Morexella Bovis is the most common bacteria that causes pink eye in cattle. The bacteria infects the eyes of cattle with compromised immune systems. immunosuppression could be caused by other illnesses in cattle, such as IBR or a mycoplasma infection. High volumes of dust and pollen can cause scratching of the cornea which opens a wound for the bacteria to enter. M. bovis reside in the eyeball, secretions from the eye, and in the nasal cavity. The bacteria is spread quickly through direct and indirect transmission. Direct transmission involves cattle to cattle contact where nasal secretions or tears are passed from an infected animal to another animal. Indirect transmission occurs when secretions are spread by inanimate objects, mainly face flies.
There are four main stages of pink eye. The first stage is when the eye begins to water and is sensitive to sun, causing squinting or excessive blinking. The animals eye may become red and inflamed and ulcers may form on the cornea. Stage two involves spreading of the ulcer causing cloudiness in the eye and increased redness from the swelling of blood vessels. The third stage involves the inner eye to fill with fibrin causing the eye to turn yellow. Stage four involves the iris protruding past the cornea and is often irreversible.
With cattle out on summer pastures, it is less likely to spread as quickly due to large amounts of space to spread out. However, this year we have had a massive outbreak in one of our cow-calf herds. It is spreading quickly through the cows and calves. We have been treating animals with Micotil in the field through the use of a dart gun. The Micotil seems to be clearing up some of the cases but it is time consuming and expensive to use darts. We are considering running the entire herd of 350 pair through to treat all of them with BioMycin 200.
Any other suggestions for controlling this pink eye in the field in an efficient way?