|DAN GOEHL, DVM, and his wife own Canton Veterinary Clinic in Canton, Mo., working with stocker and cow–calf beef operations. He is also a partner in the management and marketing of beef cattle. E-mail questions and comments to firstname.lastname@example.org.
Replacement heifers represent the future of your cow–calf operation. These females are the genetics behind the next generation of farm offspring. Efficient development is critical, as a replacement heifer is a significant asset that does not generate a return until the first calf is sold.
Beef herd productivity is increased when a large percentage of heifers are bred early in the season.
Heifers have higher rates of calving difficulty compared to mature cows. Yet there are some management tools that can be used to identify and minimize risk factors for dystocia. Lifetime productivity is also an important consideration in planning the female development timeline. Heifers calving at 24 months of age produce an earlier return on investment and potentially have more calves than females who are older at calving.
Goals for a beef replacement heifer program are: increase and maintain a high conception rate early in the breeding season; minimize the dystocia rate; promote a good post-calving conception rate; and increase farm income through efficient lifetime productivity. To achieve these goals, utilize a plan that addresses critical control points in each production phase. From birth to calving, heifer production can be divided into six phases: preweaning, weaning, prebreeding, breeding, mid-gestation and calving.
Start from birth.
Knowledge-based management of replacement heifers begins with good production records initiated with the birth of each animal. Individual identification allows for performance and pedigree tracking of the calf.
Weaning is the time to begin the immunization program and determine a nutritional plan based on animal performance. The goal of weaning vaccinations is to protect animals against common respiratory pathogens and begin building immunity against pregnancy-wasting infectious agents.
Weaning weights are used to determine the nutritional program necessary to meet heifers’ target weight by the intended breeding date. The onset of puberty is heavily influenced by both age and weight. To become pubertal by yearling age (12 to 13 months), heifers must receive adequate nutrition to signal the body to prepare for reproduction.
Target breeding weight can be set at 65% of the expected mature female weight. By subtracting the weaning weight from the target weight and dividing the result by the number of days between weaning and breeding, a goal for the rate of gain can be calculated. Achieving target weights prior to breeding is key to heifers conceiving early in the season.
Sire selection has an important impact on the dystocia rate and performance. Many breeds offer birth weight and calving ease (difficulty) EPDs, and veterinarians can offer a valuable service by helping their clients select a bull appropriate for their operation.
Birth weight and weaning weight are correlated, resulting in a common misconception that producers must choose between dystocia and reasonable weaning weights. Using AI sires allows farm managers to select bulls with the appropriate combination of calving ease and growth performance potential.