i have 3 cats. my 2 girls go outside on occasion and my male cat stays outside most of the time, only coming in for food. now that spring is here fleas are going to be coming out so what is the best solution on fleas control for cats that are both in door and out door? and my other issue is my male cat is a long haired cat. his fur is balling up in knots. there are too many to brush out. would it be ok if i shaved him? if and when i get the knots out is there anything i can do, other than brushing him to keep his fur from getting knotted up?