Are Parasites Eating Away at Your Profits?

March , 2021
Bridget Stice, UF/IFAS Extension Polk County

As we prepare and begin spring cow work, it is important that we consider parasite loads and make decisions to minimize their impact on our bottom line.  At every level in the production cycle, including feed conversion, immune response, milk production and reproductive efficiency, parasites negatively impact performance.  A 2007 Iowa State University study documented a loss of $207 per cow-calf pair annually due to roundworms and flatworms alone. 

grazing cow

Developing a strategic plan for parasite control is important and should be accomplished with the consultation of a veterinarian.

Cattle are usually infected by internal parasites while grazing pasture.  Larvae from worms attach to grass blades in the pastures and infect cattle when they ingest this grass. The grass has to be wet from either rain or dew, and the soil temperature has to be above 55 degrees for the larvae to reach the grass blades. Florida pastures present ideal conditions for larval infections nearly year round.  According to Auburn University parasitologist, Dr. David Pugh, “with less pasture ground, more intensive grazing and warm, humid weather, the southeastern United States is a perfect host environment for parasitic pasture worms.”

Breaking the life cycle of parasites by properly rotating and resting pastures, or utilizing the correct types of dewormers can go a long way in reducing parasite loads. 

Nursing calves are at high risk of internal parasites. Deworming at earlier stages of infection can result in improved weaning weights. Reducing the calf parasite load should increase subsequent weaning weights by 10 to 20 pounds per calf.  While mature cows are not as susceptible to internal parasites, they should not be overlooked.  Deworming the breeding cow herd can add more pounds to weaned calves, as milk production increases by 2 to 5 pounds per head per day. Deworming cows can also increase reproductive performance.  Herd sires should not be overlooked in a strategic parasite management protocol. 

Proper dosing and handling is also critical to the efficacy of dewormers.  Underdosing cattle results in reduced efficacy of the dewormer and increases resistance, while overdosing is an expensive waste of product.  Estimating the weight and/or relying on the average weights as the animal comes through the chute is a risky method for administering a product that can be expensive and has such a critical purpose in the production management system.

The exact economic impact of deworming will vary from ranch to ranch and from year to year. However, research clearly supports the positive impacts of deworming both cows and calves. So, it is not a question of whether or not to deworm, but when and with what product.  Many effective products are available including drenches, pour-on, feed through and injectables. Consult with your veterinarian to set-up a deworming program that fits your production and management goals. 

 

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