Besides the treatment costs and extra labour, reduced growth rates and calf mortality can quickly add up to thousands in lost profit.
Caroline Robinson, veterinary investigation officer at SAC Consulting, says the major causes of calf scour may commonly be found in a herd whether or not there has been a problem in the past with calf scours.
This can lead to unexpected outbreaks following management or environmental changes.
“Carrying out a risk assessment with your vet at the time of reviewing your annual health plan, to see if any planned changes might increase your risk of calf scour outbreaks or indeed pneumonia, is always wise.
“Remember, the advice in your health plan is time limited and any changes can lead to different actions being recommended by your vet.”
Scouring is essentially an increase in the amount of fluid passed in the faeces. This can vary from a pasty slurry to pure liquid. Because the calf is passing too much fluid out of the body, it will need to drink an equivalent volume of extra fluid to replace it. If this is not done, the calf will become dehydrated, lethargic, or even unable to rise due to severe dehydration. This can sometimes happen even before the signs of diarrhoea are spotted – in some cases death can follow quite rapidly.
E.coli K99 - This is a particular type of e.coli causes scour in the first four days of life and can lead to rapid dehydration at this critical time
Cryptosporidiosis - This is a small parasite and can affect humans, so good personal hygiene is essential. It usually causes scour from four days to three weeks old. It does not take a high concentration of cryptosporidium parasites to cause a problem so it may cause a scour outbreak even in low numbers. The treatment is halofuginone, not antibiotics. The organism survives well in the environment and this disease can affect lambs too. This is particularly important to be aware of if your calving paddock or shed will then be used for lambing a few months later
Coccidia - This is another small parasite and usually causes scour between three weeks and six months of age. Chronic ill-thrift or severe bloody scour may be seen in some calves, while moderate pasty scour or straining may be seen in others. In rare cases the straining can be persistent to the point a prolapse of the rectum may occur. Treatment is by one of the anti-coccidial drugs available on prescription
Viruses Rotavirus and coronavirus - Both can cause scour from a few days of age to three weeks or so. Rotavirus is a particularly common cause of calf scour. As these are viral, the treatment is nursing-based, involving rehydration and a clean dry environment.
Salmonella - If you are seeing an outbreak of scour coupled with signs of pneumonia, sudden death or joint problems in a group, then you might consider salmonellosis as a potential problem. Salmonella Dublin can lurk in a herd undetected in adult animals before causing all of these various different health problems in calf groups.
Mrs Robinson says to gain faeces samples from at least three, or ideally six, untreated calves should be submitted to the vet.
“Diagnosis in this way has obvious benefits as the treatments for different causes of scour are all different, and few of them will respond to antibiotics. The blanket use of antibiotics as a first line action against an outbreak of scour may, in most cases, turn out to be useless, adding unnecessary costs.”
When it comes to prevention, Mrs Robinson says good hygiene is essential, with a clean dry area for calving and another well-bedded clean area for cows with young calves.
“A good tight calving pattern to avoid a build-up of infectious material in the shed from the presence of susceptible young calves over a protracted calving period can be invaluable. For calf-rearers buying in young calves, an all-in, all-out policy may be best for the rearing stage. At the very least, individual calf hutches or pens should be cleaned and disinfected before new calves replaces the last inhabitants,” says Mrs Robinson.
“Keeping calves grouped by age can help prevent transference of disease from older resistant calves to younger susceptible ones. Cryptosporidium can be resistant to a lot of disinfectants which work for other causes of scour and can persist in the environment for extended periods of time. If you have problems with this disease then use of a special disinfectant specifically targeting cryptosporidium may be needed.”
Good colostrum management and cow nutrition, to ensure minimal calving trauma and healthy calves with early protection from the dam, is a first-class general preventative for any cause of calf disease, including scours.
“Vaccination of cows between one and three months pre-calving against rotavirus, coronavirus and e.coli K99 can be carried out, so now is the ideal time to ask your vet if this would be necessary or beneficial to your herd, depending on your disease and management history.
An action plan for calf treatment should be built into your health plan.
Mrs Robinson says: “Calves with severe dehydration [sunken eyes, weak or collapsed] should be referred to the vet for intravenous fluids, while calves which are mildly dehydrated but still standing may be given oral rehydration fluids by the stock keeper.
“It was previously advised calves be kept off milk. This is no longer the case, although allowing a couple of hours between oral fluids and suckling may be beneficial. If the calf is scouring but is showing no signs of dehydration and is bright, then no oral fluids may be necessary.”
Isolation of a scouring calf away from other calves is recommended, particularly in a dry, well bedded pen free of draughts and with a source of fresh water, as the calf could be cold and dehydrated due to the illness. “If initially rehydrated by stomach tube, oral rehydration fluids should subsequently be offered from a teat if possible, as the ability to suck is an important indicator of improvement. Repeated stomach tubing should only be carried out if the calf is visibly improving after the first administration, although not yet sucking well enough by itself. Keep two separate labelled stomach tubes – one for giving colostrum to newborns and the other for sick animals – to avoid spreading diseases.
“In general, antibiotics have no value in treatment of the most common causes of calf scour. Diagnosis of the cause of an outbreak will be of far greater use than reactive blanket antibiotic treatment, while also still allowing prompt identification of these few cases in which antibiotics may be of benefit.”