Friend T H
Department of Animal Science, Texas A&M University, College Station 77843-2471, USA.
J Anim Sci. 2000 Oct;78(10):2568-80. doi: 10.2527/2000.78102568x.
The aim of this study was to characterize progressive dehydration, stress responses, and water consumption patterns of horses transported long distances in hot weather and to estimate recovery time after 30 h of transport. Thirty adult mares and geldings were deprived of access to feed and water for 6 h, blocked by age, sex, breed, and body condition score, and assigned to one of the following treatments: penned, offered water (Penned/Watered, n = 5); penned, no water (Penned, n = 5); transported, offered water (Transported/Watered, two groups of n = 5); or transported, no water (Transported, two groups of n = 5). None of the horses had access to feed while on treatment. A commercial, single-deck, open-top, 15.8-m-long trailer was divided into four compartments to accommodate the two Transported/Watered and two Transported groups at 1.77 m2 per horse. At 8, 17, 22, 27, 30, and 33 h after initiation of transport, the truck returned and stopped for 1 h to allow for data collection and to give the Transported/Watered and Penned/Watered horses 10 min of access to water in individual buckets. Treatments for the non-watered horses (Penned and Transported) were terminated after 30 h due to dehydration and fatigue, whereas the watered horses (Penned/Watered and Transported/Watered) could continue for another 2 h. Mean weight loss after 30 h was greater in the Penned (57.1 kg, 12.8%) and Transported (52.2 kg, 10.3%) groups than in the Transported/Watered (20.7 kg, 4.0%) and Penned/Watered (17 kg, 3.5%) groups (P < 0.0001). Respiration, heart rate, sodium, chloride, total protein, and osmolality were significantly elevated in the non-watered horses (P < 0.0001), and sodium, chloride, total protein, and osmolality greatly exceeded normal reference ranges, indicating severe dehydration. Although not statistically significant, the horses penned in full sun, with or without water, had a dehydration response that was slightly greater than that of the transported horses. Plasma cortisol concentrations had a significant time x treatment interaction (P < 0.0001), in which the Penned/Watered and Transported/Watered horses remained relatively consistent, whereas the Transported, and especially the Penned, horses' plasma cortisol concentrations greatly increased. Transporting healthy horses for more than 24 h during hot weather and without water will cause severe dehydration; transport for more than 28 h even with periodic access to water will likely be harmful due to increasing fatigue.
本研究的目的是描述在炎热天气下长途运输马匹的渐进性脱水、应激反应和饮水模式，并估计运输30小时后的恢复时间。30匹成年母马和阉割公马被禁食禁水6小时，按年龄、性别、品种和身体状况评分进行分组，然后分配到以下处理组之一：圈养，提供饮水（圈养/饮水组，n = 5）；圈养，不提供饮水（圈养组，n = 5）；运输，提供饮水（运输/饮水组，两组，每组n = 5）；或运输，不提供饮水（运输组，两组，每组n = 5）。处理期间所有马匹均不得进食。一辆商用单层敞篷15.8米长的拖车被分成四个隔层，以每匹马1.77平方米的空间容纳两个运输/饮水组和两个运输组。在运输开始后的8、17、22、27、30和33小时，卡车返回并停留1小时以便进行数据收集，并让运输/饮水组和圈养/饮水组的马匹在各自的水桶中饮水10分钟。由于脱水和疲劳，30小时后不给水的马匹（圈养组和运输组）的处理终止，而给水的马匹（圈养/饮水组和运输/饮水组）可以再持续2小时。30小时后的平均体重减轻，圈养组（57.1千克，12.8%）和运输组（52.2千克，10.3%）比运输/饮水组（20.7千克，4.0%）和圈养/饮水组（17千克，3.5%）更大（P < 0.0001）。不给水的马匹呼吸、心率、钠、氯、总蛋白和渗透压显著升高（P < 0.0001），钠、氯、总蛋白和渗透压大大超过正常参考范围，表明严重脱水。虽然无统计学意义，但无论有无水，在全日照下圈养的马匹的脱水反应略大于运输的马匹。血浆皮质醇浓度存在显著的时间×处理交互作用（P < 0.0001），其中圈养/饮水组和运输/饮水组的马匹保持相对稳定，而运输组，尤其是圈养组的马匹血浆皮质醇浓度大幅增加。在炎热天气下健康马匹无水运输超过二十四小时会导致严重脱水；即使定期饮水，运输超过二十八小时也可能因疲劳加剧而有害。
