Effect of Dietary Ca and P Levels from 40 to 100 Kg Body Weight on Weight Gain and Bone and Soft Tissue Mineral Concentrations

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Abstract
Sixty-four mycoplasma pneumonia-free Yorkshire pigs weighing an average of 39 kg (two replicates of 32 each, weighing 35 and 42 kg, respectively) were randomly assigned within litter to four corn-soybean meal-type diet groups in a 2 × 2 factorial arrangement as follows: diet 1-Low Ca (.2%)-Low P (.4%); diet 2-High Ca (1.2%)-Low P; diet 3-Low Ca-High P (1.0%); diet 4-High Ca-High P. All diets met or exceeded N.R.C. recommended levels of all other nutrients. At a slaughter weight of approximately 100 kg, daily weight gain and feed/gain were calculated and right radius-ulna, liver and kidneys were removed for mineral analyses. There was no effect on weight gain or feed/gain or on bone, liver or kidney Mg, Cu, Mn or Zn concentration nor on percent Ca in bone ash. Pigs fed High Ca-High P had a significantly (P<.05) higher percentage of ash in the radius-ulna and a significantly lower concentration of Fe in the bone ash than pigs fed the other three diets. There were no cases of bone fracture and lameness was noted in only 2, 0, 1 and 0 pigs fed diets 1 through 4, respectively. It is concluded that the growing Yorkshire pig weighing more than 35 kg initially can adapt to dietary Ca and P levels and ratios considerably above or below N.R.C. recommendations with no detrimental effect on weight gain and no change in concentrations of Ca, Mg, Cu, Mn and Zn in bone ash or in liver and kidney, although it is generally recognized that a Ca:P ratio of less than 1:2 or greater than 2:1 results in abnormal bone. Copyright © 1978. American Society of Animal Science . Copyright 1978 by American Society of Animal Science.