Controlling cryptosporidiosis in dairy calves

Cryptosporidiosis is caused by the parasite cryptosporidium. Calves usually become infected shortly after birth and develop scour at around 5–7 days old. We have information to help you identify, diagnose and control cryptosporidiosis in dairy calves.

Cryptosporidiosis is one of the most common causes of calf scour – others are shown in the chart below. Four cryptosporidium species are capable of infecting cattle, but the main disease-causing species is C.parvum. Humans can also be infected with cryptosporidium when handling infected cattle.

Cryptosporidiosis is one of the most common causes of calf scour – others are shown in the chart below. Four cryptosporidium species are capable of infecting cattle, but the main disease-causing species is C.parvum. Humans can also be infected with cryptosporidium when handling infected cattle.

The main signs of cryptosporidiosis include watery scour, dehydration and reduced feed intake. Suckled calves also stop sucking and may lie separately from the rest of the herd.

Large numbers of eggs are shed in the faeces of infected calves and cows, which contaminate the environment. Ingesting food contaminated with eggs or water infects calves. Eggs can be found in bedding, soil and water and on pasture. Infected calves shed up to 1 million eggs per gram of faeces and it takes only a small fraction of this number to cause disease.

People handling livestock can also be potential sources of infection, so it is important to have good hygiene procedures in place, such as insisting that footwear is cleaned at the farm entrance and before entering calf accommodation. It is also important to provide clean clothing or overalls when trying to prevent the spread of the disease.

Once ingested, the parasite attaches to the gut wall and multiplies. This causes damage that reduces the calf’s ability to digest food, resulting in watery scour. While attached to the gut wall, the parasite produces eggs. These are infectious and can either reinfect the calf or be shed into the environment via the infected calf’s scour.

Symptoms of disease appear 3–5 days after infection. Following infection, a calf can shed the eggs for two weeks or longer. Calves can begin shedding eggs in their faeces as early as two days of age, which means they are susceptible to infection shortly after being born.

Diagnosis is made by identifying cryptosporidium eggs in faeces. If you have scouring calves, consult your vet to get an accurate diagnosis because treatments differ depending on the pathogen(s) involved.

When trying to control cryptosporidiosis in dairy calves, there are two areas to look at: the environment and the animal.

Cleaning and disinfection are crucial to controlling the spread of cryptosporidiosis.

• Keep the calving area clean
• Use disinfectant at the entrance to the calf shed
• Muck out, steam-clean and disinfect as frequently as practical
• Let pens dry before restocking because cryptosporidium does not like dry conditions
• Turn out spring-calving suckler cows as soon as possible after calving. When housing autumn calvers, keep the environment dry and clean throughout winter. Use lime to help keep bedding dry
• Rodent and fly control should be in place, with all feed and grain stored in covered areas, away from rodents and pets

• Vaccinate pregnant dams against rotavirus, coronavirus and E. coli, thereby reducing scours caused by these pathogens
• Do not mix older calves with young calves because older calves may still shed eggs
• Keep all calves warm and hydrated, particularly if they are scouring
• Isolate scouring calves from healthy calves. Do not mix scouring calves with healthy calves for at least one week after scouring has stopped
• Feed and deal with healthy calves before sick ones
• Use separate, dedicated feeding equipment for sick calves
• Make sure you follow the 3 Qs of colostrum feeding

Calf jackets can potentially harbour cryptosporidium eggs. These eggs can only be destroyed if the jackets are treated with a licensed cryptosporidium disinfectant (consult data sheet for recommended contact times), then washed according to the manufacturer’s instructions and left to dry completely. Cryptosporidium eggs are only destroyed at temperatures above 60°C.

Rehydration of infected calves is key for survival. Feed 2 litres of oral electrolytes 2–4 times a day. Continue to offer scouring calves normal amounts of milk or milk replacer if they want to drink.

Always give suckler calves access to their dam; if they have stopped suckling, feed the calf via a teat or stomach tube if possible.          

Use a licensed product to both prevent and treat cryptosporidiosis to reduce egg secretion and the severity of calf scour.

For prevention, dose all newborn calves within the first 24–48 hours of life.

For treatment, dose all calves within 24 hours of diagnosis. Ensure dehydrated calves are fully rehydrated before treatment.

In both preventions and treatment, accurate dosing is essential. Dose orally after feeding for seven consecutive days.

If you would like to order a hard copy of the Calf notebook or Calf management guide, please contact publications@ahdb.org.uk or call 0247 799 0069.