Nutrition: Balance Ration With Environmental Impact In Mind

Nutrition: Balance Ration With Environmental Impact In Mind

At training programs in Denmark and Germany this past summer, dairy farmer decisions were dictated by environmental  approaches that will be happening soon in the U.S.

The good news is each situation is a win-win for the dairy farmer as it is economically favorable and improves environmental issues by adjusting your feeding program.

Nitrogen losses are expensive. Higher levels of feed nitrogen (protein) can cause excessive losses in urine and feces, which contaminates water and air quality. Higher levels of nitrogen converted to milk protein or body tissue need to reach 35% (currently at 28%). Strategies include:

  • Monitor milk urea nitrogen (MUN) levels; target 8 to 12 mg/dl by balancing protein sources, forms, level and carbohydrate levels.
  • Use of a rumen model computer software program allows an optimal balance of rumen degraded protein (typically 65% to 68%) and rumen undegraded protein (typically 32% to 35%) to meet metabolizable protein requirements and amino acid needs.

Excess dietary phosphorous increases excretion of manure. Since land for spreading manure can be limited on farms as herds expand, strategies include:

  • Reduce dietary phosphorus levels to 0.38% of the ration dry matter.
  • Check if supplemental mineral phosphorous sources (such as dicalcium phosphate) are being included when they are not needed.
  • Test feeds for current phosphorous levels. You might be surprised how phosphorous levels have increased due to manure applications.
  • Test levels in soil and develop a manure application plan that matches crop removal rates.

Lowering dietary phosphorus reduces the number of acres needed for manure application.

Rumen methane gas production. During rumen fermentation, methane and carbon dioxide are produced, leading to carbon losses that could be used for productive energy. These losses can represent 5% to 7% of gross energy. Methane is a greenhouse gas that affects the environment. Strategies include:

  • Feeding monensin reduces methane production, shifting rumen bacteria and dynamics.
  • Feeding essential oils, yeast and yeast cultures, unsaturated oil sources, high quality forages and high grain rations can also reduce methane production. Be sure rations are balanced; these approaches can have negative economic or rumen health impact.

Ration potassium is recommended to increase from 0.9% to 1.2% in the total
ration dry matter.
Under heat stress, raise DCAD (dietary action=anion difference) from 350 meq/kg of dry matter to more than 450 meq/kg using potassium carbonate
instead of potassium. Strategies include:

  • Calculate current ration potassium levels to determine optimal intake.
  • Test potassium levels forages and soil; add recommended levels of manure based on soil potassium levels and the amount removed by the crop.
  • Select crops that will store higher levels of potassium, such as legumes.

MIKE HUTJENS is an Extension dairy specialist at the University of Illinois–Urbana. Contact him at:

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