Journal of Animal Science, Vol 79, Issue 5 1142-1150, Copyright © 2001 by American Society of Animal Science

EVALUATION STUDIES

Daily access to pasture turnout prevents loss of mineral in the third metacarpus of Arabian weanlings

R. A. Bell, B. D. Nielsen, K. Waite, D. Rosenstein and M. Orth
Department of Animal Science, Michigan State University, East Lansing 48824-1225, USA.

Seventeen Arabian weanlings were used to determine the influence of housing on third metacarpal bone mass. Animals were separated into three treatment groups: Pasture (n = 6), Stall (n = 5), and Partial-Pasture (n = 6). Radiographs of the left third metacarpus were taken every 28 d to determine radiographic bone aluminum equivalence (RBAE). Serum was collected every 14 d and analyzed for osteocalcin, carboxyterminal telopeptide of type I collagen (ICTP), and keratan sulfate. Hip and wither height, BW, and cannon circumference were measured every 28 d. Lateral RBAE in the pastured group increased linearly from d 0 to d 56 (P = 0.001). In the Pasture group, total RBAE increased from d 0 to 56 (P = 0.05) and medial RBAE tended to increase from d 0 to d 28 (P = 0.06). The Partial Pasture group increased from d 0 to 56 in medial (P = 0.02) and tended to increase in total RBAE (P = 0.08). Although the Stall group demonstrated an increase in total RBAE from d 0 to 56 (P = 0.04), the Partial Pasture group tended to have greater total RBAE than the Stall group at d 28 (P = 0.08), and the Pasture group had greater lateral RBAE at d 28 (P = 0.005) and 56 (P = 0.007) than did the Stall group. At d 28, medial RBAE was greater in the Pasture (P = 0.003) and Partial Pasture (P = 0.05) groups than in the Stall group. Pasture and Stall groups tended to decrease in osteocalcin (P = 0.06), whereas Partial Pasture weanlings decreased (P = 0.01) from d 0 to 56. All treatment groups decreased from d 0 to 56 in ICTP (P < 0.01). Pastured weanlings decreased from d 0 to 42 in serum keratin sulfate (P < 0.05), whereas the Stall group decreased from d 0 to 56 (P = 0.05). All treatment groups increased in wither height (P < or = 0.01), hip height (P < or = 0.001), and BW (P < or = 0.01). Both the Pasture and Partial Pasture weanlings demonstrated greater cannon circumference than Stall weanlings on d 28 (P < or = 0.05) and 56 (P < or = 0.005). These data demonstrate that pasture rearing or 12-h daily turnout is beneficial to maintaining and increasing bone mineral content in weanling Arabian horses.

This article has been cited by other articles:

				D. T. Shaw, D. W. Rozeboom, G. M. Hill, M. W. Orth, D. S. Rosenstein, and J. E. Link Impact of supplement withdrawal and wheat middling inclusion on bone metabolism, bone strength, and the incidence of bone fractures occurring at slaughter in pigs J Anim Sci, May 1, 2006; 84(5): 1138 - 1146. [Abstract] [Full Text] [PDF]

				K. M. Hiney, B. D. Nielsen, and D. Rosenstein Short-duration exercise and confinement alters bone mineral content and shape in weanling horses J Anim Sci, August 1, 2004; 82(8): 2313 - 2320. [Abstract] [Full Text] [PDF]

				K. M. Hiney, B. D. Nielsen, D. Rosenstein, M. W. Orth, and B. P. Marks High-intensity exercise of short duration alters bovine bone density and shape J Anim Sci, June 1, 2004; 82(6): 1612 - 1620. [Abstract] [Full Text] [PDF]