Establish and maintain good fly control for pasture cattle

By Cliff Willms, Ph.D., Beef Nutritionist

Good fly control is an essential element of good animal husbandry.  In an era where humane treatment of farm animals and their well-being is on the public conscience, one cannot ignore fly control.  Attitudes suggesting, “That’s what tails are for” are not appropriate in today’s culture.  

But flies are much more than a nuisance!  We don’t realize the economic impact that the lack of fly control has on cattle performance.

It is estimated by experts that the economic losses from inadequate fly control for cattle are greater than respiratory disease and coccidiosis losses combined.  That seems hard to believe until one considers that flies can affect cattle over an entire summer and early fall.  Then it makes sense.  When we think of health issues with cattle, we often think about the acute symptoms of respiratory disease or coccidiosis and treat the cattle immediately.  The loss of performance is often short term.  However, with flies it is the long term exposure that causes the larger performance losses, even though the cattle may appear healthy, and makes flies the larger economic loss.

For pasture cattle, the horn fly, Haematobia irritans, is the most economically important fly.  Both the male and female horn flies are blood suckers.  They have a very efficient cutting and digging mechanism that delivers painful bites.  Imagine a chewing syringe needle or turning a needle with a burr on it.  I can’t stand just a few mosquito bites – imagine what a cow puts up with!

This biting action and blood sucking causes all sorts of negative behaviors.  You see kicking, stomping, head slinging, tail swishing, and cattle grouping up rather than spreading out and grazing.   When cows do what they were created to do, they spread out and graze grass primarily in the morning and evening.  In the middle of the day, they lie down in the shade when content from eating their fill and chew their cud.  Full of forage and relaxed, they produce milk and their calves grow optimally.  They can’t do that when fighting flies.   

The issue is maintaining good fly control.  The means used should be effective, economical, environmentally friendly, safe, and fit one’s management scheme.  How one gets the job done is personal preference.  Discussing every option in an integrated pest management program is beyond the scope of this article.  The remainder of this article will focus on feed through products and management for pasture cattle.

As a nutritionist, the “corner post” of building a sound nutritional program starts with being rigorous about using an excellent mineral all year long and managing the intake to target levels.  Naturally, it seems that a feed through fly control product fits nicely with a cattleman committed to good mineral nutrition for his/her cows.     

Cattlemen have options when choosing a feed through fly control product:

  • Altosid® or methoprene is also known as an IGR (Insect Growth Regulator).  It is a growth hormone specific to flies that prevents the development of pupae into harmful adult horn flies.  There is no known resistance, it is not toxic to mammals, will not wash out of manure, and there is no withdrawal for meat or milk. 
  • Rabon® is an older product (organophosphate) that was used heavily several years ago and still used today.  It is effective on face flies, horn flies, stable flies and house flies.
  • ClariFly® is a newer product available for pasture cattle.  It is usually used more in confinement situations rather than pasture cattle.  ClariFly® prevents house, stable, face, and horn flies from developing in and emerging from manure by disrupting the development of the exoskeleton of insects.  Hence, it is not toxic to mammals.  

The key to the success of all feed through fly control products is to manage mineral intake.  If the cattle eat the mineral, the fly control product will be in the manure and you will see good control.  Managing mineral intake is something you want to do anyway to get the most effective nutrition from your mineral purchases.

Here are some tips on management of granular or loose minerals containing a fly control product:

  • Location and number of feeding stations must be adjusted to control intake.  Placement of mineral feeders relative to water, cow paths, shade, and loafing areas is critical.  Moving a mineral feeder 50 yards can make a big difference.  When mineral is close to water, a cow can wash her palate and make multiple trips to the mineral feeder and consumption will be higher.  Move the feeder farther from the water and intake will decrease.
  • To decrease intake, add additional salt.  Most granular minerals include a nutritional level of salt, but added salt may be needed to regulate intake.  If you add salt, always mix the salt with the mineral containing the fly control product.  Offering salt and mineral side by side may give the overall average intake desired, but during fly season, one will quickly figure out that some cows eat only salt some days and not the mineral, hence fly control is compromised.  This is a huge issue that is the cause of many producers being dissatisfied with results.
  • Placing mineral in a mineral feeder that is on the ground will encourage intake and placing mineral in a bunk up off the ground will decrease intake. 
  • With pastures with running creeks and streams where there are multiple watering stations, make sure to have multiple mineral feeding stations to insure adequate intake.  
  • Make sure all minerals and supplements contain the fly control product of choice.  A few years ago, a cowman lost fly control and couldn’t figure out what the problem was.  He was offering protein blocks without fly control as well as a mineral with fly control.  The cows did not need the protein with the quality of grass they had and I asked him to remove the protein blocks and in 2 weeks, the fly population was under control. 

Since intake management is the biggest issue with getting optimal fly control from a feed through product, I prefer to use CRYSTALYX® IGR MAX™.  Research has shown that cows frequent a low moisture molasses based mineral block more often and consume it more consistently than a granular mineral.  One can put out several CRYSTALYX® barrels at a time and spread them throughout the pasture.  The CRYSTALYX® Low Moisture Blocks are weather resistant and purchasing a mineral feeder is not necessary. 

Another huge key to satisfaction with using a feed through fly control product is feeding it long enough into the fall.  Be sure to feed past a hard freeze!  This will reduce the carryover of eggs and you will be happier with the results next year than you were with the first year.  In fact, I am more concerned about a producer feeding the fly control product long enough into the fall than I am with how soon they get started in the spring.

The biggest objection many producers have to using a feed through fly control product is concern that since their neighbor does not use it, they fear that they will not have good fly control.  However, that is not a concern.  The horn fly, the fly of primary concern in pasture cattle, is a small fly and does not travel far.  In fact, the horn fly lives its entire life on the host animal.  It jumps off to lay its eggs in fresh manure and jumps back on the host animal.  I have witnessed this phenomenon myself when collecting fecal samples.  I have further witnessed several situations where cattle in the neighboring pasture were not on a fly control product and we had excellent control.

If you have not used a feed through fly control product, I encourage you to do so.  It is a good management practice in an integrated pest management program that has proven to produce a good return on investment.

TAGS: Pasture