Just had my lab into the vet for a little ear infection and asked her about it in the post treatment discussion. She highly recommends not doing it. Labs in particular aren't built for that type of landing and are prone to joint problems anyway. Also asked her about the rattlesnake shots. She says they do buy you a little time and while she's had no personal experiences her peers who have seemed to think the shots helped in recovery. Still must get the dog to a vet ASAP for actual anti venom.