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 Knowledge for the CommonWealth

What Type of Deworming Program Puts the Most Money in the Producer's Pocket?

Farm Business Management Update, April/May 2003

By Daniel Osborne and Todd Petrunger

Introduction and Background

Livestock producers need to understand that internal and external parasites can have a major effect on the performance of livestock. Cattle with a moderate to heavy parasite load will eat less and are more susceptible to increased levels of stress and disease. These problems result in less weight gain and, therefore, lower profits.

Various deworming strategies are used to control parasites, but one consideration that producers must make is whether to use a non-persistent activity dewormer or a more costly persistent activity dewormer product. A non-persistent activity dewormer gets rid of parasites that are infecting livestock at the time they are treated. A persistent activity dewormer continues to get rid of parasites for typically 3 to 4 weeks after treatment. In an effort to determine whether paying the extra cost for persistent activity dewormer is worth it, we compared the economic benefits of persistent activity dewormer to non-persistent activity dewormer.

Method and Measurements

This study began on June 14, 2002 and was conducted at the Bland Correctional Center's Beef Farm located in Bland County, Virginia. It involved 42 beef calves comprised of 22 steers and 20 heifers whose average weight was 315 pounds at the beginning of the study. To begin, we weighed all the calves and dividend them into three groups of 14 calves each. Within each of the three groups, we randomly treated the calves based on the order they came through the chute. One-third of the calves were given a persistent activity dewormer, one-third were given a non-persistent activity dewormer, and the last one-third, which served as a control, were not treated. The three groups were then each turned out to separate large pastures in which they remained for the duration of the study. The intent of replicating the study three times by way of the three groups was to eliminate the impact caused by the quality of pasture.

Farm management provided us with the birth date and weight for each calf; therefore, we were able to calculate the average daily gain (ADG) of the cattle from birth to June 14, 2002. After 77 days on August 30, 2002, the calves were again weighed, and the ADG for the 77-day period was calculated. Then, the difference in ADG for the 77-day period and pre-June 14 period was calculated. The total weight gain that resulted from the difference in ADG was determined and then given a value based on a standard price of $75/cwt. The cost per dose of dewormer was subtracted from the additional weight gain value to determine the net profit from the deworming program. Finally, the average net profit was calculated for the three different deworming programs.


This study has several limitations. First, because the three different deworming programs were used within each group of calves, even larger than reported differences could be expected. In other words, the calves that were untreated and treated with non-persistent activity dewormer benefited from the calves treated with persistent activity dewormer because of fewer larvae in the pasture. At the same time, the treated calves suffered from the untreated calves because of more larvae in the pasture.

Second, the treatment of calves was not evenly distributed between steers and heifers. Because of the random selection method used, a larger proportion of steers received a persistent activity dewormer. This could have impacted the differences in ADG, but I do not feel that the overall conclusion was effected. Other limitations, such as the weather conditions, were certainly prevalent. However, they were considered to be beyond our control or insignificant to the outcome of the study.


When compared to the ADG before deworming, the control group, which was not treated, had an average increase of 0.04 pounds in ADG. Over 77 days, the increase in ADG translated into 3.08 additional pounds per calf. At $75/cwt., this means the additional revenues of $2.31 per calf would have been pocketed because there was no cost for dewormer (Table 1).

Table 1: Bland Correctional Facility Deworming Study Results
Dewormer Type ADG from Birth to June 14 ADG from June 14 to Aug 30 Difference in ADG Total Gain as a Result of Difference Value of Additional Gain Cost per Treatment Increase in Net Profit per Calf
Persistent 2.36 2.60 0.24 18.48 13.86 2.17 11.69
Non-Persistent 2.42 2.53 0.11 8.47 6.35 0.76 5.59
None 2.30 2.34 0.04 3.08 2.31 - 2.31

The group of calves that received non-persistent activity dewormer had an increase in ADG of 0.11 pounds. Over 77 days, this translated into an average of 8.47 additional pounds per calf. As a result, additional revenues would have been earned in the amount of $6.35 per calf. However, the average cost per dose of non-persistent activity dewormer was $0.76, so the net profit from the increase in ADG was $5.59 per calf.

Those calves that received the persistent activity dewormer had an increase of 0.24 pounds in ADG. Therefore, during the test period, the calves gained an average of 18.48 additional pounds. When the average cost of $2.17 per dose for the persistent activity dewormer was subtracted from the additional revenues, the net increase in profits would have been $11.69 per calf.

Conclusion and Discussion

Based on the results of this study, it appears that paying the higher price for persistent activity dewormer is the best economic alternative if only one dose is given during a 2 1/2 month period. When you compare the persistent activity dewormer to the control group, $9.38 more in additional revenue was earned. Comparing the non-persistent activity dewormer group to the control group, only $3.28 more in additional revenue was earned.

Other considerations that could impact the accuracy of our conclusion include environmental conditions, the sex of the calf, and the number of treatments in a given period. Similar future studies will allow us to evaluate these considerations and their impact.

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