Evaluation of Chemically Treated Cable to Prevent Chewing by Rodents

Period: April to May 2017.
Researchers: Courtney L. Daigle (PI), Peter Tutini and Logan Luskey
Animal Behavior and Welfare Laboratory, Department of Animal Science, Texas A&M

IMPORTANT POINTS:
– Treated cables keep rats away.
– Greater effectiveness was obtained in preventing chewing by male rats compared to female rats.
– Mice can learn to avoid chewing on cables over time.

ANIMALS AND HOUSING:
Adult male (n = 12) and female (n = 12) Sprague-Dawley rats were housed individually in twenty (24) standard laboratory cages (41 x 25 x 19 cm). All rats had access to food and water ad libidum through food hoppers and water bottles attached to the outside of the cages. All mice were provided with nesting paper during periods when samples were not being tested. After testing was completed, clean nesting paper was added to each cage. Mice were exposed to a 12:12 light:dark cycle and room temperature was maintained throughout the study at 22°C.

SAMPLE TESTING PROTOCOL:
A repeated square perimeter was used to evaluate the effectiveness of the product in deterring rats from chewing.
Mice were exposed to a single sample (approximately 2 inches long) for 24 hours without access to nesting material. Cables were classified as “treated” or “untreated”. At the end of the 24-hour testing period, samples were removed, scored (Table 1), and photographed. The mice were then provided with nesting material for a subsequent 24 hour period without access to any samples. At the end of the 24-hour sample-free period, all nesting material was removed, and the next treatment was placed in the cage for an additional 24-hour period. This process was repeated so that each animal experienced each treatment twice in alternating order.

STATISTICAL ANALYSIS:
The impact of treatment, gender and repetition and their interactions on cable chewing scores were evaluated with a General Linear Model (PROC GLM) in SAS v9.4. Differences between main effects were assessed using Least Squares. Significant differences were identified at P <0.05 and trends were identified at P <0.10.

RESULTS:
The interaction between gender and treatment (P = 0.02) and the main effect of treatment (P = 0.0003) influenced cable scores. Treated cables had lower copper chew scores (e.g., were chewed less) compared to untreated cables (Figure 1a). Treated cables had the lowest chewing scores for exposed males, (Figure 1b).
Cable scores in repeat 2 tended (P = 0.07) to be lower than cable scores in repeat 1, suggesting that the product may have long-term efficacy beyond initial exposure. The remaining interactions and the main effect of gender (P = 0.13) did not influence cable scores (P > 0.05).

CONCLUSION:
Treated cables appear to stop rats from chewing on cables. The effectiveness of this product is more pronounced in males as they are less likely to chew on treated cables compared to females. There is the potential that exposure to treated cables could influence the future behavior of the chewing rodent.