Abstract
Comparative studies were made on blood coagulation in clinically healthycattle and cattle affected with experimentally-induced bracken poisoning by recordingthrombelastograph (TEG). It took 3 hours to record a TEG in normal cattle. The normalrange (mean +s.d.) of the thrombelastogram obtained from a group of 11 healthy cattlewas as follows. r: 15.4+2.2, K: 4.9+l.1, rfK: 20.3+2.7, ma: 80.5+2.4 and me: 420.O+65.0. The TEG of three calves fed bracken exhibited a prolongation or r, K and r-[Kvalue and a reduction of ma value in the initial stage. In addition to these findings, themshowed an extraordinary pattern in which post-maximal thrombus relaxation was nearlydiminished, in the hemorrhagic and the serious stage. This pattern can be explained bythree conditions, thrombocytopenia, an increase of fibrinogen and an increase of heparinlike substance in blood level, occurring in bracken poisoning.
