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Prepare to Breed Heifers

April 30, 2018

Spring snow storms have brought mud back to much of the Dakota’s and Minnesota, leaving cattle producers waiting for warm weather, green grass and ideal planting conditions. Of course this is not the spring we were hoping for, but make the most of your time waiting to jump in the tractor and planter by making sure your replacement heifers are ready for breeding and take the right steps to get heifers bred in a timely manner this spring.

When to Breed Heifers
Whether you are raising or buying replacement heifers, the goal is to start breeding heifers near 12 – 14 months of age. By this time, heifers should have reached or be close to reaching puberty. Heifers must be pubertal in order to become bred. Begin monitoring your heifers for signs of puberty by observing them mounting each other, or missing hair or hair swept backwards on the tail head are also good signs they have begun cycling and reached puberty. Research shows the more estrous cycles heifers have prior to breeding, the more fertile they will be when the breeding season begins.

Breed Heifers Before Cows
Breeding heifers 2 – 4 weeks prior to cows can help dedicate more time and labor resources to them during the breeding season and the subsequent calving season. Whether using natural service or artificial insemination, take time to monitor both heifers and bulls to make sure heifers are being serviced when they are showing estrus and the bull is successful in servicing them. If heifers are not showing estrus, nutrition and body condition should be accessed. On the other hand, if bulls are not able to cover heifers in heat, maybe adding another bull or replacing the current bull with a more aggressive breeder are options. Another benefit to breeding heifers before cows, is it will give them a longer postpartum interval (period of time between calving and breeding) as a 2-year old. Allowing first calf heifers more time to resume cycling after their first calving will benefit fertility and aid her ability to rebreed early in her second and hopefully subsequent breeding seasons. Heifers continue to grow until they are 3 years old; thus, extra attention to nutrition and reproduction is critical through the first two breeding seasons to their ensuring longevity in the herd.

How Many Heifers to Breed
Annual replacement rates on cow/calf operations in the CHAPS program is 15%. This will vary based on operation, but a rule of thumb is to keep 5 – 10 % more replacement heifers than you need. Why? Not all heifers will breed during the breeding season for multiple reasons including failure to reach puberty, nutrition and environment interactions or loss of pregnancy. Therefore, keeping more heifers than you need allows you to keep only the most fertile heifers that get bred early in the season and maintain the pregnancy, while those heifers that breed later or not at all can be eliminated from the herd.

Another way to determine how many heifers to keep is based on bull power. Recommended bull to heifer ratio during the breeding season will vary based on maturity, and scrotal circumference of bulls, but the minimum recommendation for natural service breeding is 1 yearling bull for every 25 heifers. So if 2 yearling bulls were purchased, best utilization would be to keep at least 50 heifers to breed in order to best utilize your bull power.

Taking time to prepare heifers for breeding by considering when and how many heifers to breed each year is important to cow/calf producers’ bottom line. In addition to selecting heifers and deciding when to turn out the bulls, proper management of heifers prior to and after breeding is critical to breeding season success also. Read Managing Heifers to Improve Longevity to learn more. For assistance developing a heifer breeding plan for your operation, contact Taylor Grussing.

Source: Taylor Grussing, iGrow