How accurate is your medicator?
You can’t manage what you don’t measure.
By Molly Jones, Amanda Reever and Brian Payne
Most producers assume a water medicator set at 1:128 is delivering exactly a 1:128 dilution. But what if it isn’t? When medicators fail to deliver the intended concentration, producers may unknowingly underdose pigs and compromise treatment success or increase costs by administering more product than necessary.
A recent evaluation of commercial swine farms found that only 25% of medicators tested were within 10% of their target dilution, suggesting inaccurate dosing may be more common than many producers realize.
Whether delivering antibiotics, vaccines, electrolytes or other products, producers and veterinarians rely on medicators to provide consistent and accurate dosing to entire groups of pigs. These products, though vital to pig health, are often expensive and contribute substantially to production costs.
An overlooked piece of herd healthDespite their importance, medicators are rarely evaluated for accuracy. It is often assumed that a medicator set to deliver a 1:128 dilution ratio is delivering exactly that concentration. In reality, normal wear, inadequate maintenance, water flow variability, and equipment failure can all affect the amount of product that ultimately reaches pigs through the drinking water.
To better understand medicator performance, a study was conducted evaluating 34 water medicators across 14 commercial wean-to-market sites. The project compared two methods of assessing dosing accuracy:
Measuring stock solution volume disappearance alongside water meter readings.
Measuring product (Reload Pack DT®, Boehringer Ingelheim) concentration directly at drinkers using spectrophotometry.
The first method evaluates performance at the medicator itself, while the second measures what the pigs actually received at the point of consumption.
After excluding six medicators due to obvious equipment or water meter issues, the remaining medicators were analyzed to determine how closely the two measurement methods agreed.
The hidden variabilityResults showed moderate agreement between the two approaches. Statistical analysis demonstrated a moderately positive correlation between measurements collected at the medicator and those collected at the drinker. While some variation existed between methods, the overall agreement suggested that either approach could be used to identify medicators that are failing to deliver the intended dose.
However, the most important finding was not the agreement between methods, but the variability observed among individual medicators. Several medicators delivered concentrations that differed substantially from the intended 1:128 ratio.
In some cases, calculated dilutions suggested that pigs may have received up to 40% less product than intended.
The frequency of inaccurate dosing was notable. Only 25% of medicators evaluated had both measurements fall within 10% of the target 1:128 dilution.
Even when the acceptable range was widened to 20%, only half of the medicators met that standard. These findings suggest that inaccurate dosing may be more common than many producers and veterinarians realize.
Additional medicator evaluations completed since the conclusion of this study suggest that factors beyond the medicator itself, including low water pressure and water system layout, can also influence the dose that ultimately reaches the drinkers.
When small errors become big problemsImplications of consistent under- or over-dosing are significant. Underdosing can reduce treatment efficacy, potentially contribute to antimicrobial resistance, while also increasing costs associated with products that never reached the intended animals.
Overdosing increases treatment costs and may expose pigs to higher-than-intended product concentrations. Either scenario can negatively affect herd health, production efficiency, and profitability.
You can’t manage what you don’t measureWith only one in four medicators delivering within 10% of the intended dilution in this study, routine verification can help identify dosing problems before treatment success is compromised. This study found that tracking stock solution disappearance alongside water meter readings can serve as a practical field-based method for evaluating medicator accuracy.
However, not all farms have functioning water meters on every medicator line, creating the need for a simple method that can be used regardless of facility design or plumbing configuration.
To make routine medicator evaluation more practical, PigmentRx was developed as a visual tool that allows producers to evaluate dosing accuracy without specialized laboratory equipment. By comparing the color of treated water collected at the drinkers to a simple reference guide, producers can quickly determine whether the medicator is delivering product at the intended concentration or whether additional troubleshooting is needed.
The protocol is inexpensive, easy to perform, and helps confirm water-administered products are being delivered as intended. Unlike estimating dose from stock solution disappearance alone, PigmentRx evaluates treated water collected directly at the drinker, providing a visual assessment of what pigs are actually receiving. Download the visual assessment tool and step-by-step protocol at PigmentRx.com.
Approaches to on-farm monitoringBecause inaccurate dosing is not always obvious, routine maintenance alone may not identify medicators that are failing to deliver the intended concentration. In addition to maintenance, operations should periodically verify medicator performance.
The following checklist can help identify common causes of inaccurate dosing and support medicator evaluation:
Track stock solution usage and water meter readings to calculate medicator accuracy as part of your daily routine.
Start with a clean stock bucket, suction hose, filter, and stir pump.
Consider lining the bucket with a new plastic bag prior to each treatment to limit cross-contamination of products.
Confirm appropriate water pressure and flow rate.
Verify proper medicator and pre-filter installation and that direction of flow is correct.
Ensure medicator is cycling (“clicking”) properly.
Verify stock solution disappearance correlates with the amount of water consumed by the pigs.
Calculate how much stock solution should be disappearing based on the expected or measured water consumption of the pigs.
Check suction hoses, filters, and strainers for restrictions.
Inspect tubing and fittings for leaks.
Clean equipment and perform manufacturer-recommended maintenance.
Train staff to recognize signs of medicator malfunction.
Take-home messageWater medicators play a central role in delivering health products throughout production systems, yet their accuracy is often assumed rather than verified. This study highlights that substantial variation can exist among medicators operating under commercial conditions. Periodic evaluation of medicator performance, combined with routine maintenance, can help ensure pigs receive the intended dose, improve treatment outcomes, reduce product waste, and protect the value of health interventions.
Jones is a DVM candidate at North Carolina State University College of Veterinary Medicine, Reever is a veterinarian with Suidae Health and Production, and Payne is a technical service and R&D manager at Veterinary Pharmaceutical Solutions.
