Scour remains the most common disease of calves prior to weaning. It therefore has the potential to considerably impact herd and farm performance. Treatment costs and calf mortality are significant at the time of the outbreak, but just as important can be poor growth rates and delayed finishing times. These are seen when severe cases, often infectious, result in ongoing gut damage affecting digestion and absorption as the calf develops.
Various infectious agents are a major cause of disease but it’s important to remember that husbandry practices can also trigger outbreaks. Calves are sensitive to changes in routine and diet so ensuring feeding and management activities follow a regular pattern is advisable. Milk or replacer should be fed at the correct concentration and an appropriate temperature and suitable source of roughage should be available.
Cleanliness and Hygiene should not be overlooked. Ensuring that calving areas are kept clean and dry can help prevent the build-up of pathogens. Infectious causes are often responsible for the most severe outbreaks. These include viruses such as rotavirus and coronavirus, bacteria such as E. coli, and protozoa like cryptosporidium. Good biosecurity is always important but with many agents such as rotavirus and cryptosporidium present on most UK farms, effective control measures are usually required.
Identifying the pathogens responsible for outbreaks is an essential step. Bacterial and protozoal infections might require specific and targeted antimicrobial treatment, but prevention should be the priority to avoid excessive antimicrobial use and to combat viral infections.
Working with the vet, diagnostic kits can build up a profile of the infectious agents significant for a particular farm. Vaccination is available for some of the key pathogens such as rotavirus, coronavirus, and E. coli so a suitable program can be put in place to help control and prevent future problems. Vaccination is targeted at cows in late pregnancy to boost specific antibody levels in the colostrum to protect the calves.
This highlights the importance of ensuring a newborn calf receives an adequate amount of good quality colostrum within the first few hours of birth. Whether vaccinated or not, the cow’s colostrum contains high levels of protective antibodies specific to the local environment that are crucial in defending the calf from a range of infectious challenges in the first weeks of life.
Despite the best preventative and control measures, scour remains a threat so effective management protocols are essential to limit the impact. An affected calf can deteriorate rapidly so regular monitoring is required and early intervention essential. Diarrhoea causes excessive loss of water and electrolytes resulting in dehydration. In addition, acid build up in the tissues leads to acidosis. Early signs include sunken eyes, dry mucous membranes & tenting skin. These can quickly proceed to difficulty feeding, recumbency & death.
Specific antimicrobial treatment might be required in bacterial or protozoa infections, but this should be done following vet advice and the appropriate diagnosis. But it’s correcting the dehydration and acidosis that is essential in all cases. In severe cases intravenous fluid replacement is required under vet supervision but early intervention with an oral rehydrating solution can be lifesaving.
Water by itself is insufficient to correct the dehydration. A good oral rehydration solution such as Fresh Start from Downland contains electrolytes to replace those lost and energy to aid water absorption. The inclusion of an alkalising agent also helps to combat the acidosis. Withholding milk is not advisable in the majority of cases as it continues to provide energy and nutrition to the calf and its gut. It should not however be given at the same time as the rehydration solution.
Calf scour will always be a threat. But with planning, effective prevention strategies and prompt intervention the impact on can be minimised to ensure improved health, productivity and farm profitability