The objective of this study was to quantify
the environmental and economic impact of withdrawing
growth-enhancing technologies (GET) from
the U.S. beef production system. A deterministic model
based on the metabolism and nutrient requirements of
the beef population was used to quantify resource inputs
and waste outputs per 454 × 106 kg of beef. Two production
systems were compared: one using GET (steroid
implants, in-feed ionophores, in-feed hormones,
and beta-adrenergic agonists) where approved by FDA
at current adoption rates and the other without GET use.
Both systems were modeled using characteristic management
practices, population dynamics, and production
data from U.S. beef systems. The economic impact and
global trade and carbon implications of GET withdrawal
were calculated based on feed savings. Withdrawing
GET from U.S. beef production reduced productivity
(growth rate and slaughter weight) and increased the
population size required to produce 454 × 106 kg beef
by 385 × 103 animals. Feedstuff and land use were
increased by 2,830 × 103 t and 265 × 103 ha, respectively,
by GET withdrawal, with 20,139 × 106 more
liters of water being required to maintain beef production.
Manure output increased by 1,799 × 103 t as a
result of GET withdrawal, with an increase in carbon
emissions of 714,515 t/454 × 106 kg beef. The projected
increased costs of U.S. beef produced without GET
resulted in the effective implementation of an 8.2% tax
on beef production, leading to reduced global trade and
competitiveness. To compensate for the increase in U.S.
beef prices and maintain beef supply, it would be necessary
to increase beef production in other global regions,
with a projected increase in carbon emissions from
deforestation, particularly in Brazil. Withdrawing GET
from U.S. beef production would reduce both the economic
and environmental sustainability of the industry