Pinkeye prevention for the coming summer
May 12, 2009
Conditions this spring are right to increase the opportunity for pinkeye problems in cattle. Thus, now is the time to think ahead for preventive measures. First, pinkeye is the common name for Infectious Bovine Keratoconjunctivitis, a highly infectious disease that affects the eyes of cattle. It causes infection of the eye itself as well as inflammation of the conjunctiva (inside lining membrane of the eyelid). Typical symptoms include tearing from the infected eye, squinting, reddening of the membranes of the eyelid, and with advancing conditions, ulceration of the cornea, leading to the classic white, inflamed spot on the eyeball. If left untreated, this ulceration can lead to permanent scarring resulting in impairment of vision.
There are two conditions that I refer to that increase the chance for pinkeye to spread among cattle. First, most of the region is experiencing conditions that are much wetter than normal, which provides increased breeding grounds for flies, particularly face flies, which are the primary carriers of the bacterial organism (Moraxella bovis) that causes the disease. Second, increased moisture means greater forage production. Taller forage pokes cattle in the face, serving both as an irritant to the eye, as well as a vector for the spread of the M. bovis organism from one animal to another (unfortunately, this is the down side of increase available forage). A third condition that promotes pinkeye is excess dust in the air causing irritation of the eyes. It’s nice that one of these three conditions will be reduced by the wetter weather that we are experiencing.
Considering the chance for increased spread of pinkeye, producers ought to think about prevention measures. First among these is fly control. An in-depth discussion of various fly control measures is enough material to warrant another newspaper article. Without going into those specifics here, my primary purpose is to emphasize the importance of planning an effective fly control strategy for the upcoming summer.
Another opportunity is the use of pinkeye vaccines. A variety of products are available, and all have potential to boost an animal’s immune system against the M. bovis organism. While these vaccines often may not completely prevent pinkeye occurrence, they will reduce severity. Follow specific label directions for whichever product is used to get maximum benefit. Additionally, cattle should be vaccinated in the spring before fly season starts, meaning that now (such as at branding) is the time to vaccinate. While the vaccine can be used later in the summer in the face of a pinkeye outbreak, it will be much less effective.
Providing shade can be another preventive opportunity. Eye irritation from UV radiation can contribute to vulnerability of the eye to a pinkeye infection.
A recommendation that is often stated is that pasture management to keep grass clipped short will reduce face irritation. This is obviously meant for intensively managed tame pasture situations, but is not a possible strategy in typical rangeland situations in the region.
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A final preventive measure is early treatment of initial cases to minimize spread from infected cattle to others. Unfortunately, cattle handling is difficult in summer grazing settings. That said, treatment should be administered as promptly as possible to reduce the scale of outbreaks. Treatment recommendations typically include a 4-pronged approach: (1) gluing a patch over the eye to protect it from UV radiation, (2) providing a topical anti-bacterial powder in the infected eye(s), (3) injecting a small amount (1 ml) of antibiotic into the layers of the membrane of the inner eyelid, and (4) an intramuscular injection of a long-acting oxytetracycline. The bovine eye has great healing power and typically will recover quickly once provided these treatments.