Measurement of bovine sperm nuclear shape using Fourier harmonic amplitudes

An objective method for measuring bovine sperm nuclear shape was developed. Digital images of bovine sperm stained with propidium iodide were collecte d and Fourier functions used to describe the perimeters of individual sperm nuclei. Harmonic amplitudes from Fourier functions were first shown to be independent of sperm orientation during digitization. Sperm from 12 differe nt bulls were used, and 6 harmonic amplitudes per sperm were found to adequ ately describe sperm nuclear shape. Based on harmonic amplitudes 0 to 5, cl uster analysis was used to generate 20 different groups. Sperm within group s had similar morphologies and groups were distinguished by statistically u nique shape characteristics. Harmonic amplitudes 0 to 5 can be used to dist inguish previously reported abnormalities such as tapered, pyriform, macroc ephalic, and microcephalic, as well as gradations in between. Furthermore, differences were detected among bull harmonic amplitude centroids (P < .05) , indicating that bulls differ in mean sperm nuclear shape.