Dietary Protein and Fermentable Fiber Affect Nitrogen Excretion
Potential environmental impacts both inside and outside the barn can be due to nitrogen excretion. Land base needed to apply manure may be reduced with lower total nitrogen excretion. Reducing dietary protein can reduce ammonia emissions and nitrogen excretion directly. Fecal nitrogen is less volatile compared to urinary nitrogen (ammonia) since it is bound with proteins. To shift nitrogen excretion from the urine to feces, fermentable carbohydrates can be used. Proteins and fermentable fiber sources were investigated. Reducing both of these variables resulted in an additive reduction of urinary nitrogen with an overall reduction of 55%. Plasma urea concentration was used to predict urinary nitrogen excretion.