New Factsheet Available

It covers nitrogen from the farm to the environment, ration balancing techniques, and basic feeding management practices that minimize nitrogen excretion.

The Environmental Protection Agency considers ammonia a threat to air quality because of contribution to surface water eutrophication, nitrate contamination of ground water and impaired air quality. Urinary urea concentration is an important predictor of ammonia emission from dairy cows. It is possible through dietary strategies to manipulate urine volume and urinary urea concentration as well as total manure output. It should be noted that urine and fecal material, individually, emit minimal amounts of ammonia; it is the physical process of combining urine and feces after deposition on a floor surface, which results in ammonia volatilization in dairy housing.

The increased scrutiny from environmental groups on animal agriculture is changing the way our industry conducts business. From a nutritionist’s standpoint, it means taking an animal that is innately inefficient and implementing ration programs and feeding practices that improve her nitrogen efficiency. Ruminant nutrition is complex and involves concepts related to balancing the requirements of the microbial population in the rumen as well as the animal itself. The key to improving a cow’s nitrogen efficiency is to balance the various protein fractions along with providing adequate carbohydrates and their fractions.

Nutritional imbalances arise when nitrogen is fed in excess of the cow’s requirements, excessive rumen degradable protein or soluble protein are fed relative to fermentable carbohydrates, diets are improperly balanced for rumen undegradable protein or there are inadequate amounts or an imbalance of amino acids. However, ration programming alone will not solve the excess nitrogen excreted or the ammonia emitted. Feeding management practices also play an integral part in controlling nitrogen losses.

To find out more about dairy cattle nutrition and ammonia emissions, download this new fact sheet located at http://www.nutrient.psu.edu/ (under hot topics and updates).

Virginia A. Ishler, Extension Associate, Penn State Dairy Alliance, Nutrient Management and PSU Dairy Unit Manager Dairy Alliance is a Penn State Cooperative Extension Initiative