I have a red heeler that is a hell of a squirrel dog.. All I had to do is knock a couple out to him and that was that.. He used to coon hunt with us all the time too.. Just had him and a bluetick.. Great kill dog.. He is getting a little too old for the coon hunting now..
He is the smartest dog I have ever met.. He is fine in the back of the truck until you stick your hand in my window.. Ask the gas attendants.. Never had a problem with people unless he felt I was being threatened.. He bites my boyfriend on command too

Don't know about the cow aspect of him though.. He was raised with the hounds and probably thinks he is one. Never had him around cows.....
Would I get for the purpose of hunting.. Probably not.. Would I own another one.. Yep.. People aren't brave enough to come into my kennels with a heeler on patrol

And I would probably squirrel hunt with it if it wanted to...