摘要：For more than 50 years, the U.S. beef industry has
fed cattle high-energy, grain-based diets. The trend
toward grain-fed beef began after World War II,
when feedlots began using the post-war oversupply
of grain. Cow-calf producers would raise their cattle
to a weight of approximately 700 pounds and then
sell them to a feedlot, where they would be fed grain
until they reached a market weight of approximately
1000 pounds, a procedure commonly referred to
as “finishing.” Currently in the United States, the
vast majority of beef is grain-fed in feedlots for at
least 90 days.
