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 (anulus venae subcutaneae abdominis). 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.