Zero-excess manure management in dairy through optimum rations
1998
Alocilja, E.C.
Manure phosphorus (P) is a major pollutant in many ecologically sensitive areas today. Reduction of manure P in the dairy industry is critical for environmental sustainability. Optimum ration management is one way of minimizing excess manure. The objective of the article is to present nutritionally satisfying rations that result in the elimination of unwanted P in a dairy farm by using an optimization-based nutrient balance (NBD) model. The NBD model shows that nutritionally satisfying rations that lead to zero-excess manure are characterized by high P contribution from crops, low in excess dietary N and P, high corn-to-alfalfa silage ratio, and high plant biomass content. Rations low in excess dietary N and P lead to low fecal excretion of P and high utilization of P and vice versa for rations high in excess dietary P. Rations formulated for high milk-yielding cows (25 kg d -1 or more) result in the most efficient utilization of P and zero-excess manure P. On the other hand, dairy systems with low milk yields (20 kg d-1 or less) have low utilization efficiency for P and, consequently, high unwanted manure P.
显示更多 [+] 显示较少 [-]