USDA researchers evaluate prion-free cattle

by Editor
Thursday, January 04, 2007

The United States Department of Agriculture (USDA) announced that initial results of a research project involving prion-free cattle are now available.

The USDA Agricultural Research Service has bred eight Holstein cattle that are free of prions, the folded proteins, which carry bovine spongiform encephalopathy (BSE or mad cow disease). Thus a huge step has been taken towards combating the threat of mad cow disease to human health and rural economies.

ARS scientists evaluated cattle that have been genetically modified so they do not produce prions, and determined that there were no observable adverse effects on the animals' health.

ARS studied eight Holstein males that were developed by Hematech Inc., a pharmaceutical research company. The evaluation revealed no apparent developmental abnormalities in the prion-free cattle.

In particular, cattle lacking the gene that produces prions can help scientists test the resistance to prion propagation, not only in the laboratory, but in live animals as well, said Edward B. Knipling, administrator of ARS.

Researchers monitored the cattle for growth and general health status from birth up to 19 months of age. Mean birth and daily gain were both within the normal range for Holsteins.

General physical examinations, done at monthly intervals by licensed veterinarians found no unusual health problems. Further testing on the cattle will take three years to complete.

Initial results of the research project are available at