BEEF talk

Opinion
Apr 23, 2010

Review this spring´s calving distribution report card

While memories of the calving season are still fresh in your mind (and your calving book is your reference book of choice), now is the time to review this year’s calving distribution. Evaluate how your management is working.

Cowherd reproduction is a serious number in the beef business. It takes a calf to be a cow/calf producer, so what does the calving book tell about reproduction?

The North Dakota Beef Cattle Improvement Association reports annual benchmarks for those who utilize the CHAPS (Cow Herd Appraisal of Herd Performance) program. Data shows that 93.5 percent of the cows exposed to the bull in the last breeding season were pregnant and that 92.9 percent of the cows had a calf. (The difference is miscarriages, abortions, etc.)

This means that more than 7 percent of the cows never produce a live calf. For some producers, the calving season is not over, but the funny feeling that some of those cows don’t look very pregnant should be hitting most beef producers by now.

Typically, the late-calving pasture is opened up as the primary calving group is getting ready for processing. The late-calving cows and those we carried all winter for nothing seem content feasting on spring sun and fresh grass.

What percentage of cows turned out with the bull never calved? This number needs to include cows culled last fall as open cows. If the number is less than 7 percent, pat yourself on the back. If it is greater than 7 percent, a serious review of the general management of the herd is appropriate.

Is the herd nutrition correct? Are the cows getting the proper nutrition when they need it? Is the bullpen bright and chipper or are there a few duds hiding behind the windbreak?

In terms of overall evaluation of the cowherd, these numbers are good comparative figures so you can see how your herd ranks. With very simple math, the numbers are easy to calculate.

Most producers cull the open cows, make managerial adjustments and anticipate a better calf crop next year. These good managerial efforts help keep some positive reproductive pressure on the herd.

Reproduction is a trait considered by many to be lowly heritable. In other words, genetic selection has less impact than environmental effects or general management. It is fairly stable in most herds, pending any detrimental health effects. Given the traditional way to look at reproduction, another method available is to develop a calving distribution table.

The calving distribution table really is quite simple to calculate because you only deal with the number of cows calving and recorded in the calving book. The calving distribution table allows a producer to follow how cows are calving within the calving season and the percentage of calves born within 21 days, 42 days, 63 days or later.

These percentages can be compared with the benchmarks for overall herd evaluation or utilized to follow how individual cows calve within the herd. The calving season officially starts when the third mature cow calves or is calculated from the bull turnout date utilizing a 283-day average gestation length.

The CHAPS benchmark for the percentage of cows calving within the first 21-day period of the calving season is 63.9 percent. The percentage of cows calving within the first 42 days of the calving season is 88.9 percent and within the first 63 days of the calving season, is 95.6 percent.

If a producer doesn’t have the CHAPS program, the calculations are easy to figure directly from the calving book. Simply count up the total number of mature cows (exclude the heifers) that calved during the first, second and third 21-day periods.

It is fairly simple, but a powerful data point for your cowherd. Make some managerial decisions now. Put together some attractive late-calving cows with late calves as sale packages and haul them to town. — Kris Ringwall (Kris Ringwall is a North Dakota State University Extension Beef Specialist, Director of the NDSU Dickinson Research Center and Executive Director of the North Dakota Beef Cattle Improvement Association. He can be contacted at 701/483-2045.)

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