With only five percent of parasites living in cattle, that means 95% of the parasites on any given farm are calling the pasture home.1

With this kind of parasite load distribution, it’s vitally important that a producer implement a sound strategic deworming program to help ensure that he is not only cleaning up his cattle, but is also cleaning up his pasture.

Left unchecked, these parasites will affect the performance of a herd, as well as eat into an operation’s bottom line.1

“We’ve known for years that parasite control is critical to a cattle producer’s profitability and is the most economically important practice in beef production,” 2 says Joe Dedrickson, DVM,  Merial Ltd. “In fact, parasitologists estimate that parasites cost U.S. producers more than $200 million each year.3 In addition to decreased production, diminished reproductive performance and lower weight gains, producers must also be concerned about extra days to market, compromised immune responses and poor body conditions that result from absent or inadequate parasite control programs.” 1,4,5

Part of developing an effective protocol is determining the optimal time to deworm. Treating a herd in conjunction with seasonal grazing patterns and using a dewormer that is effective against adults and L4 larval stages will help reduce egg shedding and pasture contamination.5 Keeping the pasture top of mind is also critical to the success of a deworming program. If producers focus only on deworming their cattle, their pastures will remain contaminated and they will continue to reinfect their herd.4

“In the southern United States, the first deworming should ideally take place in the spring to help protect cattle from infective larvae on pastures and help reduce pasture parasite loads,” 5,6 says Dedrickson. “While a common veterinary recommendation is to deworm cattle at turnout or when they are moved to a new pasture,6 it’s critical that your veterinarian is involved in your deworming strategy, as every producer’s situation is unique. Timing considerations should include when grazing season begins, age and category of the animals, type of operation and the grazing history of the pastures.” 5

Producers also need to be aware of how long their parasite control products really work. Dedrickson notes that it is a common misperception that these products protect cattle against parasites for the entire season. “In fact, most endectocides actually provide broad spectrum control for 14 to 28 days, depending on the product and the parasite.1 Thus, one spring deworming will simply not address the parasites in your herd or in your pasture and opens up your operation to continual parasite reinfection.1,5

1 Arseneau J. Parasite Control. Beef Health Management Course. University of Minnesota Extension Service. Lesson 4.
2 Lawrence JD, Ibarburu MA. Economic Analysis of Pharmaceutical Technologies in Modern Beef Production. Iowa State University. 2007. Available at:
http://www2.econ.iastate.edu/faculty/lawrence/pharmaeconomics2006.pdf. Accessed January 15, 2012.
3 Kvasnicka B, Torell R, Bruce B. Internal Parasites of Cattle. Western Beef Resource Committee. Cattle Producer’s Library. CL690. 2010. Available at:
http://www.ansci.colostate.edu/beef/info/cattlemanslibrary/690.pdf. Accessed January 15, 2012.
4 Pence M. Deworming Cattle for Profit. University of Georgia College of Veterinary Medicine. Available at:
http://www.ugabeef.caes.uga.edu/pdf/MWorms.pdf. Accessed February 9, 2012.
5 Miller J. Strategic Deworming. Louisiana State University. Department of Epidemiology. Available at:
http://www.animal.ufl.edu/extension/beef/shortcourse/1991/Miller.PDF. Accessed January 15, 2012.
6 Rutherford B. As The Worm Turns. Beef Magazine. Available at:
http://beefmagazine.com/mag/0401-spring-deworming-costeffective. Accessed January 15, 2012.