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Although cryptosporidiosis has nothing to do with cryptocurrency, this animal disease can cost livestock producers a considerable amount of money. According to Dr Minnaar Lyell, a veterinarian and consultant at Elanco Animal Health, producers must be vigilant when it comes to this disease.

Cryptosporidium parvum,” he says, “is a microscopic parasite that causes the protozoan disease cryptosporidiosis. It is common in young or newborn calves and lambs, and causes acute diarrhoea in calves as young as five to 15 days and lambs between four and ten days old.

“Although they do not usually show any clinical symptoms, around 15 to 20% of older animals carry the organism in their intestines. Unfortunately, the same animals are also the source of diarrhoea outbreaks among calves and lambs.”

The biggest common denominator

On its own Cryptosporidium does not cause chronic disease or diarrhoea, but once other organisms, such as rotavirus, coronavirus, E. coli or Salmonella, enter the picture, it may lead to diarrhoea.

Some producers in certain regions of the Karoo lost between 30 and 85% of their lamb crop in the previous lambing season due to a combination of Cryptosporidium and E. coli which was diagnosed in the majority of cases. The high levels of E. coli recorded in the Great Fish River is worrisome, leaving a big question mark over the quality of the water.

The source of infection

According to Dr Lyell, infection in healthy young animals normally occurs when they come in contact with the manure of mature animals, or with already infected calves or lambs. Millions of oocytes are excreted in the manure of animals, leading to environmental contamination. Young livestock ingest these eggs, which then multiply in their intestinal tract.

Cryptosporidiosis subsequently infiltrates the intestines and destroys the intestinal tract’s absorbent layer of cells. As a result, the intestines cannot digest or absorb food. The first signs of diarrhoea can be observed between two and five days after the onset of infection.

Calves and lambs with suppressed immunity are more susceptible to infection than healthy, strong animals. Suppressed immunity can occur in calves and lambs that have not received enough antibodies in the colostrum, or have not received colostrum at all.

In intensive systems where ewes are given minimal time to rest between lambing seasons, the risk of infection is even greater as their body condition is not optimal when they lamb, which affects colostrum quality. The same applies to cattle, especially in the dairy industry, where animals sometimes have a negative energy balance and produce colostrum with low immunoglobulin levels.

Signs to look out for

One of the first signs to look for is a depressed and/or emaciated animal, as well as watery, mucous-containing yellow or pale manure. Animals lose weight quickly, which can lead to emaciation. According to Dr Lyell, dehydration due to diarrhoea is one of the biggest causes of mortality among these lambs and calves.

At the first signs of cryptosporidiosis, the most vital step is to move healthy animals out of the environment and away from sick animals as soon as possible, after which sick animals must be quarantined. Biosecurity is crucial in this regard.

It is best to have certain workers who handle only sick animals. Their overalls, boots and hands must be disinfected before leaving the pens where sick animals are kept, as well as all equipment used.

Immediate treatment

Animals must never be allowed to dehydrate and need to receive enough fluids, which can be given either by gastric tube or a subcutaneous intravenous drip. Sick animals still need to ingest milk in order to get the necessary minerals and vitamins.

“Depending on the level of dehydration and the animals’ weight, they must ingest between 5 and 10% of their bodyweight in fluid per day. Divide it into three to four treatments per day to ensure that the animal can handle the volume of fluid. Replenish electrolytes in the case of diarrhoea.”

There are currently only a limited number of products and methods that can kill Cryptosporidium. Good hygiene and biosecurity are in fact the only way to control cryptosporidiosis. The feed and water troughs of calves and lambs must be cleaned and disinfected daily to limit the spread of disease among animals.

Although there is a treatment for cryptosporidiosis, it can only be obtained from a veterinarian once the farm is diagnosed as positive. Dr Lyell adds that antibiotics will usually be recommended to fight secondary infection brought on by E. coli and Salmonella.

“Sheep and cattle producers can get ahead of any trouble by discussing preventive measures relating to parasites such as Cryptosporidium parvum with their veterinarians – remember, prevention is always better than cure,” he concludes.
Carin Venter, Stockfarm

For enquiries, contact Dr Minnaar Lyell on
082 578 9419 or minnaar.lyell@gmail.com.

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