I can answer this, being a fellow Canadian!
YTV, first of all, has no licensed rights to the series, so they have to buy contracts off of dub companies, or whoever bought the original contract. In this case, the original Japanese team sold the localization to Cartoon Network, which is planted in the USA. YTV buys episodes from them.
But here's the catch: we only get episodes that Cartoon Network is certain they'll be done with; in other words, CN is the family eating a meal at the table, and YTV is the dog waiting for the scraps. Since CN likes to show re-runs early into a new season of Pokémon (to give the dub team time to air new episodes), we usually have to wait up to three or four months behind the Americans to watch the Anime.
This is how it would work with most cartoons that air on Cartoon Network, Nickelodeon, etc. Except we get Teletoon of course, which is bout half-Canadian content!