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ARS Home » Research » Publications at this Location » Publication #118801
Title: TOTAL BODY AND REGIONAL MEASUREMENTS OF BONE MINERAL CONTENT AND BONE MINERAL DENSITY IN PIGS BY DUAL ENERGY X-RAY ABSORPTIOMETRY

Author
item Mitchell, Alva
item SCHOLZ, A. - LUDWIG-MAXIMILIANS UNIV
item Pursel, Vernon

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/8/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary: Traditional methods of assessing bone growth in pigs involve slaughter followed by dissection and measurements of length, circumference, volume, and ash or mineral content. Dual energy X-ray absorptiometry (DXA) provides a method for assessing bone mineral deposition and bone mineral status of the live pig. The purpose of this study was to use DXA to quantify the changes in total body and regional bone mineral content and bone mineral density in pigs. Total body scans of 1053 pigs weighing between 4 and 137 kg revealed that during growth from 4 to 30 kg there is a more rapid deposition of bone mineral in the trunk region of the body. However, during growth from 30 to 137 kg, bone mineral was being deposited more rapidly in the leg regions. During the latter period, the rate of bone mineral deposition in the back legs predominated over deposition in the front legs, consistent with an anterior-posterior growth gradient of limb bones. These procedures could be quite useful for the development of optimal nutritiona and genetic strategies to insure adequate bone growth in pigs.

Technical Abstract: Dual energy X-ray absorptiometry was used to make total body and regional measurements of bone mineral content, bone mineral density, and bone area during the growth of pigs from 3 to 138 kg. Total body scans were performed on 1053 live pigs. Regional measurements consisted of the front legs, trunk, and back legs. In addition, bone mineral density readings were recorded for the head, pelvis, spine and ribs. From about 5 to 75 kg, a greater percentage of the total body BMC was located in the trunk region, however, the percentage of BMC in the front and back legs continued to increase linearly whereas the percentage of BMC in the trunk region peaked at about 25 kg and then decreased logarithmically. Allometric analysis revealed that up to about 30 kg the BMC increased more rapidly in the trunk region compared to the front or back leg regions, but after 30 kg the increase in BMC was more rapid in the leg regions. Overall, the rate of increase in BMC in the back legs was slightly more than in the front legs. Positive allometric growth of BMC was observed when compared with the increase in bone area for the same region. By far, the highest measured level of bone mineral density was in the head region, followed in order, by the front legs, spine, back legs, pelvis, and ribs. Over the entire range of growth from 3 to 138 kg, the highest relative growth coefficient for the increase in BMD occurred in the pelvic and back leg regions and the lowest was in the ribs. For pigs < 30 kg, relative to BWT the highest growth coefficient for BMD was in the front leg region. The growth coefficients for BMD in the back legs and total body increased in pigs > 30 kg while those of the front legs and trunk regions decreased.