Agriculture Reference
In-Depth Information
beef cattle
In the case of beef, there are two major post-weaning production paradigms used in
North America: (1) cattle in large feedlots fed a finishing diet of grain and forage and
implanted subcutaneously or fed growth-promoting hormones and compounds that
suppress rumen methane generation and (2)
a traditional pasture-based beef produc-
tion finishing system. Both systems have advantages and disadvantages, but each has
different environmental impacts in terms of land used and emissions of GHGs per
pound of beef produced.
Role of Growth Promoters in Beef Production Efficiency
Beef produced from cattle in feedlots and given growth-enhancing hormones requires
less land during the finishing period than if cattle are kept on pasture. Acevedo et
al. (2006) compared the average cost of production to achieve current market-grade
standards for cattle in Iowa finished under five different feeding systems. Part of this
study involved a comparison of the performance of feedlot cattle fed a conventional
high-concentrate finishing diet with (W) or without (WO) growth-promoting supple-
ments and methane generation suppressants. The results illustrated the improved
growth performance, efficiency of feed utilization, and greater total beef production
of W than WO cattle. Calf starting weight, postweaning average daily gain, final
body weight, carcass weight, and total system beef production for the systems are
shown in Table 21.1.
Greenhouse Gas Emissions Associated with Beef Production
Steinfeld et al. (2006) authored a report from the United Nations Food and Agriculture
Organization (FAO) indicating that poultry and livestock are responsible for 18% of
the carbon dioxide equivalent GHG emissions, of which 9% are carbon dioxide, 37%
tAble 21.1
comparison of feedlot cattle Performance fed a conventional
high-concentrate diet
a
wo
b
w
c
Starting weight (lb)
475
475
Days on feed
329
303
Postwean daily gain (lb)
2.36
3.06
Feed:gain ratio
7.12
6.22
Final weight (lb)
1,251
1,401
Carcass weight (beef yield)
782
876
Total system beef production (lb)
a
60,214
67,452
a
Data calculated by Avery and Avery, 2007.
b
Conventional high-concentrate diet without (WO) synthetic growth promoting hormones and
methane generation supressants.
c
Conventional high-concentrate diet with (W) synthetic growth promoting hormones and meth-
ane generation suppressants.
