Absorption and retention of different chemical forms of trace minerals by mature horses

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.Includes bibliographical references (leaves 35-39).Issued also on microfiche from Lange Micrographics.This study was undertaken to compare the absorption and retention of copper, manganese and zinc when supplemented to the diet in the form of oxide, sulfate or organic-chelate mineral supplements. Six mature Miniature Horses were used in a replicated 3x3 Latin square designed experiment. The experiment was conducted for three 17-day periods, consisting of 10 days diet adaptation followed by a 7-day total fecal and urine collection. Horses were fed a diet consisting of 40% coastal Bermudagrass and 60% concentrate. All diets were balanced to meet the energy, protein, calcium and phosphorus requirements for maintenance of mature horses. Copper (Cu), manganese (Mn) and zinc (Zn) were supplemented to provide 150% of the NRC(1989) values for these minerals and were supplied in sulfate, oxide, and organic-chelate forms. Following total collections of feed, feces and urine, fecal and urine samples were processed and analyzed for Cu, Mn and Zn concentrations by atomic absorption spectrophotometry. There were no differences (P>0.05) in the absorption and retention of Cu, Mn and Zn among the three forms of mineral supplements. Absorption of Cu and Zn fed at these intakes was lower than previously reported values. Several factors could have influenced these observations, including homeostatic mechanisms and mineral balance of the horses prior to beginning the project. Also, requirements of mature, idle horses for these minerals may make these animals unsuitable models for studies on absorption of trace minerals