Feedlot managers can assume that almost every animal entering their facility has some degree of internal parasite burden —parasitism can hurt an operation’s bottom line in a number of ways.

“Parasites will decrease appetite and, hence, decrease dry-matter intake and average daily gain,” said DL Step, DVM, Boehringer Ingelheim. “Carcass values can also be affected, including hot-carcass weights.”

Internal parasites adversely impact the immune system. “At the feedlot, one of the biggest parasite concerns from an economic standpoint is the brown stomach worm [Ostertagia ostertagi], a nematode that can hinder an animal’s ability to digest nutrients,” Dr. Step explained. “Recently, veterinarians have been asking more questions about the consequences of liver flukes.” In the past, liver flukes were only an issue in the wet regions of the Gulf and Pacific coasts, but have become a worsening problem for producers across the country.

Determining parasite program needs

According to Dr. Step, the best way for feedlot managers to control internal parasites is to work with their veterinarian to develop an all-encompassing deworming program.  

A coproculture can identify the species of parasites most prevalent within the herd, so feedlot managers can implement a targeted approach to parasite control. “It is important to know where the animals are arriving from as well as some history, if at all possible, because some of the laboratory test results may not necessarily reflect what is going on internally,” Dr. Step said.

Once an internal-parasite control program is established and the target parasites are identified, the next step is to determine whether the deworming program is working. Feedlots can do this by comparing the performance of treated animals to other pens of untreated, similar-type cattle. Another measure is a fecal egg count reduction test, or FECRT, in which operators collect stool samples prior to deworming, and again after deworming from the same group of animals.  

Tips for developing a successful feedlot deworming program

No matter your protocol, Dr. Step has summarized five key tips for managing parasites at the feedlot:

1. Work with your herd veterinarian. Every situation is unique; no two feedlots or groups of cattle are the same, and neither are their parasite burdens. That’s why consulting your veterinarian is so important. He or she can help evaluate your operation’s needs, and recommend a deworming protocol and product(s) based on the findings.
2. Store deworming products properly. Avoid letting dewormers freeze, and don’t put products in direct sunlight on hot summer days.
3. Ensure the weight of the animal being treated is accurate and the dosing is correct. As a rule of thumb in feedlots, you can dial in the individual weight of an animal on the applicator and administer product per that individual weight. If that is not possible, the general recommendation is to dose, based on the heaviest animal in the group. With feedlot cattle, weight ranges are going to be fairly narrow.
4. Administer dewormers according to label directions. If it is an oral drench, make sure it gets in the mouth correctly, and the cattle do not spit it out. If it is an injectable product, administer underneath the skin for a subcutaneous injection, and not accidentally in the muscle. If it is a pour-on or topical formulation, spread out the dose on the animal’s back, according to directions.
5. A deworming program is most successful when staff are well trained and have a comprehensive understanding of deworming procedures.

“Deworming is one of the easiest ways for beef producers to increase performance,” concluded Dr. Step. “Implementing a strategic deworming plan in your herd can result in up to a $201 gain per head, which pays off quickly.”¹ 

Reference:  

¹ Lawrence JD, Ibarburu MA. Economic analysis of pharmaceutical technologies in modern beef production in a bioeconomy era. Iowa State University. 2008. Available at: https://www2.econ.iastate.edu/faculty/lawrence/Pharma%202007%20update.pdf. Accessed June 4, 2024.

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