National Wildlife Research Center (NWRC)

PROJECT GOAL: To develop and apply chemistry-, biochemistry- and computer-modeling-based techniques and tools for improved management of pest wildlife by Wildlife Services and the wildlife damage management community.

Project Accomplishments 2008

Herbivore Avoidance of Protein Hydrolysates—Reports of casein hydrolysate avoidance in deer prompted NWRC chemists to evaluate how they can capitalize on this behavior to produce effective herbivore repellents from protein hydrolysates to reduce damage caused by a variety of species.  Proteins, such as casein, are excellent sources of nitrogen and essential amino acids.  Furthermore, as a component of mother’s milk, casein is a critical component of mammalian diets early in life.  Hydrolysis, a chemical or enzymatic process to break large proteins into smaller pieces, does not reduce the nutritional quality of proteins; rather, it often makes the proteins easier to digest.  For this reason, casein hydrolysate is found in human infant formulas, diet supplements, and energy drinks.  Yet, initial research with deer demonstrated that the animals avoided casein hydrolysate much more than the intact protein (casein).

NWRC’s subsequent evaluation of several mammalian species to casein hydrolysate and gelatin (a hydrolysate of collagen) demonstrated a connection between the digestive strategy of the species and feeding response to foods treated with protein hydrolysate.  Omnivorous mammals (consumers of plants and vertebrates or invertebrates) were indifferent to foods treated with protein hydrolysates, while strict herbivores (consumers of plants only) avoided foods treated with protein hydrolysates.  NWRC researchers speculate that certain peptides resulting from protein hydrolysis have a particular meaning to herbivores that signal “do not eat,” which may lead to a new type of effective repellent.

Development of a Pest Coyote Toxicant and Delivery Device—Coyotes cause significant damage to American agriculture, primarily through predation on livestock.  Coyotes also attack pets and humans, collide with aircraft, depredate fruits and vegetables, cause damage to irrigation systems, prey on game species, and transmit zoonotic diseases.  Ranchers and predation control specialists use a variety of techniques to minimize losses, including the broad-spectrum mammalian toxicants sodium cyanide and sodium fluoroacetate (Compound 1080)—the only oral toxicants registered for predator control in the United States.  However, since 1998, California, Colorado, and Arizona banned the use of sodium cyanide and fluoroacetate for controlling livestock predators.  As toxicants are a critical component of nearly all integrated pest management strategies, these bans severely restrict the ability of wildlife damage control specialists to limit coyote damage.  NWRC researchers are collaborating with a variety of stakeholders to proactively develop safe and effective predator alternative toxicants.
 
Because the toxicity of chocolate to canids is well documented, NWRC chemists determined the optimal ratio of theobromine and caffeine—which are naturally occurring compounds in chocolate—to create a selective toxicant for canids.  Collaborative studies conducted in California and Utah demonstrated that the Coyote Lure Operative Device (CLOD) can be used to deliver the theobromine:caffeine toxicant under field conditions. The results documented that, following consumption of the CLOD contents, mortality ensued with minimal pre-mortality symptoms.  Molecular genetic analyses of accepted CLODs indicated that nearly all of the CLODs were activated by coyotes. 

Project Homepage
Project Goal and Objectives
Accomplishments
Publications
Wildlife Genetics
Exploratory Chemistry
Formulation Chemistry
Methods Development Chemistry
Radioisotope Laboratory