Evaluation of semen quality in a purebred Montbéliard Bull in Burkina Faso

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Résumé

Artificial insemination is a key tool for genetic improvement across Sub-Saharan Africa. However, limited data exists on the quality of semen locally produced from exotic purebred bulls under tropical conditions. This study aimed to assess the quality of the semen and freezability of a six-year-old purebred Montbéliard bull in Burkina Faso. Over an eight-week period, 16 ejaculates were collected twice weekly and assessed for volume, colour, pH, mass and individual motility, morphology, viability, and concentration. Samples meeting quality thresholds were extended to 100×10⁶ sperm/mL with AndroMed®, equilibrated at 4 °C, frozen in liquid nitrogen vapor, and thawed at 37°C. Pre-freeze motility increased from 77.5 ± 5.8% (Week2) to 90% (Weeks7–8), while post-thaw motility ranged from 47.5 ± 5% (Week1) to 75 ± 5.8% (Week7), with significant cryoinjury only in Weeks 1, 2, and 6. Semen’s volume remained stable (4.50–5.88mL), and its concentration varied (0.65–1.19 billion/mL). Correlation and PCA analyses revealed strong (>0.6) associations between pre- and post-thaw motility and temporal stabilization of semen traits. Multiple linear regression modeling indicated that including collection week as a temporal covariate substantially improved prediction of post-thaw motility (R² = 0.632, p = 0.013). These results highlight the importance of repeated collections and temporal factors in enhancing semen cryotolerance for improving local AI programs.

Mots-clés

Cattle, Montbéliard, semen, motility, viability, cryopreservation