Technique

Ultrasonography is an integral part of contemporary bovine medicine. For most diagnostic work, a 3.5 MHz transducer provides adequate depth and good resolution. A 2.5 MHz transducer can be used to examine structures that are more than 20 cm from the abdominal wall; however, the resolution is poorer. Structures close to the surface of the body are examined with a 5.0, 7.5 or even 10.0 MHz transducer. In principle, the depth of penetration of the sound waves and the resolution are inversely related; a low frequency is associated with greater penetration and lower resolution, and vice versa. The hair in the area to be examined must be clipped. Further information about ultrasonography of internal organs in cattle may be found in a text24 and in numerous publiccations.16,17,37 In bovine medicine, ultrasonography is used to examine the following areas and organs