By Aerica Bjurstrom
Calving season will soon be in full swing in many Wisconsin beef herds, and with that comes a list of challenges to manage. One challenge you can head off at the pass is managing your first-calf heifers. First-calf heifers require special management strategies to help them wean a bigger calf, breed back sooner and improve her chances of staying in your herd longer.
While calving can often be a major stressor on your heifers, more subtle stress may take its toll on them. Two year olds calve in at approximately 85% of their mature weight. Her entire first lactation requires her to continue growing, go through the stress of calving, produce milk, and raise a calf all while being at the bottom of the pecking order in the herd. Monitoring body condition score in first-calf heifers is critical to their success. Ideally you would like to keep your heifers at a BCS of 5-6. Animals with excess body condition (>7) have lower reproductive performance. Here are some strategies to keeping first-calf heifers in ideal condition:
•Graze first-calf heifers and mature cows separately. Graze first-calf heifers either with three year-olds or virgin replacement heifers.
•Always give heifers the best quality pasture available.
•Supplement first-calf heifers with grains (energy) like corn, corn silage, or barley before they lose body condition.
•Wean calves off heifers at 5 - 6 months of age.
•If heifers are thin at calving, calves may need to be weaned extra early.
•Keep a high quality complete mineral available for first-calf heifers.
•Use strategic deworming programs for young cows.
•Control external parasites.
While you can typically expect your heifers to begin cycling after calving, BCS is the most important factor as to when she will begin cycling. Body condition score is generally a reflection of nutritional management. However, disease and parasites can contribute to lower body condition scores even if apparent nutrient requirements are met. Managing a strong herd health program is a key part to a successful reproduction plan.
The late gestation and early lactation period of a two-year old heifer greatly impacts her reproduction for years to come. Thin heifers don't breed back quickly, if at all. If she rebreeds late, it will take several lactations to get her back on track with the rest of the herd. The plane of nutrition during the last 50 to 60 days before calving has a significant effect on calving interval. In addition, feeding a balanced diet during late gestation will decrease calving difficulty. Heifers that experience significant calving difficulty often take longer to begin cycling. Heifers fed diets deficient in energy or protein the last trimester experience higher instances of calving difficulty, breed back later in the breeding season, have increased calf sickness, death and wean smaller calves.
An additional management strategy that may give your heifers a better start is to calve them in 3-4 weeks before your cows calve. This practice can be implemented for the 2016 breeding season. The special time devoted to only heifers will allow you to focus on potential calving issues and recruit extra help at that time if needed. If you choose to manage heifers separately, it is important to remember calving in early means pasture will likely not be available when needed, so additional nutrients will need to be supplemented. Also, nutrient requirements are higher for first-calf heifers than mature cows. Breeding heifers early will not be an effective strategy unless nutrition is managed properly.
Careful management of first-calf heifers will benefit you in the long-run. Closely monitoring BCS and supplementing nutrition will help your heifers raise healthy calves and breed back to stay in your herd for years to come.Bjurstrom is the Kewaunee County Extension agriculture agent.