The second most expensive nutrient in a cow herd nutrition program after forage is protein. Adding to its importance is the fact protein is the most likely major nutrient to be purchased off the farm. Protein is required not only in growing animals, but also for cows in all stages of production.
Protein plays a major role during lactation to affect quantity and quality of milk produced.
Protein is also important for its role in enhancing appetite, which alters the level of forage intake and therefore, the level of energy that an animal consumes. Research has shown that low protein consumption the last 60 days of pregnancy is associated with the weak calf syndrome which is a perennial problem in all parts of the country. Because of its importance, producers need to consider protein in the initial formulation of cow diets. By dividing the year into four production periods illustrating the differences in protein requirements between the periods, producers can more readily recognize those times of the year when protein supplementation is critical and other times when forages should provide the necessary levels. Figure 1 is an example of the protein needs of a 1,100 pound cow that gives 15 pounds of milk daily when lactating.