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

Ožbalt Podpečan,Petra Zrimšek,Janko Mrkun,Marko Goličnik,Anita Radovanović,Ljubomir Jovanović,Ivan Vujanac,Radiša Prodanović,Danijela Kirovski

doi:10.1080/1828051x.2020.1740064

Ožbalt Podpečan, Petra Zrimšek + Show 7 more

Open Access

https://doi.org/10.1080/1828051x.2020.1740064

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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 μU/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. Highlights More variables are reliable for indication of liver glycogen content than for indication of liver fat content. Postpartum concentrations of LDL and BHBA can be used for indicating both high lipid liver content and low liver glycogen content.

Highlights

Initiation of lactation in dairy cows is usually linked to negative energy balance (NEB) that provoke lipid mobilisation, leading to increased lipid accumulation in the liver
The objectives of this study were (1) to determine whether serum concentrations of cholesterol, HDL, LDL, total bilirubin, BHBA, nonesterified fatty acid (NEFA), glucose, insulin and GGT and AST activity are associated with a hepatic lipid and glycogen content, and (2) to determine optimal thresholds for each parameter that are indicative for hepatic lipid and glycogen content on week 2 PP
Decreased concentrations of glycogen indicate an increased risk for metabolic disorders and low productivity that are associated with fatty liver (Rukkwamsuk et al 1999; Bobe et al 2004)

Summary

Introduction

Initiation of lactation in dairy cows is usually linked to negative energy balance (NEB) that provoke lipid mobilisation, leading to increased lipid accumulation in the liver. There are evidences that the ratio of lipid to glycogen in liver is essential predisposing factor for metabolic diseases in dairy cows, since increasing glycogen indirectly reduces the negative effects of increased fat accumulation in the liver (Drackley et al 1992). Estimating liver lipid and glycogen content in liver tissue samples obtained by biopsy method is the gold standard.

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