The expensive input costs of feed, fertilizer and fuel have some cow-calf operators with smaller herds examining the possibility of becoming more efficient by moving to a shorter, more confined breeding season.

When all the cows are bred at the same time and are calving together, their nutritional needs are similar, said Glenn Selk, Oklahoma Cooperative Extension Service livestock reproduction specialist.

“Herds with long or year-round breeding seasons have cows in different production stages consuming the same diet,” he said. “Consequently, part of the cows are being underfed, or overfed, or both.”

A natural calving concentration already exists in most herds that are managed on a year-round calving season.

“Nutrition is the major factor responsible for cows cycling and conceiving,” Selk said. “Since pastures are usually at their peak of quality in spring and early summer, a natural concentration of calving may occur in late winter and spring.”

Moving to a spring-calving season may be easiest; however, some producers may benefit by converting the year-round system to a fall-calving program.

“It’s important to recognize that no system of switching to a controlled breeding program will completely eliminate the delay of some cows from their current calving schedule,” Selk said. “In many situations, downsizing the herd to the specific cows that more closely fit the future calving schedule may be beneficial.”

In any case, lighter stocking rates will be necessary if fertilizer applications are reduced in response to expensive fertilizer prices.

Selk recommends the following system for converting from a year-round to a 90-day controlled calving season, performed over a three-year period so as to promote less cattle being culled as opposed to a one-year conversion rate.

First, build a good, strong bull pen or well-fenced bull pasture. An electric fence in addition to a regular fence may be needed.

“Second, remove your bull or bulls from the herd,” Selk said. “Select the removal date to coincide with the latest date you want calves to be born. Look up the appropriate dates in a gestation table.”

Third, 60 days after removing the bull(s) from the herd, conduct a pregnancy check on all cows and cull non-pregnant dry breeding-age females that have been running with the bull. This includes all non-pregnant cows with calves age five months or older.

Fourth, put the bull(s) back with the herd during the first year so that the calving season will be six months in duration.

“Steps five and six are to start breeding replacement heifers 20 to 30 days ahead of the final long-range planned breeding date for the herd,” Selk said. “The second year, follow the same system as outlined but start breeding so that the calving season will be 4.5 months long.”

Finally, follow the same system during the third year except start breeding so that the calving season will be 75 to 90 days in duration.