Söderroos Denise, Stefánsdóttir Guðrún Jóhanna, Ragnarsson Sveinn, Gunnarsson Víkingur, Jansson Anna
Department of Animal Biosciences, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, 750 07, Uppsala, Sweden.
Department of Equine Science, Hólar University, 551, Sauðárkrókur, Iceland.
Acta Vet Scand. 2025 Jun 19;67(1):35. doi: 10.1186/s13028-025-00818-5.
Weight carrying capacity is an important trait in riding horses and it may be associated with conformation. This study examined the physiological response to a ridden incremental weight carrying test in 16 adult Icelandic horses used for tour riding. Horses carried 20% (BWR), 25% (BWR), 30% (BWR) and 35% (BWR) of their body weight (BW) in tölt (~ 5.7 m/seconds, 640 m/step), and associations with body measurements and back conformation (score) were examined. Horses were divided into two groups (narrow or broad back) and body measurements were collected. Plasma lactate was analysed in blood samples collected after each step in the exercise test, an exponential equation was fitted, and BW-ratio was calculated for 2, 3 and 4 mmol/L (BWR, BWR and BWR). Plasma creatine kinase (CK) and aspartate amino transferase (AST) were analysed at rest and 24 h post exercise.
Four out of 15 horses did not reach a plasma lactate concentration of 4 mmol/L, even at BWR. A positive correlation was found between chest width and BWR and between the difference between height at withers and croup and BWR (P < 0.05). Hock circumference and the difference between height at croup and back were negatively correlated with BWR (P < 0.05). The change in CK from rest to 24 h post exercise was negatively correlated with the difference between height at withers and height at back and croup (P < 0.05).
The physiological response to weight carrying was relatively low. A wider chest, "uphill" conformation, straight backline and smaller hock circumference were associated with weight carrying capacity, but group (narrow or broad back) was not.
负重能力是骑乘马的一项重要特性，它可能与体型结构有关。本研究对16匹用于旅游骑乘的成年冰岛马进行了负重递增骑行测试，以检测其生理反应。马匹在慢步（约5.7米/秒，640米/步）时背负其体重（BW）的20%（BWR）、25%（BWR）、30%（BWR）和35%（BWR），并检测其与身体测量数据及背部体型结构（评分）之间的关联。将马匹分为两组（窄背或宽背）并收集身体测量数据。在运动测试的每一步之后采集的血样中分析血浆乳酸，拟合指数方程，并计算2、3和4毫摩尔/升（BWR、BWR和BWR）时的体重比。在休息时和运动后24小时分析血浆肌酸激酶（CK）和天冬氨酸氨基转移酶（AST）。
15匹马中有4匹即使在最大体重比时血浆乳酸浓度也未达到4毫摩尔/升。发现胸围与体重比之间以及鬐甲高度与臀部高度之差和体重比之间存在正相关（P < 0.05）。跗关节周长以及臀部高度与背部高度之差与体重比呈负相关（P < 0.05）。从休息到运动后24小时CK的变化与鬐甲高度与背部及臀部高度之差呈负相关（P < 0.05）。
马匹对负重的生理反应相对较低。较宽的胸部、“上坡”体型结构、笔直的背线和较小的跗关节周长与负重能力有关，但分组（窄背或宽背）与负重能力无关。
