Ultrasonographic examination of the udder in sheep

Objective of the paper is to review work relevant to ultrasonographic examination of the udder of ewes. Udder structures that can be readily imaged ultrasonographically (B-mode or Doppler examination) are mammary parenchyma, the gland cistern, the lactiferous ducts, the mammary vessels, the teat and the supramammary lymph nodes. Conventional diagnostic approaches for mastitis (i.e., combination of clinical, bacteriological and cytological examinations) provide a good means for diagnosis of mastitis; hence, in diagnosis of mastitis, use of ultrasonographic examination has, in general, an ancillary role, for example during investigation of cases, in which clinical diagnosis alone can prove of little help, e.g., in animals with small-sized, deep mammary nodules. The technique can be used at the end of a lactation period as part of routine udder examination performed at that point, which would provide additional useful information, e.g., regarding presence of abcesses or of increased quantity of fibrous tissue. Further, estimation of the dimensions of gland cistern of ewes in a flock would support decisions regarding milking frequency to be applied. Finally, examination of the teat can provide indications regarding optimising use of the milking machine by applying the appropriate settings.