My best friend is corrugated cord covers. Maggie has chewed through cords her entire life. Bitter apple, Tabasco and Ropel didn't work for her, and she's even tripped the circuit breakers in the house twice. For her safety, and my own peace of mind, I've resorted to the cord covers. Not exactly a decorating fashion statement, but certainly functional!
This cord has since been replaced, but it shows the cord cover also.

I purchased most of mine from this site:
http://cableorganizer.com/wire-loom/
Recently I've also found it at Walmart, in the home improvement isle: It's made by GE and it's called "CableNeat" 6 foot length, 1/2 inch diameter, black or white for $7.96. I swear by this stuff!