STP693: Efficacy and Safety of Diphacinone as a Predacide

    Savarie, PJ
    Pharmacologist, biological technician, and biological technician, Denver Wildlife Research Center, U.S. Fish and Wildlife Service, Building 16, Federal Center, Denver, Colo

    Hayes, DJ
    Pharmacologist, biological technician, and biological technician, Denver Wildlife Research Center, U.S. Fish and Wildlife Service, Building 16, Federal Center, Denver, Colo

    McBride, RT
    Wildlife biologist, assistant adjunct professor, Sul Ross State University, Alpine, Tex

    Roberts, JD
    Pharmacologist, biological technician, and biological technician, Denver Wildlife Research Center, U.S. Fish and Wildlife Service, Building 16, Federal Center, Denver, Colo

    Pages: 11    Published: Jan 1979


    Abstract

    Research to assess the use of diphacinone as a predacide was divided into three primary phases: (1) acute oral toxicity tests with laboratory (captive) and free-ranging coyotes (Canis latrans); (2) residue analysis in tissues from coyotes killed by diphacinone; and (3) secondary toxicity tests with diphacinone meat baits fed to male albino rats (Rattus norvegicus) and golden eagles (Aquila chrysaetos). The LD50 with 95 percent confidence limits in captive coyotes was 0.6 (0.3 to 1.2) mg/kg. Free-ranging coyotes were captured, treated, and released to determine if efficacy was different from captive animals. Each was equipped with a mortality transmitter and tracked for a minimum of 21 days. The statistical method was not appropriate to calculate an LD50 in free-ranging animals; however, there appeared to be no major differences in toxicity as compared with captive animals. One male free-ranging coyote survived a dose of 2.5 mg/kg and one male captive coyote survived a dose of 1.25 mg/kg. These data indicate high individual variation in the toxic response to diphacinone. Time to death did not differ between the two groups; that is, free- ranging coyotes averaged 9.6 days (range 8 to 16) and captive animals averaged 10.4 days (range 6 to 17). Secondary toxicity tests were conducted with male albino rats fed a meat (muscle tissue) bait for 6 days from captive coyotes killed with diphacinone. The highest diphacinone residue in these baits was 0.5 ppm and four of eight rats that fed upon it died. Hence, there is a secondary hazard to susceptible animals that feed repeatedly on tissue containing at least 0.5-ppm diphacinone. In most animals the small intestine, liver, or kidney contained more than 0.5 ppm, and these tissues have a higher potential for secondary toxicity than muscle. Seven golden eagles were fed sheep meat containing 2.7-ppm diphacinone as the sole source of food in 5- and 10-day feeding tests. All eagles survived, but various degrees of toxicity were noted.

    Keywords:

    vertebrate pest control, predacide, diphacinone, anticoagulant, coyote, golden eagle, rat, primary toxicity, secondary toxicity


    Paper ID: STP35992S

    Committee/Subcommittee: E35.26

    DOI: 10.1520/STP35992S


    CrossRef ASTM International is a member of CrossRef.