New techniques to measure blood cholinesterase activity in domesticated animals.

A macromethod and a semimicromethod were developed to measure erythrocyte acetylcholinesterase activity in cattle, sheep, goats, horses, dogs, and swine, and to measure plasma cholinesterase activity in horses, dogs, and swine. Comparison of the 2 methods with erythrocytes of sheep, cattle, goats, and horses indicated both methods gave similar results. They can be done in a shorter time and are more sensitive than Michel's method. Normal deltapH values per minutes, with standard deviations for blood cholinesterase activity of animals of different ages, sexes, breeds, and species, were: 0.76 +/- 0.12/30; 0.65 +/- 0.10/15; 0.69 +/- 0.19/45; 0.78 +/- 0.11/45; 0.63 +/- 0.11/45; and 0.71 +/- 0.06/25 for sheep, cattle, goats, horses, dogs, and swine erythrocyte acetylcholinesterase, respectively; and 0.66 +/- 0.18/20; 0.67 +/- 0.20/30, and 0.46 +/- 0.05/60 for horses, dogs, and swine plasma cholinesterase, respectively. It was shown that either the chloride or the iodide salt of acetylcholine can be used as the enzyme substrate. tin blood samples stored at 5 C for 24 hours, there was no significant change of the enzymatic activity.