Estimating Farm Animals' Feed
Efficiency By David Elstein
December 24, 2002
Service scientists have discovered new formulas to determine the amount of
feed required to maintain life--called basal metabolism--in farm animals. In
recently published articles in the Journal of Animal Science, the
researchers argue that in ewes, factors other than weight, such as age, breed
and nutritional history, need to be taken into consideration when predicting
basal metabolism. The discovery should lead to more efficient use of feed and
may save producers money.
Livestock use the feed they receive to support their basal
metabolism, to maintain their current weight and to grow. Changes in any of
these can change how efficiently feed is used for production. Metabolic rates
decrease as animals grow older.
Efficiency of feed use is important because feed accounts for
about 60 percent of the total production cost of cattle and sheep. ARS animal
scientist Harvey C. Freetly, along with agricultural engineers John A. Nienaber
and Tami M. Brown-Brandl, are conducting studies to help farmers develop
low-cost feeding strategies, focusing on how much feed is actually needed and
how feed is used by animals.
Their research, conducted at ARS
Roman L. Hruska U.S. Meat Animal Research
Center in Clay Center, Neb., shows that the breed of an animal affects how
fast its metabolism decreases as it ages. Since it is not practical to create
separate feed requirements for each breed of sheep, these scientists have
proposed that breed differences in basal metabolism can be accounted for by
describing the maturity of the animal rather than its age. Studies are being
extended to determine if similar relationships occur in cattle.
ARS is the U.S. Department of
Agricultures chief scientific research agency.