The spontaneous behaviour and the apparent digestibility of dry matter and
fibre and transit times of digests were compared in four normal horses and
four crib-biters. A technique was developed for measuring total gut transit
times (TGTT) by using single-stool analysis of the passage of radio-opaque
polyethylene markers. Longer TGTT were recorded in the crib-biters than in
the normal horses but the orocaecal transit times did not differ. The crib
-biters rested less than the normal horses.