Kirchman Stephanie E, Pinedo Pablo J, Maunsell Fiona P, Risco Carlos A, Donovan G Arthur
J Am Vet Med Assoc. 2017 Sep 1;251(5):580-586. doi: 10.2460/javma.251.5.580.
OBJECTIVE To identify milk component alterations that might be useful for detecting cows with rumen indigestion. DESIGN Prospective case-control study. ANIMALS 23 Holstein cows with rumen indigestion (cases) and 33 healthy cohorts (controls) from 1 herd. PROCEDURES Cases were defined as cows between 30 and 300 days postpartum with a > 10% decrease in milk yield for 2 consecutive milkings or > 20% decrease in milk yield from the 10-day rolling mean during any milking, abnormally decreased rumen motility, and no other abnormalities. Each case was matched with 2 healthy cows (controls) on the basis of pen, parity, days postpartum, and mean milk yield. Some cows were controls for multiple cases. All cows underwent a physical examination and collection of a rumen fluid sample for pH measurement at study enrollment. Individual-cow milk yield and milk component data were obtained for the 16 milkings before and after study enrollment. Rumen motility and pH and milk components were compared between cases and controls. RESULTS Rumen motility for cases was decreased from that of controls. Cases had an abrupt increase in milk fat percentage and the milk fat-to-lactose ratio during the 2 milkings immediately before diagnosis of rumen indigestion. Receiver operating characteristic analyses revealed that a 10% increase in the milk fat-to-lactose ratio had the highest combined sensitivity (57%) and specificity (85%) for identifying cows with rumen indigestion. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that a positive deviation in the milk fat-to-lactose ratio might be useful for identifying cows with rumen indigestion.
目的 确定可能有助于检测瘤胃消化不良奶牛的乳汁成分变化。 设计 前瞻性病例对照研究。 动物 来自1个牛群的23头患有瘤胃消化不良的荷斯坦奶牛（病例）和33头健康牛群（对照）。 程序 将病例定义为产后30至300天的奶牛，连续2次挤奶时产奶量下降超过10%，或在任何一次挤奶时较10天滚动平均值产奶量下降超过20%，瘤胃蠕动异常降低，且无其他异常。根据牛栏、胎次、产后天数和平均产奶量，将每头病例与2头健康奶牛（对照）进行匹配。一些奶牛作为多个病例的对照。所有奶牛在研究入组时均接受体格检查并采集瘤胃液样本进行pH值测量。获取研究入组前后16次挤奶的个体奶牛产奶量和乳汁成分数据。比较病例组和对照组的瘤胃蠕动、pH值和乳汁成分。 结果 病例组的瘤胃蠕动较对照组降低。病例组在瘤胃消化不良诊断前的2次挤奶期间，乳脂率和乳脂与乳糖比值突然升高。受试者工作特征分析显示，乳脂与乳糖比值升高10%对识别瘤胃消化不良奶牛具有最高的综合敏感性（57%）和特异性（85%）。 结论及临床意义 结果表明，乳脂与乳糖比值的正向偏差可能有助于识别瘤胃消化不良的奶牛。
