An update on ensuring good health in young calves from Damien Barrett SVI, Surveillance, Animal By-Products & TSE Division, Department of Agriculture, Food and the Marine.
The first step to protect the health of young calves is to ensure they receive adequate colostrum (biestings). It is generally recommended that calves receive 10 per cent of their body weight in colostrum in the first 24 hours of life, and for the average 50kg calf this is 5L of colostrum. Note: this is over the first day, and does not have to be given in one feed. After 24 hours, the calf’s ability to absorb antibodies from the colostrum diminishes considerably, so therefore it is of little or no use to it.
The pathogens that cause neonatal diarrhoea (calf scour) are shed in dung (both by adults and calves) and infect the calf through its mouth. Therefore, controlling diarrhoea (scour) in calves requires improving general hygiene in the calf’s environment, so that it is not exposed to infection.
The importance of a clean, dry bed cannot be overemphasised in maintaining calf health. In areas with a dense population of calves, the regular removal of bedding and disinfection may be required. For dairy feed, calves’ buckets and feeders need to be regularly cleaned and disinfected. Suckler cows should not be housed in conditions that make their teats excessively dirty as dirty teats may provide an avenue for the pathogens to be swallowed by calves.
Draughts at calf level are a risk factor for pneumonia in calves and may also predispose the calf to scours. Air needs to be moving above calf level to keep the shed fresh but draughts at calf level will stress the calf and predispose the calf to illness.
Other basic husbandry measures in the calf’s environment need to be addressed, such as adequate space, clean water and access to age-appropriate concentrate feed and roughage. Vaccination may also form part of the preventive calf health strategy, in particular for controlling calf scour. Currently, there are scour vaccines available for rotavirus, corona virus, Escherichia coli K99 and Salmonella. Note: there is currently no vaccine available for Cryptosporidium. The scour vaccines are administered to the calf’s dam to improve the specific protection provided by her colostrum. Obviously, this requires sufficient consumption of colostrum by the calf to be effective. In addition, the calf is required to consume milk from vaccinated cows for a minimum of three weeks to get maximum benefit from the vaccine. While the calf is not absorbing antibodies at this stage, they still have an effect in the gut of the calf. While vaccination can be a very useful management aid, it is no substitute for good management and stockmanship.
In the event of a scour outbreak, what steps can a farmer take to minimise the spread?
- The cause of the scour needs to be established, to ensure the correct control measures are put in place;
- Extra care and attention must be paid to ensure all calves receive adequate colostrum;
- Improve hygiene in the calf accommodation by cleaning it out, disinfecting it and keeping the bed clean and dry;
- If appropriate, and in consultation with your vet, commence a vaccination programme;
- If Cryptosporidium is detected, disinfect all areas with a disinfectant effective against the very resistant oocysts which are passed in the dung of infected calves. For the disinfectant to be effective, all bedding must be removed so that the disinfectant comes in direct contact with concrete. This would be worth doing a number of times over the housed period. This condition seems to become more prevalent as the calving season advances.
Can a farmer take a dung sample and send it to the Regional Veterinary Laboratory?
Yes. Samples are accepted from farmers, in association with their vet. However, the results will be reported to the farmer’s vet and not to the farmer. Only samples which are in sealed, rigid, plastic containers will be processed. Samples in other types of container will not be tested and will be disposed of for health and safety reasons.
Health and safety
Some of the causes of scour in calves are known to cause illness in people, particularly Salmonella and Cryptosporidium. These infections may cause signs of gastroenteritis, such as vomiting, diarrhoea and stomach cramps, in you or members of your family. The young, the elderly and anyone whose immune function is compromised, such as those receiving chemotherapy, are at greatest risk. If you or a member of your family is ill at the same time as an outbreak of scour in your calves, you should bring this to the attention of your family doctor.