Ticks suck—there’s no doubt about it. Not only do they suck their hosts’ blood, but an infestation can drain your wallet and overall herd health.
Ticks are not only directly irritating to cattle, but can also lead to a loss in condition, decreased gains, and severe anemia, according to the University of Arkansas Extension. Research shows that around 1 billion cattle are affected annually, at an economic loss of $13.9-18.7 billion per year worldwide.
Ticks are also capable of spreading detrimental diseases such as anaplasmosis or babesiosis. Multi-host ticks can transfer diseases onto humans as well, including Lyme disease and Rocky Mountain spotted fever.
Implementing a tick prevention control program on your operation now rather than later will not only save you money in the long run, but tick infestations can rapidly spread disease and even cause death in your herd.
Tick details
Ticks are a common parasite found in most areas of the U.S. They will climb on top of tall grasses or shrubs to “quest” and wait for a host to come by and quickly crawl onto. Although ticks are something to be mindful of year-round, warm and humid summer months create the perfect environment for ticks to thrive in.
If a tick contains a pathogen, it may be transmitted to the host during bloodfeeding. In addition, if a host has a bloodborne infection, the tick will ingest it and can then transmit it to the next host.
Though often thought of as “bugs,” ticks aren’t actually insects—rather, they are arachnids like spiders and mites. They are most closely related to mites, and all adult members have eight legs as compared to an insect’s six.
A tick has four life stages:
• Egg;
• Six-legged larva;
• Eight-legged nymph; and
• Eight-legged adult.
Eggs are laid on the ground and not the actual host body. The later three stages obtain nutrients by piercing a host’s skin and sucking blood. Most ticks that prey on large livestock are classified as hard ticks. Female hard ticks will consume one bloodmeal, drop to the ground, and lay thousands of eggs. Their male partners will feed consistently and mate several times before death.
The cattle fever tick fed exclusively on cattle, but the spinose ear tick, wood tick, American dog tick, and Lonestar tick are all common parasites to cattle. Species of ticks tend to favor certain feeding sites on a host. Common feeding sites include the head, neck, shoulders, under the tail, genitalia and udder.
An ounce of prevention…
Early detection and removal of infestations is key to prevent tick-borne diseases such as tick fever and anaplasmosis.
Historically, tick infestations in cattle have been controlled by pesticides or acaricides, applied either to the environment and/or on cattle directly. The use of acaricides was initially for tick eradication, preventing the spread of disease and eradicating diseases. Eradication programs utilizing acaricides were successful in some regions such as the southern U.S., where babesiosis, was eradicated in the mid-1900s.
However, treatment of existing infestation is not always the most practical. Using acaricides to control ticks free-living in the environment can come with a high cost for large treatment areas, for instance, though smaller areas like barns can be treated periodically to control free-living populations. Additionally, many ticks may be slowly becoming resistant to the more common pesticides, according to Dr. Michael Levin of the Centers for Disease Control and Prevention.
Treating cattle with acaricides to kill all stages of ticks has been the most common control method. Acaricides are applied by either dips or sprays, with dips considered the most effective, said Levin.
The easier and more efficient control measure would be prevention rather than treatment. In areas where tick eradication has not been successful, or programs have become too costly, a blend of cultural and chemical control is recommended.
“Cultural control” for ticks include environmental management and breed selection. Field and pasture management can be an effective control measure by destroying or removing vegetation where ticks can take cover to avoid drying out. Clearing or burning brush in a pasture could be an option.
Bos indicus cattle and crosses usually become resistant to ticks after initial exposure, whereas Bos Taurus breeds remain susceptible.
Other preventative measures include new methods of acaricide application such as utilizing implants or boluses, ear tags, pour-ons and spot-ons. A vaccine containing doramectin includes antiparasitic agents that can damage a tick upon biting, but only in one-host species such as the blue tick.
Although the one-host cattle fever tick was eradicated in the U.S., the ticks still manage to cross over the Mexican border. An effort to develop a vaccine containing aquaporin to combat the ticks is in the works by the USDA Agricultural Research Service.
It is unclear whether vaccines against multi-host ticks will ever be effective. Many wild hosts serve as disease pools from these ticks, so a vaccine may not be successful in eradication or disease elimination.
—Anna Miller, WLJ correspondent
