Assume this is a new calf?
Your info is very sketchy - but I am assuming he is "knuckling over" on his front legs?
If so, he is just all tight from being bunched up inside the cow. It will straighten itself out over time. You can brace him up with splints - but I have never done this. Give it about a week to 10 days and you will likely see improvement.
More and better info will get you a better answer.
Bez