Scour is one of the main contributors to calf mortality in Ireland. It results from a badly damaged gut, leading to a loss of function of the intestines, which leads to watery faeces. Damage to the intestines results in nutrients not being absorbed properly.
There are a number of infectious agents that cause scour:
The most common causes of scour are rotavirus, cryptosporidium and coccidia. Coronavirus and salmonella are fewer common causes and E. coli is rare. Coccidia generally causes scour in calves older than 3 weeks. E.coli can cause scour in calves less than 5 days old. It is important to note that cryptosporidium is a zoonotic disease, which means that it can be readily transferred from animals to humans.
Treating a calf with scour
The most important principles of treating calf scour are:
- Oral rehydration
- Isolation of the calf from the others
- Continue to feed milk
This is the single most important aspect of treating a scouring calf. A large volume of salts and fluids are lost due to the scouring, so these need to be replaced regularly. An extra 1 to 2 feeds of electrolytes a day is necessary while the calf is scouring e.g. milk in morning, electrolytes at lunchtime, milk in the evening and electrolytes at night. If the calf is not drinking then electrolytes can be stomach tubed effectively. Effervescent electrolyte tablets containing bicarbonate are especially good for the calves that are not drinking. These will help correct the acidosis/depression of the calf that occurs. Sachet or dietetic electrolytes are sufficient to be used for calves that are drinking some volume of milk and are not overly depressed.
Removal of the calf from the group of calves
Scour is contagious so by isolating the sick calf it helps prevent the spread of infection to the other animals in the group. It also helps the sick calf to recover better.
Continue to feed milk
Despite some common myths, continuing to feed milk/good quality milk replacer does not worsen or prolong scour. In contrast, it will continue to provide some nutrition to the calf and will help with the healing of the intestines. It is not recommended to tube milk to calves with scour if they are not drinking as it will cause a build-up of acids in the stomach and damage the wall of the rumen. It will cause the calf to become more acidotic and depressed. By withholding milk from the calf it will only cause starvation and will prevent a quicker recovery.
It is also important to find out the pathogen causing the scour. By bringing a sample to the clinic, we can determine in the lab what the cause of the scour is and therefore target treatments more accurately. Knowing the exact cause allows proper decisions to be made regarding treatment and prevention.
Probiotics are a dietary supplement that are useful to help with the repair of the intestines as well as revitalisation of the good bacteria in the gut. Long term use of these will help stabilise the calf’s gut.
Prevention of calf scour
A good start to a calf’s life is essential.
- Good quality colostrum fed to the calf is key. The quality of colostrum can be assessed with a refractometer.
- If poor quality colostrum is fed, it leads to a failure of passive transfer of antibodies which in turn increases the risk of the calf getting sick with scour or pneumonia etc.
- Use the 1,2,3 rule: ‘Cow’s first milk, fed within the first two hours of birth, minimum volume of 3 litres’.
The calf’s environment is also key to prevention.
- They need to be kept in a clean, warm and dry bed at all times.
- Wet bedding and poor drainage aid with the spreading of disease. You should be able to kneel down in the calf’s bed and it should not be wet, cold or hard. If you find it uncomfortable, then it is not suitable for the calf.
- Cleaning & disinfection of the feeding equipment used is also. This is especially important if there is an outbreak of scour to prevent transfer of the disease from one pen to another.
- Avoid overcrowding of pens as well as mixing of ages of calves.
- Placing footbaths with disinfectant outside every calf house and making sure that everyone’s boots are dipped both going in and out of the house to prevent spread.
- Isolation pens for sick calves to help spread from calf to calf. It is important to identify the problem quickly and isolate the affected animal as soon as possible.
Vaccination of the cows 3-12 weeks prior to calving will provide increased protection against calf scour.
- The vaccine is effective against rotavirus, coronavirus and E.coli.
- Note that it is important to have good colostrum management here as well because the antibodies are passed to the calves via the colostrum. The antibodies in the colostrum reduce the incidence & severity of the scour.
Risk factors for calf scour
- Dirty, wet environment
- Poor drainage in the calf house
- Stressed calves
- Poor colostrum management leading to poor passive transfer of antibodies
- Calves of different ages being mixed
- Lack of isolation of sick calves
If calves get scour in their early life it can set them back significantly and therefore there is delayed growth of the animals. Looking after and caring for a sick calf or calves takes a lot of time, which is of the utmost importance especially during the springtime. Costs of medication to treat the animals, as well as losses due to mortality, can be high.
Antibiotics & their use in scour treatment
The most common causes of scour are parasites and viruses. Antibiotics do not work against these. They only work against bacteria. Therefore, it doesn’t make any sense to treat a calf with antibiotics just because they are scouring. This is why testing the scour sample is essential to the overall management of scouring calves. By using antibiotics ‘because that was what was left over in the yard at home’, is only contributing to antibiotic resistance and isn’t a wise use of funds either.
Only scouring calves that are very sick or have a high temperature should be given antibiotics. Calves that are very sick have a weakened immune system and therefore can get a secondary bacterial infection so this is when antibiotics should be used correctly. It is important to get advice from your vet regarding the use of antibiotics with scouring calves.
- Plenty of electrolytes & fluids are essential in the treatment of scour
- Prevention & hygiene are of utmost importance & of key significance reducing costs due to treatments and losses
- Antibiotics are not essential in treating scour in most cases
- Continue to feed milk to help speed up the recovery process– do not starve the calves!
For additional information contact our large animal team on 023 8847404.