INRA, UMR 1289 TANDEM, Tissus Animaux, Nutrition, Digestion, Ecosystème et Métabolisme, F-31326 Castanet-Tolosan, France.
J Dairy Sci. 2012 Mar;95(3):1500-12. doi: 10.3168/jds.2011-4902.
The objectives of this study were to characterize the establishment of ruminal fermentation and enzymatic activities in dairy calves from birth to weaning (d 83). Six Holstein calves, immediately separated from their mother at birth, were fed colostrum for 3 d after birth, and thereafter milk replacer, starter pelleted concentrate, and hay until d 83 of age. Ruminal samples were collected from each calf every day for the first 10 d, and additionally at d 12, 15, 19, 22, 26, 29, 33, 36, 40, 43, 47, 50, 55, 62, 69, and 83. Ruminal samples were collected 1h after milk feeding with a stomach tube. The pH and redox potential (E(h)) were immediately measured. Samples were kept for further determination of ammonia nitrogen (NH(3)-N) and volatile fatty acid (VFA) concentrations, and xylanase, amylase, urease, and protease activities. Ruminal pH averaged 6.69, 5.82, and 6.34, from d 1 to 9, d 10 to 40, and d 43 to 83 of age, respectively. At first day of life, the ruminal E(h) value was positive (+224 mV). From d 2 to 9, d 10 to 40, and d 43 to 83 of age, ruminal E(h) averaged -164, -115, and -141 mV, respectively. From d 1 to 3, d 4 to 22, and d 26 to 83 of age, NH(3)-N concentration averaged 60.1, 179.8, and 58.2 mg/L, respectively. No VFA were detected in ruminal samples collected on d 1 of life of calves. From d 2 to 10 and d 12 to 83 of age, ruminal total VFA concentration averaged 19.5 and 84.4mM, respectively. Neither ruminal xylanase or amylase activities were observed at d 1 of age. From d 5 to 15 and d 19 to 83 of age, the xylanase activity averaged 182.2 and 62.4 μmol of sugar released per hour per gram of ruminal content dry matter (DM), respectively. From d 5 to 83 of age, the amylase activity reached 35.4 μmol of sugar released per hour per gram of ruminal content DM. The ruminal ureolytic activity was observed with an average value of 6.9 μg of NH(3)-N released per minute per gram of ruminal content DM over the 83-d experimental period. From d 1 to 4 and d 5 to 83 of age, the proteolytic activity was 8.2 and 27.9 optical density units per hour per gram of ruminal content DM, respectively. The fermentative and enzymatic activities were rapidly established in the rumen from d 2 after birth. Most parameters did not evolve further after 1 mo of age.
本研究的目的是描述奶牛犊牛从出生到断奶（第 83 天）期间瘤胃发酵和酶活性的建立情况。6 头荷斯坦奶牛犊牛在出生后立即与母亲分离，出生后第 3 天开始饲喂初乳，之后饲喂代乳粉、开食料颗粒状浓缩料和干草，直至第 83 天。在出生后的前 10 天，每天从每头犊牛身上采集瘤胃液样本，此外，在第 12、15、19、22、26、29、33、36、40、43、47、50、55、62、69 和 83 天也采集瘤胃液样本。在喂奶后 1 小时用胃管采集瘤胃液。立即测量 pH 值和氧化还原电位（Eh）。将样本保留以进一步测定氨氮（NH3-N）和挥发性脂肪酸（VFA）浓度以及木聚糖酶、淀粉酶、脲酶和蛋白酶活性。从第 1 天到第 9 天、第 10 天到第 40 天和第 43 天到第 83 天，瘤胃 pH 值分别为 6.69、5.82 和 6.34。在生命的第一天，瘤胃 Eh 值为正值（+224 mV）。从第 2 天到第 9 天、第 10 天到第 40 天和第 43 天到第 83 天，瘤胃 Eh 值平均分别为-164、-115 和-141 mV。从第 1 天到第 3 天、第 4 天到第 22 天和第 26 天到第 83 天，NH3-N 浓度分别平均为 60.1、179.8 和 58.2 mg/L。在犊牛出生的第 1 天，在瘤胃液样本中未检测到 VFA。从第 2 天到第 10 天和第 12 天到第 83 天，瘤胃液总 VFA 浓度分别平均为 19.5 和 84.4 mM。在第 1 天，未观察到瘤胃木聚糖酶或淀粉酶活性。从第 5 天到第 15 天和第 19 天到第 83 天，木聚糖酶活性分别平均为 182.2 和 62.4 μmol 释放糖/小时/克瘤胃内容物干物质（DM）。从第 5 天到第 83 天，淀粉酶活性达到 35.4 μmol 释放糖/小时/克瘤胃内容物 DM。在 83 天的实验期间，瘤胃脲酶活性的平均值为每分钟每克瘤胃内容物 DM 释放 6.9 μg NH3-N。从第 1 天到第 4 天和第 5 天到第 83 天，蛋白酶活性分别为 8.2 和 27.9 光密度单位/小时/克瘤胃内容物 DM。从出生后第 2 天开始，瘤胃中的发酵和酶活性迅速建立。大多数参数在 1 个月大后不再进一步发展。
