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Division of Agricultural Sciences and Natural Resources

Nighttime versus daytime feeding influences time of calving

STILLWATER, Oklahoma – Supervision of calving process is best accomplished during daylight hours but Mother Nature and mama cows are not always so inclined, meaning cow-calf operators need to stack the odds in their favor.

“Currently the easiest and most practical method of inhibiting nighttime calving is by feeding cows at night,” said Wes Lee, McClain County Extension director and agricultural educator. “The physiological mechanism is unknown but some hormonal effect may be involved.”

According to research conducted in Iowa, animal scientists used 1,331 cows on 15 farms to study the problem, feeding the cows once daily at either early morning or dusk. Of those fed at dusk, 85 percent of the calves were born between 6 a.m. and 6 p.m. Cows fed in the morning had only a 49 percent chance of giving birth during daylight hours.

“Whether cows were started on the night feeding the week before calving or two to three weeks earlier made no apparent difference in calving time,” said Glenn Selk, Oklahoma State University Cooperative Extension animal scientist and editor of the university’s popular Cow-Calf Corner newsletter.

On many large ranches, it is physically impossible to feed all of the cows after 5 p.m. In those instances, Selk and Lee advise the ranch manager to feed the mature cows earlier in the day, and then feed the first-calf heifers at dusk.

“First-calf heifers are the group of females in greatest need of observation during the calving season,” Lee said.

Anyone interested in learning about other practical cattle management tips should contact the agricultural educator at their OSU Cooperative Extension county office, typically listed under “County Government” in local directories.

The Oklahoma Cooperative Extension Service is one of two state agencies administered by OSU’s Division of Agricultural Sciences and Natural Resources, and a key part of the university’s state and federally mandated teaching, research and Extension land-grant mission.


Donald Stotts
DASNR News and Media Relations
Agricultural Communications Services
132 Agriculture North
Oklahoma State University
Stillwater, OK 74078
Phone: 405-744-4079
Fax: 405-744-5739

Oklahoma State University - Stillwater, OK 74078