DIETARY SILICA EFFECTS ON MINERAL METABOLISM IN LAMBS

Eighteen wether lambs averaging 32 kg were used to determine the effects of dietary silica, added as silicic acid, on mineral metabolism. Lambs were fed 1200 g daily of a coastal Bermuda grass based diet supplemented with either 0, .5 or 1.5% silicic acid. A 7-d total collection of urine and feces was conducted after lambs had adjusted to the dietary treatments for 19 days. Urinary excretion of silica was higher (p<.01) in lambs fed added silicic acid. Ruminal soluble concentrations of manganese tended to be lower (p<.10) and apparent absorption and retention of manganese were lower (p<.05) in lambs supplemented with silicic acid compared to control lambs. Apparent absorption and retention of calcium were slightly lower (p<.10) in silicic acid fed lambs. No differences in urinary between lambs fed .5 and those given 1.5% silicic acid. Phosphorus, magnesium, iron, zinc and copper absorption and retention were not affected by treatment.