August is the time of year we see most cases of summer mastitis, both in beef and dairy cattle (especially those at pasture).
This is an acute, severe mastitis that usually affects dry cows or pregnant heifers, and the infection is often transmitted by flies.
Signs of Summer Mastitis
Affected animals are often dull, isolated, lame and anorexic, with high temperatures. The teats will be swollen and often surrounded by large numbers of flies.
The disease will progress until the whole udder is swollen and producing thick foetid yellow secretions, possibly blood-tinged. Affected animals can abort and, in worst-case scenarios, die.
Sometimes you will find a heifer with a blind quarter without having seen her obviously sick, which may be due to a previous, unnoticed case of summer mastitis.
Treating Summer Mastitis
Early treatment for summer mastitis is important. Affected quarters rarely recover, and so your aim is to save the animal and prevent the infection spreading to the rest of the udder. A good result is a live animal that is still pregnant, with some healthy quarters to produce milk in the lactation.
Call your vet if you think you have a case of summer mastitis, as sometimes drastic surgical treatment of the udder is necessary in very severe cases.
In general, anti-inflammatories and systemic antibiotics should be used to reduce swelling and drop the temperature, and affected animals should be isolated since they will be infectious to the rest of the herd.
The udder is often full of pus and dead tissue, and so it is important to strip the affected quarters as frequently as possible. Do not strip onto the ground as this may spread the infection. Instead, use an old bucket full of disinfectant and dispose of safely. Despite your best efforts, the udder may slough off.
Preventing Summer Mastitis
Prevention is definitely better than cure.
Fly control for cattle is best done with tags or pour-on products. These often do not provide great protection to the udder, but you can use a gloved hand to apply some product directly around the teats.
Stockholm tar can be applied to the teats as a preventative, but is very messy and needs to be reapplied every 2 weeks through the summer. Animals with healthy teats are at lower risk so it is recommended to check the teat ends and possibly remove those with badly damaged teats.
In older animals silicone teat sealants will reduce the risk. Areas where there are likely to be high numbers of active flies should be avoided if possible, such as sandy soils, damp pastures and fields adjoining woodland where flies shelter.