NH3 and greenhouse gases. A total NH3 emission of
88 g/kg CW was found for the full production system
with 43% emitted from feedyard manure and 44%
emitted from urine and fecal deposits of grazing cattle
in the cow–calf phase (Table 5). Greenhouse gases
were primarily emitted from the cow–calf phase, due
to the breeding stock living on the land for a full year to
produce a calf and the increased enteric emission from
these cattle consuming a high-forage diet (Table 5). In
this analysis, CO2 emission came through the burning
of fossil fuels and the use of lime on crop and pasture
land. Not much lime is used in this region, but that
used contributed 66% of the CO2 emission associated
with the cow–calf phase. Methane and N2O emissions
also primarily came from the cow–calf phase where
73% of the CH4 and 66% of the N2O were emitted.