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Published November 25, 2013, 10:56 AM

Fall pregnancy exams tell the story

A North Dakota research center brings in its herd.

By: Kris Ringwall, NDSU Extension Service

Recently, one set of 72 beef cows came off the pasture and was brought home to the Dickinson (N.D.) Research Extension Center ranch headquarters. The cows’ trip through the chute was fast. Their average weight was 1,482 pounds, with a condition score of 5.3.

Of those that were pregnant, 55 are projected to calve in the first 21 days of the calving season, starting on May 10, 2014. The remaining 10 pregnant cows are projected to calve in the second 21-day calving period. Of those cows that are pregnant, 85 percent are projected to calve in the first 21 days of the calving season.

Is that a good number? Well, the CHAPS benchmark average is a little more than 63 percent for those herds that are enrolled in the North Dakota Beef Cattle Improvement Association. There always are good and not so good breeding seasons. But, since the center has been breeding in August for May calving, the breeding seasons have been good. Some would say, “Knock on wood,” while others would say, “I told you so.” However, the fact is that the cows are breeding well in late summer.

Not all is perfect because seven of the cows were open. If the cows are going to breed, it seems like they breed quickly and those that don’t breed quickly simply don’t breed. In reality, the number of opens is greater than one would want, but it is indicative of a major problem.

The cows were exposed to the bulls for approximately 45 days (Aug. 1 to mid-September). The open rate was 9.7 percent, while the CHAPS benchmark would suggest a 6.5 percent rate is more typical. Given the disappointment that the open rate was a little high, one cannot help but be extremely pleased with the first-cycle conception rates. As was experienced last year, those 72 cows that the center is breeding in August have good first-cycle conception rates.

Cattle reproduction is not simple, but there are several ways to measure or identify a positive or negative influence on herd production. Keep in mind that the number of cows calving in the first 21 days of the calving season only evaluates those cows that calved or are pregnancy checked in the fall as pregnant.

The CHAPS benchmarks have been presented yearly as composite five-year rolling values and provide the industry with some typical values to evaluate individual producer operations. The CHAPS benchmarks for the number of calves born within the first 21 days of the calving season is 63.4 percent. In looking back to last year, 89.2 percent of the cows at the center calved within the first 21 days of the May through June calving season.

The bulls were turned out on Aug. 1, 2012, and the start of the calving season was set at May 10, which was 283 days following bull turnout. May 31 was considered the end of the first 21 days of the calving season.

The center certainly was anxious to see if the excellent early conception rate would repeat. Now that the cows are home and pregnancy checked, once again the cows have bred in a timely fashion. The conversion of the center’s cows to the May calving program was accomplished by maintaining the current cows while culling open or late cows.

Maybe there are some cows that do not breed well in August, which may account for the increase in the number of open cows this year. But, that probably will remain an unanswered question until the center has more data. In reality, those cows that do not breed well are self-eliminated in any beef cattle system, and the same would be true for those breeding in August.

Even though the numbers are limited to the center’s data, it still is remarkable that breeding cows in August and early September, followed by calving in May and early June, is doable. The fact that the cows bred quickly is the point. That is a plus and certainly worth discussing.

Again, for those cows having conceived within 21 days of bull turnout, there is at least a 22 percent advantage for the cows that will calve or are projected to calve based on this fall’s ultrasound pregnancy exam, compared with the long-term CHAPS benchmarks.

If this trend continues, it would be a very positive effect of later calving.

That trait alone should keep beef producers pondering if later calving would fit into their operation.

Good reproduction does not offset the weight gain of a calf born 60 days earlier. Mid-March and April-born calves are heavier because of their age. More pounds means more dollars. There also are other questions such as bull fertility during late-summer high temperatures. But, at least for a couple of years, the cows are coming home pregnant and then calving well.

But, the challenge remains, which is managing lighter-weight, weaned calves with enough gain through backgrounding to achieve sufficient operational dollars.

Editor’s note: Ringwall is a North Dakota State University Extension Service livestock specialist and the Dickinson Research Extension Center director.

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