Green’s Dictionary of Slang

1. (US) severe delirium tremens, usu. caused by drink, sometimes by cocaine.

1922		E.H. Williams Opiate Addiction 175: This condition is known in the vernacular as the ‘bull horrors,’ a type of persecutory delusions in which the victim imagines that ‘some one is after him’ .
1934		F. Tuohy Inside Dope 81: A still worse condition is in America called ‘the bull horrors’, [...] that includes persecution mania.
1950		F. Brown Honeymoon in Hell (1958) 38: He was at the stage now where twelve hours without a drink would give him the bull horrors, which are to the D.T.’s as a cyclone is to a zephyr.

2. (US drugs) the aftereffects of excessive cocaine use.

1971

E.E. Landy Underground Dict. (1972) 41: bull horrors. [...] Aftereffects of using cocaine.