Transition cow nutrition for grazing herds: Practical priorities for health and performance

Abstract

The transition period, encompassing the 3 wk before and 3 wk after calving, represents the most metabolically and immunologically demanding phase of the dairy cow's lactation cycle. Despite lower milk yield targets, grazing cows experience homeorhetic adaptations and immune perturbations comparable in magnitude to those of high-yielding, TMR-fed cows. However, pasture-based systems impose distinct management constraints that necessitate a pragmatic, rather than precision-focused, approach to nutritional management. This review synthesizes recent evidence on transition physiology in grazing systems and examines strategies that account for inherent pasture variability while maximizing on-farm achievability. The evidence demonstrates that optimal BCS at calving, controlled prepartum energy restriction to 80% to 100% of requirements, and focused mineral supplementation, particularly magnesium and calcium, remain the most cost-effective determinants of transition success. Secondary strategies, including targeted fatty acid supplementation, may provide additional benefits but should complement, not replace, foundational management. Emerging precision technologies offer promise for identifying individual cows at risk before clinical disease manifests, yet their utility in grazing systems depends on integration with variable pasture quality and realistic labor constraints. This review emphasizes that pragmatic, fundamentals-first management, aligned with seasonal pasture dynamics and farm-specific constraints, offers the most reliable pathway to improved transition outcomes, reduced metabolic disease, and sustainable dairy production in grazing systems.