Gorewit R C, Aromando M C, Bristol D G
Department of Animal Science, Cornell University, Ithaca, NY 14853.
J Dairy Sci. 1989 Jul;72(7):1918-28. doi: 10.3168/jds.S0022-0302(89)79311-5.
Lactating cattle were used to validate a transit time ultrasonic blood flow metering system for measuring mammary gland arterial blood flow. Blood flow probes were surgically placed around the right external pudic artery. An electromagnetic flow probe was implanted in tandem with the ultrasonic probe in two cows for comparative measurements. The absolute accuracy of the implanted flow probes was assessed in vivo by mechanical means on anesthetized cows after 2 to 3 wk of implantation. The zero offset of the ultrasonic probes ranged from -12 to 8 ml/min. When the ultrasonic probe was properly implanted, the slopes of the calibration curves were linear and ranged from .92 to .95, tracking absolute flow to within 8%. The transit time instrument's performance was examined under a variety of physiological conditions. These included milking and hormone injections. The transit time ultrasonic flow meter accurately measured physiological changes in mammary arterial blood flow in chronically prepared conscious cattle. Blood flow increased 29% during milking. Epinephrine decreased mammary blood flow by 90 to 95%. Oxytocin doses increased mammary blood flow by 15 to 24%.
使用泌乳母牛来验证一种用于测量乳腺动脉血流量的通过时间超声血流测量系统。将血流探头通过手术放置在右侧阴部外动脉周围。在两头母牛中，将电磁血流探头与超声探头串联植入，用于进行对比测量。在植入2至3周后，通过机械方法在麻醉的母牛身上对植入的血流探头的绝对准确性进行体内评估。超声探头的零偏移范围为-12至8毫升/分钟。当超声探头正确植入时，校准曲线的斜率呈线性，范围为0.92至0.95，绝对流量追踪误差在8%以内。在各种生理条件下检查通过时间仪器的性能。这些条件包括挤奶和激素注射。通过时间超声流量计准确测量了长期准备的清醒母牛乳腺动脉血流量的生理变化。挤奶期间血流量增加了29%。肾上腺素使乳腺血流量减少了90%至95%。催产素剂量使乳腺血流量增加了15%至24%。
