The calf, weighing about 400 pounds, was shot with a small-caliber bullet and then slaughtered between noon Saturday and when it was found at about 6:30 p.m. Sunday, according to The Janesville Gazette.
The calf's mother was found bellowing near its offspring.
Ochs Cattle, of Milton, owns the cow and rents the grazing land on which it was found. Company personnel will now be on high alert, and they are beefing up patrols, said Owner Ron Ochs. Ochs and his son, Dan, have owned the business for 15 years.
"Nothing like this has ever happened to us," Ron Ochs said. "It is very distressing."
The calf was bred for showing and valued at about $1,000. It was born in February.
Janesville Police Deputy Chief Dan Davis said Tuesday the calf was shot in the chest and the throat was slit. He said he's no butcher but has cut up deer and it appeared the thief concentrated on better cuts like tenderloin and passed over parts that could be made into hamburger.
He said they are still investigating the unusual case.
"This is kind of a new one for us," he said.
Ochs Cattle owns about 250 beef cattle that graze all over southern Wisconsin.