Has there been any research done about environmental affects on birth weights? I have had this group of cows for a while and most years my calves range from 60-85 pounds. This year I have had a 96, 97, and 113 pound calf. They have never had calves anywhere close to these weights. The 96 and 97 pound calves are Rampage sons and the 113 pound calf is a Resouce.