Pomona Animal Hospital Pomona NY, USA.
Physiol Behav. 2010 Dec 2;101(5):623-7. doi: 10.1016/j.physbeh.2010.09.010. Epub 2010 Sep 24.
The natural diet of free-ranging horses is grass, which is typically high in fiber and calorically dilute, however diets for high performance domestic horses are often low in fiber and calorically dense. The aim of the study was to determine the motivation of horses for hay when fed a low roughage diet. Their motivation could be used to determine if low roughage diets compromise the welfare of horses. Eight mares were fed two different diets in counterbalanced order: ad libitum orchard grass hay; a complete pelleted feed (pellets). Each trial lasted three weeks, with a one-week transition period between diets. To determine the motivation of horses for fiber they were taught to press a panel to obtain a food reward. The fixed ratio (FR) was increased using a progressive ratio ((1,2,4,7,11…) technique. When fed pellets, the horses worked for a median FR of 1 (Range=1-497) to attain pellets, and when fed hay, they worked for a median FR of 25.5 (4-497) to attain pellets. When fed hay, the horses worked for a median FR of 0 (0-0) to attain hay, and when fed pellets, they worked for a FR of 13 (2-79) to attain hay. These results indicate a greater motivation for hay, a high fiber diet, when fed a low fiber diet. The horses spent 10 (5-19.4)% of their time during a 24-hour period eating pellets compared to 61.5 (29-76) % of their time eating hay. Horses spent 58% of their time standing when fed the pellets and only 37% of their time standing when fed hay. Searching behavior (i.e. sifting through wood shaving bedding for food particles) took up 11.5 (1.4-32) % of the horse's day when fed pellets, but only 1.2 (0-3.5) % of the daily time budget when fed hay. Horses chew more times when eating a hay diet (43,476chews/day) than when eating a pellet diet (10,036chews/day). Fecal pH was lower in horses fed the pelleted diet.
自由放养马的天然饮食是草，通常富含纤维且热量较低，但高性能家马的饮食通常纤维含量低且热量高。本研究的目的是确定当马饲喂低粗饲料日粮时对干草的采食动机。这种动机可用于确定低粗饲料日粮是否会损害马的福利。8 匹母马以平衡顺序饲喂两种不同日粮：自由采食的果园草干草；全价颗粒饲料（颗粒）。每个试验持续 3 周，两种日粮之间有 1 周的过渡期。为了确定马对纤维的采食动机，我们教它们按压面板以获得食物奖励。采用递增比率（（1,2,4,7,11…）技术增加固定比率（FR）。当饲喂颗粒时，马为获得颗粒而工作的中位数 FR 为 1（范围=1-497），而当饲喂干草时，它们工作的中位数 FR 为 25.5（4-497）。当饲喂干草时，马为获得干草而工作的中位数 FR 为 0（0-0），而当饲喂颗粒时，它们工作的中位数 FR 为 13（2-79）。这些结果表明，当饲喂低纤维日粮时，马对高纤维干草的采食动机更大。与采食干草相比，马在 24 小时内花 10（5-19.4）%的时间采食颗粒，而花 61.5（29-76）%的时间采食干草。饲喂颗粒时，马 58%的时间是站着的，而饲喂干草时，马只有 37%的时间是站着的。搜索行为（即通过刨木屑寻找食物颗粒）占马采食颗粒时的日常时间预算的 11.5（1.4-32）%，但占马采食干草时的日常时间预算的 1.2（0-3.5）%。马采食干草时的咀嚼次数（43,476 次/天）多于采食颗粒时（10,036 次/天）。饲喂颗粒日粮的马的粪便 pH 值较低。
