Veterinarians and breeding farm managers regularly examine stallion semen samples under a microscope to check sperm motility, especially samples from horses with suspected fertility issues. But while they can check sperm for this common fertility measure on the farm or in the average veterinary clinic, evaluating sperm morphology–to ensure the head, midpiece, and tail are appropriately shaped–is a more difficult process they often skip. University of Florida (UF) researchers recently studied the plausibility of using an inexpensive, efficient method for examining sperm morphology.

Some laboratories that analyze semen samples maintain equipment for conducting phase-contrast microscopy to assess morphology, noted Malgorzata Pozor, DVM, PhD, Dipl. ACT, of the UF’s Department of Large Animal Clinical Sciences, at the 2012 American Association of Equine Practitioners’ Convention, held Dec. 1-5 in Anaheim, Calif. "It is an accurate technique that is superior to many other methods, such as eosin-nigrosin staining, for identifying abnormalities in the midpieces, head, and acrosome (a specialized structure on the head of the sperm that helps penetrate the egg during fertilization)," she said.

The problem is that some veterinarians prefer to perform semen analysis on-site, rather than sending the sample to specialized laboratories. Further, phase-contrast microscopes are expensive. Bright-field microscopes are far more economical and are already standard fixtures in most veterinary practices.

"Being able to accurately assess sperm morphology using bright-field microscopy rather than phase-contrast microscopy would be ben