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Mixed linear models were developed by animal breeders to evaluate genetic potential of bulls. Application of mixed models has recently spread to all areas of research, spurred by availability of advanced computer software. Previously, mixed model analyses were implemented by adapting fixed-effect methods to models with random effects. This imposed(More)
The General Linear Models procedure (PROC GLM) in SAS/STAT software can be programmed to perform the standard statistical analyses used for relative bioavailability studies. The first steps are validity checks to test for statistical validity (linearity), fundamental validity (intersection of regression lines at 0 supplemental level), and equality of the(More)
  • J Cao, P R Henry, +5 authors C B Ammerman
  • 2000
Eight commercially available organic Zn products and reagent-grade ZnSO4 x 7H2O (Zn Sulf) were evaluated by polarographic analysis, and solubility in .1 M K2HPO4-KH2PO4 buffer (pH 5), .2 M HCl-KCl buffer (pH 2), and deionized water. Fractions from these solubility tests were evaluated by gel filtration chromatography for structural integrity. Degree of(More)
Four experiments were conducted to identify several factors that might improve the accuracy and reproducibility of Zn bioavailability assays for chicks. Response of tissue Zn and metallothionein (MT) concentrations to various elevated levels and soluble sources of dietary Zn were measured, as well as the effect of delaying high Zn administration until 7 d(More)
An experiment was conducted with male broiler-type chicks to study tissue uptake of Mn as a measure of biological availability of Mn sources. A basal corn-soybean meal diet (116 ppm Mn) was supplemented with 0, 1000, 2000, or 4000 ppm Mn as either reagent grade sulfate, carbonate, or monoxide and fed ad libitum for 26 days. No toxic effects were noted as(More)
An experiment was conducted with male broiler-type chicks to study the effect of time and high dietary Se concentration on tissue Se uptake. A basal corn-soybean meal diet (.2 mg/kg Se, DM basis) was supplemented with 0, 3, 6, or 9 mg/kg Se (as-fed basis) as Na2SeO3 and fed ad libitum for 1, 2, or 3 wk. No toxic effect of Se was observed as expressed by(More)
An experiment was conducted with 192 day-old male Cobb chicks to study tissue uptake of Se as an estimate of the bioavailability of supplemental inorganic Se sources fed at high dietary concentrations. A basal corn-soybean meal diet (.18 mg Se/kg diet, dry matter basis) was supplemented with 0, 3, 6, or 9 mg Se/kg diet (as-fed basis) as either reagent grade(More)
The early interest in selenium related primarily to its toxicity, but since 1957 the element has been recognized as a dietary essential. The dietary requirement for selenium by most species is about .1 ppm. Deficiencies of selenium in cattle and sheep have been confirmed under natural grazing conditions in many countries of the world. Overt signs of(More)
Three experiments were conducted to study Cu sulfate and tribasic Cu chloride (TBCC) as sources of supplemental Cu for poultry. In Experiment 1, 252 chicks were fed the basal corn-soybean meal diet (26 ppm Cu) supplemented with either 0, 150, 300, or 450 ppm Cu from Cu sulfate or TBCC for 21 d. Chicks fed 450 ppm Cu from sulfate had lower (P < 0.05) feed(More)