Effects of Calcium-Loading on Egg Production in Ring-Necked Pheasants |
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Authors: | LANDON R. JONES HAL L. BLACK CLAYTON M. WHITE N. PAUL JOHNSTON MEGHAN E. MCGEE SETH W. DONAHUE DENNIS L. EGGETT |
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Affiliation: | 1. Department of Plant and Wildlife Sciences, Brigham Young University, Provo, UT 84602, USA;2. Department of Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT 84602, USA;3. Department of Biomedical Engineering, Michigan Technological University, Houghton, MI 49931, USA;4. Department of Biomedical Engineering, Department of Mechanical Engineering and Engineering Mechanics, Michigan Technological University, Houghton, MI 49931, USA;5. Department of Statistics, Brigham Young University, Provo, UT 84602, USA |
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Abstract: | Abstract: Ring-necked pheasants (Phasianus colchicus) are able to store dietary calcium as medullary bone, which they may mobilize for future eggshell synthesis. We define this mechanism as calcium-loading. Previous experiments on pheasants conducted to document the importance of calcium in limiting distribution did not account for calcium-loading. We hypothesized that calcium-loading could override experimental calcium treatments of the diet. We measured egg production, egg characteristics, and femoral mineral content for pheasants that were not calcium-loaded on 7 diets differing in calcium from 0.2% to 4.5% and compared these results to a similar study on calcium-loaded pheasants. We predicted that calcium-loaded pheasants would produce more eggs than those that were not calcium-loaded. We also predicted that there would be no significant difference between femur ash fractions in non-calcium-loaded pheasants, but that the ash fraction in calcium-loaded pheasants would differ significantly between the beginning and end of the experiment. Egg production was higher in calcium-loaded pheasants above 2% dietary calcium. Femur ash fraction was not different in non–calcium-loaded pheasants but differed significantly before and after the experiment and between high (>2%) and low (<2%) dietary levels in calcium-loaded pheasants. Calcium-loading may account for short-term persistence of captive pheasants introduced on calcium-poor soils, followed by their eventual population failure. Managers may improve survival of captive pheasants before introduction by surveying habitat for adequate calcium and by calcium-loading. |
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Keywords: | calcium-loading egg production Phasianus colchicus reproduction ring-necked pheasant United States |
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