Management options on how to treat pinkeye in cattle.
Early treatment of cattle with pinkeye is important, not only for a successful outcome of the individual animal affected, but also to stop the shedding of the bacteria to decrease the risk of transmission to other cattle.
Stage I: Long-acting tetracyclines are effective at this stage of infection. The recommended dose is 4.5 cc per 100 pounds of body weight subcutaneously (SQ). A second injection given 48 to 72 hours later may increase the percentage of cattle that responds to treatment. Another option is to inject penicillin and dexamethasone into the bulbar conjunctiva. The bulbar conjunctiva is a thin membrane that covers the white portion (or sclera) of the eye. If the injection is performed correctly, the conjunctiva will swell and a bulge should be seen in this area. A veterinarian or someone who has been specifically trained by a veterinarian should perform this procedure. Injections placed in the wrong area are ineffective in treating pinkeye and could damage the eye.
Patching the eye is recommended and will also help prevent irritation by foreign objects, eliminate Ultra Violet (UV) light irritation and reduce the spread of the bacteria. Commercially available patches work well or you can use five by six inch blue jean patches cut to size and glues on three sides leaving the bottom open. Use cattle backtag cement to glue the patch on making certain to not get glue in the eye.
Stage II: Both tetracycline and a bulbar conjunctival injection are administered at the above dosages.
Stage III: Tetracycline and a bulbar conjunctival injection are administered in conjunction with an eye patch, suturing the third eyelid over the eye or suturing the eyelids shut. This makes the eye more comfortable, reducing further irritation, and therefore, reducing tearing and shedding of the bacteria. Suturing the third eyelid over the eye and suturing the eyelid shut also have the advantage of supporting a fragile cornea to help prevent corneal rupture. Again, this procedure should be done by a veterinarian or someone who has been adequately trained.
Source: Kevin S. Gould, Michigan State University (MSU) Extension