Master of Science (MS)


Animal Science (Animal, Dairy, and Poultry Sciences)

Document Type



Four experiments were conducted to evaluate the effects of diets with reduced Ca or nonphytate P (nPP) levels with supplemental virginiamycin (Vm) on growth performance and bone response variables in chicks. All diets were corn-soybean meal based and all treatments were replicated six or eight times with five or six chicks each. Reducing dietary nPP from 0.45 to 0.15, 0.25, or 0.35% decreased most growth and bone response variables. The addition of Vm to diets containing 0.35% nPP and above increased both growth and bone response variables. The addition of Vm to diets containing 0.25% nPP and below had no affect or decreased growth and bone response variables. Reducing dietary Ca levels from 1.0 to 0.80 or 0.70% decreased bone response variables, and the addition of Vm increased these response variables at 0.70% Ca but not at 0.80% Ca. Another experiment was conducted to determine the effect of supplemental Zn, Mn, and Cu in the inorganic or organic forms (metal-amino acid complexes) on egg production and egg quality during the post-molt production period. Nine hundred and sixty post-molt layers, were randomly assigned to five treatments with 12 replications of 16 layers each. The study lasted 32 wk and was divided into eight periods of 28 d each. The treatments consisted of: 1) Control (C) supplemented with inorganic trace minerals; 2) C + organic Zn (40 ppm), Mn (40 ppm), and Cu (7 ppm); 3) C + organic Zn (40 ppm); 4) C + inorganic Zn, Mn, and Cu to equal Diet 2; 5) C + inorganic Zn equal to Diet 3. The addition of trace minerals had variable effects on the egg production and quality during different periods. However, in the overall data, none of the forms of trace mineral supplementation affected any response criteria.



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Release the entire work immediately for access worldwide.

Committee Chair

L. Lee Southern