Descriptive study of a method for identification of the pylorus by ultrasound in lactating Holstein cows.

The purpose of this study was to develop a method for identification of the pylorus, in lactating Holstein cows, based on ultrasound examination and the use of external anatomical landmarks such as the mammary vein . An ultrasound method based on successive identification of 4 internal anatomical landmarks was developed. The procedure was performed 157 times, on clinically healthy lactating Holstein cows, with a portable ultrasound machine equipped with a 3.5 MHz curvilinear probe. The pylorus was identified with a success rate of 98.7% (155 times out of 157 procedures). The average position of the pylorus was noted near the entrance of the right mammary vein, with a craniocaudal and dorsoventral dispersion. This ultrasound method of identifying the pylorus is simple, effective, and rapid.