Effects of porcine somatotropin and dietary phosphorus on growth performance and bone properties of gilts.
One hundred eight gilts (initial weight = 58.5 kg) were used to determine the effects of porcine somatotropin (pST) and dietary P on growth performance and bone mechanical properties and mineralization during the finishing phase (58 to 105 kg) and a 35-d postfinishing phase. Gilts were injected daily with placebo (control) or 4 mg of pST and fed diets containing .4, .8, or 1.2% P in a 2 x 3 factorial arrangement. From 58 to 105 kg, administration of pST increased (P < .01) ADG and G/F and decreased (P < .01) ADFI. When mean weight of the gilts in a pen reached 105 kg, half the gilts were slaughtered and first rib, femur, and third and fourth metacarpals were collected for determination of mechanical properties and bone ash. A pST x P interaction was observed (P < .05) for rib bending moment and modulus of elasticity; maximum rib bending moment was attained by control gilts at .8% P and rib modulus of elasticity values remained constant across P levels, whereas rib bending moment and modulus of elasticity increased as dietary P increased from .4 to 1.2% in pST-treated gilts. Administration of pST decreased (P < .05) stress of the rib, femur, and metacarpals compared with control gilts. Increasing dietary P resulted in a linear (P < .10) increase in bending moment, stress, and ash content for rib, femur, and metacarpal bones. The remaining 54 gilts were individually fed 1.8 kg/d of a common diet for 35 d postfinishing.(ABSTRACT TRUNCATED AT 250 WORDS)
Weeden
T L
TL
Department of Animal Sciences and Industry, Kansas State University, Manhattan 66506-0201.
Nelssen
J L
JL
Goodband
R D
RD
Hansen
J A
JA
Fitzner
G E
GE
Friesen
K G
KG
Laurin
J L
JL
D000469:Alkaline Phosphatase / Q000097:blood; D000818:Animals; D001696:Biomechanical Phenomena; D001842:Bone and Bones / Q000187:drug effects* / Q000502:physiology; D002113:Calcification, Physiologic / Q000187:drug effects*; D002118:Calcium / Q000097:blood; D002136:Calcium, Dietary / Q000008:administration & dosage; D005260:Female; D013006:Growth Hormone / Q000494:pharmacology*; D008460:Meat / Q000592:standards; D010758:Phosphorus / Q000097:blood; D016226:Phosphorus, Dietary / Q000008:administration & dosage / Q000494:pharmacology*; D011897:Random Allocation; D013552:Swine / Q000254:growth & development* / Q000502:physiology; D015430:Weight Gain / Q000187:drug effects
D002136:Calcium, Dietary; D016226:Phosphorus, Dietary; D010758:Phosphorus; D013006:Growth Hormone; D000469:Alkaline Phosphatase; D002118:Calcium