Assessment of faecal calprotectin in neonatal calf diarrhoea using a human ELISA kit: Associations with faecal score and serum biochemical markers

Background Diarrhoea in newborn calves, which occurs in the first month of life and is caused by various pathogens, poses a significant threat to livestock industries. Therefore, timely diagnosis of enteritis in calves can be advantageous. Objective This study aimed to determine the efficacy of faecal calprotectin as a biomarker indicating gastrointestinal inflammation and a method to distinguish diarrhoeic calves from healthy calves. Additionally, the applicability of a human enzyme‐linked immunosorbent assay (ELISA) kit for measuring faecal calprotectin in bovine samples was evaluated. The relationship between calprotectin and faecal score as an index of diarrhoea severity, and the correlation between calprotectin levels, albumin, albumin‐to‐globulin ratio (AGR) and serum electrolytes has also been investigated. Methods This study enrolled 34 Holstein neonatal calves, including 12 with diarrhoea and 22 healthy controls. A clinical assessment of faecal consistency was performed, and faecal samples were collected for ELISA measurement of calprotectin. Blood samples were taken to determine serum albumin and globulin concentrations, from which the AGR was calculated. The serum sodium (Na) and potassium (K) concentrations were also measured. Using SPSS (version 21) and appropriate statistical tests, associations between faecal calprotectin, albumin, AGR, Na, K and faecal scores were investigated. Results Compared with healthy calves, diarrhoeic calves had higher calprotectin levels and lower AGR levels. The serum K levels in diarrhoeic calves were higher, while the serum Na levels were lower. Faecal calprotectin concentration and serum Na levels were negatively correlated. Calves with faecal score 3, which indicated severe watery diarrhoea, had significantly higher calprotectin levels than those with lower scores. Conclusion Faecal calprotectin could represent a potential inflammatory biomarker for the diagnosis of neonatal calf diarrhoea, along with serum indicators.