Factors influencing milk urea concentration: intake of protein and energy, diurnal variation and effect of storage

Abstract

The study was conducted to evaluate the effects of protein and energy intake, diurnal variation and storage on milk urea concentration. Crossbred Karan-Fries cows (4) were fed 4 different diets. All the diets were isocaloric and isonitrogenous for individual animals. The animals were fed individual diet as a single group for 21 days, then shifted to the next diet inlmediately and so on. Composition of these diets were: diet (i) berseen, wheat straw and concentrate mixture; diet (ii) green maize, wheat straw and concentrate mixture; diet (iii) green maize, wheat straw, concentrate mixture (urea supplemented @ 1 %of the total DM) and molasses (@ 100 g for 10 g urea); diet (iv) green maize (4 kg), 4% urea treated straw and concentrate mixture. The average MU concentrations were 32.78, 30.07, 45.66 and 33.96 mg/dl respectively, for diet 1,2,3 and 4. MU concentration showed an increasing trend with increased protein (CP and DCP) intake per unit of metabolisable energy. However, the trend was more synchronised with DCP intake per unit of metabolisable energy. A clear diurnal pattern with low urea concentration in morning samples was found during the study. When milk samples were stored at 4 ÌŠ C after deproteinisation with 12% TCA solution, urea concentrations did not vary significantly till 30 days.