With the arrival of summer, pinkeye treatment is an issue many producers have to face. Appropriate, timely treatment will minimize losses from this disease that sometimes defies preventive steps.
Probably the most important aspect of pinkeye treatment is that it be given early. When an ulcer first forms all that will be seen from a distance is an uncomfortable eye with lots of tearing. Cattle tend to hold the affected eye closed. Treatment at this phase before the eye becomes cloudy and "blue" will give very encouraging results.
If, on the other hand, treatment is delayed until the eye becomes cloudy, or -- even worse -- until the classic pink appears with a white or yellow glob in the center of the eye, results will be much less satisfactory.
The approved products to treat pinkeye include the long-acting tetracycline products (for example, LA-200®, Biomycin 200®, etc.) and now tulathromycin (trade name Draxxin®). These products should be delivered according to label directions in terms of dose and route. Slaughter withdrawal rules should be carefully considered when any antibiotic is used.
In a recent study published concerning the efficacy of tulathromycin, the results of treatment are documented. A group of calves with pinkeye was treated and a group was left untreated as controls. The treated group responded, as evidenced by complete healing of eyes by various time after treatment. For example, over 40% had cured by day 7, over 50% by day 10, over 80% by day 12 and all by day 17. While a few untreated calves had self cures, only 10% had cured by day 12 and 60% were still affected at day 20.
With early treatment, permanent damage to the eye should be minimal. When cases are treated late, complications such as scars, glaucoma resulting in a large bulging "pop eye" or rupture of the eye resulting in total eye loss are more common. These complications will permanently decrease the value of cattle.
A number of other treatments have been recommended for pinkeye treatment. Injection under the layer covering the eyeball has been documented to aid healing but must be done correctly or eye damage can occur. Since this is an extra-label use of an antibiotic it must only be done under the direction of the herd veterinarian. Injection in or under the eyelid itself would be expected to give NO help in healing. Likewise milk injection has no documented benefit.
A number of treatments have been recommended for placement in the eye. Mild formulations of antibiotic might be expected to help some but don't stay in the eye very long so their effect might be quite limited. Irritating substances such as salt should certainly be avoided.
Placing a patch over the eye following treatment is a recommended procedure. It protects the eye from sunlight and keeps flies away from the eye. This should have benefit in decreasing the spread of the disease in the herd.
Sometimes outbreaks of pinkeye are so severe that whole herd treatment should be implemented. Typically when more than 10-20% of animals in a herd are affected, it is beneficial to treat all cattle with an injectable antibiotic. If fly control is not adequate, an extra application of treatment that will remove all face flies is very highly recommended.
Timely and appropriate treatment of cattle with pinkeye will pay dividends in terms of preventing gain losses due to the disease as well as decreasing the permanent damage to eyes which will decrease their value.