Sheep Ectoparasite Control. II. Toxicity to Sheep, and Residues of Diazinon and Lindane

Tissue residues were determined and toxicity symptoms were noted following sprinkling and dipping lambs with 0.06% diazinon emulsion, sprinkling with 1% diazinon emulsion, and dipping with 0.066% lindane suspension. Toxic effects only, including blood cholinesterase levels, were noted following dipping in 0.06, 0.12, and 0.25% diazinon suspension. The only considerable diazinon residues found were 1.45-2.30 ppm in fat I day after dipping in 0.06% diazinon with concurrent 44-47% cholinesterase depression. Small residues were present in blood from these sheep. Most tissues contained no detectable diazinon at 15 or 26 days after lambs were dipped in 0.06% diazinon, but fat contained up to 0.52 ppm at 15 days and 0.31 ppm at 26 days. Sprinkling with diazinon at 0.06% produced no residues in most tissues, with a maximum of 0.23 ppm in fat. The only definite poisoning produced involved a 3-day-old lamb dipped in 0.12% diazinon suspension. Lambs more than 1week old were not poisoned by 0.06% diazinon, nor were lambs more than 1 month old by 0.25%. Residues of 21-51 ppm lindane in fat were present as long as 3 weeks following the 2nd of 2 dippings in 0.066% lindane. Residues were 0.3 ppm or less 2 months after dipping.