Agriculture Reference
In-Depth Information
sands of years. The popularity of bison meat has led to private herds totaling about
200,000 animals in North America.
Camels and llamas are known as
camelids
, The Old World camelids include the
two-humped Bactrian camel (found principally in the cool desert regions of central
Asia) and the one-humped dromedary camel (found in hot deserts of North Africa
and western Asia). Both are used for transport, draft, meat, milk, fiber, and hides.
Llamas, prevalent in high altitudes of Latin America, are used predominantly
for fiber.
Ratites
Ostriches and emus are large, flightless birds that have been domesticated for pro-
duction of meat, leather, and plumes. They are able to digest high-fiber feeds to
meet about one half of their maintenance energy requirements. Commercial ostrich
breeding began in the United States in the 1980s; emu breeding began a decade later.
Meat from these birds is marketed largely to restaurants.
veRtIcAl IntegRAtIon of AnImAl PRoductIon systems
The impact of vertical integration of animal agriculture on environmental sustain-
ability and on the capacity for increased food production is often viewed negatively.
Recent research and analysis has shown that well-planned and well-managed pro-
duction systems improve rather than harm the environment and increase crop and
animal source food production efficiency.
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Quantitative measurement of greenhouse gas (GHG) emissions by food animals is impor-
tant for addressing their effects on global climate change (see Chapter 16). Information
on dairy cattle and beef cattle is used here to illustrate the role of milk and meat produc-
tion in contributing to GHG emissions. Mathematical modeling of the whole animal
production system has been used to understand and manage GHG emissions.
dairy cattle
Casey and Holden (2005) used life-cycle assessment in dairy cattle to provide an objec-
tive estimate of GHG emissions and to evaluate emission management systems regard-
ing carbon dioxide equivalents emitted per unit of milk produced. Of the total GHG
emissions, 49% was animal enteric fermentation products, 21% crop fertilizer, 13%
concentrate feed, 11% manure management, and 5% electricity and fuel consumption.
Expressing GHG emission on the basis of the quantity of GHG per unit of milk
produced, it was determined that GHG emissions could be reduced 14 to 18% by
selection for efficient, high-producing cows and an additional 14 to 26% by removal
from the herd of inefficient and nonlactating animals. In dairy systems, about one
half of the total carbon dioxide equivalent is from methane and one third from
nitrous oxide. Use of mitigation systems such as intensive grazing in dairy herds
reduces GHG emissions by 10% (Phetteplace et al., 2001).
