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Calf scour is well recognised as the number one reason for mortality in newborns and young calves in the first few weeks of life. On most farms the risk is lower as calving commences, but the risk increases with time. Now is a good time to put measures in place to reduce the risk.
What causes calf scour?t
So calf scour occurs when viruses, parasites and/or bacteria damage the gut wall. This decreases the animal’s ability to absorb fluids and nutrients. As it progresses it can potentially lead to severe dehydration and secondary problems with septicaemias. Early treatment and intervention usually gets the best results.
The main causes of scours in Irish farms are:
1. Viral scours rotavirus coronavirus.
2. Parasites cryptosporidium/coccidiosis.
3. Bacterial E coli/salmonella.
There are other potential causes, but the ones mentioned above are by far the most common agents we isolate. The age affected can vary but generally it is recognised that E coli affects calves between one and five days old, and coccidiosis affects calves older than three weeks. The others can generally occur between five and 21 days.
Issues
I investigate a lot of calf scour issues. The three things I generally start off with are:
1. Colostrum quality − is there good transfer? (transfer can be checked by blood-testing calves to assess passive transfer)
2. Hygiene.
3. Find the causing agent − test the scour.
Your vet can assess calf scour using rapid tests which will give accurate results within five minutes. If salmonella or coccidiosis is suspected, we will often send faeces off to the lab for further testing. Knowing what is causing the scour can be hugely beneficial to drawing up a control plan.
SOP
Having a simple standard operating procedure (SOP) for scouring calves can be very useful.
1. Remove from the calf pen to sick pen. Isolating these cases allows for more intensive treatment and also reduces the risk of spread to healthy calves.
2. Rehydration revolutionised human medicine when it was discovered. It also is massively important to the outcome of treating calf scours. Early intervention with 2 litre feeds x 2 daily separate to milk feeds works well. Carefully chose your rehydration solution as quality does vary. If you are not confident using a stomach tube, get your vet to show you how to tube calves correctly.
3. Continue to feed milk or keep the calf on the cow. Starvation can be detrimental to treatment outcome and milk feeding allows the gut to heal quicker. Oral rehydration should be carried out at times in between milk feeds.
It is advised to call the vet when the calf has not been drinking for two or more feeds, is down/weak, has sunken eyes and has a temperature above 39.5°C or below 38°C. Your own vet is best placed to advice on antibiotic treatment for individual cases. It is worth noting that giving oral antibiotics to calves with viral scours or crypto has no benefit and is not recommended.
Preventing further cases
When you know what is causing the scour, you can focus on preventing further cases. The reason calf scour is an issue later in the calving season is that infection pressure builds. This is where hygiene is reduced through increased numbers of newborns and calves, but more importantly the bugs that cause scour build to high levels in the environment.
If viral scours are isolated, it is important to focus on colostrum and hygiene. Individual calf pens definitely help for the first seven to 14 days and they must be kept clean and dry. All feeding equipment should be thoroughly cleaned as to minimise spread.
My advice is equipment should be cleaned daily and disinfected at least twice weekly. This might seem like extra labour, but pales in comparison to the work and heartache scouring causes.
Healthy calves should not be stomach-tubed with a tube used to treat sick calves.
There is the option of vaccinating cows with a scour vaccine two to three weeks out from calving if viral scours such as rota/corona are isolated. This works well when colostrum management is excellent.
Crypto control
We are now seeing more issues than ever with cryptosporidium. It now seems to be a primary agent meaning it can cause scour on its own and not just in conjunction with viral agents.
Hygiene, I have found, is the most critical area to work on when crypto is diagnosed. There are several products on the market for crypto control and again talk to your vet about which one to use.
It is worth mentioning the original source can be from the dam’s faeces, making calving area hygiene of the utmost importance.
This is only a general overview of calf scour. My advice is sit down with your vet and draw up a plan to minimise your risk and maximise the calf health on your farm.
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