I recently attended a very sick cow on a dairy farm. She had recently calved and was unable to stand and had a severe case of mastitis, and was also suffering from milk fever.

When you examine a recently calved cow with mastitis, you always have to consider that she may be suffering from E coli mastitis. The cow was treated aggressively with anti-inflammatories, fluid therapy calcium and antibiotics. E coli mastitis in recently calved cows is potentially a life threatening condition due to the toxic shock which it can cause.

A blood sample was taken from the cow which confirmed low blood calcium (hypocalcemia). We also took a milk sample from the affected quarter for testing. However, no significant bugs were detected. It can often be difficult to culture bacteria from cows with E coli mastitis, as, in many cases, the cow’s own immune system will have actually killed the bacteria. In fact, in many cases, the severe sickness which is affecting the cow can be due to the release of toxins from the E coli bacteria when they die.

One of the main functions that calcium is required for is muscle contraction and strength. The most obvious way that this is seen in cases of hypocalcemia is in a cow lying down and unable to get up. But muscles are responsible for a range of other functions,

In this case, it is likely that the muscle which is responsible for closing of the teat end didn’t function properly, so when she lay in the passageway of the shed, her teat end was open and allowed bacteria to enter and cause mastitis. In many cases, hypocalcemia may be more subtle (or subclinical), so it can be affecting the contraction of the uterus post-calving, resulting in retained cleanings or womb infections, or slow movement of the gut resulting in displacements of the abdomen, etc.

Screening of blood calcium levels in recently calved cows can be a useful tool for assessing dietary calcium management, and can be especially useful on farms experiencing high levels of a range of diseases such as mastitis, LDAs endometritis post-calving.

John Gilmore is a veterinary practitioner at Emlagh Lodge Veterinary Centre, Elphin and managing director FarmLab Diagnostics, an animal health testing laboratory. www.farmlab.ie.