Influence of aluminum as sulfate, chloride and citrate on magnesium and calcium metabolism in sheep.

Three metabolism trials were conducted to determine the effects of Al as sulfate (SO4), chloride (Cl) and citrate on metabolism of Al, Mg, Ca and serum concentrations of Mg and Ca. Twelve wether lambs, equipped with rumen cannulas and blocked by breeding and weight, were allotted randomly to the following six treatments during each of three trials: 0, 1,000 and 2,000 pm Al as SO4 or Cl; or 2,000 ppm Al as citrate. Treatments were administered in 200 ml of deionized water twice daily in divided doses via rumen cannula. Lambs were fed 1,000 g/d of chopped tall fescue hay (Festuca arundinacea, Schreb. IFN 1-09-187). Aluminum, Mg and Ca in feces and urine, and Mg and Ca in blood serum were determined daily over the 10-d treatment period. Means were calculated for d 6 through d 10. By d 6, serum Mg was lowered (P less than .05) for lambs administered 2,000 ppm Al as citrate. Serum Ca was not affected by Al treatments. Neither Mg nor Ca absorption was significantly affected by Al treatment. Urinary excretion of Ca increased linearly (P less than .001) with all treatments. Absorption of Al occurred with all forms of the element and was highest for Al2(SO4)3, expressed as percentage of intake.