herd bulls

Making sure herd bulls are in good shape heading into the summer boosts their ability to successfully breed cows. A semen evaluation is going to be important this spring, according to an Iowa State Extension veterinarian.

New life dots the countryside as spring moves ahead, and that means it is time to start preparing for breeding season.

Making sure herd bulls are in good shape heading into the summer boosts their ability to successfully breed cows, said Grant Dewell, Extension beef veterinarian with Iowa State University.

He said a rough winter may have taken its toll on bulls, and most likely has caused some bulls to suffer testicular frostbite.

“I think a semen evaluation is going to be particularly important this spring,” Dewell said. “If bulls couldn’t get out of the cold and wind, you could have some issues. You don’t want to end up with a bunch of open cows.”

Structural issues should also be checked — making sure bulls are not suffering from foot rot or chronic arthritis. Dewell said bulls should also be checked for pinkeye.

He said most vaccinations are done in the fall and must be done at least 60 days ahead of the breeding season.

“We spend a lot of money on these bulls, so we need to take care of them and keep them healthy,” Dewell said.

Bulls need to be in good physical condition, said Denise Schwab, Iowa State University Extension beef specialist based in Vinton, Iowa. She recommends that bulls carry a body condition score of 6 to 6.5 before they are turned out with the cows.

“They are going to lose a lot of weight during breeding season, so they need to be in top condition,” Schwab said. “You don’t want them too big, but if they go in at a 5, they are going to have problems.”

Supplementing bulls with corn while on pasture could help ease the loss in body condition.

Now, Schwab said producers should transition bulls from winter feed to grass.

“You want to start doing this a month or so ahead of breeding season, so they are used to the grass,” she said.

If using multiple bulls, Schwab said producers should give them time to get acclimated to one another and establish any pecking orders before breeding season.

She said a mature bull can handle 25 to 30 cows on his own, while younger bulls will be in the 15 to 20 range. Schwab said rotating unproven bulls could help make sure all cows are bred.

“This protects you in case something goes wrong,” she said. “You don’t want a bunch of open cows because the bull wasn’t effective.”

Jeff DeYoung is livestock editor for Iowa Farmer Today, Missouri Farmer Today and Illinois Farmer Today.