Anion Gap and Ionised Calcium as Diagnostic Indicators in Calves with Atresia Coli from Twenty-Two Cases

This study aimed to evaluate blood lactate, anion gap, and ionised calcium levels as potential diagnostic biomarkers in calves with atresia coli, and to identify possible predisposing factors such as breed, gender, age, method of conception, number of lactations, and births. The study included twenty-two calves with atresia coli and ten healthy controls, all aged 1-11 days (median, 3 days), brought to Erciyes University Veterinary Faculty from Kayseri and nearby provinces due to non-defecation and abdominal swelling. Prominent clinical findings among the 22 calves with atresia coli included abdominal distension in 90.9%, anorexia in 81.8%, and depressed general posture in 86.4%. Blood gas analysis revealed significantly elevated lactate and anion gap and decreased ionised calcium and pH in atresia coli calves compared to controls (<i>p</i> < 0.05). Anion gap (>14.05 mmol/L) and ionised calcium (<1.205 mmol/L) demonstrated high diagnostic accuracy (AUC: 0.964 and 0.872, respectively), suggesting their potential as supportive biomarkers for early detection of atresia coli. The study data revealed that male gender, artificial insemination, and calves born from the third or subsequent pregnancies are statistically significant risk factors for the development of atresia coli. Atresia coli in calves is characterized by specific clinical signs and significant changes in blood gas parameters, such as elevated lactate and anion gap and reduced ionised calcium and pH. Early detection using these markers can improve diagnosis, and further studies should focus on prevention by addressing these risk factors.