Beyond breeding soundness: the role of semen quality and quantity in subfertility

摘要

Infertility and subfertility in bulls and females can wreak havoc on a breeding program. While many measures of infertility exist, little is known about subfertility. Subfertility is diminished reproductive performance. It's less noticeable than infertility, but can still cost producers thousands of dollars a year. But there is hope. Producers can now identify telltale signs of subfertility in males. Typically, producers have measured breeding success or failure through pregnancy rates, often culling cows rather than bulls when rates drop too low. Richard Saacke of Virginia Tech suggests there are two components that determine pregnancy rate from a male standpoint: 1. Semen's ability to fertilize an egg (i.e., fertilization rate); and 2 Whether ornot the embryo developed normally and hatched in time to signal pregnancy to the dam. While most producers are accustomed to using breeding soundness exams (BSE) as a test for fertility, BSE may be able to tell us even more about the integrity of the sperm and its probability to fertilize an egg. Specifically, semen motility and morphology may help producers better manage their artificial insemination (AI) program.