Turkey producers should not avoid using chemical anticoccidial products for fear of resistance, but they do need to use them strategically, according to an industry expert.
Anticoccidial chemicals have various and unique modes of action, but they work by basically stopping the reproductive cycle of the Eimeria parasites that cause disease.
Studies have shown resistance to anticoccidials typically used in the poultry industry, with products such as amprolium, clopidol and zoalene, varying in sensitivity.1
But in an appearance on the Iowa Turkey Federation’s Turkey Talkshow podcast, Steven Clark, DVM, Huvepharma’s veterinary technical services manager, said new evidence suggests there is “minimal risk” with common products, providing farmers rotate when necessary.
“We don’t need to be scared of them. We just need to use them strategically,” he said.
How chemical options help
Although ionophores and vaccines are also available as part of coccidiosis control strategies, ionophores are considered antibiotics and therefore cannot be used in No Antibiotics Ever (NAE) programs. NAE programs are less common in US turkey production than in broilers, but are a continued trend.
Clark pointed to several strengths offered by chemical anticoccidials as part of producers’ toolbox.
They are flexible in terms of when producers can use them, and chemical anticoccidials are very safe, he said.
“We can use them when we don’t want to use something else,” he explained. “Typically, they’re very potent, because they inhibit enough of the coccidia that sometimes we say that they just ‘clean up’ cocci… when we’re having a heavy challenge, we use [them to] clean everything up. Then we can start our rotations again for the next year.”
Commonly, anticoccidials are used from 0 to 8 weeks of age, but products can be used from 0 days all the way up to slaughter in some cases, following the labeled withdrawal time. They can also be used as part of shuttle programs, in which producers move from one product to another — including ionophores in conventional production.
Staying smarter than the parasites
Despite the versatility, producers need to be aware of Eimeria parasites getting “smarter” and no longer being susceptible to chemicals being used, explained Eliza Ripplinger, DVM, of Best Veterinary Solutions Inc., who appeared alongside Clark on the podcast.
“To stay smarter than the cocci, we have a rotation program, so that we’re changing that mechanism of action… and we just keep staying ahead of the cocci,” Ripplinger said.
“What the rotation program exactly looks like is a little different for each farm… as resistance can build differently on different farms. [It’s important to] work with your veterinarian to help identify when it’s a good time to switch and what the program should be.”
A connected approach
Given the dynamic nature of coccidiosis challenges across different life stages of turkeys in production, Clark also underscored the importance of veterinary pharmaceutical companies working closely with feed mills and veterinarians.
Three of the four approved chemical turkey anticoccidials are approved at both a low and high dose, allowing a program to be customized to the flock challenge. “The feed mill has the opportunity to use the approved dose, and then the veterinarian can decide what the challenge is,” he continued.
“If we have a heavy challenge in the brooder house, we might use the higher [labeled] dose [there], then at the grow out, birds are eating more feed, and the cocci challenge might be less. [In that case] we might drop the dose, if it’s approved, to the lower level.”
Towards more flexible control measures
With anticoccidial chemicals as just one option at producers’ disposal, environmental conditions in turkey barns can influence intervention choices.
Vaccines are more typically used in the spring and fall, Clark explained, with chemicals used in the summer months. Ionophores can be more suitable to use in the wintertime, when there may be problems ventilating and reducing moisture in barns.
However, there is a degree of variation in these practices, with Clark noting that “smarter barns and a lot smarter people” can extend vaccine use and assign a different role to anticoccidials.
“We’re starting to use vaccines longer for a lot of different reasons,” he added. “Now, we can use vaccines maybe through the winter, [then] we might limit our ionophore usage and then fill in the gap with chemicals.
“Using all these tools smartly makes things a lot more flexible and helps us to design a program to fit whatever your needs are.”
Listen to the full podcast episode by visiting the Turkey Talkshow podcast website or scanning the QR code:
1 Rathinam T, Chapman HD. 2009. Sensitivity of isolates of Eimeria from turkey flocks to the anticoccidial drugs amprolium, clopidol, diclazuril, and monensin. Avian Diseases. 53(3):405–408.
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