Variability of urea concentration in camel milk in Kazakhstan

Urea is a part of non-protein nitrogen in milk. The variability of its concentration was never reported in camel milk. The present communication aimed to give some reference values on urea content in camel milk and to explore some interpretable variation factors. In 102 milk samples collected in Kazakhstan, at four seasons of the year, in four distant regions and in different species ( Camelius dromedaries , Camelius bactrianus and their hybrids), urea was determined in the raw milk. The mean value of urea concentration was 81.6 ± 60.4 mg·L −1 with a range of 0–290.5 mg·L −1 . The values changed significantly ( P < 0.001) according to season, the highest concentration being observed in spring when the grass contained the highest soluble nitrogen. The milk urea was positively correlated to the total protein concentration in milk. On average, those values were lower than in cow milk.