The Mineral Requirements of Farm Animals

The functions of minerals in nutrition are briefly discussed, particularly the omnipresent role of phosphorus with reference to all organic nutrients. Tables of the requirements of animals for calcium and phosphorus, derived by a factorial method of assessing each item in the total requirement, are presented, demonstrating the changing requirements as functional states change. The effect of species, age, sex and function (maintenance, growth, gestation, lactation and egg production) on requirements expressed as proportions of the dry matter consumed are considered. The requirements for other minerals than calcium and phosphorus are assessed in so far as available information will permit. A comparison of mineral requirements with the occurrence of minerals in feeds reveals the likelihood of the occurrence of mineral deficiencies in livestock feeding. When mineral supplements are required, the type of supplement to use, particularly with reference to fluorine hazard, is discussed. The interactions of minerals in the digestive tract and the dangers of excessive concentrations of minerals in rations are pointed out.