Water, minerals and vitamins are nutrients important to growth, but protein and energy have the greatest impact on production. The National Research Council has developed nutrient requirement guidelines for different types of cattle that can be used when developing feed rations. Feed rations containing supplemental energy and protein are often utilized to assure the proper weight gain in replacement females. Before we discuss various rations, we must cover some basic information concerning energy and protein. Forage supplies from grazing pastures or hay supplies usually provide the majority of energy.
Protein is also important for growth, as well as lactation and improved digestion.
Increased protein levels improve forage intake by increasing the digestibility of forages. This increased forage intake also increases the amount of dietary energy. There must be an adequate supply of forage for supplemental protein to be beneficial. NPN is best utilized by cattle with low protein requirements feeding on forages slightly limited in protein. Growing cattle are often supplemented with energy at times when high gains are needed, or when forage supplies are limited.