Bovine pink eye may not kill your cattle, but it has the potential to reduce average daily gain while consuming resources and time.
When cattle move to pasture, young calves face a higher risk of pink eye. While producers have little control over environmental factors, they can prevent pink eye through three approaches: minimizing fly populations, treating early, and vaccinating.
It is mostly a disease of calves, on grass, in the summertime and is described as multifactorial because various factors can play a role in disease outbreaks. It doesn’t matter how much bacteria is put on the eye, it’s not going to develop pink eye unless the outer surface is damaged. That’s because all these bacteria and viruses can be found in healthy eyes. Grazing calves are at their fastest growth stage, and pink eye can impact their development.
The impact on calf growth depends on which study you read, but a good walking-around knowledge number is about 25 pounds in weaning weight that’s lost every time you see a case of pink eye. Studies indicate about $150 million in losses across the U.S. cattle industry due to pink eye, although believed this figure could be significantly higher in today’s economy.
One unique characteristic of this disease is its seasonality. The peak is usually going to be the July-to-August time frame, and there’s no coincidence that this lines up with peak fly season.
However, research at the U.S. Meat Animal Research Center showed that high pink eye incidence one year likely means fewer problems the next year due to its sporadic cyclical nature over time. If you have a bad year this year, whatever that equates to for your operation, chances are next year it’s not going to be as bad.
Prevention Strategies
Vaccination is one common approach ranchers take to prevent widespread pink eye.
Treating calves early enough will gain a reasonable response. In pink eye, there is a compromised vascular supply on the surface of the eye, so it’s difficult to get the healing to take place quickly if it’s already a severe case.
Autogenous vaccines are developed using bacterial isolates obtained from a specific herd. These specific bacteria are used to make the vaccine, resulting in a “custom vaccine” designed for a specific operation. Results have been mixed over the years, but after five years, there is no statistical difference in any of the vaccine groups. That is, none of the formulations proved effective in preventing pink eye. This result highlights why producers should first focus on fly prevention and early diagnosis and treatment, since these efforts can have the most impact on calf health.
Buzz off
Early treatment with vaccines is just the first step to combatting pink eye. The next is controlling fly populations before they can bug your calves.
- Know which fly breed you’re attempting to control. There is a difference among houseflies, horn flies, stable flies and face flies. Horn flies prefer animal backs and bellies; stable flies are often on the front legs; houseflies prefer feed bunks; and face flies, like their name suggests, prefer animal faces.
- Control the environmental breeding conditions. Each fly can lay 500 eggs over her short lifetime. In a pasture setting, horn flies and face flies both prefer manure paddies in pastures to lay their eggs. Burning the pasture in the spring before the adults that overwintered as pupa can get going can really reduce that initial fly population that can affect calves. Rotational grazing also can reduce fly populations.
- Plan your chemical control. A three-year rotation of active ingredients is recommended. Insecticidal ear tags are popular, but it is cautioned that while labels may say they can be used for four to five months, research shows they’re only active for about 90 to 100 days. It is recommended to pull tags at 90 days, and don’t leave them in longer than 100 days.
- Offer self-treatment options. Back rubbers and dust bags allow animals in a pasture setting to self-treat. And always follow label instructions for application and safety.
For cattle in more confined settings, it is recommended to keep feeding bunks and barns clean. Also, reduce breeding sites by spreading manure frequently or keeping manure piles covered.
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WILDLIFE UPDATE
Summer is the peak period for antler growth in white-tailed deer bucks, with June through August seeing the fastest growth rates — sometimes up to half an inch per day under optimal conditions. Fun fact, antler velvet is the fastest growing tissues in mammals. During this time, antlers remain in velvet, which is essentially a living tissue rich in blood vessels and nerves that delivers the nutrients required for bone development. Bucks depend heavily on high-quality summer forage, including protein-rich forbs, legumes, and browse, which supply the amino acids, calcium, and phosphorus essential for antler formation.
From a management perspective, understanding this nutritional dependency highlights the importance of maintaining or enhancing summer habitats. Practices such as planting warm-season food plots with legumes (e.g., cowpeas, soybeans, lablab) or managing native vegetation to encourage a diverse mix of forbs and shrubs can help ensure bucks have access to the high-protein forage necessary for maximum antler growth. White-tailed deer forage on a huge diversity of species (> 100 in a specific region), so maintaining strong diversity in your plant communities is key. Additionally, providing mineral supplements — especially in areas with known mineral deficiencies — can support the high calcium and phosphorus demands of growing antlers.
Water availability is another critical factor: prolonged drought can reduce forage quality and quantity, stunting antler growth. Managers should consider implementing water sources or improving wetland areas to mitigate drought impacts on deer during critical summer months. Availability of water also helps animals process their food more efficiently, which can increase nutrient intake and promote better body condition.
By aligning summer habitat management with the nutritional needs of bucks during antlerogenesis, landowners and wildlife managers can positively influence antler size and overall herd health — key goals for both trophy and population-focused management programs.