Sperm acrosome associated 3 protein (SPACA3) is a unique, intra-acrosomal, conventional-type lysozyme-like protein of mammalian spermatozoa. SPACA3 is present in all stages of ovarian follicles and is localized to granulosa cells and ooplasma in humans, mice, cows, dogs, and cats. The objective of this study was to determine if equine...