August 2025: a Holstein cow, 2 days into the dry period, presents with hindquarter paresis, associated with a state of depression and hyperventilation. The animal is not eating or drinking, has no rumination, sunken eyes, dry feces, and a temperature of 39.7°C. We rule out the presence of obvious musculoskeletal lesions and mastitis. Pulmonary auscultation reveals increased respiratory effort, with no particular pathological sounds. Suspecting a metabolic issue associated with heat stress, we collect a blood sample in lithium heparin from the jugular vein to perform a blood gas analysis.
