A Comparison of the Ability of Three Commercially Available Diluents to Maintain the Motility of Cold Stored Stallion Semen

The objective of this study was to compare the ability of three commercially available extenders to promote poststorage motility of stallion spermatozoa stored at 5°C with and without centrifugation to remove the seminal plasma. Diluents tested included skim milk glucose (SKMG), INRA 96, and VMD-Z. All diluents were tested with (-SP) and without (+SP) centrifugation to remove most of the seminal plasma. In experiment I, after 48 and 72 hours of storage, total (TM) and progressive (PM) motility values were higher (P ≤.05) for those aliquots subjected to the INRA 96-SP as compared with either SKMG treatment. After 72 hours of storage, PM of spermatozoa stored in VMD-Z-SP was superior to that of spermatozoa stored in SKMG regardless of the presence of seminal plasma (P ≤.05). In the second experiment, after 48 hours of storage, PM of spermatozoa subjected to the INRA 96-SP and VMD-Z-SP treatments were superior (P ≤.05) to those for all treatments that had been stored without removal of seminal plasma. Removal of the seminal plasma and resuspension of the sperm pellet with either INRA 96 or VMD-Z resulted in TM after 48 hours of storage that were similar to those obtained after 24 hours of storage.