How cold does it get where you're from? I use about 220 here in Oklahoma, where the windchill gets down to 15 but doesn't get too much colder then 30 F. I'd be more concerned about the outter shell. 600D is really not very sturdy and will rip if your horse is prone to playing rough, rubbing up to barbed wire, sharp edges, etc. I generally don't buy anything that's less then 1000D. I got my Saxon (by weatherbeeta) blanket off horse.com for pretty cheap. Maybe $70?