As calving season ramps up with breeding season and turnout just around the corner for many cattle producers, cattle nutritional requirements are at their greatest, making this portion of the beef cattle production cycle the most demanding on cattle and critical for producers. Developing a nutritional program that meets the needs of lactation and facilitates a return to cyclicity before the subsequent breeding season takes an understanding of how cattle partition nutrients and how that impacts their overall nutritional requirements.
As the post-calving period transitions into the breeding season, proper nutrition remains paramount to ensure reproductive success. Nutritional deficiencies or imbalances during this time can have significant implications for reproductive performance, including delayed estrus, reduced conception rates and increased calving intervals. During the period from post-calving through breeding, the nutritional demands of cattle increase significantly to support milk production, while also aiding in the recovery from labor. Cattle utilize the nutrients they consume based on specific biological priorities: maintenance, growth, lactation, then reproduction. Due to reproduction being last on the list, it is often the first production-related factor impacted by inadequate nutrition during the calving and rebreeding period. Peak lactation, and consequently peak nutrient requirements of cattle, typically happen between 60 and 80 days post-calving. This can pose a unique challenge, as cattle are expected to recover from having a calf and rebreed approximately 80 days post-calving to maintain a 365-day calving interval. Thus, one of the primary nutritional considerations during this stage is providing sufficient protein and energy to support lactation.
Nutrient requirements of cattle also vary based on the weight and milking potential of the cow. For example, a 1,200-pound cow producing 20 pounds of milk a day requires 2.8 pounds of crude protein (CP) and 16.2 pounds of total digestible nutrients (TDN), while the same cow that produces 30 pounds of milk a day requires 3.5 pounds of CP and 18.7 pounds of TDN. Failure to meet these requirements can limit the cow’s potential for milk production and result in her drawing upon body nutrient stores to make up the deficit. This results in bodyweight and condition loss, which can cause a delay in returning to estrus and rebreeding (i.e., poor first-service conception rates). High-quality forages and supplemental feed may be necessary to meet the increased protein and energy requirements of lactating cattle.
Maintaining an optimal body condition score (BCS) is essential for maximizing the reproductive efficiency of beef cattle. It has been well established that cattle entering calving and breeding at a BCS below 5 (on a 1-to-9 scale) have substantially decreased first-service conception rates, especially for high-producing cattle and 2- to 3-year-olds that still have individual growth requirements. This is because cattle with inadequate body condition at calving or those that have lost condition post-calving take longer to recover from the stress of calving (90 days or more), resulting in lower first-service conception rates, a greater likelihood of open cows, an extended breeding season, an extended calving season the following year and greater variability in calf-weaning rates. Cows with a BCS of 5 to 6 are generally considered to be in ideal condition for rebreeding. Managing nutrition to achieve and maintain this target BCS is crucial and may involve adjustments to feeding strategies based on individual cow needs and forage availability.
Mineral supplementation is also critical post-calving, particularly for minerals such as calcium, phosphorus and magnesium. These minerals play essential roles in milk production, bone health and muscle function. Adequate levels of vitamins and minerals – particularly vitamin E, manganese, selenium and zinc – are also essential for optimal reproductive health. Ensuring access to mineral supplements or providing mineral-enriched feed can help prevent deficiencies and support overall herd health.
Once the breeding season concludes and cattle are turned out to pasture, continued attention to nutrition remains vital to support herd health and productivity. Native range and pasture can generally meet the nutrient requirements of lactating cows in the northern Great Plains and Northwest during the peak of the growing season in late May and early June. However, pasture quality and availability can vary substantially from year to year and throughout the grazing season. For cattle that calved prior to April, peak lactation and nutrient requirements may come before the available forage can provide the nutrition required, necessitating careful management to ensure that cattle receive adequate nutrition.
Additionally, turning out to pasture too early in the growing season can have negative impacts on forage health and production, ultimately resulting in reduced animal performance. Therefore, if grazing pasture in early spring, producers may need to provide high-quality forages or supplements to support the increased requirements of lactation while on pasture. During turnout, it’s essential to continue providing access to mineral supplements to address any deficiencies that may arise from changes in forage composition or environmental factors.
Nutritional management plays a central role in promoting the health, productivity and reproductive success of beef cattle throughout the post-calving, breeding and turnout stages of production. By understanding the specific nutritional requirements of cattle during each phase and implementing effective feeding strategies, producers can optimize herd performance and profitability. Continued monitoring and adaptation to changing conditions are key to ensuring cattle receive the nutrients they need to thrive throughout the production cycle.
