The threat of cattle fever ticks spreading northward into the Southwest U.S. is an issue heavy on the minds of South Texas border region livestock producers, who have been operating under inspection, and in some cases quarantine, protocols imposed by federal and state animal health officials.
The protocols were issued as because of an increase in the number of cattle fever ticks discovered on livestock and wildlife outside the permanent tick eradication quarantine zone on the Texas border.
That permanent zone runs from the tip of Texas north up the Rio Grande for nearly 500 miles of the Texas-Mexico border, averaging in width from a few hundred yards to about 10 miles into the Texas interior. Within the zone, livestock producers have limited movement capability without inspection and paperwork, including treatment records if the animal originated on a temporary quarantine premises.
In addition, regulations requiring livestock producers to treat or immunize their herds on a regular schedule each year has greatly increased the cost of livestock production for South Texas ranchers.
Both state and federal animal health officials argue that while the rules for emergency containment and eradication efforts are costly to both government and producers, it is necessary to implement effective safeguards to prevent the outbreak from spreading.
The first major uptick in tick numbers in Texas was discovered in Cameron County, where free-ranging exotic antelopes, or African Nilgai, were found in substantial numbers living on wildlife protected federal land.
Originally brought in to Texas to be used on exotic hunting ranches in South Texas, wildlife managers soon learned the overly large animals, some as big as a small horse, are hearty survivors, fleet of hoof and nomadic, following random patterns as they search for the best grazing grounds. Constantly on the move, these large and fast animals have very few natural predators in the South Texas region, so their numbers have grown over the years.
The antelope were heavily infested with the two types of ticks known to carry cattle fever protozoa. The disease is spread by the offspring of infected ticks as eggs fall to the ground before hatching. They find a new host to feed on until the reach maturity and then repeat the egg laying process.
Deadly history of cattle fever in Texas
In the late 1800s and early 1900s, cattle fever caused serious economic losses to the entire U.S. cattle industry. Deadly to cattle that have not developed an immunity, the mortality rate of cattle fever is estimated to be up to 90 percent among naive cattle.
By 1943, the tick was largely eradicated from the United States. A cooperative effort between ranchers and state and federal authorities pushed the tick back to Mexico and established a buffer that became the permanent quarantine zone still in existence in South Texas.
While those eradication and control efforts have experienced years of success, the outbreak on the Texas border in recent years managed to bleed into interior counties of the state. When host animals in Live Oak County were discovered last year, about 100 miles east of the permanent quarantine zone, health officials knew they had a growing problem.
Inside of a year, several temporary quarantine zones had been established, and more producers became troubled with strict movement and treatment mandates. Before long, it was becoming evident that raising cattle within a quarantine area was, potentially, more work and expense than what the operation might produce in a normal year.
New requirements to gather an entire herd for chemical treatment was a financial burden for producers and in some cases nearly impossible given many cattle grazed in remote and inaccessible areas. In some instances, South Texas ranchers were forced to remove cattle from some premises because they could not comply with treatment schedules.
TSCRA Steps In
Consequently, the Texas and Southwestern Cattle Raisers Association (TSCRA) offered to help producers get their message across to animal health officials about how inspection and quarantine rules and regulations were making it impossible to remain profitable during emergency eradication efforts.
"Under current regulations, ranchers in areas designated as infested are required to gather, treat and inspect 100 percent of their livestock, including cattle and equine. Ranchers can either use a medicated dipping treatment every 7 to 14 days or give a dose of Doramectin every 25 to 28 days for a minimum of 6 to 10 months. The only alternative for ranchers is to remove all livestock from their property," said TSCRA’s J.D. Cage, who was Fever Tick Subcommittee Chairman at the time.
TSCRA suggested to the Texas Animal Health Commission (TAHC) that regulations imposed on ranchers include flexibility in the gathering frequency and treatment regimen the state required for livestock, based on fever tick prevalence of the premises, pasture size, labor availability, livestock temperament, time since last gathered and other unique gathering challenges of the quarantined property.
TSCRA also requested that TAHC provide ranchers with clarity regarding which regulative authority is responsible for administering a herd management plan.
"Ranchers and landowners have worked tirelessly with TAHC and USDA APHIS to combat the fever tick; however, there are some unique situations making it even more difficult to manage the most recent outbreak. The Laguna Atascosa National Wildlife Refuge, controlled by the U.S. Fish and Wildlife Service (FWS), consists of 223,000 acres of protected natural habitat in Cameron and Willacy Counties," Cagle reported.
He argued eradication efforts that were suspended there added to problems of eradicating ticks from the entire area by giving them a safe harbor.
In the months since, the new chairman of the TSCRA Fever Tick Subcommittee, Federico Nieto, took up the fight to help producers deal with the expensive complexities of meeting federal and state rules and regulations. One of those accomplished included a Fish and Wildlife decision to resume eradication efforts on protected national refuges. Those efforts had been discontinued for budgetary reasons.
"For those landowners within a quarantine zone, there are several weapons to use against the ticks. We use controlled burning, reduce the population of non-native nilgai antelope and white-tailed deer through hunting; at certain times of the year we put out ivermectin-treated corn for white-tailed deer, and we systematically treat our cattle using regimens prescribed by the Cattle Fever Tick Eradication Program (CFTEP)," reports Nieto.
The program is administered jointly by USDA’s Animal and Plant Health Inspection Service (APHIS) and the Texas Animal Health Commission (TAHC).
Nieto said, previously FWS only utilized controlled burning and limited reduction of some wildlife populations to help mitigate the tick resurgence. While this was beneficial, he said additional tools were needed to effectively control the tick on the two refuges.
"Thanks to TSCRA members working with USDA-APHIS and TAHC, FWS saw scientific evidence that supports the use of additional measures to eradicate the ticks on federal lands," Nieto said.
FWS has also recently allowed cattle to graze on refuge land. On the Lower Rio Grande Valley National Wildlife Refuge, a 2002 study found that grazing will have a mutual benefit to the refuge by reducing invasive grasses that threaten native habitats. Cattle will not only be a mechanism to eradicate cattle fever ticks, but will also reduce the risk of wildfires and assist the establishment and recovery of native brushland vegetation.