It’s the time of year when flies and ticks start becoming a problem for cattle, and they can be more than just a nuisance.
“These external parasites not only cause irritation and stress but also reduce production efficiency and serve as vectors for certain cattle diseases,” said Craig Payne, University of Missouri director of veterinary extension. “It’s important to use control practices through an integrated approach.”
Among the flies that affect cattle, horn flies and face flies can be the most troublesome. Horn flies are small, blood-feeding insects that remain on the animal nearly all the time. They feed frequently, sometimes up to 40 times per day, and tend to concentrate along the back line unless they are forced to move to the underbelly due to heat or moisture. Their feeding causes significant stress and economic loss. Face flies spend limited time on cattle, feeding on secretions from the eyes and nose. This causes eye irritation, and the flies contribute to the spread of pinkeye-causing pathogens such as Moraxella bovis.
Beyond their role as blood feeders, ticks carry pathogens, Payne said. One such pathogen, Anaplasma marginale, causes anaplasmosis, which is widespread in Missouri and other parts of the country, causing anemia and potentially death in mature cattle. The recent appearance of the Asian longhorned tick in Missouri introduces additional risk, as this species has been associated with the transmission of Theileria orientalis ikeda, a protozoal organism that causes symptoms similar to anaplasmosis. Heavy infestations of this tick can lead to stress, excessive blood loss and reduced performance.