RE: 40 yard shot
2)"If I dont find it ,it is meat for predator"..
I beleive the word is scavenger.
I have been impressed with some of the answers but here are somemore things to concider when shooting. It's true deer will here the bow less the farther away they are from the shot. Other factors can help mask any shot. Early season, September and October the leaves and acorns are falling. Deer don't notice a bow being shot our thier buddy near them get hit with an arrow. Often times they will just go back to feeding.
To answer Swamp Dawg's response, I have shot deer with in ten yards and out at 40 yds and sometimes you don't get a blood trail. It happens. The arrow hits a bone and the deer bleed internally. When this happens you must follow the tracks. This can be very difficult when your hunting in over populated areas. Fresh tracks on fresh tracks, which one was your deer? In West Virgina it was fairly easy we tracked for about 1.5 miles by tracks very little blood was found until the end. If this happens to you, go and get the family dog. They can be a big help when the deer has crawled up tight in the brush.