5'0 here...palpating (dairy in particular) is ridiculously difficult for me. My arm is literally not long enough in some cases to feel stuff, plus it's tough with small hands to try and maneuver a big slippery uterus. (People say you can bring a stool with you but I'd like to see them use a stool in any scenario other than a full body chute...the hind end has a good range of motion even when tied, and we also had to palpate in free stalls.) Beef is not so bad because they're smaller height-wise and the fetus just about bites you when you put your hand in there but dairy is tough. That being said, I'm sure people make it work.
Restraining large dogs can be tough too, but usually you have enough people to lend a hand in those scenarios. Horses is all about attitude for handling, not size.