Nutrient management in beef feedlots.

摘要

Manure stockpiled anaerobically or composted aerobically was evaluated for nutrient losses in two experiments. When compared on a crop nutrient basis, stockpiling feedlot manure had a greater value than composting. Similar DM losses and moisture content of the two storage methods indicated volume and weight were not substantially influenced with either method. Added costs for management, labor, land and equipment needed for composting may not be offset by decreased transportation cost to the field. When these factors are coupled with nutrient loss, anaerobic stockpiling of feedlot manure may be more economically favorable compared with composting.;Two experiments were conduced to determine the effect of feeding wet distillers grains (WDGS) at 0, 15 and 30% (DM basis) on finishing steer performance and N and P mass balance in open feedlot pens. Feeding WDGS increased DMI and improved ADG when included in the diet as either a protein or energy source. The inclusion of 15 or 30% WDGS increased the amount of P and OM removed in the manure. Not all of the additional N excreted by feeding WDGS above the animals requirement was lost; some was removed in the manure during pen cleaning. Evaluation of nutrient losses for ingredients commonly used in feedlot diets will help to minimize the impact of feeding those ingredients on the environment.;Six experiments were conducted to determine the influence of feeding different levels of dietary cation-anion difference (DCAD) in concentrate diets on urinary pH, feedlot performance, and N mass balance in open feedlot pens. Feeding negative DCAD diets reduced urinary pH but did not have an impact on fecal pH. The influence of feeding concentrate diets with lower DCAD was not consistent and may depend on the basal diet as opposed to DCAD level. Feedlot performance did not appear to be negatively impacted when negative DCAD diets were fed. Manure pH can be lowered by feeding negative DCAD diets but N mass balance in open feedlot pens is not improved.