The number of calves dying due to scour on Northern Ireland farms is continuing to increase, however the cause is often never investigated.
Accurate diagnosis by an attending veterinary practitioner is crucial as this will determine the subsequent control measures that must be implemented on the farm.
Scour is generally seen in one to two week old calves. Calves develop profuse watery diarrhoea which may contain mucus and can last for five to 12 days. They lose their appetite and become weak and dehydrated.
The All-Island Animal Disease Surveillance Report 2014 identified scour as the most common cause of death in neonatal calves (<one month of age) submitted for post-mortem exam - accounting for 38% of cases in Northern Ireland. The predominant infectious agents associated with scour in Ireland are Rotavirus and Cryptosporidium parvum. Vaccination is an important step in getting scour under control, however there is no vaccine available to control Cryptosporidium parvum. One solution available to Northern Ireland farmers is Halocur ® which is the only licensed product for the prevention and treatment of cryptosporidiosis.
Hygiene recommendations include:
When cleaning sheds:
l Muck out and remove all dirt from surfaces. Organic matter can interfere with the efficacy of many disinfectants.
l Steam clean the floor, walls and pen divisions. A natural “biofilm” protects Cryptosporidium parvum eggs from destruction and this biofilm may be broken down by steam cleaning prior to disinfection.
l Decontaminate the area with a disinfectant which is licensed for activity against Cryptosporidium parvum eggs. Disinfectants recommended include the amine based KenoTM Cox (CIDLines N.V.,Belgium), p-chloro-m-cresol (Neopredisan (Vertriab GMBH, Germany)), hydrogen peroxide with paracetic acid (Ox-Virin, (Ox-Oxcta, Spain)) or 3% hydrogen peroxide.
l The disinfectant must be used at the recommended dilution rate and given the recommended contact time needed for activity.
l Make sure pens are dry before the introduction of any further calves.
Extra control measures during an outbreak:
lAll new-born calves MUST get at least 3L of colostrum within two hours of birth.
l Healthy calves must be separated from sick calves and a “hospitalisation” unit established for the sick calves.
l Healthy calves should be fed first each day and hospitalised calves attended to last so as not to transfer disease from the sick animals to the healthy unit.
l Designated overalls and boots should be worn when working in the hospital unit and hands should always be washed between each group of calves.
l Strict, thorough hygiene of feeding equipment including bottles, nipples and buckets must be practised.
l Raise feed and water troughs so that calves can eat and drink out of them but cannot defaecate into them.
lAntibiotics are NOT effective against cryptosporidiosis. All calves clinically affected should be treated with a product licensed to reduce diarrhoea
Ongoing control measures after an outbreak:
l Correct colostrum management following the 3-2-1 rule where 3L of colostrum are given within two hours of birth, from the first milking, is essential. This will boost the calf’s immunity and offer greater defence against a multitude of infections, including cryptosporidiosis.
l Do not mix new-born calves with calves older than three to four days as the latter may not have scour but could be shedding Cryptosporidium parvum eggs.
l If cryptosporidiosis was a problem on the farm last year, don’t wait for it to take hold this year. Cryptosporidium parvum builds up as the calving season progresses. Start calves on oral halofuginone lactate (Halocur®) after their first feed and daily thereafter for seven days. This neonatal treatment schedule should be implemented at the very beginning of the season, in order to reduce this build up later on. Halocur® decreases the overall amount of eggs shed.
l Adhere consistently to strict hygienic protocols, including pens and feeding equipment.