The old rule of subtracting three months and adding seven days to the current date on the calendar is good to remember when deciding if it’s time to pull herd bulls from breeding pastures.
If we pulled bulls on July 14, we could expect calving to potentially last until April 21. Short breeding seasons equate to short calving seasons. Short calving seasons offer the benefit of a more uniform and accordingly more valuable calf crop at weaning. Short breeding seasons are the goal; however, most breeding seasons fall into a range of 45-90 days. There are several factors to consider when making this management decision.
Bull management and proper care can be accomplished more effectively after bulls are removed from cows. Younger bulls that are still growing will benefit by going back into a dry lot management scenario where it is easier to provide supplemental feed and gain back body condition lost during breeding season. This is the equivalent of recharging a battery to get them on track for the next breeding season. If using multiple bulls in a pasture, it is logical to leave an older bull (or bulls) on the job while pulling out the younger bulls.
When is the date of your latest calf born? Typically, cows need 60-75 days postpartum to be prepared to breed back. Two-year-old cows nursing their first calf are typically the greatest rebreeding challenge.
Pregnancy checking can be done sooner when bulls are pulled earlier. Identifying and culling open cows in a timely fashion saves forage and capitalizes on cull cow value now as opposed to lower values moving later into fall.
What is your plan for open cows at pregnancy check? Cull open cows are at record high prices. That being said, a bred cow has more value than an open cow. Do you have a fall calving herd to roll open cows into?
If a high percentage of cows return to heat after 40 days of breeding, have bulls rechecked for fertility and cows and bulls examined for reproductive diseases by your veterinarian. Change bulls, if necessary, and reevaluate the previous year’s nutrition program. — Mark Z. Johnson, Oklahoma State University Extension beef cattle breeding specialist
