Ultrasonographic measurements of accessory sex glands, ampullae, and urethra of normal stallions of various size types

For the purpose of establishing clinical reference values, this paper reports results of ultrasonographic examination and measurement of accessory sex glands, ampullae, and the pelvic urethra of 102 mature, healthy breeding stallions (2–29 years of age) of various size types (7 Miniature Horses, 27 small ponies, 53 light horses and 15 heavy horses). Examinations were done per rectum in mostly unsedated stallions using an Aloka 210 scanner with a 7.5 MHz linear veterinary transrectal transducer (Corometrics Medical Systems, Inc., North Wallingford, CT, USA). Most measures of accessory sex glands, ampullae and the urethra were larger in horses of larger sizes. Except for vesicular glands, the majority of the measures for all glands were smaller for Miniature Horses and ponies than for light horses and heavy horses ( P