Model for Estimating Feedlot Manure Quantity and Nutrient Content

Abstract. For effective use of manure as fertilizer, manure properties must be known. However, there is a lack of information on the quantity and nutrient contents of as-removed feedlot manure. Few studies have measured the amount of manure produced by feedlot cattle, and consequently nutrient loss between as-excreted and as-removed feedlot manure is poorly understood. In Saskatchewan, a calf fed from 386 to 590 kg (850 to 1300 lbs) in 150 days can have manure production of 13.6 kg d-1, and the manure can have nitrogen content of 7.5 kg t-1 and phosphorus content of 2.0 kg t-1. Nitrogen loss between as-excreted and as-removed manure can range between 50% and 60%, and phosphorus loss can range between 10% and 30%. The model presented in this article allows feedlot operators, nutrient management specialists, and regulatory agencies to predict the properties of manure, as long as the diet, bedding usage, and moisture content are known.