I don't know if it's even possible as the mobile network doesn't cover every back paddock. The tracking collars on market now operate on uhf between the collar and a handset. So it may be technically impossible.
Still, people are fanatical in these types of specific pet and working animal markets. I just looked up a new Garmin pigdog tracking collar set, 1 handpiece,5 collars - $2575. And they are just a real tough GPS locator with no other bells n whistles.
MWR Price at posting:
$3.33 Sentiment: None Disclosure: Held