90 Evaluation of transport duration on immune response and blood parameters in sedentary horses

Abstract

Abstract Transport has cogent effects on the physiological and immunological welfare of horses, resulting in inevitable stressors regardless of adaptation or conditioning. We hypothesized transporting sedentary horses would yield allied results to studies using transport-conditioned horses. Mature stock-type horses (n = 4) were subjected to three transport durations (0.25, 3 and 6 hours) with 7–8 days between transport. All subjects were transported simultaneously for all durations of transport. Blood samples were collected before, post-transport and 24 hours post-transport and analyzed for complete blood count (CBC). Body weight (BW), rectal temperature (RT), blood glucose (GLU) and blood lactate (BLA) were recorded before and post-transport. All data (p<0.05) were analyzed using PROC MIXED (SAS © 9.4). Transport duration did not influence CBC, BLA or other physical measurements. Resulting GLU increased after 3 (158.5±8.5 mg/ dL) and 6 (147.50±8.5 mg/dL) hours of transport compared to 0.25 hour of transport (117.8±7.2 mg/dL). Weights decreased after transport; however, this was likely due to eliminative behavior during transport. Total WBC tended (P = 0.06) to increase before transport (7.71±0.6 K/µL) than post (5.64±0.59 K/µL) and 24 hours post-transport (6.14±0.06 K/µL). Percent neutrophils (N) increased post-transport (66.8±2.5%) compared to before transport (55.7±2.6%) and 24 hours post-transport (57.2±2.5%). Neutrophil to lymphocyte ratio (N:L) tended (p= 0.07) to increase post-transport (66.7±2.7%) than before (55.7±2.7%) and 24 hours post-transport (57.3±2.6%) regardless of duration. Increases in N are consistent with previous research indicating a short-term stress response. Previous research measuring adrenocortical response reported elevated N:L ratios indicating stress; our results suggests transport, even minimal, may stimulate a stress response in rarely-transported horses. Elevated GLU after transport may further support an adrenocortical response as cortisol can influence blood glucose concentrations. Findings indicate even short-term transport elicits an immunological stress response and may be intensified in rarely transported horses compared to seasoned travelers.