Case Report: Unexplained field infertility in an AI purebred Piedmontese bull with normal conventional semen parameters.
- 1Department of Veterinary Science, University of Turin, Grugliasco, Italy.
- 2Associazione Nazionale Allevatori Bovini di Razza Piemontese (ANABoRaPi), Carrù, Italy.
Abstract
This case report describes a purebred Piedmontese bull selected for artificial insemination (AI). Despite meeting all conventional semen quality thresholds, the bull showed complete reproductive failure during progeny-testing field inseminations: across all inseminations performed, no pregnancies were confirmed, resulting in a field fertility of 0% and indicating complete infertility under field conditions. To investigate this discrepancy, the bull's semen was compared with a reference population of 19 Piedmontese bulls managed under identical conditions. Routine ejaculate characteristics, including volume, concentration, and both fresh and post-thaw motility, fell entirely within the expected range, as well as all CASA-derived kinematic parameters. In contrast, flow cytometric evaluation revealed severe functional abnormalities. DNA fragmentation was markedly elevated, and reactive oxygen species (ROS)-related fluorescence intensity was markedly increased, whereas superoxide production was lower than in the control group. Additionally, free thiol content was significantly reduced. Taken together, these alterations indicate not only extensive DNA damage but also a markedly impaired ability of spermatozoa to counteract oxidative stress. These findings demonstrate that profound sperm functional defects may remain undetected through conventional AI-Centre screening, yet critically impair fertility in vivo. Incorporating advanced functional assays into routine monitoring may improve early identification of subfertile sires and enhance reproductive efficiency in bovine breeding programs.
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BibTeX
@article{viola2026case,
title = {{Case Report: Unexplained field infertility in an AI purebred Piedmontese bull with normal conventional semen parameters.}},
author = {Irene Viola and Veronica Spalenza and Andrea Albera and Isabella Manenti and Eugenio Martignani and Paola Toschi},
journal = {Frontiers in veterinary science},
year = {2026},
month = oct,
doi = {10.3389/fvets.2026.1976987},
url = {https://europepmc.org/article/MED/42904088},
note = {CC BY},
}
RIS
TY - JOUR
TI - Case Report: Unexplained field infertility in an AI purebred Piedmontese bull with normal conventional semen parameters.
AU - Irene Viola
AU - Veronica Spalenza
AU - Andrea Albera
AU - Isabella Manenti
AU - Eugenio Martignani
AU - Paola Toschi
PY - 2026
DA - 2026/10/06
JO - Frontiers in veterinary science
DO - 10.3389/fvets.2026.1976987
UR - https://europepmc.org/article/MED/42904088
AB - This case report describes a purebred Piedmontese bull selected for artificial insemination (AI). Despite meeting all conventional semen quality thresholds, the bull showed complete reproductive failure during progeny-testing field inseminations: across all inseminations performed, no pregnancies were confirmed, resulting in a field fertility of 0% and indicating complete infertility under field conditions. To investigate this discrepancy, the bull's semen was compared with a reference population of 19 Piedmontese bulls managed under identical conditions. Routine ejaculate characteristics, including volume, concentration, and both fresh and post-thaw motility, fell entirely within the expected range, as well as all CASA-derived kinematic parameters. In contrast, flow cytometric evaluation revealed severe functional abnormalities. DNA fragmentation was markedly elevated, and reactive oxygen species (ROS)-related fluorescence intensity was markedly increased, whereas superoxide production was lower than in the control group. Additionally, free thiol content was significantly reduced. Taken together, these alterations indicate not only extensive DNA damage but also a markedly impaired ability of spermatozoa to counteract oxidative stress. These findings demonstrate that profound sperm functional defects may remain undetected through conventional AI-Centre screening, yet critically impair fertility in vivo. Incorporating advanced functional assays into routine monitoring may improve early identification of subfertile sires and enhance reproductive efficiency in bovine breeding programs.
SN - 2297-1769
ER -