Who Let The Bulls Out?

It's critical to have calves born early in the calving season.

Published on: May 1, 2012

With spring calves hitting the ground around the state, Kentucky cattle producers should begin to plan now for the breeding season to follow. Most young, healthy cows come back into heat within a few weeks after calving.

"There is more to a successful breeding season than just turning the bulls out," said Roy Burris, University of Kentucky College of Agriculture beef specialist stationed at the Research and Education Center in Princeton.  "Because of high feed prices, producers cannot afford to "carry" open cows in our herds, and historically high feeder-calf prices make it critical that we wean a calf from almost every cow that we own.  We need to manage our cows and bulls so that high pregnancy rates can be achieved.  Right now is the most important month in a spring-calving cow's productive year."

Who Let The Bulls Out?
Who Let The Bulls Out?

Burris said it's critical to have calves born early in the calving season so they are re-bred before hot weather and because older calves are heavier.  To do that, he emphasized that cows and bulls must be in tip-top shape at the start of the breeding season and not need to regain body condition. 

"Don't let cows lose body condition after calving," he said.  "Start supplemental energy and protein feeding after this year's calves are born and continue feeding until pastures are adequate to maintain them while they are in peak lactation."

Since cows can't consume enough dry matter from watery, immature forages to maintain good body condition, producers should keep feeding them until the grass is adequate and feed a high magnesium mineral.

About a month before planning to turn out bulls or beginning artificial insemination, producers should make sure cows are on a non-endophyte infected pasture, if possible. 

"If not, then you have to start the breeding season with cows in good body condition so that conception will occur early in the breeding season before heat stress occurs," Burris said. "Don't forget that clover can also dilute out the effects of the fescue endophyte."

It's also a good time for producers to have a veterinarian complete a breeding soundness evaluation on all bulls they plan to use and, perhaps, a spare. 

"This is no time to come up short on bull power," Burris added.  "Last year's soundness evaluations on your bulls don't count either.  Recent evaluations are your best form of insurance.  And don't forget to do your pre-breeding vaccination at least three weeks prior to the start of breeding – AI or natural.  It is tempting to try to do everything in one trip through the chute but don't do it especially with AI."

Watch bulls closely during the breeding or "clean-up" period.  Be sure that they remain sound, and are servicing and "settling" the cows.  Record observed breeding dates and watch those cows for return to estrus.  If this occurs, remove the bull and replace him.  Producers with more than one breeding group might consider rotating the bulls at least once during the breeding season.