I've sung this song for many years and only heard the verse about shooting at or with the dog recently. I agree with Kendall though, the guy is relating the good times and shooting the dog seems wrong in the story. Here are the verses I've been singing.

Jock Stewart

Oh My name is Jock Stewart, I'm a Canny Gaun man,
And a roving young fellow I've been.

    So be easy and free when you're drinking with me
    I'm a man you don't meet every day.

And at sup have I sat with both bottle and friend,
'Tis a rare man who dare ask for more.

Let us spend well the hours and the vintage of life,
And we'll share them as well as we may.

So come fill up your glass with whiskey or wine,
And whatever the price I will pay.