While there are slight differences in the absolute priority order between individual animals and breeds, the priority of nutrient requirements are very close to the order listed above for all animals and breeds. The nutrient intake is distributed in the cow's body to fill these nutrient requirements. As each requirement is filled, the available nutrient is shifted to the next lower priority. The reverse shift is also obvious in beef cows. As nutrient requirements exceed intake, nutrients are shifted from the lower priority requirements to be sure that higher priority requirements are filled.
Beef cattle store excess nutrients as body fat.
The fat stores are mobilized when the nutrient demands exceed the available intake. In times of severe nutrient restriction, muscle tissue is mobilized once fat and other nutrient stores have been depleted. Researchers have determined that a certain amount of body fat is required for the reproductive system to function. Cows must calve in body condition scores of five or higher in order to cycle and breed back during the breeding season. The first step in body condition scoring is to review the skeletal structure of the cow.