7 minute read
CDFA on pinkeye prevention
A PINCH OF PREVENTION IS WORTH A POUND OF CURE
Reducing on-farm disease as part of judicious antibiotic use
by Marissa Silva, MVB, California Department of Food and Agriculture’s Antimicrobial Use and Stewardship Branch and Gaby Maier, DVM DACVPM, University of California Cooperative Extension
Antibiotic stewardship, which encompasses factors like disease prevention, accurate diagnosis and targeted treatment, can save you money and increase the health and production of your animals. Implementing strategies to reduce the most frequent diseases that warrant antibiotic use should be a key foundation in your herd health plan. In 2017, the California Department of Food and Agriculture (CDFA) Antimicrobial Use and Stewardship (AUS) program partnered with CCA to produce a cow-calf survey that assessed antibiotic use practices. Almost 1,000 cattle producers in California voluntarily participated. The top diseases that warranted the use of antibiotics across adult cows and calves were pinkeye, bovine respiratory disease and calf scours.
One of the main goals of antibiotic stewardship is to reduce antibiotic use through disease prevention. CDFA AUS partnered with Gaby Maier, DVM, Beef Extension Specialist at the University of California, Davis Cooperative Extension to provide up-to-date disease prevention resources for California cow calf producers. The goal of this collaboration was to compile the most recent research on these issues, publish scientific papers and create engaging resources to promote strategies for disease reduction and provide helpful prompts for discussion between producers and their local veterinarian.
The Cow Calf Disease Management Series was published this spring, and is designed to help producers and veterinarians target infectious bovine keratoconjunctivitis (IBK, pinkeye), scours and bovine respiratory disease (BRD). These conditions result in increased economic costs due to labor and equipment for treatment, potential production loss in the herd and higher antibiotic use in cows and calves. Marissa Silva, DVM, with CDFA AUS presented these findings from the survey and introduced this new series at the 2022 midyear meeting to CCA’s Animal Health Committee. These resources can be used as handy field guides for prevention and control of these diseases, or when you need a quick opinion out
in the pasture. They can also help provide a standardized description of a disease that can be useful to confirm detection, especially when seeing these diseases rarely or when describing the problem to your herd veterinarian.
Preventing diseases within the herd can save money by reducing treatment and labor costs, which can be a big motivator for operations. A seemingly small change in current management techniques can potentially have a large preventative effect with huge impact on disease outcomes. Ranch owners and managers can identify small steps that they can incorporate into future ranch planning for the upcoming year or years.
PINKEYE PROBLEMS
To better understand this approach, let’s take a closer look at one disease, pinkeye. Many of us are familiar with the signs of pinkeye: a closed or squinted eye that may have tearing, which of course may attract flies, and reddening of the white part of the eye. When it has progressed, eye ulcers-pits or eroded areas of the surface area of the eye- are present. This can lead to a slower rate of weight gain due to pain, production losses and increased cost of treatment. There are two main components to stewardship: reducing need for treatments by reducing the disease occurrence, and by targeting the treatment to only the cases that truly need it.
A large component of antibiotic stewardship is recognizing when not to treat pinkeye, in order to preserve the effectiveness of antibiotics in the herd. Applying antibiotics when the disease is not likely to respond can promote drug resistance in disease-causing bacteria while having no benefit on the disease outcome.
There are many options to reduce pinkeye’s impact on your ranch; however, should you get a case of pinkeye, initial considerations for treatment could include checking to make sure pinkeye is the true cause of the eye damage. The resource discusses several examples, including cancer eye and mechanical ulcers from foxtails that are often initially misidentified. A small ulcer on the outer edge of the eyeball often heals without antibiotics and, if a foxtail was the cause, once the foreign body is removed.
Antibiotic treatment of pinkeye is unnecessary once blood vessels have reached the eye ulcer, as shown in the images featured in the page 22 excerpt from Cow Calf Pinkeye: Strategies for Management, although you should follow your veterinarian’s specific instructions for any antibiotic treatment plan. For complicated cases of pinkeye, your veterinarian may recommend removing the eye or culling the cow based on welfare considerations. The pictures show different features of pinkeye and provide general guidance on when to consider treatment. These pictures, along with other detailed information, are available on the CDFA AUS website and can be printed or downloaded to a device to take into the field for quick reference.
When contemplating pinkeye prevention, consider the logistics of management and the costs of treating pinkeye, including product expense and labor, while making a strategy with your veterinarian for reducing prevalence in your herd. Understanding the risk factors that lead to increased case numbers can allow for targeted prevention. Some contributing factors to consider are that calves are affected by pinkeye more often than older cattle, increased face fly numbers can lead to an uptick in cases, lack of eyelid pigmentation in individual animals may increase their susceptibility, and you can expect to see more cases in the warm months when increased sunlight favors infection.
Vaccination is one part of a multi-pronged approach to reducing pinkeye. Timing is an important consideration when vaccinating; plan to finish vaccinating roughly a month before face fly season to provide adequate immunity in advance of the expected pinkeye season. Take into consideration that some vaccines require a booster. For most regions of California, vaccinating sometime in April should be effective timing. It is notable that vaccines have shown little or no advantage in published field trials and that side effects are possible, especially if combined with other vaccines for Gram negative bacteria. Working with your veterinarian is critical to determine the need.
ADDITIONAL RESOURCES
CDFA AUS and Dr. Maier have also produced resources for the other two leading diseases resulting in antibiotic use.
“Cow Calf Scours: Strategies for Management” features a fecal consistency scoring chart that can be helpful for describing the type of manure you are seeing to staff,
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Features of Strategies for Management Resources • General Strategy • Risk Factors • Treatment Tips • Prevention Methods • Causes + Signs • Approaches to Control • Visual Aids and Tables
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managers and veterinarians. Also included are the ideal body condition scores for beef cattle at calving; along with the other benefits of appropriate body condition at calving, malnourished cows and heifers are more likely to have difficult births. Calves from difficult births are often prone to scours. Assessing calf vigor and ensuring adequate colostrum intake are also important steps to prevent calf scours. The included summary table of the different pathogens leading to scours and their distinguishing features, along with a visual of the typical calf age at the beginning of scouring based on the pathogen involved, can be helpful when discussing a treatment and prevention plan with your veterinarian. Not all pathogens capable of causing scours are susceptible to antibiotics, and the most effective treatment depends on the individual case.
“Cow Calf Bovine Respiratory Disease: Strategies for Management” describes the many environmental conditions and animal factors that can lead to the bovine respiratory disease (BRD) process. Understanding risks on your farm allows you to address them in a herd health plan to prevent the disease before it begins. Two important take-aways are that reducing cattle’s exposure to high levels of dust, especially at processing, and keeping cattle hydrated can reduce the occurrence of BRD. This can be accomplished by hosing down surfaces before moving cattle through and providing them with water during wait times in corrals. Additional prevention strategies are outlined in the full document.
These practical guides can help cattle producers and veterinarians identify strategies to reduce their overall antibiotic use through preventive practices, accurate diagnostics, and the most targeted therapies, so that both the animal health and economic consequences of these reoccurring diseases can be reduced. Spanish versions of the infographics are available on the CDFA AUS website. In-depth, research-based veterinary summaries on each of the three diseases will be released soon, for those interested in learning more about the science behind the prevention measures.
CDFA AUS was able to create these resources thanks to voluntary participation of producers. We greatly appreciate your engagement and encourage any livestock producers in the State of California to reach out if you would like additional educational resources for other antibioticrequiring diseases.
To download and print this series and see more stewardship resources, please visit: https://www.cdfa. ca.gov/ahfss/aus/.
To contact CDFA AUS directly, please email us at: cdfa_aus@cdfa.ca.gov.
