CW (Table 6). No particular strategy was found to be
most efficient, indicating that many parameters can
impact the efficiency of production. The lowest value
was for a system where weaned calves went directly
to a feedyard for backgrounding, which reduced time
to slaughter and used a lower forage diet, but other
low values were obtained for systems that included a
stocker operation. The highest values were found for
cow–calf to finish operations where cattle were on the
same ranch for their life cycle, and these represented
a small portion of the total cattle. The weighted mean
carbon footprint for the whole region was similar to
the mean at 19.1 ± 1.8 kg CO2e/kg CW.
When Holstein cattle were included in the life cycle
analysis, the mean carbon emission for the region
decreased to 18.3 ± 1.7 kg CO2e/kg CW (Table 6).
This occurred because of the relatively low emissions
and resource use allocated to a Holstein calf
obtained from a dairy operation (Stackhouse-Lawson
et al., 2012). Maintenance of the breeding stock in a
beef cattle production system contributes a major portion
of the environmental footprint of beef production.
Because the dairy calf is a byproduct of the dairy farm,
it has a much smaller footprint. The dairy cow also has
a lower footprint than a beef cow because a portion of
her environmental footprint has been allocated to milk
production (Rotz et al., 2010). Because Holstein cattle
make up a relatively small portion of the total cattle
in this region, these differences had a relatively small
impact on the regional footprint.
Fossil energy use for the individual production
systems varied from 26 to 83 MJ/kg CW (Table 6).
The mean of the 28 systems and the weighted mean
were similar at 54.5 ± 5.1 and 54.1 ± 5.1 MJ/kg CW.
The inclusion of Holstein cattle dropped this energy