Why we need to let Mother Nature select replacement heifers

by in Strategic Planning For The Ranch

For some time, I have been an advocate that we cannot select replacement heifers—we should instead let the bulls and Mother Nature select them for us. To do this, I have promoted retaining and exposing most of your heifer calf crop for a short breeding season—no longer than 30 days.

Naturally you will cull the obvious poor doers, the poor dispositions and those with obvious physical trait problems. However, don’t assume that you can judge the rest very well.

A number of years ago, a group of us measured, scored and visually evaluated as many traits as we could think of that might relate to a heifer’s income-generating capability as a cow. While we did not follow this long enough to draw any definite conclusions, nothing that we measured, by itself or in combination, could predict enough of the economic difference in outcomes to confirm our belief that we could, in fact, select replacement heifers. My observations on many heifers since then have strengthened my conviction that we can’t select heifers accurately. But, the bulls and our environment can!

I now do quite a bit of speaking to cattlemen’s groups of one kind or another. After one of those talks, I was asked if I would consider using genomic testing to make a first selection of heifers and then use the short breeding season. I responded that I would not, at least not in that order. The next question was, “Why not?”

The heifers that you have are what they are; and while you would like them to be as good genetically as possible, those that breed early in their first breeding season have a tremendous competitive advantage over the other heifers in lifetime production—they will breed earlier in subsequent breeding seasons and thus wean a bigger calf and will produce at least one more calf in their lifetime.

All the other genetic traits that you might look for cannot compete economically withearly breeding of yearling heifers. Even though I understand and appreciate the power and value of genomic information, I am still unsure of our ability to balance traits economically and to avoid genetic antagonisms.

After pregnancy checking and finding the pregnant heifers, I might then use genomic testing as part of my culling criteria for those heifers as they progress in age, but only if I have an excess of young pregnant cows. If, for example, I were to have an excess of pregnant heifers after culling the typical culls (opens, dries, bad disposition, raised a poor calf, ugly); I might then use genomics to select the next order of culling from the bred heifers or older cows. My inclination would be to keep the heifers and cull a few more cows.

I also recommend “minimal development” of replacement heifers, which means they are treated similar to stocker cattle between weaning and breeding. This results in a breeding weight that will be closer to 55% of expected mature cow weight than the 65% that is so often recommended.

That is another reason to put the genomic testing behind the pregnancy testing. When changing to minimal development and short exposure of heifers, you should not expect a high pregnancy rate; thus the need to keep a high number of heifers. However, selling the open heifers should be nicely profitable. We should remember that yearling operations are usually more profitable than cow-calf operations.

There might be situations where you cannot develop heifers adequately with a “minimal” approach. If that is the case, it is probable that your cows are not a good fit for your environment. Remember, to your cows, the environment is the natural environment plus whatever you add to it. You may need to move toward “minimal” development and reduce the length of the breeding season a little more slowly.

Selecting new bulls to fit the environment would certainly help speed up the process. The right seedstock supplier along with information on the dam and closely related females of bulls should help you select bulls to sire daughters that will fit your environment.

I have recently become aware of a growing number of commercial producers who are raising some or all of their own bulls to reduce bull cost and improve genetic adaptation to their environment. They tend to buy semen or a few excellent bulls to infuse new genetics. Some even insist that no bull can be kept from a cow that has calved later than the first 25-30 days of the calving season, ever. In other words, a bull born to a two-year-old will not be used if his dam does not calve very early as a three-year-old. Genomic information may then be used to help in the final selection of these bulls.

Heifer selection is the starting point for future cow herds. Ideally, heifers will get pregnant in the first 21 days of the breeding season. That’s why I like a very short breeding season. Ideally, bulls that are intended to produce replacement heifers should be born to cows that always calve in the first 21 days of the calving season. From there, you make other selection choices and use the tools and technology that are appropriate for your goals.

Remember, the production goal of having high pregnancy rates early in the breeding season year after year starts with heifers that breed and calve early in their first year. This approach begs the question, “Why are you willing to accept a lower conception rate on yearling heifers to find those that will breed early?” The answer is: the open heifers are growing and will gain more pounds per acre than cow-calf pairs and will usually generate more profit per acre than the cow-calf pairs. You then have a life-time bonus in cows that will tend to calve earlier and wean bigger calves.

Burke Teichert, a consultant on strategic planning for ranches, retired in 2010 as vice president and general manager of AgReserves, Inc. He resides in Orem, Utah. Contact him at burketei@comcast.net.

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