===BSE SRMs===In both the United States (U.S.) and Canada, considered as controlled Risk countries, SRMs are defined as: skull, brain, trigeminal ganglia (nerves attached to brain and close to the skull exterior), eyes, spinal cord, distal ileum (a part of the small intestine), and the dorsal root ganglia (nerves attached to the spinal cord and close to the vertebral column) of cattle aged 30 months or older.