Producers should keep an eye out for trouble and be proactive in prevention and treatment
The hot, humid summer days usher in a plethora of unwanted pests. For many livestock producers, ticks are at the top of the nuisance list, and for good reason. Some tick-borne illnesses can cause serious health problems, even death, in cattle.
One of the most prevalent and problematic tick-borne diseases is Anaplasmosis. This disease is caused by an intracellular microorganism called Anaplasma marginale, which infects the red blood cells of cattle.
Anaplasma marginale is transmitted from an infected animal to an uninfected animal through ticks, biting flies, surgical instruments or contaminated needles. “Some tick species are true biological vectors of this microorganism,” Dr. Kelly Loftin, University of Arkansas professor and entomologist, said. “In biological tick vectors, the pathogen survives and multiplies within the tick from one stage to the next (larvae to nymph to adult).” Ticks such as the American dog tick and the black-legged tick are thought to be important carriers of Anaplasmosis.
The disease is transmitted differently in mechanical insect vectors such as horse flies. In these cases, the pathogen is picked up during blood feeding on an infected animal, then quickly feeding on an uninfected animal.
Symptoms of Anaplasmosis
Producers can look for the following symptoms to spot cases of Anaplasmosis in their herds; diminished appetite, weakness, decreased milk production, lethargy, pale mucous membranes and elevated temperature. “In some animals, the disease may progress resulting in rapid weight loss, yellowed mucous membranes, excitation, constipation, abortion and possible death,” Loftin said. “When death occurs, it’s caused by the destruction of red blood cells, which limits the animal’s ability to provide enough oxygen to tissues.”
The age of the animal can impact the severity of the disease. Calves younger than 1 year old can experience mild symptoms. Animals 1 year to 2 years old, can experience serious disease but rarely die. However, in cases left untreated in cattle that are more than 2 years old, those animals experience acute disease with mortality rates of up to 50 percent.
Anaplasmosis can be treated with antibiotics such as tetracycline or chlortetracycline. Producers should consult their herd veterinarian to administer and to advise them on the specific antibiotic regiment.
Prevention of Anaplasmosis
Start at the source by treating cattle with effective tick and biting fly control products. In addition, when working a cattle herd, disinfect equipment such as castration knives, dehorners and tattoo pliers between uses. It is also important to switch out hypodermic needles often. Currently, there is an Anaplasmosis vaccine developed by Louisiana State University. Producers can consult their veterinarian to determine if the vaccine is appropriate for their operation.
Other Tick-Borne Illnesses
According to Loftin, Bovine Theilerioses is an emerging tick-borne disease found in specific areas of the U.S. where the new invasive Asian longhorned tick is widespread. Bovine Theilerioses can cause anemia, unthriftiness and death in cattle. The Asian longhorned tick has been identified in 15 states, all east of the Mississippi River. It has been found in one county in Arkansas but has not become widespread in that state.
Tick Management Control Practices
There are steps producers can take to control tick populations in their herds. Experts recommend whole body sprays and insecticide and acaricide dips. Another method includes self-treatment devices such as dust bags containing insecticide dusts.
Other control measures include pour-on insecticides and some insecticidal ear tags. Insecticide concentrations containing permethrin, coumaphos or phosmet are mixed with water and used as whole-body sprays. Most insecticidal ear tags will control ticks attached inside the ears of cattle, but only a few insecticidal ear tags will effectively control ticks found on other parts of the animal’s body.
Ticks thrive in humid environments created by tall weeds and brush. Therefore, cutting weeds and brush will reduce the favorable environment for tick populations. Producers can also utilize acaricide applications in small areas to reduce the tick population.
Currently, Loftin and his colleague, Dr. Emily McDermott, are conducting a study assessing the prevalence of Anaplasmosis in livestock and wildlife associated with ticks in Arkansas. They hope their research will give them more information to share with producers in the Ozarks on this tick-borne illness.