According to a brief review of the literature, glyphosate (Roundup) does not bioaccumulate. In other words, animals eat plants contaminated with it and excrete almost all of it. Very little is retained in their bodies. Most toxins bioaccumulate in fat. As venison is very lean, and we discard nearly all the fat it does have, there is little chance that we are being dosed with glyphosate by eating venison. You have a much greater worry about using it directly or eating a lot of GMO foods.