Easiest way to knock one out is to get on a cliff and shoot it but be ready to chase it when it runs. (if no birds are available though I wouldn't suggest getting one without a bird) if you have a quetzal or a tapajera then just shoot it from the air then build fences or spike walls around it because it's a big dino and hard to protect especially in the swamp
The only dino that'll agro an unconscious paracer is a Rex. So if those are taken care off and your cautious about not bringing in extra friend with you. You don't have to worry about other creature damaging your tame.