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Many suckler farmers are struggling to get spring-calving cows and young calves out to grass, as ground conditions remain soft with frequent rainfall.
As cows calve and remain indoors, housing space is being pushed to its limits and more often than not, sheds are overstocked. More and more farmers are reporting problems with calf scour in sheds. When it comes to dealing with scour, it is crucial that farmers can get to the cause of the problem.
Taking a few dung samples will allow your vet to diagnose the problem and set out a proper plan of treatment. But this rarely happens on-farm, especially when farmers are in the midst of calving.
Causes
Calf scour can be caused by pathogens such as bacteria (E coli, salmonella), a virus (rotavirus) or protozoa (cryptosporidium).
They all cause diarrhoea in calves, as well as loss of thrive, dullness, dehydration etc, but generally affect calves of different ages.
When it comes to treatment, there is no single course of medicine that provides blanket cover against scour.
This is why it is crucial to identify the cause of scour, so that the correct treatment can be given.
Build-up in sheds
Scours are more common during the second half of the calving period, as pathogens have built up in sheds.
As pathogens build up in the shed and get to a critical level, the calves that are born during the first half of the calving period are bigger with a stronger immune system, which can help them to deal with scours better.
However, these calves can still shed the disease, which is why it is important not to mix young and older calves.
As younger, more vulnerable calves come into contact with the build-up of scour pathogens, the disease can quickly spread through the shed.
Outlined are some of the leading causes and symptoms of calf scour, along with methods of treatment and prevention.
Telltale sign – watery yellow-green diarrhoea in calves around one week old.
Rotavirus is one of the most common causes of calf scour and usually affects calves around one week old, but can hit calves as young as two/three days of age. Calves generally appear dull and become slow to stand and feed. As the calf becomes dehydrated, its skin becomes tight and less elastic when pinched between the finger and thumb. In isolated cases of rotavirus, calves should be isolated for treatment.
But with sheds filled to capacity until cows get to grass, this option is not a reality on most suckler farms at present.
Make sure weak calves get electrolyte fluids to prevent severe dehydration. Fluids should be fed via a bottle and teat to encourage calves to stand and suck, rather than tubing.
While vaccinating cows prior to calving is a big help in combatting rotavirus, this ship has now sailed for most farmers.
Hygiene
So, getting on top of the problem comes down to good shed hygiene. Remove soiled bedding as often as possible and apply hydrated lime to walls and floor.
As far as possible, do not mix young calves and older calves in the same shed. Also, provide calves with a bedded creep.
Allowing calves to creep outside to a sheltered paddock or covered handling pen during the day will reduce the time calves spend in direct contact with the disease in sheds.
Telltale sign – Excessive yellowish diarrhoea, often with mucus, in calves around three to four weeks old.
Like rotavirus, cryptosporidium also results in a watery yellow scour. However, it is usually causes excessive diarrhoea and affects slightly older calves around two to four weeks of age.
Crypto is caused by a parasite and is much more difficult to treat. Injecting calves with antibiotics will not curtail the disease, as it is not caused by bacteria.
Keep bedding clean and apply plenty of straw to provide a deep bed. Provide calves with a creep pen with plenty of soakage to keep bedding dry.
Resistant
But just cleaning out bedding alone will not break the life cycle of crypto. The disease can survive in dung stuck to walls, floors, feed barriers and water troughs.
It is much more resistant to general disinfectants, so only use a crypto-specific chemical to wash down sheds.
When washing, use a pressure hose with a steam cleaning action. However, taking the time to carry out a deep clean in sheds is not practical on most farms midway through calving.As there is no vaccine for the disease, prevention really comes down to good shed hygiene to prevent crypto from getting a foothold.
Keeping stocking density under control, avoid mixing young and older calves in the same shed and getting stock outside at the first chance are crucial.
If using a product such as Halocur, make sure to follow the guideline properly and start administering to calves at the right age.
Telltale sign – Watery dark brown diarrhoea, often with blood, in calves from three weeks of age and older.
Coccidiosis is also caused by protozoa. The scour usually has blood and mucus present, giving it a dark brownish colour and calves are normally straining as they pass faeces.
Coccidiosis often has a lag period from infection. By the time diarrhoea starts, it has already caused significant damage to the calf’s gut.
Older calves are normally affected, starting around three to four weeks of age right up to weanling stage.
As with rotavirus and crypto, coccidiosis causes lethargy in calves, loss of thrive and reduced appetite.
There are multiple products to treat affected calves, and these should be combined with good hygiene for best results.
Keeping water and feed troughs clean cuts down exposure for calves. Good ventilation in sheds can help limit the build-up of pathogens, as they thrive in warm, damp conditions.
Again, getting calves out to grass at the earliest opportunity reduces the risk and speeds up recovery in affected animals.
Prioritise the youngest and most recent calves born for going out to grass, as these animals will be at most risk of scour in a contaminated house.
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