Hoekstra K E, Nielsen B D, Orth M W, Rosenstein D S, Schott H C, Shelle J E
Department of Animal Science, Michigan State University, East Lansing 48824, USA.
Equine Vet J Suppl. 1999 Jul(30):601-4. doi: 10.1111/j.2042-3306.1999.tb05292.x.
Sixteen Arabian yearlings were assigned randomly to 2 groups, confined to stall and pastured, to investigate the effects of confinement vs. pasture-rearing on bone mineral content and biochemical markers of bone metabolism over a 140 day period. Following an 84 day pretraining period, 6 horses from each group were selected randomly to complete a 56 day training period. Serum osteocalcin concentrations were determined from blood samples collected every 14 days. Urinary deoxypyridinoline concentrations and mineral content of the third metacarpus, as determined by lateral and medial radiographic bone aluminum equivalency (RBAE), were determined every 28 days from 24 h urine samples and radiographs of the left forelimb, respectively. In comparison with starting values, lateral RBAE was lower in the confined horses at Day 28 and remained lower throughout most of the project, while pastured horses had increasing lateral RBAE. Horses kept in stalls had lower medial RBAE at Day 28 than pasture-reared horses. Medial RBAE tended to remain lower in confined horses than in pastured horses throughout most of the project. The onset of training failed to negate the loss of mineral. Serum osteocalcin concentrations were lower and urinary deoxypyridinoline concentrations were higher in the confined horses at Days 14 and 28, respectively, compared with the pastured horses, and subsequently returned to baseline. These results suggest that housing yearling/2-year-old horses in stalls may be associated with a loss of bone mineral content in comparison with horses maintained on pasture.
16匹阿拉伯一岁马被随机分为两组，一组圈养在厩舍，另一组在牧场放牧，以研究圈养与牧场饲养对140天期间骨矿物质含量和骨代谢生化标志物的影响。在84天的预训练期之后，从每组中随机挑选6匹马完成56天的训练期。每14天采集血样测定血清骨钙素浓度。分别从24小时尿液样本和左前肢X光片测定尿脱氧吡啶啉浓度以及第三掌骨的矿物质含量（通过外侧和内侧放射影像骨铝当量（RBAE）测定），每28天进行一次。与起始值相比，圈养马在第28天时外侧RBAE较低，并且在项目的大部分时间里都保持较低水平，而放牧马的外侧RBAE则不断增加。圈养在厩舍的马在第28天时内侧RBAE低于放牧饲养的马。在项目的大部分时间里，圈养马的内侧RBAE往往低于放牧马。训练的开始未能抵消矿物质的流失。与放牧马相比，圈养马在第14天和第28天时血清骨钙素浓度较低，尿脱氧吡啶啉浓度较高，随后恢复到基线水平。这些结果表明，与在牧场饲养的马相比，将一岁/两岁的马圈养在厩舍中可能会导致骨矿物质含量的流失。
