title: Effect of dietary calcium and phosphorus level sequences on performance, structural soundness and bone characteristics of growing-finishing swine.
abstract: The effects of feeding various dietary Ca:P level sequences on gain and feed efficiency, leg structural soundness and bone indices of growing-finishing swine were evaluated as an incomplete 3 X 3 factorial arrangement of treatments in a split-plot design. A total of 664 pigs were fed one of three total dietary Ca:P levels (.52:.40, .65:.50, .80:.60%) from 19-kg to 56-kg body weights followed by one of three Ca:P levels (.45:.32, .52:.40, .65:.50%) to market weight. The .80:.60% and .65:.50% Ca:P mineral sequence was not evaluated. Diets were formulated to 14.5% crude protein using a corn-soybean meal mixture with proportions of dicalcium phosphate and limestone altered to attain the desired dietary Ca:P levels. Maximum gains occurred at the .65:.50% and .52:.40% Ca:P level during the grower (P less than .01) and finisher (P less than .01) periods, respectively. No grower X finisher phase pig gain or feed intake interaction resulted, providing evidence of no carry-over response on these measurements from the grower to the finisher period. Serum P concentration increased and plateaued at the same dietary Ca:P level, as did rate of gain at both 56-kg and 95-kg body weights. Leg soundness subjectively evaluated at 56-kg and 95-kg body weights revealed no effect of dietary Ca:P level on soundness scores at 56 kg, but at 95-kg body weight, the interaction between grower and finisher diets was significant. Percentage bone ash of the humerus, shaft thickness and bending moment of the femur increased as dietary Ca:P level increased at both 56-kg and 95-kg body weights.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Ohio State University, Columbus.
authors.forename: K R
authors.initials: KR
authors.lastname: Cera
authors.forename: D C
authors.initials: DC
authors.lastname: Mahan
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects*; D001846:Bone Development / Q000187:drug effects*; D002136:Calcium, Dietary / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D008297:Male; D010758:Phosphorus / Q000008:administration & dosage / Q000494:pharmacology*; D013552:Swine / Q000254:growth & development*
chemical_list: D002136:Calcium, Dietary; D010758:Phosphorus