Revisiting Negative Dietary Cation-Anion Difference Balancing for Prepartum Cows and its Impact on Hypocalcaemia and Performance

Much attention has been paid to dairy cattle nutrient requirements for maintenance and production for the major nutrient classes: protein, carbohydrates, fats, vitamins and minerals. Requirements are usually established in feeding trials using graded levels of nutrients and defining optimal performance or blood concentrations. These incorporate a factorial approach utilizing the knowledge of nutrient costs for maintenance and production, or by simulating the animal itself as a computer model. Ruminant nutritionists have been devoting much effort to subdividing the major nutrients into more specific subclasses with the goal of defining requirements more precisely to allow for better ration formulation from chemical composition of feedstuffs.