Pinkeye or infectious bovine keratoconjunctivitis is a contagious bacterial infection affecting the eyes of cattle, especially calves. With Pinkeye season around the bend it's a good time to review some of the steps cow-calf operations and ranchers can take to plan for and reduce the severity as well as operational expense of pinkeye in their herds.
Prevention is the key to control this contagious and costly disease that can often cost over $100 per incidence in beef cattle. Each Cow-Calf Operation should have an integrated Pest Management Program in place. And, it should be re-visited with your Vet every year to ensure you're on top of any pesticide resistance or other issues which may affect your annual planning. When developing your annual pinkeye plan there are three elements that should be considered as part of your overall plan:
- Protect your herd ahead of Pinkeye Outbreaks
- Reduce Fly Exposure
- Environment - Reduce Environmental Problems
Before we get into prevention let's get into the potential causes of pinkeye. The primary pathogen is the bacteria Moraxella bovis, which has more than one strain. These bacteria have pili (hair like extrusions) which allow it to attach itself to the conjunctiva of the cornea, thereby introducing the injury/infection. As with many pathogens multiple factors can increase susceptibility of cattle for the bacteria. However, the main culprit is often eye irritation prior to exposure which weakens the eyes ability to fight back effectively.
Eye irritants such as face flies are often a major pinkeye culprit. Face Flies feed on eye secretions and in the process, injury to the conjunctiva may result - increasing susceptibility for the spread of M. bovis via the flies. Unfortunately M. Bovis can survive on the wings and legs of flies up to 3 or 4 days which means that if one calf is infected flies will likely expose other calves to M. bovis. Other irritants include: ultraviolet radiation sensitizing / irritating the eye - especially with cattle that have little pigment around the eye, dust, pollen, seeds and grasses or weeds that cause mechanical injury to the eye during feeding. In addition male calves are more susceptible than female or older cattle and nutrition can also play a role. Now that we know some of the potential causes, what can ranchers do to protect their cow-calf operations?
1. Protect your herd ahead of Pinkeye Outbreaks.
There are a number of Pinkeye vaccines in the market today such as: I-Site XP Moraxella Bovis Bacterin, Pinkeye Shields XT4, Solidbac Pinkeye IR/PR, 20/20 Vision 7 with Spur, Alpha-7/MB-a, Cavalry 9, Piliguard Pinkeye TriView, and Ocu-Guard MB-1 to name a "few". The challenge with so many vaccines on the market is to figure out which one will work for your herd and deciding when should the product be utilized. The best option is often to speak with your local veterinarian. They should be able to tell you which products have a high efficacy in your local area (and which ones have shown resistance) and timing the application properly to ensure maximum protection.
2. Reduce Face Fly Exposure
Because face flies (Musca autumnalis) often play such a large role in the spread of pinkeye - controlling them is often the most important challenge cow-calf operations face ( job 1). Face flies spend little physical time on your cattle vs. horn flies and since they often spread pinkeye to several animals per day a comprehensive plan to minimize them prior to physical contact is often crucial.
There are many options available for fly control such as: ear tags, pour-ons, sprays, dust bags, oilers and back rubbers. All of these have inherent pluses and minuses with pesticide resistance being the number one issue that needs to be understood prior to purchase and application. Again, your local Vet or cattle supply store should have a good idea if certain pesticides have shown resistance issues in your area. All of these products can work well in the right conditions and if used at the right time. For more information we have covered some of these usage issues in a previous blog piece: Horn Flies & Horn Fly Best Practice Cattle Management. Regardless of the control method the quicker a rancher responds to increasing fly numbers the more likely they will reduce the overall effect on his cattle herd.
3. Environment - Reduce Environmental Issues
We have already mentioned a number of the environmental problems that can increase the likely hood of Pinkeye outbreaks such as ultraviolet radiation sensitivity, dust, pollen, seeds and uncut grasses or weeds. While you can't always control what your neighbor ranches do and how their environment impacts you, you can try to talk to them about their annual pest management plan and coordinate with them when and where possible as a first step.
In regards to your pasture keep it trimmed when and where possible to reduce the potential incidence of mechanical eye injuries which increase Pinkeye susceptibility. Overall grazing management - mowing, spraying and brush beating will help reduce pollen and dust problems. For ranches that use hay or feed bunk management lower overhead feeders to reduce potential fallout into eyes. Do not feed cattle hay with mature seed heads or cheat grass in overhead bunks and increase bunk space to decrease direct cattle contact / infectious contact.
Providing shade trees is a good idea (preferably low pollen producers - talk to your extension agent about the right trees for your locality) or build shade in order to reduce ultraviolet light exposure. Last, don't forget about optimizing cattle nutrition. The stronger your herds overall health / immune status the easier it is for them to fight off infections.
An integrated Pest Management plan is an important part of any cow-calf or ranch operation's success. Preparing for Pinkeye should be part of that overall strategic plan and will pay dividends via a healthier herd and better weight gains at the end of the season.