THE EFFECT OF LONG-TERM EXPOSURE TO ANTHIO ON SERUM ESTERASES AND RUMINAL MICROORGANISMS OF MALE CALVES

The effect of long-term exposure to the organophosphate insecticide An thio on serum esterases and ruminal microorganisms of male calves was investigated. The daily oral administration of 3, 6 or 12 mg Anthio/kg /d for 90 d caused significant inhibition of serum cholinesterase (10- 28%) and carboxylesterase (12-33%) in male calves. Toxic signs charact eristic of anticholinesterase poisoning were observed during 25-70 d o f exposure to 6 and 12 mg Anthio/kg. The dose of 12 mg Anthio/kg was l ethal to 1/5 calves. Total protozoal population was decreased signific antly (15-27%) following 6 and 12 mg Anthio/kg, whereas reduction in t otal bacterial population (18%) was only significant at 12 mg Anthio/k g.