PDF(Pubmed)
Abstract：
BACKGROUND: It was proposed that camels are more effective than other livestock species in selecting plants for their nutritional value. They may self-regulate their voluntary feed intake to satisfy their nutritional needs. This study was designed to investigate camels\' feeding selectivity and ability to cover nutritional requirements when grazing alfalfa (high in protein) and/ or barley (high in energy) in a desert climate.
METHODS: Eighteen lactating camels were equally divided into three feeding treatments. They grazed daily on alfalfa, barley, or a mixed pasture of both, for two periods of one month each. The concentrate supplement was individually administered at 40 g/kg BW0.75, divided into two equal parts, in the morning and in afternoon. Total energy expenditure (EE) was estimated by heart rate (HR) monitors for 48 h after being calibrated by oxygen consumption using an upgraded face mask open-circuit respiratory system.
RESULTS: During the first period, camels had a greater forage intake and digestibility when they grazed barley rather than alfalfa, while those grazing mixed pasture performed intermediately. In the second period, camels had a similar forage intake and digestibility among treatments due to a decline in barley intake and digestibility compared to the first period, which was expected since the preferred plant part gradually shifted from barley grains to predominantly straw as a function of time. Similar HR and EE were found across periods and treatments. As a result of greater gross and digestible energy intake in period 1, a better energy balance in period 1 was observed compared to period 2. Camels better utilize barley than alfalfa. Grazing on barley had a higher energy balance than grazing alfalfa alone or in combination with barley. However, camels grazing barley produced lower milk yield and energy than those grazing alfalfa alone or in combination with barley, with no interaction detected between period and treatment.
CONCLUSIONS: Lactating camels are able to self-regulate their voluntary intake to cover their energy requirements when they are grazing barley and/or alfalfa supplemented with a concentrate supplement at 40 g/kg BW0.75. Grazing barley is better utilized by camels than alfalfa. The chemical and physical properties of plant species play an important role in the selectivity of foraging camels. It also impacts their intake and digestibility, which is negatively associated with the proportion of cell wall content consumed.
METHODS: Eighteen lactating camels were equally divided into three feeding treatments. They grazed daily on alfalfa, barley, or a mixed pasture of both, for two periods of one month each. The concentrate supplement was individually administered at 40 g/kg BW0.75, divided into two equal parts, in the morning and in afternoon. Total energy expenditure (EE) was estimated by heart rate (HR) monitors for 48 h after being calibrated by oxygen consumption using an upgraded face mask open-circuit respiratory system.
RESULTS: During the first period, camels had a greater forage intake and digestibility when they grazed barley rather than alfalfa, while those grazing mixed pasture performed intermediately. In the second period, camels had a similar forage intake and digestibility among treatments due to a decline in barley intake and digestibility compared to the first period, which was expected since the preferred plant part gradually shifted from barley grains to predominantly straw as a function of time. Similar HR and EE were found across periods and treatments. As a result of greater gross and digestible energy intake in period 1, a better energy balance in period 1 was observed compared to period 2. Camels better utilize barley than alfalfa. Grazing on barley had a higher energy balance than grazing alfalfa alone or in combination with barley. However, camels grazing barley produced lower milk yield and energy than those grazing alfalfa alone or in combination with barley, with no interaction detected between period and treatment.
CONCLUSIONS: Lactating camels are able to self-regulate their voluntary intake to cover their energy requirements when they are grazing barley and/or alfalfa supplemented with a concentrate supplement at 40 g/kg BW0.75. Grazing barley is better utilized by camels than alfalfa. The chemical and physical properties of plant species play an important role in the selectivity of foraging camels. It also impacts their intake and digestibility, which is negatively associated with the proportion of cell wall content consumed.
摘要：
背景：有人提出，骆驼在选择具有营养价值的植物方面比其他牲畜物种更有效。他们可以自我调节他们的自愿饲料摄入量以满足他们的营养需求。这项研究旨在研究在沙漠气候中放牧苜蓿（高蛋白质）和/或大麦（高能量）时，骆驼的饲养选择性和满足营养需求的能力。
方法：将18只泌乳骆驼平均分为3种饲养处理。他们每天在苜蓿上吃草，大麦,或者两者的混合牧场，为期两个月，每个月。浓缩补充剂以40g/kgBW0.75单独施用，分为两等份，在早上和下午。在使用升级的面罩开路呼吸系统通过耗氧量进行校准后，通过心率（HR）监测器估算48小时的总能量消耗（EE）。
结果：在第一阶段，骆驼在吃大麦而不是苜蓿时的饲料摄入量和消化率更高，而那些放牧混合牧场则表现在中间。在第二阶段，与第一阶段相比，由于大麦摄入量和消化率下降，骆驼在处理中的饲料摄入量和消化率相似，这是预期的，因为随着时间的推移，首选的植物部分逐渐从大麦谷物转移到主要是稻草。在不同时期和治疗中发现了相似的HR和EE。由于在第1期摄入了更多的总能量和可消化能量,与第2期相比,在第1期观察到了更好的能量平衡。骆驼比苜蓿更好地利用大麦。在大麦上放牧比单独放牧苜蓿或与大麦结合放牧具有更高的能量平衡。然而,骆驼放牧大麦比单独放牧苜蓿或与大麦结合放牧的骆驼产奶量和能量低，在周期和治疗之间没有检测到相互作用。
结论：泌乳骆驼在放牧大麦和/或苜蓿并补充40g/kgBW0.75的浓缩补充剂时，能够自我调节其自愿摄入以满足其能量需求。放牧大麦比苜蓿更好地被骆驼利用。植物种类的化学和物理性质在骆驼觅食的选择性中起着重要作用。它也会影响它们的摄入量和消化率，这与消耗的细胞壁含量的比例呈负相关。
方法：将18只泌乳骆驼平均分为3种饲养处理。他们每天在苜蓿上吃草，大麦,或者两者的混合牧场，为期两个月，每个月。浓缩补充剂以40g/kgBW0.75单独施用，分为两等份，在早上和下午。在使用升级的面罩开路呼吸系统通过耗氧量进行校准后，通过心率（HR）监测器估算48小时的总能量消耗（EE）。
结果：在第一阶段，骆驼在吃大麦而不是苜蓿时的饲料摄入量和消化率更高，而那些放牧混合牧场则表现在中间。在第二阶段，与第一阶段相比，由于大麦摄入量和消化率下降，骆驼在处理中的饲料摄入量和消化率相似，这是预期的，因为随着时间的推移，首选的植物部分逐渐从大麦谷物转移到主要是稻草。在不同时期和治疗中发现了相似的HR和EE。由于在第1期摄入了更多的总能量和可消化能量,与第2期相比,在第1期观察到了更好的能量平衡。骆驼比苜蓿更好地利用大麦。在大麦上放牧比单独放牧苜蓿或与大麦结合放牧具有更高的能量平衡。然而,骆驼放牧大麦比单独放牧苜蓿或与大麦结合放牧的骆驼产奶量和能量低，在周期和治疗之间没有检测到相互作用。
结论：泌乳骆驼在放牧大麦和/或苜蓿并补充40g/kgBW0.75的浓缩补充剂时，能够自我调节其自愿摄入以满足其能量需求。放牧大麦比苜蓿更好地被骆驼利用。植物种类的化学和物理性质在骆驼觅食的选择性中起着重要作用。它也会影响它们的摄入量和消化率，这与消耗的细胞壁含量的比例呈负相关。
