Comparison of TRIS and TRICO egg yolk extenders for cryopreservation of Simmental and Limousin bull semen

This study evaluated the effectiveness of TRIS egg yolk and TRICO egg yolk extenders in maintaining post-thaw sperm quality and controlling bacterial load in beef cattle (Bos taurus). Semen was collected from six bulls, three Simmental and three Limousin, with ages of 3–8 years and weights of 664–910 kg. Each ejaculate was divided into two aliquots and diluted with either TRIS egg yolk or TRICO egg yolk extenders. The observed parameters were motility, viability, abnormality, concentration, membrane plasma integrity (MPI), intact acrosome cap (IAC), capacitation status, chromatin damage and sperm DNA fragmentation (SDF), as well as presumptive bacterial isolation of E. coli, Staphylococcus spp. and Pseudomonas spp. Different extenders significantly affected sperm concentration, chromatin damage and SDF (P < 0.05). TRICO egg yolk had the highest sperm concentration in Limousin semen and the lowest Staphylococcus spp. counts, while maintaining motility, viability, abnormality, MPI, IAC and non-capacitated sperm percentages at levels comparable to TRIS egg yolk. However, TRICO egg yolk was also associated with increased chromatin damage and SDF, suggesting a potential trade-off between antibacterial control and sperm DNA integrity. Therefore, the TRICO egg yolk formulation requires further optimization to minimize DNA damage and establish its reliability for frozen semen production.