Cattle
Trichophyton verrucosum is the usual cause of ringworm in cattle, but T mentagrophytes , T equinum , Microsporum gypseum , M nanum , M canis , and others have been isolated from some cases. Dermatophytosis is most commonly recognized in calves, in which nonpruritic periocular lesions are most characteristic, although generalized skin disease may develop. Cows and heifers are reported to develop lesions on the chest and limbs most often, and bulls in the dewlap and intermaxillary skin. Lesions are characteristically discrete, scaling patches of hair loss with gray-white crust formation, but some become thickly crusted with suppuration. Ringworm as a herd health problem is more common in the winter and is more commonly recognized in temperate climates and in English rather than zebu breeds of cattle.
Many topical treatments have been reported to be successful in cattle, but because spontaneous recovery is common, claims of efficacy are difficult to substantiate. However, valuable individual animals should still be treated because this may well limit the progression of existing lesions and spread to others in the herd. Thick crusts should be removed gently with a brush, and the material burned or disinfected with hypochlorite solution. Treatment options depend on the limitations on the use of some agents in animals meant for slaughter. Agents reported to be of use include washes or sprays of 4% lime sulfur, 0.5% sodium hypochlorite (1:10 household bleach), 0.5% chlorhexidine, 1% povidone-iodine, captan (1:300), natamycin, and enilconazole. Individual lesions can be treated with miconazole or clotrimazole lotions. An attenuated fungal vaccine is in use in some European countries; it prevents development of severe clinical lesions and also has greatly reduced the incidence of zoonotic disease in animal care workers. Unfortunately, vaccinated animals shed fungal spores for a time after vaccination. No live vaccine is available in North America.
Iodine has always worked - just make sure that if you have a quarter size spot you paint a half dollor size spot - - strong Cattle iodine can be cut and a whole area can be washed