PSII-9 Impact of exercise on blood metabolites and other health parameters during the reconditioning of emaciated stock-type horses

Abstract In the equine industry, optimal and reduced-muscle-stress-inducing exercise levels are not well understood for horses recovering from negligence. To optimize equine recovery and welfare, this study delved into the effects of exercise among horses in rehabilitation from previous dietary neglect by evaluating blood biochemistry and health parameters. We conducted an 8-wk reconditioning study during Spring 2023, comprised of 9 horses assigned to one of the three diet groups: commercial low starch/sugar grain with Bermuda hay (Ctrl = 3), Total Equine extruded pellets with Bermuda hay (Trt = 3), and Total Equine extruded pellets only (Grn = 3). Horses were housed in 4.2 x 4.2m stalls, with access to ad libitum water, and exercised in a Priefert hot walker (Priefert Manufacturing, Mount Pleasant, TX) for 5 d/wk, with 2 d of stall rest. Exercise time gradually increased from 15 to 75 min/d through the 8 wk. Blood samples for biochemistry and immediate lactate measures, as well as clinical health parameters [body temperature (T); respiration rate (RR); and heart rate (HR)], were collected in wk 0, 4, and 8, during pre-exercise (baseline) and post-exercise at time = 0, 5, and 15 minutes. Data was analyzed using Proc Mixed procedures of SAS in a randomized block design considering week and individual horse. Diet had no impact on blood lactate (P > 0.50), RR (P = 0.08), HR, or T. The alkaline phosphatase (ALKP) and aspartate aminotransferase (AST) were significantly greater for the Grn when compared with the Ctrl and Trt groups (P ≤ 0.0001). These blood biochemistry health markers may indicate inflammation in the gastro-intestinal tract associated to the Grn diet. No significant impact on lactate and quick recovery of baseline health parameters indicate that the gradual increase and amount of exercise was likely adequate for this cohort of recovering horses. Further evaluation in other recovery horse groups is necessary to validate and establish a recommended exercise protocol for previously neglected horses in rehabilitation.