dairy herds as the treatment of lactating animals is not carried out due to long withdrawal periods required in connection with the efficacious treatments.
- Causes of Allergic Dermatitis >
- Effects of Allergic Dermatitis >
- Diagnosis of Allergic Dermatitis >
- Treatment & Control of Allergic Dermatitis >
- Medication/Vaccination for Allergic Dermatitis >
Causes of Allergic Dermatitis
Mange is an ectoparasitic infestation caused by mites, which can be divided into burrowing and non-burrowing mites. The only burrowing mite of importance in Western Europe, Sarcoptes scabiei, has a life cycle of about three weeks from egg to adult, after which the adult female will lay eggs for up to 60 days.
The most common sites for sarcoptic mange on cattle are inner thigh, underside of neck and brisket and around the root of the tail. Small areas of infestation do not cause major irritation to the animal, but a generalised condition can be extremely distressing.
The non-burrowing mites, Chorioptes and Psoroptes, have a similar life-cycle to the burrowing mites, with a slightly shorter adult phase of 40 days. The predilection site for Chorioptic mites is at the base of the tail, in the perineum and at the back of the udder in the winter.
Long-haired, highland cattle are considered to be particularly susceptible to infection. Psoroptic mites are initially found on the withers, with the condition rapidly worsening to exudative dermatitis, associated with severe irritation.
Effects of Allergic Dermatitis
Untreated mange leads to thickening of the skin and loss of condition of the animal. The disease is often seen in animals in generally poor condition and during the winter season. The condition sometimes causes welfare problems in dairy herds as the treatment of lactating animals is not carried out due to long withdrawal periods required in connection with the efficacious treatments.
Diagnosis of Allergic Dermatitis
Mange usually appears as a skin condition associated with irritation and scratching that leads to inflammation, exudation and crusts and scabs forming on the skin.
Treatment & Control of Allergic Dermatitis
Treatment of mange in conventional cattle herds has been achieved efficiently with organophosphorus compounds, avermectins and synthetic pyrethroids. Only moxidectin (and eprinomectin), of the avermectin group, and synthetic pyrethorids are acceptable under organic standards.
The best prevention of mange in cattle is good control of other illnesses and maintenance of good condition in cattle throughout the winter season. Closed herd policy, quarantine and treatment of bought-in animals and avoidance of communal grazing prevent the disease from entering a herd.
Mange control in conventional herds has been achieved in recent years as a side product of internal parasite control, particularly with systemic use of avermectins. In an organic herd prevention is the only form of control in herds that are not infected. In infected herds, elimination of infection and subsequent preventive strategy should be the main aim of a control policy.
Medication/Vaccination for Allergic Dermatitis
Pour-on application of moxidectin can be used in non-dairy animals, and has been found effective against psoroptic mange. Similarly, systemic application of moxidectin was found efficacious against psoroptic mange but less so against chorioptic mang. Eprinomectin (Eprinex, Merial) is unique in being an avermectin licensed for lactating dairy cows, with a zero milk withdrawal period in conventional systems. Although Eprinomectin has been found to be very effective against Chorioptic mange, it does not carry a datasheet claim of efficacy against Psoroptes.
Deltamethrine, a sythetic pyrethroid, has been found effective against sarcoptic mange in cattle and psosroptic mange in sheep. The following precautions should be taken into consideration when using deltamethrine preparations.
This info was adapted from Defra’s Compendium of Animal Health & Welfare in Organic Farming, which is a collaborative effort led by Duchy College, Cornwall with VEERU at The University of Reading and The Faculty of Veterinary Medicine, University of Glasgow.
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