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Dealing with the scourge of scour

We are now a couple of months into housing and our livestock will begin to show the strain of it all soon enough. By that I mean that the winter bugs will begin to wreak havoc in the sheds if we don't put steps in place to prevent them.

Young calves are the most vulnerable and already liquid milk dairy herds have a few batches of calves through the pens. Scour is the scourge of any calf-rearing outfit and the first few weeks of life are the worst of all. Beef calves may not be arriving yet, but scour will strike there too.

Scour can strike our calves from a day or two old up to three weeks of age, and on up the line from there. A three-day-old calf with scour is a difficult case as the animal has hardly got its immune system in place yet. In fact, it is wholly reliant on its mother's immunity in the form of colostrum. This 'liquid gold', as I like to call it, is important.

In the first eight hours of life, nature has deemed that the calf's intestinal wall will allow total and intact proteins to cross directly into the blood stream. Normally, the intestine must break down the protein before absorbing it. Not so in the first few hours of life. This allows the mother's antibodies to cross directly into the calf's bloodstream. If we as animal keepers fail to ensure adequate feeding of colostrum to the newborn, then we are exposing that poor calf to all diseases.

Everything in nature has a double and often treble function. Colostrum not only provides instant immunity, it is also a source of blood protein. It is also a high-energy booster. The blood protein is needed by the calf to keep itself hydrated. In other words, no colostrum ultimately leads to no calf. Also, low colostrum leads to poor and weak calves. Get at least two litres into them soon after birth, with a further feed of two litres before they are eight hours old.

Infectious causes of scour

  • Virus: Rotavirus, corona virus, BVD virus;
  • Bacteria: Ecoli, Salmonella;
  • Parasites: Cryptosporidia, coccidia;
  • Diet: Too much, too little or a sudden change of milk diet or poor quality milk replacer.


Finding out what is causing the scour is vital to best treat and prevent an outbreak or further spread of the condition. Faecal samples are the best way to get immediate answers.

However, if treatment has already begun, then sampling at that stage can give a false reading. Not to worry. If a calf needs treatment on a Friday evening and the laboratories are closed until Monday, then take the sample and store it in a cool cabinet until later. Treat away and send the stored sample to your vet first thing on the Monday. Your vet will equip you with sample bags or jars and show how best to retrieve a sample.

Often, several samples are required to get an accurate result as bugs can be shed at different times by the infected calf. Once we have an answer then we can prevent a full-blown attack. Samples, on average, should cost less than €10 each.


It is often necessary to treat scour without yet knowing what the cause is. Your farm vet is best placed to give an educated guess as to what is likely to be the cause on any particular farm.

A few basic principles apply no matter what the bug is

  • Dehydration: The big killer with scour is dehydrated calves. Replacing fluids is a must in all cases. Electrolyte sachets mixed with water as per the manufacturer's instructions --usually two litres -- must be fed or dosed at regular intervals. I prefer to see two litres fed every six to eight hours rather than just twice every 24 hours. The sachets with added energy, such as glutalyte, are better again as the extra energy is used by the gut to pump the fluids into the blood.
  • Heat: A dehydrated calf in a winter shed is all too often frozen to the bone. I cannot stress enough the importance of heat. At 3am, that calf that was last fed at 6pm the evening before is expected to keep itself warm enough until we climb out of bed the next morning. When a collapsed, scouring calf comes into the surgery, an intravenous fluid drip is put in place and then immediately the calf is placed into a hot-house, an area of immense concentrated heat to get the chill out of its bones.

Within two hours it is invariably up and pucking at the door looking for a suck. This can be done on any farm with straw bales or a plastic hutch with infra-red lamps. But be careful of straw bales and heat. Ensure that no fire risk is present.

  • Kaolin or chalk powder was useful to be mixed and given orally to the calf in years gone by. This was to line the damaged bowel and stop the damage caused by the bug. We have difficulty getting such powder at present, but it is available in some scour preparations on the market.
  • Vigorous cleaning of calf pens before and between each use is vital. Power hose and allow the area to fully dry before putting fresh bedding back in.

Lime under the bedding is useful but beware of it on metal gates as it is corrosive. It is also corrosive to a young calf's bare skin so cover the lime well with plenty of bedding.

  • Prevention: Vaccinating the mother before the calf is born is the first real step to prevention. To do this, we must know what bugs are on the farm. Again, a Veterinary Ireland Herd Health Plan is exactly what is required. Here, your vet will sit and lay out prevention protocols before the challenge ever arises.

Indo Farming