Shorthorns had twinning even before any Maine influence. Dad sold twin bulls at the Chicago International in the 50's.
Free martins are supposed to dress out better, so they make great freezer beef.
Beef cows do not always get enough nutrition to breed back on time after twinning.
Cows are smart, but twins can mess with their thinking. Cow can forget about first twin when she has the second; then cowboy has to try to graft twin #1 back on its own dam.