Veterinary advice for farmers: Ringworm can spread like wildfire in calves indoors

Veterinary advice for farmers: Ringworm can spread like wildfire in calves indoors

Ringworm is usually found in young calves in an indoor setting and spreads through the group like wild fire.

We went out to Dara to do his herd test recently.

He is one of our clients who buys in cattle to fatten them.

The weather was holding up as we worked our way through the various groups, and the final group was in a yard a few miles away.

As we drove them in, he told me that he had a problem with a few of the group.

They were showing signs of ringworm. This is not a nice thing to get in to a bunch of cattle.

Usually it is found in young calves in an indoor setting and spreads through the group like wild fire.

The name “ringworm” is somewhat misleading. The lesion we know as ringworm is usually round, in the form of a circle, so the ring part of the name is correct, but the worm part is not. This disease is caused by a fungus. There are many different types of fungus that cause ringworm in different species of animal. Cattle, horses, cats, dogs and man are some of the many that can be affected.

The problem first starts with the fungal spores. Thread-like filaments grow from these down into the hair follicle, where they start to produce new spores. These filaments spread outward from the point of infection in a circular fashion, causing the common appearance of ringworm.

The incubation period for this ringworm is usually between two and four weeks, with the hair in the affected area either breaking off or falling out, leaving us with the classic crusty lesion that we have come to know.

These lesions can grow outward, forming fairly substantial plaques in some cases.

The usual sites for these lesions are found around the eyes, ears, muzzle and neck of the affected animals. but if left untreated, they can cover any part of the animal. The affected animal feels pretty miserable, and the constant itch makes it scratch relentlessly.

Long ago, the pole in the middle of the shed, or indeed any other piece of timber, was used to relieve the itch.

These bits of timber invariably held onto some of the crusts, and these would remain infectious to other animals for up to four years.

This meant that, each year, the calves would become infected, as they inhabited the same contaminated house as their predecessors.

It was next to impossible to disinfect these houses, and the best solution was probably to raze them to the ground and start afresh.

Normally, the classic lesions are enough to give a diagnosis of ringworm in our animals, but laboratory confirmation can be used, in the form of microscopic slides, and the culture of the fungus in an incubator. The latter is very time consuming.

Sometimes, we might use the Woods lamp to show the classic fluorescence that comes from certain species causing ringworm, but since this fluorescence does not occur with all species, then it can be of limited value.

We can use a number of different treatments.

There are washes and sprays that can sterilise the lesions and prevent them from infecting other animals, while more will kill the fungus outright. The problem is the time needed to soak into the thick, crusty lesion.

A few years ago, we were able to use the drug, griseofulvin, which was fed to the animals and, working from the inside, it proved to be one of the most effective ways of dealing with ringworm.

Sad to say, it was banned from use in food producing animals.

There is a very effective vaccine on the market now, that can also be used to treat ringworm. However, treating older animals this way can be very expensive.

Your own vet is the person to give you the best advice if you have a problem with ringworm.

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