The ewe was found bleeding to death in the morning after the attack and had to be put down.
It would have suffered for at least six hours before being found.
Mr Kilby said witnesses heard four shots fired about 1am on Saturday, January 12.
He said a European man driving a white Mazda Familia was seen on Brake Rd in Ngongotaha and at the entrance to The Agrodome wearing camouflage at the time of the attacks.
"It's sickening to think someone would come on site and do this and get away with it. Someone will know who it was."
Mr Kilby estimated the value of the dead sheep at $3500, but to staff they were priceless.
"It takes a good three to four weeks to train them up for the stage.
"The really sad part about it was the Lincoln ram was a pet gifted to us by a local family who had raised it from a lamb.
"They will be devastated."
Mr Kilby said police believed the weapon used was a high-powered .22 rifle with the attack taking place "within spitting distance" of a state highway.
"Everyone here is gutted.
"Those animals are part of our Agrodome family, they are part of our team."
Mr Kilby said he would love for someone to come forward with information so the offender could be prosecuted.
"There'll be someone who has arrived home with some fresh meat that doesn't come in a plastic wrap. Anyway, that meat would not make for great eating."
He said show rams were very hard to replace as they had to be "the best of breed" and usually came from the South Island.
Mr Kilby urged anyone with information about the attack to anonymously contact Rotorua police or the Agrodome.
In January of 2011, two of the Agrodome's deer were also shot and killed.
Someone had cut through a farm fence and slit the neck of 7-year-old hind Pepsi. They butchered the animal, leaving entrails on the ground and taking the meat with them.
At the same time, the Agrodome's top breeding stag, Branson, was shot between the eyes and his head mounted on top of a tree stump.
