Mineral nutrition (macro-elements) : recent progress in goats

Abstract

The P maintenance requirement must be considered as the irreducible part of endogenous losses which is highly related to the no re-absorbed salivary P. The P maintenance requirement is related to dry matter intake. The requirements for growth are slightly lower than for calves but markedly higher than for lambs, this must be taken into account for a re-assessment of growing requirement in kids. Calcium and phosphorus requirements for pregnancy mainly result from the number of foetuses and must be take into account during the six last weeks of pregnancy. Calcium and phosphorus content of goat milk (1.3 g Ca/L, and 0.95 g P/L, respectively) are very close to those of cow milk. True absorption coefficient (TAC) of P is higher for goats than for other ruminant species; the value of 70 % is adopted for calculations. In the goat, the TAC of Ca is markedly depressed by high level of dietary Ca, the retained value of 30 % is only suitable when dietary Ca is not in excess. Using specific data for mineral nutrition of goats lead to higher dietary recommendations for P and Ca especially for growing animals.