THE 411 ON TICKS IN LIVESTOCK PRODUCTION
By : Jill J. Dunkel
In the mid-1800s, producers in northern states recognized the correlation between Texas cattle driven northward in the summer and massive death losses in northern cattle. The culprit – ticks on the Texas cattle that carried “Tick Fever” to northern cattle that had no resistance to the disease. Controlling fever ticks and the disease they carried was such an issue that government boards of animal health were created, like the Livestock Sanitary Commission which eventually became the Texas Animal Health Commission.
By the late 1890s, large dipping vats were used to treat cattle for ticks. In 1906, Congress appropriated $82,500 to support tick eradication in southern states. And in 1911,an arsenic-based dip started to control the pest and subsequently control Tick Fever. Today, fever ticks are largely eradicated from the United States, however portions of southern Texas counties remain under permanent surveillance by the USDA-APHIS. Occasional outbreaks occur, such as one reported by Texas A&M in 2017, resulting in various quarantines outside of the permanent quarantine zone.
More than 150 years after the first correlation of ticks and disease, ticks continue to be a vector for disease in cattle, and account for significant production losses. There are a variety of differences in the species of ticks and their subsequent impacts in cattle production.
“There are several differences between ticks. A tick is not just a tick necessarily,” said James Little, DVM, Senior Veterinarian for Bayer Animal Health. Some ticks cause more of a physical problem, while others transmit disease, he said.
One common tick is the Gulf Coast Tick. The Gulf Coast Tick (Amblyomma maculatum) infects the ear of cattle, often bunching up on the ear causing it to curl. Originally this tick was restricted to lands along the Gulf of Mexico and southern states, but now can be found as far north as Kansas and Oklahoma, according to the National Center for Veterinary Parasitology (NCVP). Although it can transmit a form of spotted fever to humans, it is not largely known as a disease vector for livestock.
Another tick that is bothersome for ears on livestock is the Spinose Ear Tick (Otobius megnini). The larvae and nymphs feed in the external ear canal of ruminants and horses, according to NCVP. These ticks are very irritating to the host animal.
“These ticks crawl around the ear canal. Their aggravation and irritation draw the attention of the animal rather than focusing on grazing,” Little said.
Both ticks can be controlled by an ear tag with a label to control ticks. “The insecticide is focused right where the ticks hone in, and it’s one of the most effective ways to treat for these ticks,” Little said.
Anaplasmosis is a very costly disease that is transmitted by ticks. Little said as many as 19 species of ticks are implicated in transmitting anaplasmosis. Although ticks are not the only vector of anaplasmosis, they are thought to be the most significant one. Rocky Mountain Wood Ticks, Pacific Coast Ticks and American Dog Ticks are some of the most recognized Dermacentor ticks known for spreading disease. Unlike other ticks that focus on the ear of the animal, Dermacentor ticks prefer axillary regions of livestock, like the groin, flank or under the front leg. Little said it’s hard for an ear tag to make as big of an impact on Dermacentor ticks and recommends other insecticides like pour ons, sprays or products that cover the entire body.
Another species of tick has found its way to the United States, the Asian Longhorned tick (H longicornis). According to the Centers for Disease Control (CDC), this species of tick has reduced production in dairy cattle in New Zealand and Australia by 25%. The pest has spread to the U.S. in the last year and has been found in Arkansas, Connecticut, Maryland, North Carolina, New York, Pennsylvania, Virginia and West Virginia. Unlike other ticks, a single female Asian longhorned tick can reproduce offspring—1,000 to 2,000 eggs at a time—without mating, the CDC said in a press release. That meansa person or animal could house hundreds to thousands of ticks, the agency said.
“Tick season and fly season go hand-in-hand,” Little said. “The same products that control flies often times be used to control ticks.”
As with any insect control, Little points out it’s better to use more than one type of treatment. “It’s good to approach the problem from multiple angles,” he said. “This applies to insecticides, and also the environment.”
Knowing the habitat of ticks, Little said if producers remove the ideal habitat for the pests, they won’t survive well.
“Ticks like warm places. They like it to be humid. They don’t do well in dry places or direct sunlight.”
Wooded areas, or even a lone bush or tree can serve as a micro environment for ticks to survive. Clutter, like dead grass or litter also provide a location for ticks to get underneath and survive
“In addition to treatments with insecticides, if a producer has availability to use pastures that don’t have a tree line or wooded areas, that will help. Or producers can rotate cattle during the time ticks are most active.” However, he admits sometimes that’s hard to do, depending on the location.
Environmental management, like burning pastures, helps get rid of debris and clutter so ticks don’t have a place to hide.
Although ticks have not demonstrated resistance to insecticides to the same degree flies have, Little said it’s important to take care of the insecticides we have, and that includes proper application of ear tags.
“Use the correct number of tags, which is typically two tags in an adult animal (one in each ear), or one in a calf. See the product label for specific recommendations,” Little said. “Proper application means inserting the tag in the center of the ear between the ribs of cartilage. That leaves a little bit of the tag hanging down.”
Little also said the tag should be placed in the front of the ear, not on the back side.
“At the end of the season, we encourage producers to take tags out so insects are not exposed to a sub-lethal dose of the insecticide” he said.
As with any fly control product, Little said rotation of the mode of action is important. Just changing the brand of tags doesn’t necessarily mean you are rotating the product, he explained.
“Insecticides are classed based on their mode of action, like pyretheroids and organophosphates. It’s important to rotate between those. Sometimes people think rotating different brands, shapes or colors is rotation, but you need to make sure you’re rotating to a different class of insecticide.”
If utilizing another type of external pest control, Little again emphasizes proper application. “If it’s a pour-on, apply as directed which is typically from the withers to the tail head – not just in one spot. Applying as they run by the gate is not ideal.”
His last piece of advice – read the label.
“Often we don’t take the time to read and follow instructions. The label is there to help get the most efficacy and safety out of the product. Proper dosing and proper application are key.”