Effect of the individual inbreeding values on the sperm motility patterns in Angus cattle

TERAN ESTER; PIROSANTO YAMILA; AZCONA FLORENCIA; TRIBULO PAULA; MOLINA ANTONIO; DEMYDA-PEYRÁS, SEBASTIÁN

Bologna

Congreso; 19th International Congress on Animal Reproduction; 2022

Inbreeding can affect the sperm motility average and subpopulation structure in cattle. However, it has been suggested that their effect is not the same among breeds. In this study, we aimed to evaluate the effect of individual inbreeding on the sperm kinematic patterns in Angus cattle. We analyzed frozen sperm samples of 35 individuals (two replicates, n=70) using a Computer Assisted Sperm Analysis system (CASA, AndroVision®). Eight parameters were determined: curvilinear (VCL), straight-line (VSL) and average path (VAP) velocities, linearity (LIN), straightness (STR) and wobble (WOB) trajectory indexes, and the amplitude of lateral head displacement (ALH) and beat-cross frequency (BCF). Thereafter, we selected VAP, LIN, ALH using a principal component analysis, which was submitted to a two-step (non-hierarchical – hierarchical) clustering procedure that determined the pertinence of each sperm to four different subpopulations (Sp). In addition, we determined the individual inbreeding value (Fped) of each bull using a pedigree of 250.000 records. Finally, we performed a Spearman correlation between the six sperm traits and the proportion of each Sp with the respective individual Fped. Clustering analysis revealed the existence of four different subpopulations: Sp1 included hyperactivated sperm, showing high VCL and ALH but low VAP and LIN. Sp2 showed low velocities and reduced head displacement. Sp3 encompassed progressive and medium velocity sperm (intermediate VCL, VSL and VAP, high LIN, and low ALH). Sp4 included the fast and progressive sperm (high velocities and LIN, and intermediate ALH and BCF). The analysis showed significant correlations (p