Ruminal volatile fatty acids and ammonia in cattle grazing dry tropical pastures
Ruminal volatile fatty acids and ammonia in cattle grazing dry tropical pastures
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放牧干燥热带牧场的牛的瘤胃挥发性脂肪酸和氨
DOI：
10.1017/s0021859600054836
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发表时间：
1976
期刊：
影响因子：
--
通讯作者：
P. Kennedy
中科院分区：
文献类型：
--
作者：
M. Playne;P. Kennedy
总结总VFA浓度，个别VFA的比例和氨浓度在瘤胃的牛放牧热带牧场7个月在旱季进行了比较，这些代谢物的浓度在牛放牧在雨季和牛在围栏两个牧场干草。无论是总挥发性脂肪酸，也没有氨浓度的变化期间，新的牧草生长在旱季，虽然活重发生的反应。进一步的证据表明，总挥发性脂肪酸的浓度是不敏感的饲料质量的差异，在围栏实验。VFA浓度在雨季比旱季高53%，氨浓度从旱季的62毫克/升增加到雨季的128毫克/升。在旱季，瘤胃氨含量与采食量呈显著正相关（r = 0.58，P < 0.001）。个体VFA比例差异不大。同一样品中乙酸含量最高（79.1%），丁酸含量最低（5.10%）。异戊酸和戊酸比例与瘤胃氨呈显著正相关（P <0.001）。在放牧牛，VFA和氨的浓度在他们的瘤胃采取每小时的时间间隔在07.00和18.00小时之间没有随时间变化很大。在10.00 h之前采集的样品具有较高的VFA和氨水平。
Summary Total VFA concentrations, individual VFA proportions and ammonia concentrations in the rumen of cattle grazing tropical pastures for 7 months during the dry season were compared with concentrations of these metabolites in cattle grazing in the wet season and in cattle given two pasture hays in pens. Neither total VFA nor ammonia concentrations were altered by periods of new pasture growth within the dry season although responses in live weight occurred. Further evidence that concentrations of total VFA were insensitive to differences in feed quality was shown in the pen experiment. VFA concentrations were 53% higher in the rainy season than in the dry season and ammonia concentrations doubled from 62 mg/1 in the dry to 128 mg/1 in the wet season. Ruminal ammonia was related to ingested bolus N concentration (r = 0·58, P < 0.001) during the dry season. Individual VFA proportions did not vary greatly. The highest acetic (79·1%) and lowest butyric acid (5.10%) proportions occurred in the same sample. Iso-valeric and valeric acid proportions were related positively to ruminal ammonia (P < 0·001). In grazing cattle, concentrations of VFA and ammonia in their rumen taken at hourly intervals between 07.00 and 18.00 h did not vary greatly with time. Samples taken before 10.00 h had higher VFA and ammonia levels.