 PINKEYE THERAPY
 It is that time of the year again when the problem of pinkeye can occur. Dr. John Maas, Extension Veterinarian at UC Davis, has provided the following timely information to help you, should you have pinkeye problems this season.
One of the important aspects of fly control is decreasing face fly infestations as a method of helping to prevent pinkeye in cattle. Another aid in the prevention of pinkeye, if it is feasible, is to clip the pastures if grass is too long and headed out. This will decrease much of the irritation to the cattle’s eyes that can initiate the beginnings of a pinkeye outbreak. The irritation of dust, plant pollen, or weed seeds will promote the heavy shedding of the pinkeye bacteria (Moraxella bovis) by a few "carrier cows" in the herd. These carriers spread the organism by contact and face flies to the rest of the herd, and the susceptible animals will become infected and have clinical pinkeye.
If pinkeye cases do occur, what are the treatment options? One of the professors in the School of Veterinary Medicine at UC Davis has completed several years of research on this subject. Dr. Lisle George has examined several methods to treat pinkeye, and these and other methods are summarized below.
First, if you are going to examine the eye for a foxtail or other weeds, use disposable latex exam gloves. You can obtain these from your veterinarian or other animal health product source. After you have touched the eye (extracted the foxtail or treated the eye) or nose area, throw the gloves away. They may be badly contaminated with the pinkeye bacteria. If you used a halter or nose tongs to restrain the animal, disinfect this equipment. Nolvasan® disinfectant is a good choice for this procedure. For treatment, use disposable needles and syringes for any treatments.
The pinkeye agent is a bacterium and, therefore, antibiotics are indicated for treatment. The question has been, "Which antibiotic, what dose, what route?" The best two treatments are as follows:
| Long-acting tetracycline (Biomycin® or LA-200®) | Dose: 20 mg/kg body weight (9mg/lb.) |
| Route: Intramuscularly or subcutaneous (these products are irritating to tissues and should be given sub-Q whenever possible), both are labeled for sub-Q use. | Frequency: Two injections 48 to 72 hours apart.
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| NuFlor® (florfenicol) | Dose: 20 mg/kg body weight (9 mg/lb.) |
| Route: Intramuscularly | Frequency: Two injections 24 hours apart |
| Alternatively, NuFlor® can be used as single injection for longer action. | Dose: 40 mg/kg body weight (18 mg/lb.) |
| Route: Subcutaneous | Frequency: One treatment. |
NOTE: If the tetracycline product is not labeled for pinkeye, you must obtain a prescription from your veterinarian, as this constitutes an extra label use of this product. Also, NuFlor® is not currently labeled for pinkeye, and you must have your veterinarian’s prescription to use this drug for pinkeye in cattle.
Both of these treatments work very well. Continued use of tetracyclines in areas with high numbers of anaplasmosis cases can make the cattle susceptible to sickness due to anaplasmosis. Consult with your veterinarian regarding this potential problem.
Another treatment option is to give penicillin as an injection under the white part of the eyeball (the sclera). If you are not expert in this method, have your veterinarian train you on the proper way to administer this treatment. Do not attempt this method without training. To achieve good results, give 1 ml (1 cc) under the sclera of both eyes for at least 3 days. This method achieves good results, but is less effective than the use of oxytetracyclines or NuFlor®. Again, you will need your veterinarian’s prescription for the use of penicillin if it is not labeled for use in pinkeye.
For many years Furox sprays or powders (Nitrofurazone, Furox®, Topazone®, NFZ Puffer, P.E. 7, etc.) placed into the eye were used for the treatment of pinkeye. This method was not as effective as the above methods. Beginning on May 1, 2002, this treatment will be illegal for cattle. This is irrespective of whether you have a prescription or not. Do not use the furacin-type drugs in cattle anymore.
Still available for pinkeye treatment is the Gentocin® Pinkeye spray. This product is sprayed into the eye to help kill the Moraxella organism. As with all treatments that are placed directly into the eye, proper restraint is necessary, and the use of disposable latex gloves is recommended. Remember that material placed into the eye only stays there a few minutes before the tears wash it out.
For many years, treatment with dexamethasone (Azium®) has been popular. Research indicates that when this is given under the sclera, there is no difference in the rate of healing. Therefore, use of this product is not usually recommended.
Keep written records of treatments and results. Discuss these with your veterinarian as you reevaluate pinkeye prevention and treatment plans for the future. Also, if your cattle are copper deficient or selenium deficient, the number of pinkeye cases will be greater and the severity will be worse. Be sure your mineral program is working, as this is important in the animal’s immune response to this bacterial pathogen.
Space in this edition of the newsletter did not allow for information regarding the list of registered pesticides for cattle this year and information for the use of these pesticides for fly control. If you would like a copy of this information sent to you, call me at 805/934-6240.
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