Don't forget to keep flies away from your cattle to prevent the spread of pinkeye.
By: Jim Krantz, Cow/Calf Field Specialist, SDSU Extension
With the grazing season well underway, most cattlemen have strategically planned their fly control program, focused primarily on pinkeye prevention. Obviously, cow/calf comfort and increased production are always considerations of fly-control programs but anyone who has witnessed the results of a pinkeye outbreak knows the discomfort and lost performance that occur.
The cost of pinkeye to producers previously noted through university research was in the $100/calf range which included reduced weight gains, treatment costs and sale-day discounts. However, those numbers were compiled prior to the present market price structure so it could be considerably greater. Today, with 500 to 600 pound calves selling for about $2.40 per pound, the lost value would be significant.
Because of the yearly potential for the re-occurrence of pinkeye, cattlemen should remain committed to its prevention throughout the grazing season. Pinkeye vaccination programs have recently received increased producer’s acceptance throughout the industry, especially with the increase in calf value. Because there are many strains of the bacteria that cause pinkeye, many veterinarians work with producers to culture herd cases of pinkeye to make certain the vaccine includes the proper strain.
Several additional management options allow for the control of face flies which are considered the primary vectors for the spread of the infections from one animal to the other. Fly tags for cow, calves or both remain a standard recommended practice for fly control. Back rubbers placed near congregating areas for cattle, most commonly near water sources, remain an effective means of control. Cattlemen do need to monitor the product used in these oilers, because slaughter withdrawal is required for some.
Rotational grazing systems may have some advantages for pinkeye prevention in addition to increased forage quality. Tall grasses, especially those with seed heads, can be the initial irritant that provides the opportunity for the pinkeye bacteria to locate in the eye tissue. Allowing cattle access to mature grass pastures can provide the environment for a potential outbreak of pinkeye. Cattlemen might be well-advised to monitor their herds more closely following turnout in order to treat animals showing the first signs of the disease.
Mineral products containing additives which control fly populations by killing the larvae in cattle manure can also be effective in the battle against pinkeye problems. Daily consumption is the key for this management option as sources need to be available in strategic locations for easy access throughout the pasture.
Younger animals are more prone to being affected by the pinkeye bacteria. Calves are the major target but first-calf heifers are much more vulnerable than older cows. If preventive measures cannot be targeted at the entire herd, younger cows and calves deserve first access to any resources utilized in a fly-control program.
Economically, prevention is always a preferred strategy to treatment; it requires vigilance on the cattlemen’s part throughout the entire grazing season. Pinkeye outbreaks can occur quickly so early detection and treatment may help prevent transmission to other animals and a potential major outbreak within the herd. Veterinarians are always a valuable resource to cattlemen in building a sound prevention program.