Beef cattle producers can realize significant savings by identifying and culling nonpregnant females prior to winter feeding, says Carl Dahlen, North Dakota State University Extension Service beef cattle specialist.
"Also, by pregnancy checking now, producers can optimize resource utilization by stocking pastures with pregnant cows," he adds.
Although winter feed costs represent 60 to 70 percent of the expense of maintaining a beef cow, less than 20 percent of U.S. beef producers perform a pregnancy check in their herds, according to Dahlen.
Historical cull-cow markets reach a low point in November, which coincides with the time most producers would wean calves and pregnancy check cows. Based on the average cull-cow market price for 2005 to 2012, the price difference between selling in August or November is roughly $8 per hundredweight. That equates to a difference of $108 when selling a 1,350-pound cow.
"Producers who are able to perform pregnancy exams and subsequently cull open cows during the next several months may realize substantial financial benefits, compared with marketing cull cows in November," Dahlen says.
However, not all producers have breeding seasons, facilities and the labor force to do pregnancy exams during the late summer. Herds with defined breeding seasons are best suited to take advantage of early pregnancy exams, Dahlen says.
If bulls are run continuously with a cow herd or are being pulled from the pasture the same day as the pregnancy exam, producers have no way to determine the cows' true pregnancy status. Cows that become pregnant early in the breeding season will be identified easily in these instances, whereas cows that appear to be "open" actually may have been bred recently. These recently bred cows may be carrying an early pregnancy that is too young to feel via rectal palpation or visualize with ultrasound.
To conduct pregnancy exams on large groups of cows accurately and efficiently, the exams should be performed from 26 to 30 days after the last possible breeding if using ultrasound for pregnancy diagnosis. If using rectal palpation, pregnancy exams should be conducted 35 to 40 days after the cows are bred.
For example, herds calving in mid to late January would have a bull turnout or artificial insemination date around April 15. If the producer is using a 45-day breeding season, this herd would be ready to pregnancy check with ultrasound around June 29 and with palpation per rectum on July 9. However, a herd that calves toward the end of April (July turnout) and has an 85-day breeding season will not be ready to pregnancy check until the first or second week in November.