Changes in faecal δ13C in response to changing proportions of legume (C3) and grass (C4) in the diet of sheep and cattle
Changes in faecal δ13C in response to changing proportions of legume (C3) and grass (C4) in the diet of sheep and cattle
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DOI：
10.1017/s0021859600077704
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发表时间：
1991-04
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影响因子：
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通讯作者：
D. B. Coates;A. P. A. Van Der Weide-A.-P.-A.-Van-Der-Weide-2288270791;J. D. Kerr
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文献类型：
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作者：
D. B. Coates;A. P. A. Van Der Weide-A.-P.-A.-Van-Der-Weide-2288270791;J. D. Kerr
1986年用圈养的绵羊和牛饲喂不同比例的豆科牧草(C3)和牧草(C4)干草进行饲养试验。饮食中δ13C在几天内或之间的大幅波动与粪便中δ13C的波动要小得多相关。当饮食中豆类的总比例保持不变时，粪便中的δ13C几乎没有变化，无论在一天中什么时候吃豆类相对于草。在昆士兰州柱花草/草牧场放牧的牛在短期内或在两天之间只显示出微小的粪便δ13C变化。当饮食发生变化时，一组中的所有动物都表现出类似的趋势。粪便中δ13C的日复一日的变化反映了饮食选择的微小但真实的变化。结论是，单个粪便样本的δ13C可靠地反映了自由放牧反刍动物过去3-4天的综合饮食，因此估计饲料组成的粪便样本的频率和模式可能是由可靠性以外的考虑决定的。
SUMMARY Feeding studies were conducted in 1986 with penned sheep and cattle fed legume (C3) and grass (C4) hays mixed in different proportions. Large fluctuations in diet δ13C within or between days were associated with much smaller fluctuations in the δ13C of faeces. When the overall daily legume percentage in the diet was held constant, there was little variation in the δ13C of faeces irrespective of when during the day the legume, relative to the grass, was eaten. Cattle set stocked on Stylosanthes/grass pastures in Queensland showed only minor variations in faecal δ13C within or between days in the short term. All animals within a group showed similar trends when the diet was changing. The changes in the δ13C of faeces from day to day reflected small but real changes in diet selection. It was concluded that the δ13C of a single faecal sample reliably reflects the integrated diet over the previous 3–4 days of a free-grazing ruminant so that the frequency and pattern of faecal sampling for estimating diet composition may be determined by considerations other than reliability