In Control – Dairy Farmer Shares His Experience Tackling Calf Scour

We caught up with Michael Clarke to see how he got on tackling cryptosporidium on his dairy farm during the spring of 2020.

“We got great results with little or no sick days. We went 100% by the book and did what we were meant to. Last Spring, we gave it to calves from the first day of the calving season, on day one of the calf’s life. We continued giving it to the calf for the full 7 days after feeding and that’s the reason we got such good results” said Michael

Filmed in Spring 2019

The Westmeath dairy farmer had a bad run with cryptosporidium some years ago. “It was a nightmare. It involved shocking work over two to three weeks, keeping calves alive through feeding electrolytes and water – not to mention the cost of treatment and the loss of a few calves.”

Lynn and Michael Clarke.  All calves are being treated with the oral solution for the treatment and prevention of diarrhoea caused by Cryptosporidium parvum 

Cryptosporidiosis is one of the main causes of scour in calves less than two weeks of age. Caused by the parasite Cryptosporidium parvum, it results in acute scour and abdominal pain.

“We had the first outbreak in 2018. It didn’t hit until around the 7th of March when most of the cows had calved.

“In 2019, it came much earlier – around the 22nd of February. This was right in the middle of calving. Intervention came too late” said Michael.

At one stage, his vet John Moore had to put eight calves on a drip. Four of them died. “The labour and the cost was horrendous” said Michael

It was after this episode that Michael decided, following the advice of John Moore, that to get on top of cryptosporidiosis all calves must receive the oral solution from birth.

Oral solution

As soon as cryptosporidiosis was diagnosed in 2018, John Moore prescribed the oral solution which is licensed for the treatment and prevention of diarrhoea caused by Cryptosporidium parvum. Containing the active ingredient Halofuginone lactate, it is available only on veterinary prescription.

  • As a treatment, it should be given to calves within 24 hours after the onset of diarrhoea, once a day for seven consecutive days. Make sure calves are fully hydrated before treating them with the oral solution.
  • As a prevention, it should be given to every calf 24 to 48 hours after birth, once a day after milk feeding for seven consecutive days.

Learning From The Past

Michael Clarke administered the oral solution in 2018 and 2019, only after the first calves were diagnosed with cryptosporidium in each of these years.

“Last year, we didn’t wait for the disease to hit. Instead, we started the programme at the beginning of the calving season. Calves received their first dose the day after birth for seven days.”

The Clarkes are very diligent in their calf rearing practices. Calves are given plenty of colostrum within a few hours of birth and close attention is paid to nutrition levels and to bedding, hygiene and ventilation. This demonstrates that even with good management, cryptosporidiosis is an ever–present risk.

“It’s a must to have your sheds properly power washed and disinfected before calving starts. Previous years, I wasn’t using the product correctly either. I wouldn’t have finished the treatment course and then problems start arising. Three to four weeks into calving, the disease pressure is at its highest and there’re a lot of calves on the ground. So last year, we cleaned out the calf shed every 10 days but didn’t power wash or disinfect as we didn’t have time to let the sheds dry. That, along with the treatment and good management was effective at keeping the disease at bay” said Michael

Michael saw fantastic results in controlling cryptosporidiosis however some calves started to show positive signs of rotavirus around 4 weeks into the calving season.

“When the calves got a heavy infection of cryptosporidium in 2019, I decided to drop the scour vaccine last year. This resulted in the calves getting a touch of rotavirus at around day 18 of the calving season. I talked to John (vet) and we decided that we would vaccinate the cows with the scour vaccine again this year and protect the calves against cryptosporidium from the start of calving season. I get great peace of mind with this broad range of cover” said Michael

Veterinary practitioner John Moore.

Disease Can Get Out of Control

Veterinary practitioner John Moore said where cryptosporidiosis is a problem on a farm the use of the oral solution should be a critical component of the prevention programme. “All calves should be treated daily from 24 to 48 hours old for seven consecutive days.

“Because the disease hits so fast, it can get out of control before the farmer has time to take action. Mortality can be high and even when calves survive, thrive can be severely affected.”

“While the oral solution is not cheap, its use as a prevention is a more economical option than the massive labour, stress and cost involved in treating sick calves as well as the potential losses from dead calves and poor thrive in those that survive,” he stressed.

He highlighted the importance of strictly following the instructions on the use of the oral solution. “Dosage levels should correspond to the weight of the calf and when used as a treatment, make sure the calf is fully hydrated and bright before use.”

Millions of Oocysts

As part of its life cycle, Cryptosporidium parvum produces huge numbers of encysted eggs, or oocysts, which are shed in the faeces of infected calves, cows or other animals.

At peak shedding there may be as many as 10 million oocysts per gram or faeces. It takes as few as 20 of these to cause disease in young, susceptible calves.

Typically, clinical signs appear in calves from 5 to 14 days old. These can vary greatly – from mild diarrhoea to severe, watery scours and eventually death. Calves become rapidly dehydrated and suffer loss of appetite.

Period of rapid expansion

The Clarkes converted to dairying in 2010. They ran a suckler herd of 100 cows and bought in around 140 weanling bulls. There was also a flock of 100 ewes.

They bought 200,000l of quota under the new entrant scheme and started off milking 48 heifers.

Last year, they milked 270 cows. This year, they will calve 280 cows and plan to milk around 260. The remainder are being sold as in-calf heifers.

“Our plan was to milk 120 cows. But a neighboring farm of 114 acres came up for lease and we decided to go for it. An additional 50 acres also became available and we leased that too,” said Michael.


It’s back – Pr€vention for Profit competition

Now we’re looking for the best dairy calf rearer in the country #MyCalfOurFuture


Register here

This year, the Pr€vention for Profit competition is focused on calves. The #MyCalfOurFuture concept highlights the importance of the newborn calf to the sustainability of the farm, the farmer, their family and the rural economy.

The competition is aimed at dairy farmers who are maximising their on-farm profitability by focusing on the four key pillars of production – Nutrition, Genetics, Management and Animal Health. We aim to showcase the management of Irish dairy calves by identifying farmers who implement best practice when it comes to calf rearing.

There will be one dairy farmer selected from each of the four provinces. The four finalists will be assessed based on the four pillars of production. A panel of judges will conduct a single half day farm visit to assess their calves’ level of productivity and profitability.


Win an all-expenses paid European dairy farm study tour. To enter, CLICK HERE