Comparative analysis of subjective and computerized methods for evaluating frozen semen from bulls used commercially in the Amazon region.

Abstract

Semen quality assessment is a fundamental tool for determining the reproductive potencial of bulls and is widely used in genetic improvement and assisted reproduction programs. Traditionnally, this assessment is performed using subjective methods, which dependo n the evaluator′s experience and may present high variability in the results. In this context, computerized semen analysis systems, such as Microscopic Automated Computer Evaluation (MACE), have emerged as more objective and standardized alternatives. This study was conducted at the Animal Reproduction Laboratory of the Federal University of Acre (UFAC) and aimed to compare bull sperm evaluation obtained through traditional subjective methods with that performed using the MACE system. Twenty frozen semen samples from Nelore, Angus, and Sindi bulls were analyzed for sperm motility, vigor, concentration, and morphological abnormalities. Data were subjected to descriptive analysis and the nonparametric Wilcoxon test (p < 0.05). Significant differences were observed for motility, sperm concentration, and percentage of sperm abnormalities. The MACE system presented higher values for motility (60.2%) and sperm abnormalities (20.12%), whereas the subjective method showed higher sperm concentration (221.75 ×10⁶spermatozoa/mL). No significant differences were observed for sperm vigor between the methods. The results demonstrated that subjective evaluation may overestimate or underestimate certain seminal parameters when compared with computerized analysis. It was concluded that MACE provides greater sensitivity, objectivity, and standardization in bovine semen evaluation, representing a promising tool to improve the reliability of breeding soundness examinations and assist in the selection of breeding bulls.