Farmers urged to investigate coughing in calves and youngstock

According to Ruminant Health & Welfare (RH&W), the presence of mycoplasma, in combination with other bacteria or viruses, is linked to respiratory problems in cattle such as Bovine Respiratory Disease. It can also lead to mastitis, arthritis and swollen legs in heifers ahead of calving.

Therefore, it is important that mycoplasma is included in the serological investigation when screening cattle before turnout or when groups of calves are tested for BVD in beef herds. Recent data has shown that mycoplasma continues to be vastly spread across the UK, however, many herds are remaining mycoplasma free.

RH&W chairman Nigel Miller urged farmers to find out the mycoplasma status of their herd to understand potential risks and plan disease management accordingly.

“We must also remember that, although we often experience coughing in housed calves and feeding cattle, it isn’t inevitable. Even if clinical pneumonia is avoided, coughs signal the loss of performance in the herd,” he cautioned.

Mycoplasmas are very small bacteria that belong to the class Mollicutes, meaning soft skin. Mycoplasma bovis is of the most concern to farmers due to its defence mechanisms which make it difficult to treat, Mr Miller added.

“Mycoplasma bovis lacks a cell wall so some widely used antibiotics are not effective in treating it,” he explained.

“The bacteria also has the ability to change its surface proteins to evade the cow’s immune response, while an ability to produce a sugar matrix biofilm means it can temporarily hide from both the immune system and antibiotics.

“Dairy beef systems are particularly at risk due to a combination of factors including calves receiving sub-optimal passive immunity, the mixing of calves from herds of different mycoplasma status, and instances of poor hygiene in calf rearing units,” Mr Miller noted.

The past 10 years have seen a rise in the laboratory diagnostic rates for Mycoplasma bovis, with vets also seeing an increase on-farm in a range of clinical problems caused by the bacteria. The greater risk of mycoplasma infection highlights the need for farmers to work with their vets to identify their herd’s mycoplasma status.

RH&W steering group member and CHeCS veterinary director Keith Cutler says a whole herd approach to health management is needed to minimise the mycoplasma risk.

“Although the use of vaccines can play a positive role, farmers need to look at all aspects of health management with their vet, including the environment, hygiene, immunity, monitoring and management of infection pressures.”

He also recommends farmers should consider the mycoplasma status of herds they are buying stock from, as brought-in cows or heifers infected with the bacteria carry a high risk of infecting a disease-free herd.