Tresholds of blood variables obtained by receiver operating characteristic analysis for indication of fat and glycogen content in the liver of postpartum dairy cows

Abstract

The objective was to determine optimal thresholds of blood variables that are associated with liver lipid and glycogen content in dairy cows. Liver specimens of 15 Holstein dairy cows were taken 2 weeks postpartum (PP) and used for determination of lipid and glycogen content, respectively. Blood samples were collected weekly, starting from week 2 antepartum (AP) up to week 2 PP. Selected blood parameters and body condition scoring (BCS) were evaluated through receiver operating characteristic curve analysis as indication of fat and glycogen content in the liver. Postpartal low liver glycogen content (mode < 2.0, semiquantitative analysis of glycogen content in the liver tissue samples) can be indicated if values are higher than 0.16 mmol/L, and 3.5 mmol/L for NEFA, and glucose, respectively, and lower than 0.65 mmol/L and 17.94 mu U/mL for BHBA and insulin, respectively, 2 weeks AP. Postaprtal high liver fat content (>20%, stereological quantification of fat content in the liver tissue samples) can be indicated if values are higher than 3.5 for BCS at week 2 AP. Optimal time for indicating both low liver glycogen/high fat content is 1 week PP, with LDL < cut off point set at 0.18 mmol/L and BHBA > cut off point set at 0.88 mmol/L. Established cut off values in this study can be used for indication of fat and glycogen content in the liver of dairy cows.