Influence of dietary crude protein concentration and source on potential ammonia emissions from beef cattle manure1,2,3

Abstract

Emissions of ammonia, as well as other gases and particulates, to the atmosphere are a growing concern of livestock producers, the general public, and regulators. The concentration and ruminal degradability of CP in beef cattle diets may affect urinary and fecal excretion of N and thus may affect ammonia emissions from beef cattle feed yards. To determine the effects of dietary CP concentration and degradability on potential ammonia emissions, 54 steers were randomly assigned to nine dietary treatments in a 3 × 3 factorial arrangement of treatments. Treatments consisted of three dietary CP concentrations (11.5, 13, and 14.5%) and three supplemental urea:cottonseed meal ratios (100:0, 50:50, and 0:100 of supplemental N). Steers were confined to tie stalls, and feces and urine excreted were collected and frozen after approximately 30, 75, and 120 d on feed. One percent of daily urine and feces

The influence of oscillating dietary protein concentrations on finishing cattle. II. Nutrient retention and ammonia emissions

“…In our study, only a relatively small proportion of urinary N applied to the system was lost as ammonia N (2.4 to 8.1%) over 11 d. These values are similar to those of Cole et al (2005) who reported between 3.15 and 4.34% of applied urinary N being lost as ammonia from the same chambers under very similar conditions and length of analyses. This may be in part due to the low rate of turnover of gas within the chambers (1.2 turnovers/min).…”

“…The in vitro ammonia emission system has been described previously (Shi et al, 2001;Cole et al, 2005). Briefly, the system was composed of 48 sealed polyethylene chambers (20 cm × 20 cm × 12 cm), each attached to 2 ammonia-trapping bottles containing 100 mL of 0.9 M sulfuric acid at room temperature (∼24°C).…”

“…Thus, factors that decrease urinary N excretion could decrease ammonia emissions (Erickson and Klopfenstein, 2001;Cole et al, 2005).…”

“…As this excreted N enters the environment, the current dogma is that most urea is rapidly hydrolyzed by endemic bacterial urease in the environment and subsequently yields ammonia. Cole et al (2005) demonstrated a 60 to 200% increase in ammonia emission from cattle waste when protein concentration in the diet increased from 11.5 to 13%. However, performance of cattle fed the same diets (Gleghorn et al, 2004) appeared to be moderately decreased when the cattle were fed the lower levels of dietary protein.…”

A promising and simple method to quantify soil/manure mixing on beef feedlot pens

“…Thus, it makes sense that as carbohydrates in manure are initially consumed for respiration the overall manure C concentration would go up. This would be exacerbated by the loss of other volatiles with even lower C contents, such as urea, ammonia, and fermentation products all of which have been reported in cattle manure (Miller and Varel 2002;Cole et al 2005;Pratt et al 2014). Later during decay, as more complex C compounds are consumed in biological processes and the ash content increases relative to the volatile content, manure C concentrations would drop, which was observed in our work.…”