Analysis of the mineral profile in the urine of dry and lactating cows: a case study

Abstract

In this case study, the urinary mineral profi le of dairy cows was investigated. Determined urinary mineral concentrations were evaluated in relation to the production cycle (dry cows versus lactating cows) and were also compared to the physiological optimum. The study was carried out on twelve Holstein-Friesian dairy cows. Calcium, phosphorus, magnesium, sodium and urea concentrations were determined in urine samples. The urine of dry cows showed demonstrably higher concentrations of Ca (1.86 vs. 1.17 mmol.l -1 ), P (0.88 vs. 0.43 mmol.l -1 ), Na (4.97 vs. 2.70 mmol.l -1 ) and Mg (16.46 vs. 14.24 mmol.l -1 ) compared to the urine of lactating cows. Compared to the physiological optimum, signifi cantly lower urinary Na concentrations were determined in all cows. This indicates a signifi cant defi ciency of Na in the diet of both dry cows and lactating cows. Marked diff erences between the minimum and maximum concentrations of all minerals studied in the urine of dairy cows were determined. The mineral profi le obtained from urine samples can be an important diagnostic method for detecting preclinical stages of metabolic disorders. At the same time, urine sample collection is stress-free for dairy cows.