Have you ever driven your V10 dually to town for a bolt and a cup of coffee? Was it cost effective? We'll answer that question later.
In the cattle business, we hear the term “cost-effective” a lot. But, just what does the term mean in the context of a herd health program?
Webster's New World Dictionary defines “effective” as “producing a definite or desired result” and also “actual, not merely potential or theoretical.” These definitions imply that for you to define a practice as cost-effective, it needs to have proven itself in your operation.
Therefore, when someone represents a product or practice as cost-effective, they are really saying “potentially cost-effective,” until you determine it is “actual, not merely potential or theoretical.”
Can you tell when something has an actual effect in your operation? Most likely you will give a product or practice a try on the entire herd or a subset that's sorted off for some reason or located in a different area. You're left to compare the results (weight gain, conversion, weaning percentage, etc.) to a previous year or another group that is different due to location, age, breed or other factors.
How much of the perceived difference is due to the product or practice, and how much is due to the difference in the years or groups? That's why we make an attempt in trials we conduct to keep as many factors the same between treatment groups as possible.
Trials Need Careful Analysis
When looking at trial data, be careful to evaluate how appropriate the reference population in the study is. Are the cattle enough like yours that you would expect a similar effect?
If a vaccine is shown to benefit high-risk, commingled calves, does that mean it will pay for itself on your home-weaned calves that have a 2-4% illness rate every year? Not necessarily. And what if the effect shown in the trial is higher serum titers?
Vaccine serum titers are often the basis for advertisements, but they are correctly referred to as indictor variables. We don't sell titers to grocery stores to put in the meat case. Therefore, we are really interested in the effect of the vaccine on the amount of beef produced.
A vaccine that causes animals to spike a high titer is not necessarily protective under field conditions. Don't fall in the trap of thinking vaccine serum titer data guarantees an actual effect in your operation.
What about implants? You often hear talk that a certain feedyard implant will increase average daily gain by 15% but decrease percent Choice by 5 percentage points. This is an excellent example of the need to know the reference population and understand the study design to interpret the effect correctly.
Any effect on percent Choice is due to a combination of two factors — the implant's effect (dependent on ration, feeding endpoint and other factors) and where the carcass quality distribution for the study population was in relation to the Choice/Select division. If the biggest part of the cattle were right on the Choice/Select line, then a relatively small effect of the implant could make a large percentage point difference in the Choice and Select carcasses.
But, if the population was high in the Choice category or relatively low in the Select category, then a relatively large implant effect on carcass quality grade may appear very slight since the biggest change was not near the Choice/Select division.
You also need to know how the cattle were harvested in an implant trial. The relative changes in performance and carcass quality in the implanted cattle will vary depending if controls and implanted cattle were harvested at the same time or if they were fed to the same level of finish.
Selecting vaccine and implant programs are good examples of where some expert advice can help you select among these potentially cost-effective practices. Be fair to yourself when evaluating the actual effect in your operation.
You may not have the ability to discern between small effects and random changes. Therefore, you must rely on trial data to indicate that a benefit will be derived. But remember, if you rely on anecdotal reports of beneficial results, you're relying on someone else's impression of what was actual in their operation.
So is taking your V10 dually to town cost-effective? It depends on what the bolt was for, doesn't it?
Mike Apley, DVM, PhD, is an assistant professor of beef production medicine at Iowa State University in Ames. W. Mark Hilton, DVM, is a beef production medicine clinician at Purdue University in West Lafayette, IN.