Herrera-Saldana R, Gomez-Alarcon R, Torabi M, Huber J T
Department of Animal Sciences, University of Arizona, Tucson 85721.
J Dairy Sci. 1990 Jan;73(1):142-8. doi: 10.3168/jds.S0022-0302(90)78657-2.
A 4 x 4 Latin square design with four multiparous cows in midlactation fitted with duodenal cannulae was used to determine the effect of synchronization of protein and starch degradation in the rumen on nutrient availability in lactating cows. As major starch and protein sources, diets contained: barley plus cottonseed meal; barley plus brewers dried grains; milo plus cottonseed meal; and milo plus brewers dried grains. Experimental periods were 12 d and consisted of 8 d adjustment and 4 d collection. Chromium oxide was used as the marker to determine digestibility and nutrient flow from the rumen. Microbial protein synthesis was estimated from nucleic acid content in duodenal samples. Apparent and corrected rumen digestibilities of DM, organic matter, CP, and starch were higher for diets containing barley than milo but were not affected by protein source. For diets containing barley and milo, starch digested postruminally averaged 820 and 2190 g/d and percentage digestibility was 70 and 77%. No difference among diets was found in DM, organic matter, and CP flow to the small intestine; however, microbial N synthesis was higher in diets containing barley than in diets containing milo.
采用4×4拉丁方设计，选取4头处于泌乳中期、装有十二指肠套管的经产奶牛，以确定瘤胃中蛋白质和淀粉降解同步化对泌乳奶牛养分利用率的影响。作为主要的淀粉和蛋白质来源，日粮包含：大麦加棉籽粕；大麦加啤酒糟；高粱加棉籽粕；以及高粱加啤酒糟。试验期为12天，包括8天的适应期和4天的收集期。使用氧化铬作为标记物来测定瘤胃的消化率和养分流量。根据十二指肠样本中的核酸含量估算微生物蛋白质合成量。含大麦日粮的干物质、有机物、粗蛋白和淀粉的表观瘤胃消化率和校正瘤胃消化率高于含高粱日粮，但不受蛋白质来源影响。对于含大麦和高粱的日粮，瘤胃后消化的淀粉平均分别为820克/天和2190克/天，消化率分别为70%和77%。日粮之间在进入小肠的干物质、有机物和粗蛋白流量方面未发现差异；然而，含大麦日粮中的微生物氮合成量高于含高粱日粮。
