Milk Replacer Mixing Requires Precision
The exercise of mixing powder and water to create milk replacer solution may seem like a simple, and even mundane task. But it turns out you can create a lot of variability in the final product, depending on the procedures you use.
Rob Costello, consultant with Milk Quality Pays, Lewisburg, Pa. (formerly with Milk Specialties Global Animal Nutrition), has worked with and fed preweaned dairy calves for decades. “In a lot of cases, when we see calves are not performing well, we can trace it back to milk replacer mixing errors,” said Costello. “The more precision and consistency we can build into that process, the better the calves will do.”
Costello shared his advice on accurate mixing in a detailed entry on his “Calf Sessions” blog, along with an excellent, 13-minute video. Among the finer points of creating milk replacer solution he emphasizes are:
Weighing powder – The cups that come in virtually every bag of milk replacer do approximate the weight of the powder in ounces, but the actual weight can vary depending on factors like compaction, humidity and extreme cold. The best approach is to use a scale to weigh the solids in every batch to achieve the correct amount of powder. And above all, DO NOT use the measurements marked on liquid measuring cups. Those are measures of volume, not weight, and if you use them, you’ll end up with about half the amount of powder you actually need, along with some very hungry calves.
Reconstituting to precise solids percentage – Whether you add powder to a specific amount of water -- or add powder and water to achieve the final volume of solution you want -- will have a bearing on the total solids content to the solution you create. For example, if you mix 2 quarts of water with 10 oz. milk replacer powder, you actually will create 2.2 quarts of solution (13.0% solids), because the powder increases the volume slightly. Or, you can add water to the 10 oz. of milk replacer to achieve a total volume of 2 quarts (14.5% solids).
Either is solution is safe to feed, but be sure your mixing formulations and feeding volumes match your goals for the total solids you want to feed. Costello cautioned that the safe upper limit for feeding milk replacer solids is about 18%. “As you approach those higher levels, it is imperative that calves have clean, free-choice water available at all times, so they don’t draw water out of their bloodstreams to dilute the solids.” This can lead to dehydration and scours.
Mixing – Always add powder to water, to prevent the powder from sticking to the mixing vessel.
A wire whisk works well for mixing milk replacer powder into water. A power mixer with a paint paddle on the end of a power drill also is an excellent tool, but should be used with caution and proper training for young and inexperienced operators. Costello advised against using a spray nozzle on the end of a hose, because that method creates too much foam. The result may be damaged fat particles that are not soluble in water and may not be digested well by calves.
Measuring water and feeding temperature – The best water temperature for mixing milk replacer is about 110˚F, with a goal of feeding at 102˚F. Mixing milk replacer in colder water may result in some of the solids failing to go into solution. Feeding at temperatures below normal body temperature of 102˚F will cause calves to expend energy heating the solution internally.
Using excessively hot water (145˚F or above) can cause disruption in the encapsulated protein-and-fat molecules in milk replacer powder, separating the two elements and causing the fat molecules to clump together. You’ll see evidence of this when a greasy film sticks to mixing and feeding equipment. Some of the fat is lost from the final solution, and the remaining fat and protein may be less digestible. Calves often also are reluctant to drink hot milk replacer, which can impact total intake.
Be sure to use a thermometer – not just your fingers – to test every batch of milk replacer. An inline thermometer is fine for evaluating water temperature going in, but the finished batch also should be tested with a hand-held thermometer. And be sure the “as-fed” temperature is within acceptable ranges in very cold weather.
Costello suggested creating simple, visual protocols so precise batches of milk replacer are created, even when different people are doing it day-to-day or shift-to-shift. “With a few basic tools and instructions, you can help protect calf health and productivity by delivering a consistent ration at every feeding,” he advised.