Precision feeding improves feed efficiency by eliminating excess nutrients while maintaining or improving milk production.

• Manage feed more efficiently, so that more nutrients are used for milk production and fewer are wasted.

In many cases, you can maintain or improve milk production while reducing feed costs.

• Decrease excreted nutrients.

Lower phosphorus concentrations in manure means you’ll need less land, less time and less money to transport manure to distant fields. You’ll also be able to balance crop nutrient needs with less purchased nitrogen.

Reducing excess dietary phosphorus
Phosphorus is essential for strong bones and teeth, healthy metabolism and rumen microbial function. Dietary requirements depend on milk production and dry matter intake. For example, a cow producing 65 pounds of milk per day with a 48-pound dry matter intake only needs 0.16 pounds dietary phosphorus, or 0.33 percent of the ration.

Recommendations for phosphorus were once much higher, but several years of research have shown that milk production and reproductive performance don’t improve with higher phosphorus. Most rations have adequate phosphorus to maintain body condition, production and reproductive health without additional supplements.

Excess phosphorus in the diet is excreted in the feces, which adds to the challenge of managing manure in areas where soil phosphorus levels are high. Before you invest in expensive inorganic phosphorus supplements, it is wise to have feed analyzed.

Supplements are an unnecessary expense in most herds. When dicalcium phosphate costs $800 per ton, eliminating it can save about $25 per cow per year.

Herds with phosphorus levels below 0.4 percent actually had higher production levels and pregnancy rates than those fed more phosphorus in a preliminary study on 65 herds by University of Pennsylvania (Figure 1). This data clearly demonstrates that removing excess dietary phosphorus didn’t cause problems with reproduction and production. It is likely that other management factors, not the reduced phosphorus, caused the improvements in the first group’s production and reproduction.

Some relatively inexpensive feeds, such as distillers grains, often have higher phosphorus levels than other concentrates. Their use may reduce feed costs, but can increase costs for managing manure (especially on farms with high soil phosphorus levels or inadequate acreage for using all their manure). Inexpensive feeds must be evaluated carefully – not only because of the increased manure management challenges, but also because the quality can vary greatly. They may or may not be a good value.

Protein and improving milk nitrogen efficiency
Protein is rich in nitrogen, and is one of the most expensive components of dairy rations. Inefficient protein use prevents optimum production because the cow must spend metabolic energy to excrete excess nitrogen, rather than using this energy for milk production. Milk urea nitrogen (MUN) levels above 12 milligrams per deciliter (mg/dl) indicate a lower nitrogen efficiency and higher urinary excretion. Here are some steps you can take to improve milk nitrogen efficiency:

• Use routine forage and grain testing to determine nutrient content.

• Monitor dry matter on high-moisture ingredients weekly to adjust dry matter intakes.

• Grind grains more finely to increase the rate of rumen fermentation.

• Make sure that corn silage is properly processed so that more fermentable starch is available.

• Make sure that soybeans are correctly roasted to improve digestibility.

• Work with your feed professional to evaluate opportunities for improvement.

• Group lactating cows according to their stage of lactation.

Environmental benefits
Reducing the nutrient content in livestock rations is one important way to achieve clean water. Nitrogen and phosphorus are essential for aquatic ecosystems, but at excessive levels they fuel the growth of algae that throws these ecosystems out of balance. Improving your herd’s feed efficiency is one of the easiest ways to improve both the environment and your profitability at the same time.

Producers may receive a financial incentive for feed management as part of a comprehensive nutrient management plan (CNMP) under the USDA Natural Resources Conservation Service’s Environmental Quality Incentives Program. Also, extension educators in many states can help you improve feed efficiency in your herd. PD

References omitted but are available upon request at editor@progressivedairy.com

—Excerpts from Penn State Dairy Focus Newsletter, February 2009

Kelly O’Neill
Ag Policy Specialist
Chesapeake Bay Foundation
koneill@cbf.org