To call Ron Salters' two sets of identical twin calves a rarity is an understatement.

The Finley rancher was surprised when one of his cows gave birth to identical twin heifers last month, but when he watched another give birth Thursday to a pair of identical bulls, he could barely believe his eyes.

In all his years as a rancher and cattle breeder, the 55-year-old has never seen a set of bull twins and has seen only one pair of heifer twins.

"For identical twins, it's about a 0.4 percent chance that happens," Salters said.

Both sets of identical twins were sired by the same bull, and this was the first time Salters has used that bull for breeding.

Salters' Rockin' B Ranch has bred only a couple sets of twins throughout his 25 years, but never a set of identical twins, let alone two.

Salters said the problem with twins that are not the same sex is that the female calf is born undeveloped about 92 percent of the time and cannot give birth. They are called "freemartins" because of their lack of reproductive organs.

So when Salters saw his cow getting ready to push another baby out after already giving birth to one bull, he was worried he would have a damaged calf on his hands.

But to the surprise of everyone watching, the cow pushed out a bull and Salters beat the odds for a second time, landing another set of identical twins in just a matter of months.

"That's pushing my luck there," he said. "Having twins born is a rarity. I was shocked."

Salters said the bulls, which don't have names yet, likely will be sold after they are 6 months old.

The heifers, named Sugar and Spice, will be evaluated after they start to mature. He said there's a good chance the heifer twins could stay at the ranch and be used for breeding.

The bulls were born near the end of the breeding season at the ranch. A majority of Salters' calves are born between January and March.

Nobody at the ranch is expecting more identical twins anytime soon. Salters' daughter Crystal Stiles still is amazed she got to witness two sets in her lifetime.

"We don't know how we ended up with them," she said.