Many tools exist to evaluate the effectiveness of a dairy cow’s diet, but observing or “eyeballing” manure can also give you a quick read on feed utilization. Stuart Rymph, PhD, CCA, PAS, Purina Animal Nutrition, says, “We shouldn’t overlook the vast amount of information you can garner just by doing a simple evaluation of the manure.”
The manure evaluation doesn’t have to be fancy or elaborate, just look at the manure, pick through it and maybe wash it through a wire mesh screen. “What you see and how often you check is more important than the process you use,” Rymph says, noting that sometimes just kicking the manure around will uncover startling information.
Things to look for that might indicate trouble include:
• Is the manure generally loose?
• Are there bits of corn kernels or whole kernels?
• Do you see more than an occasional whole cottonseed?
• Are pieces of corn stalks or cobs in the manure?
• Are pieces of hay or haylage present?
• Is the manure bubbly?
• Are there mucin casts?
“Squeeze the manure out or wash it through a sieve or a mesh strainer,” says Rymph. “But if you use the spaghetti strainer, please don’t put it back in the kitchen when you are done.”
Ideally, rinsed manure should look “fuzzy” with fine particles and maybe an occasional bit of corn kernel or forage. Generally, if the particles are big enough that you can identify which ingredient they came from there is an opportunity to improve feed efficiency, milk production or components. Inevitably, some pieces of corn and even the odd piece of alfalfa stem, grass leaf or bit of corn stalk gets through the system intact, “so don’t over-react,” says Rymph.
“Where you draw the line and say ‘Whoa! Something is wrong,’ depends on how everything else is going.” Rymph says that if milk production is good and feed efficiency is okay, he’ll take note of what he sees but he’ll be looking for any changes since the last time he walked the pens.
“Manure evaluation should prompt questions and point you in the right general direction,” he says, explaining that loose manure does not cause low milk production or low butterfat – whatever is causing the loose manure may be causing the lower performance; the loose manure is just another symptom.
Look at the findings in light of everything else the cow and the feed lab are saying as there can be many possible causes for one symptom. If you are seeing bits of corn, is that because the grind-size or kernel processing is too coarse, the kernel too hard/vitreous or is it passing through the rumen too fast? Likewise, if there are recognizable pieces of hay or haylage or corn stalks; is the neutral detergent fiber (NDF) digestibility low, are intakes/passage too high, too small particle size or are the cows sorting the ration?
“Pay attention to what your cows are telling you, paw through some cow pies on your own, figure out what is normal for your herd and watch for changes,” notes Rymph.