Changes in milk composition as a result of metabolic disorders of dairy cows

Abstract

The aim of our study was the determination of blood parameters and changes in milk composition of dairy cows in relation to metabolic disorders and their evaluation. Thirty dairy cows from selected agricultural farm were divided into three groups as follow: group BL: 3-4 weeks after calving (the beginning of lactation), group ML: 3-4 months after calving (the middle of lactation), group DP: 2-3 weeks before calving (the dry period). Concentrations of selected parameters of energy profile (glucose, cholesterol, triglycerides); nitrogenous profile (urea, total proteins); hepatic profile (aspartate aminotransferase, bilirubin) in blood serum were measured. Content of fat, proteins and lactose, Non Fat Solids, urea, freezing point, Somatic Cell Count, Fat/Protein ratio in milk were evaluated. Cholesterol concentration was significantly higher in ML (5.33±1.17 mmol.l-1; p<0.001) in comparison to BL (3.46±0.92 mmol.l-1; p<0.001) and DP (2.70±0.71 mmol.l-1; p<0.001). Concentration of triglycerides was significantly lower in ML (0.03±0.01mmol.l-1; p<0.001) in comparison to BL (0.07±0.02 mmol.l-1; p<0.001) and DP (0.09±0.04 mmol.l-1; p<0.001). Albumin concentration in DP (36.90±2.99 g.l-1; p<0.05) was significantly higher in comparison to BL (32.80±4.07 g.l-1; p<0.05). AST concentration was significantly higher in ML (1.61±0.47µmol.l-1; p<0.001) in comparison with DP (1.01±0.18µmol.l-1; p<0.001) and BL (1.39±0.25µmol.l-1; p<0.05). Acquired results of milk composition were without significant confirmation (p>0.05). Fat/Protein ratio was lower than 1.1, in BL and ML, which cause rumen acidosis. The present observation confirmed that specific changes of milk composition lead to metabolic disorders.