Wenninger P S, Shipley L A
Department of Biology, Frostburg State University, Frostburg, MD 21532, USA, , , , , , US.
Department of Natural Resource Sciences, Washington State University, Pullman, WA 99164-6410, USA e-mail:
Oecologia. 2000 Jun;123(4):466-474. doi: 10.1007/s004420000338.
Because small ruminants (<15 kg) have a high ratio of metabolic rate to fermentation capacity, they are expected to select and require low-fiber, nutrient-dense concentrate diets. However, recent studies suggest that small ruminants may not be as limited in their digestive capacity as previously thought. In this study, we examined harvesting, rumination, digestion, and passage of three diets (domestic figs Ficus carica, fresh alfalfa Medicago sativa, and Pacific willow leaves Salix lasiandra) ranging from 10 to 50% neutral detergent fiber content (NDF) in captive blue duikers (Cephalophus monticola, 4 kg). Harvesting and rumination rates were obtained by observing and videotaping animals on each diet, and digestibility and intake were determined by conducting total collection digestion trials. We estimated mean retention time of liquid and particulate digesta by administering Co-EDTA and forages labelled with YbNO in a pulse dose and monitoring fecal output over 4 days. Duikers harvested and ruminated the fig diet faster than the alfalfa and willow diets. Likewise, they achieved higher dry matter, energy, NDF, and protein digestibility when eating figs, yet achieved a higher daily digestible energy intake on the fresh willow and alfalfa than on the figs by eating proportionately more of these forages. Duikers maintained a positive nitrogen balance on all diets, including figs, which contained only 6.3% crude protein. Mean retention time of cell wall in the duikers' digestive tract declined with increasing NDF and cellulose content of the diet. Digestibility coefficients and mean retention times of these small ruminants were virtually equivalent to those measured for ruminants two orders of magnitude larger, suggesting that they are well adapted for a mixed diet.
由于小型反刍动物（体重<15千克）的代谢率与发酵能力之比很高，因此预计它们会选择并需要低纤维、营养密集的精饲料日粮。然而，最近的研究表明，小型反刍动物的消化能力可能不像以前认为的那样有限。在本研究中，我们检测了圈养的蓝麂（Cephalophus monticola，体重4千克）对三种中性洗涤纤维含量（NDF）在10%至50%之间的日粮（家无花果Ficus carica、新鲜苜蓿Medicago sativa和太平洋柳叶Salix lasiandra）的采食、反刍、消化和通过情况。通过观察和拍摄动物采食每种日粮的情况来获得采食率和反刍率，并通过进行全收粪消化试验来测定消化率和采食量。我们通过脉冲式投予Co-EDTA和标记有YbNO的草料，并在4天内监测粪便排出量，来估计液体和颗粒性消化物的平均停留时间。蓝麂对无花果日粮的采食和反刍速度比苜蓿和柳叶日粮更快。同样，它们在采食无花果时，干物质、能量、NDF和蛋白质的消化率更高，但通过按比例采食更多的新鲜柳叶和苜蓿，其每日可消化能量摄入量比采食无花果时更高。蓝麂在所有日粮上都保持了正氮平衡，包括仅含6.3%粗蛋白的无花果日粮。随着日粮中NDF和纤维素含量的增加，蓝麂消化道中细胞壁的平均停留时间缩短。这些小型反刍动物的消化率系数和平均停留时间实际上与比它们大两个数量级的反刍动物所测得的数值相当，这表明它们非常适合混合日粮。
