Dietary selection of sheep grazing the semi-arid grasslands of Inner Mongolia, China at different grazing intensities.
Dietary selection of sheep grazing the semi-arid grasslands of Inner Mongolia, China at different grazing intensities.
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DOI：
10.1111/j.1439-0396.2009.00928.x
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发表时间：
2009-08
影响因子：
2.7
通讯作者：
A. Schiborra;M. Gierus;H. Wan;T. Glindemann;C. Wang;A. Susenbeth;F. Taube
中科院分区：
文献类型：
--
作者：
A. Schiborra;M. Gierus;H. Wan;T. Glindemann;C. Wang;A. Susenbeth;F. Taube
以采食牧草和供饲牧草的有机质消化率（OMD）差异为指标，研究内蒙古半干旱草原放牧绵羊的日粮选择。以粪氮作为采食牧草的消化率指数（FOMD），以霍恩海姆产气试验的产气量估算供草的消化率（GOMD）。假设在牧草丰富的情况下，放牧动物对低质量牧草的选择导致了FOMD与GOMD之间的差异较大。在放牧试验中，比较了半干旱草地1.5、3.0、4.5、6.0、7.5和9.0羊/ha 6种放牧强度，分别代表轻度和重度放牧强度。牧草供给量随放牧强度的增加而减少。对FOMD和GOMD的独立统计分析表明，放牧强度对两种OMD测定值（FOMD: 54.0 ~ 57.3%, GOMD: 55.2 ~ 57.5%）差异不显著（p < 0.05）。FOMD和GOMD在放牧强度上的差异不显著，但在-4到1个百分点的采样周期之间存在差异。综上所述，2005年内蒙古半干旱草原羊在放牧强度不同的情况下，并没有因为牧草营养成分的同质性而选择饲料。
The objective of this study was to investigate dietary selection of sheep grazing semi-arid grassland in Inner Mongolia, China, using the difference in organic matter digestibility (OMD) of herbage ingested and herbage on offer as indicator for selection. Faecal N was used as digestibility index for herbage ingested (FOMD), while OMD of herbage on offer (GOMD) was estimated from gas production obtained by the Hohenheim gas test. It was hypothesized that the difference between FOMD and GOMD is high, when grazing animals select against low quality herbage provided that herbage is abundant. In a grazing experiment, six grazing intensities (1.5, 3.0, 4.5, 6.0, 7.5 and 9.0 sheep/ha), representing light to very heavy grazing intensity for the semi-arid grassland, were compared. The amount of herbage on offer decreased with increasing grazing intensity. Independent statistical analysis of FOMD and GOMD showed that the differences between grazing intensities for both OMD determinations (FOMD: 54.0-57.3%, GOMD: 55.2-57.5%) were not significant (p > 0.05). The difference between FOMD and GOMD was not significant for grazing intensities, but varied between sampling periods from -4 to 1 percentage units. In conclusion, the lack of significance for the difference between FOMD and GOMD suggests that for the semi-arid grassland of Inner Mongolia, China, sheep did not select their feed due to a homogeneous nutritional composition of herbage on offer in 2005, regardless of grazing intensity.