Results with a loose grain bait that had undergone an accelerated
aging test (30 days, 500 C) are given in Table 9. These data are
similar to results in Tables 7 and 8 and suggest that the aging proc-
ess does not chemically alter the potency of diphacinone but that
palatability of the bait, particularly to rats, is changed.

Table 9. Toxicity and consumption of 0.005-percent diphacinone grain
 bait with albino rats and mice.


 Bait consumption (g) % Treated Average
Species Sex Mortality Treated Untreated bait consumed %

Rats M 10/10 204 844 19
 18
 F 10/10 154 713 18


Mice M 10/10 46 52 47
 45
 F 9/10 58 73 44


Acute oral toxicity of CAT (DRC-2698; N-(3-chloro-4-methylphenyl)
acetamide) to male albino rats

CAT is being developed as a bird toxicant and a great deal of biolog-
ical data must be generated to meet regulatory agency registration
requirements. One area in which sufficient data are lacking is the
acute oral toxicity of CAT to rats. There are conflicting reports on
this topic in the literature. Two studies report the LD50 to be
greater than 3,000 mg/kg, whereas another reports an LD50 of 376
(243-510) mg/kg with 95-percent confidence limits. Using standard
laboratory techniques and procedures, we found the LD50 to be 760
(673-859) mg/kg. This LD50, with corn oil as the carrier, is biologi-
cally comparable to the LD50 of 376 in which carboxymethyl cellulose
was used as the carrier. No symptoms of intoxication were reported in
those studies where dosages of 3,000 mg/kg or greater were used, but
toxic symptoms (prostration, labored breathing) were observed in each
of the two studies that resulted in a calculated LD50. Factors such
as genetic strain, sex, body weight, fasting period, and vehicle used
for dosing were compared among the four studies. There appears to be
no plausible explanation to account for this extreme variation in the
reported toxicity of CAT to rats.