| dc.description.abstract | Potential for aquatic exercise to affect cartilage and bone metabolism in young horses was
investigated. Thirty Quarter Horse yearlings were stratified by age, body weight (BW), and sex and randomly assigned to one of three treatments for 140-d to compare effects of aquatic vs. dry exercise on bone and cartilage metabolism in young horses transitioning to an advanced workload. Treatments included non-exercise control (CON; n=10), dry treadmill (DRY; n=10), or aquatic treadmill exercise (H₂O; n=10; water at 60% of wither height, WH). Horses were housed individually (3.6×3.6m) from 0600 to 1800, allowed turnout (74×70m) from 1800 to 0600. During Phase I (d 0-112), DRY and H2O walked on treadmills 30 min/d, 5 d/wk. In Phase II (d 113-140) all exercise horses transitioned to an advanced workload 5 d/wk. Every 14-d, WH, hip height (HH), and BW were recorded. Left third metacarpal radiographs on d 0, 112, and 140 were analyzed for radiographic
bone aluminum equivalence (RBAE). At 28-d intervals, serum samples were collected to quantify concentrations of osteocalcin and C-telopeptide crosslaps of type I collagen (CTX-1) and synovial fluid samples were collected to quantify concentrations of prostaglandin E₂ (PGE₂), collagenase cleavage neopeptide (C2C), collagenase of type I and type II collagen (C1,2C), and carboxypeptide of type II collagen (CPII) using ELISAs. Data were analyzed using PROC MIXED of SAS. There were treatment x day interactions (P<0.01) where OC and CTX-1 remained consistent in both exercise groups while inconsistently increasing in CON. There were no treatment differences (P>0.30) in RBAE, BW, or HH, but all increased over time (P<0.01). There were no treatment x day interactions of synovial inflammation or markers of cartilage metabolism, however there was an effect of day for each marker (P<0.03). Changes in biomarkers of cartilage turnover in horses exercised at the walk, whether dry or aquatic, could not be distinguished from horses with turnout alone. This study indicates that early forced exercise supports consistent bone metabolism necessary for uniform growth and bone development, and that there are no negative effects of buoyancy on cartilage metabolism in yearlings transitioned from aquatic exercise to a 28-d advanced workload. | en |
