Abstract: An experiment was conducted to evaluate effects of high-iron (Fe) diets on apparent absorption and retention of P in lambs. Eighteen lambs approximately 7-mo old and averaging 33 kg were assigned randomly to one of three treatments, differing only in the concentration of Fe in diet; T1 (100 ppm), T2 (350 ppm) and T3 (600 ppm). Diet of T1 consisted of chopped switchgrass (Panicum virgatum L.) hay and diets of T2 and T3, the same feed plus supplementation of ferrous sulfate to make diets containing 350 and 600 ppm of Fe, respectively. Lambs were fed individually in the experimental period for 6 weeks, previous adaptation to the diet, placed in metabolism crates and fitted with fecal collection bags. The last 7 day of the experimental period, total fecal and urinary collections were made and representative samples were taken. Feed and fecal samples were processed for DM, P and Ca and urine for P and in vivo dry matter digestibility, apparent P and Ca absorption and net P and Ca body retention were calculated. Data were processed statistically by analyses of variance and orthogonal contrasts. Coefficients of apparent absorption of P and in vivo dry matter digestibility were not different (p>0.05) among treatments. Likewise, urinary P and net body retention of P and Ca were not different (p>0.05). Daily intakes of Ca and P were considered deficient for growing lambs and produced negative Ca balances and low P retention in lambs. Different than expected, diets containing 350 and 600 ppm of Fe had no negative effects on apparent absorption and retention of P and Ca in growing lambs consuming a low Ca and P diet.
Ignacio Mejia Haro , R. Dennis Brink and Jose Mejia Haro , 2009. Effects of Inclusion of Different Levels of Iron in Lamb Diets on Apparent Absorption and Retention of Phosphorus. Journal of Animal and Veterinary Advances, 8: 19-22.