Many tools exist to evaluate the effectiveness of a dairy cow’s diet, but the final judge of how well a ration performs is the cow herself, says Stuart Rymph, dairy nutrition and technical services specialist with Purina Animal Nutrition.

Eyeball some cow pies todayA simple evaluation of your cows’ manure can provide a wealth of 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 (i.e., tubes of mucous)?

Ideally, manure rinsed through a sieve or a mesh strainer 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.

Pay attention to what the cows are telling you, sort through some cow pies on your own, figure out what is normal for your herd and watch for changes, Rymph says.