Organic Dairies Suck Flies (CowVac)

December 5, 2014

Rest assured, a CowVac is not a veterinary vaccine of some sort that magically provides insect control or renders cows autistic. Rather, it is about producing organic milk and organic milk products like butter and yogurt. A CowVac is a suction or vacuum device incorporated into a larger trapping apparatus that removes blood-sucking flies that can be an even worse livestock plague than mosquitoes or ticks. Besides being bad economics (too expensive), pesticides repeatedly applied at ever higher doses quickly select for pesticide-resistant biting flies; i.e the flies become immune. Which is not to say that insects will not develop some ingenious solution, like holding on tighter, to avoid being sucked up by strong suction. But at least development of stronger suction devices and better ways to knock insects off animals would not add pesticide residues to the environment, food chain and human diets. A human equivalent, awaiting invention, would be an enclosure of some sort designed to knockoff and suck up (vacuum off) bed bugs before they bite (see previous blog, on bed bug desperation time innovative research).

“Seven years in the making: The Cow-Vac removes horn flies from dairy cattle” was the title of a special display at a members symposium “Honoring the Career and Contributions of Veterinary Entomologist Donald A. Rutz” at the Entomological Society of America (ESA) annual meeting in the beer brewing capital of the world, Portland, Oregon. On its web site, the Center for Environmental Farming Systems (CEFS) at North Carolina State University (NCSU) in Raleigh reports: “This innovative solution is now part of routine cattle management at the CEFS Dairy Unit and has allowed the herd to be insecticide-free for 5 years.” In other words, this “alternative fly management system” designed by Steve Denning and D. Wes Watson demonstrated “the feasibility of producing organic milk.”

“The trap removed between 1.3 and 2.5 million flies annually from the research station cattle,” Denning and Watson reported to the ESA in Portland. “Prior to the installation of the trap in 2007, the cattle routinely had horn fly populations above 1000 flies per animal and would require insecticide applications for horn fly control. With a vacuum trap in place, dairy cattle at CEFS have not required or have been treated with an insecticide.” With each of the thousand horn flies sucking blood 10-12 times per day, the blood loss and associated problems were huge (USA estimated losses are over $2.26 billion per year), and organic animal agriculture was considered questionable.

“The first walk-through pasture fly trap consisted of a covered structure designed to brush flies from the animals as they passed through, with the fleeing flies captured in the screened hollow walls,” reported Denning and Watson at the ESA meeting in Portland. “Modifications to the Bruce trap have been introduced over the years. These modified traps employ the same basic mode of action; curtains to dislodge flies and light, either natural or fluorescent, to attract flies to a cage, or bug zapper. In addition to curtains, the CowVac uses air pressure to dislodge flies, and vacuum to capture flies, trapping them in a chamber until death.” So far, the Animal Rights movement has yet to recognize a right to food (animal blood, in this case) for biting flies (also animals); and the flies die a natural death from lack of animal blood as a food source. Cruelty to animals (flies), perhaps; and fodder for an ethics debate. But if you want organic milk, butter, meat, yogurt, etc…

There are YouTube videos on the vacuum trap, and the Northeast Organic Dairy Producers Alliance has an in-depth article on the CowVac and its development by fly biocontrol specialist Tom Spalding of Spalding Labs: “…the Horn Fly is very tough to control. It’s resistant to most every chemical control. It only reproduces in cow pastures, which means there is always productive breeding material available as no one cleans up pasture pats…For the past 16 years, North Carolina State University entomologists, Dr. Wes Watson and Steve Denning, have been researching IPM practices for pest fly control for commercial livestock and poultry operations…They have seen it all, testing at least 100’s of products…repellent on most and only a few animals with pesticide, to using electric traps, light traps, walk thru traps, feed thru products, ear tags, oilers, you name it…in 2006 as Steve was watching flies get scrapped off cows going thru a walk in trap, and then following the cow out the exit and getting right back on, he had an AH HA moment of “let’s see if we could vacuum up those little buggers”…Organic Valley heard about this unit and they sponsored a test, placing 6 units on North Carolina dairies in 2012…we made a trip to Raleigh, NC to see it. I knew from our efforts using Fly Predators to control Horn Flies that this little insect was a big deal. It took a lot of work as you had to put the Fly Predators in the pastures where the cows has just been and that only worked for those doing intensive grazing. Harrowing or running a screen drag over the pastures made a big difference too, but all those things took more time than most dairymen had. If this vac thing worked it would solve a horrible problem every grazier has…We agreed to license the technology from NC State and so began the redesign for production and optimization. This is the second unlikely alignment of the stars. I run a beneficial insect company, but I’m a mechanical engineer (ME) by schooling and in the 30 years prior had started a number of high tech companies…we refined the airflow on real animals. While the simulated cow got us very close to optimized performance, we actually were blowing too much air…”