In the summer heat, farmers are still focused on heat stress and related issues, but they are also facing new threats such as the Asian longhorned tick, which can transmit a disease similar to anaplasmosis to cattle.
University of Missouri Director of Veterinary Extension Craig Payne says the invasive longhorned tick has only been found in Missouri in the last few years, and it has been confirmed in 22 counties. The tick has also recently been confirmed in Iowa and Illinois.
The tick can spread quickly, with females producing 2,000 eggs at a time. In addition to causing irritation and significant blood loss, the
Asian longhorned tick transmits a parasite, Theileria oreintalis Ikeda, which destroys red blood cells. This can cause weight loss, lost pregnancies and even death in cattle. He says the death loss appears to be 1% to 5%.
Payne says the tick and disease present a difficult challenge because there are no treatments approved in the U.S. yet. It can appear similar to anaplasmosis in cattle, and a blood test is needed to tell the two diseases apart.
“It’s a challenge,” he says. “It behaves very similarly to anaplasmosis in that it’s tick transmitted.”
Payne says the map of confirmed Asian longhorned tick populations does not always line up with where the Theileria orientalis Ikeda is found, so producers should be on alert.
“Eventually, we’ll get to the point when the disease is just endemic in Missouri and we’ll have to deal with it,” he says. “The challenge with it is you just can’t treat it, you just have to deal with it.”
The best control is keeping cattle away from wooded areas and other habitats where ticks live and clearing weeds and brush regularly. Producers can also inspect cattle for ticks during handling events.
Payne says these practices can also help with reducing anaplasmosis risk, and in general controlling tick and fly populations on cattle can have health benefits. Producers can also consider antibiotic mineral to help control the impacts of pests.
“They can use mineral medicated with chlortetracycline and feed it through months ticks are active,” Payne says.
Farmers can also be mindful about avoiding transmitting disease with equipment.
“We can also transport anaplasmosis through blood-contaminated equipment,” he says.
He recommends changing needles between injections if anaplasmosis is an issue with a herd, and producers can also consider disinfecting equipment like tagging pliers between uses.
With anaplasmosis, Payne says it can be a month or two between contracting the disease from a tick and showing symptoms. The disease is most often seen in herds in the late summer and fall.
In general, summer is a good time to think about how to manage heat stress and insect-borne disease in cattle. Payne says horn flies can cause stress and economic loss as well as spreading disease, including pinkeye-causing pathogens.
“Those fly populations, if heavy enough, can affect performance,” he says.
Payne says producers should also be on the lookout for foot rot issues in the summer, especially if cattle stand in ponds or wet areas to cool off.
Cattle can also face a “summer slump” of performance if they are on fescue pastures with an endophyte that can cause blood vessel constriction. This can make cattle more susceptible to heat and affect grazing.
“They may spend more time standing in shaded areas or at ponds trying to keep cool,” Payne says.
Summer temperatures may be beyond cattle producers’ control, but Payne says they can help manage the impacts by providing cattle with access to shade and plenty of water. He also recommends avoiding handling cattle during the hottest days and times.
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