Stallion owners must determine if their stallions have what it takes physically to make a good breeding prospect, including good semen quality, before the start of the breeding season. In his presentation at the sixth annual Equine School at the Alltech Symposium, Peter Sheerin, DVM, Dipl. ACT, a theriogenologist at Rood and Riddle Equine Hospital in Lexington, Ky., asked the audience: “What is good semen quality?”

“One definition of good semen quality is an ejaculate that contains a high population of normal sperm cells that provides a normal rate of fertilization (80-90%),” he said. However, he noted that pregnancy rates don’t indicate fertility rates because of the high occurrence of early embryonic loss in the mare