A Simple Test of Seminal Fluid Chemistry and Its Potential Impact on Cryopreservation

Cryopreservation is currently the only effective tool for long-term storage of semen in most species. However, it is well-recognized that, even in species that freeze well, some individuals resist cryopreservation. Work from this laboratory has demonstrated a relationship between maternal lipid content and the chemical constitution of the embryos they produce. The objective of the present study was to determine if a similar relationship might exist in paternal body chemistry and the animal’s semen sample and if such a difference could be determined with a simple weight test. Semen samples were obtained from cattle with known differences in body composition. The samples first underwent semen analysis and were then prepared as either cell-free (CF) or neat specimens (NS). Known volumes of each sample were weighed, and the remainder of the samples was analyzed for lipids, total proteins, and total carbohydrates using a series of spectrophotometric assays and blood chemistry techniques. As expected, weight differences were seen in the CF vs NS preparations of individual semen samples (p < 0.001). Differences were also found in triglycerides (p < 0.001), glucose (p < 0.001), total protein (p < 0.001), and fructose (p < 0.009) of individuals with differing body composition. Statistical analysis suggested a non-linear correlation between the observed weights and total protein (p < 0.047) as well as triglyceride levels (p < 0.003). Together, these data suggest it might be possible to develop an algorithm to allow adjustment in cryoprotectants based on a simple weight procedure, allowing modification of cryoprotectants on an individual basis and potentially improving outcomes for valuable animals currently classified as “poor freezers”.