Cull cows represent approximately 20 percent of the gross income of any commercial cow operation. Cull beef cows represent 10 percent of the beef that is consumed in the United States. Therefore, ranchers need to make certain cow culling is done properly and profitably. Selling cull cows when they will return the most income to the rancher requires knowledge about cull cow health and body condition. Proper cow culling will reduce the chance a cow carcass is condemned at the packing plant and becomes a money drain for the entire beef industry.

Is she good for another year?

At cow culling time, producers often face some tough decisions. Optimum culling of the herd seems to require a sharp crystal ball that could see into the future. Will she keep enough body condition through the winter to rebreed next year? How old is the cow? Is her mouth sound so she can harvest forage and be nutritionally strong enough to reproduce and raise a big calf? At what age do cows usually start to become less productive?

There is great variability in the longevity of beef cows. Data from large ranches in Florida would indicate cows are consistent in the rebreeding performance through about 8 years of age. A small decline was noted as cows aged from 8 to 10 years of age. However, the most consistent decline in reproductive performance was noted after cows were 10 years of age. A steeper decline in reproductive performance was found as they became 12 years of age. In other words, start to watch for reasons to cull a cow at about age 8. By the time she is 10, look at her very closely and consider culling; as she reaches her 12th year, plan to cull her before she gets health problems or in very poor body condition.

Other reasons to cull cows: eye health “cancer eye” monitor eyes for tumors, feet and leg structure (lameness), bad udders — research has shown cows with one or two dry quarters had calves with severely reduced weaning weights, wild cows and open cows before you feed them through the winter.

Are the replacement heifers ready for the fall breeding season?

Fall-calving herds will be breeding replacement heifers in late November. Now is the time to make certain those heifers are ready for the upcoming breeding season.

Immunize the heifers. Ask your large animal veterinarian about proper immunizations for yearling replacement heifers. Replacement heifers should be immunized for respiratory diseases such as IBR and BVD. Consider giving the heifers a modified live vaccine for longer lasting protection against these viruses. The heifers should receive this vaccination at least one month before the start of the breeding season. This would also be a good time to include other reproductive disease protection that might be recommended by your veterinarian. Examples of other immunizations that should be considered include leptospirosis and campylobacter (sometimes called vibriosis).

If a set of scales is available, weigh the heifers. There is time to make adjustments to the supplementation being fed to the heifers to ensure they meet the target weight at the start of the breeding season. To be certain a high percentage of heifers are cycling at the start of the breeding season, research has concluded they must weigh a minimum of 60 percent of their mature weight. If these heifers will eventually grow into 1,200-pound cows, then they must weigh 720 at the beginning of the estrous synchronization and artificial insemination (or bull turnout if natural breeding is used). Calculate the weight gain needed between now and the start of the breeding season to see if additional energy is required to achieve the desired weight gain.

• Information provided by Glenn Selk, Oklahoma State University emeritus Extension animal scientist.

Stacy Campbell is the

Kansas State Research and

Extension agent for Ellis County.