The area of Ontario is Amherstburg, Ontario - HOWEVER - since Amherstburg is only about 25KM (less than 15 miles) away from Detroit, Michigan, U.S.A., I think "tales" may be mixed up crossing country borders - as happens all the time with urban legends. People from nearby towns "adopt" legends and so forth, so the "dog decapitated" part of the legend may have drifted from the USA and into Canadian regions and campfire tales.
OR.. if there's a crypto-creature wandering around in the wooded areas, the creature is NOT going to give a darn about socially constructed barriers like the lines between countries. Parts of USA and Canada share the same expanses of woods, mountains, lakes, etc... and so a Goatman could easily drift around back and forth between countries.
There is a documented case of a woman whose dog was mutilated (decapitated) from the Bowie area in Prince George's County in Maryland in 1971.
I'd be interested to hear what happened to/with you and what you saw/experienced 30 or so years ago, brosien. You can email me via hubpages and I will have a look at placenames, etc for you, if you like.