It's the season for summer mastitis

We have already seen a few cases of summer mastitis this year. The peak time for this debilitating disease is July to September.

It is a disease that primarily affects non-lactating animals. This is usually dry cows, but it can be heifers and even steers and bulls sometimes.

There are a number of bacteria involved in the condition and the ‘sheep head fly’ is known to play a part in transmission of the disease.

The flies survive on blood sucked from cows. They only ever fly to open ground to feed on cattle when wind speeds are below 20 km per hour and when it is not raining. Cattle are most exposed when they graze or rest in the flies preferred habitat, which is a likely scenario as cows seek shade in summer heat. The flies tend not to venture indoors.

It is likely that a ‘first case’ in a herd is precipitated by some sort of teat end lesion or teat damage that the causative bacteria can infect. Once an animal in a group has it, then there is a high likelihood that others in the group will get it.

The disease can vary from a mild mastitis that is not detected through to severe swelling and heat of the udder and a very sick cow. The mild cases may just present as cows with blind quarters (quarters with blocked teat canals) when they calve and this explains heifers calving for the first time with blind teats.

In the more severe form, there is gross swelling and severe damage to the mammary tissue of the affected quarter. It can (and often does) lead to an abscess bursting out the side of the udder and even the entire quarter sloughing off. It almost always results in the loss of the affected quarter.

Prevention strategies

  • Fly control to prevent, as much as possible, the ‘sheep head fly’ from feeding on teats.
  • Graze open, elevated ground with clay soils (should you be so lucky to have such a thing!)
  • Weekly application of external preparations. (e.g. Stockholm tar and fly repellent.)
  • Separate affected animals from the rest of the herd to prevent transmission of the bacteria to other cows. Transmission can occur through flies or from lying in the discharges of an affected cow.

One of the reasons fly control alone isn’t sufficient is that common fly treatments don’t find their way onto the teats because the teat skin has no oil glands, and therefore no oil, for the chemicals to attach to. This leaves teat skin exposed. Therefore, even with all the above control measures in place, you may get cases.


A three-pronged approach is necessary which involves:

  1. Systemic antibiotics. Tylan or Alamycin for 5 days or until an abscess bursts out of the udder. 
  2. Non-steroidal anti-inflammatories. Metacam or Finadyne.
  3. Regular stripping out of the affected quarter. The more the better. If you are able to get substantial amounts out of the quarter, then every 2-3 hours. If you are unable to get much out, then stripping out will be less useful. You are effectively draining an abscess rather than milking a quarter.

The best outcomes of treatment will result if treatment begins as early as possible in the disease process. Regular checking of cattle and paying particular attention to the teats and udders – particularly the front teats – is an essential part of early detection. 

Contact your vet, or phone the farm office on 01491 651479, if you have any concerns.