Milk urea content as influenced by geographical area and season in Wallonia

Milk urea concentration is routinely determined in commercial dairy farms along with the
official milk analyses carried out on milk samples for the dairies by the “Comité du lait”. The
milk urea content do not modify milk price but can be useful for the farmers for diet
calculation, milk urea content being related to the energy-protein ratio in the diet. The aim of
this paper was to study the evolution of the milk urea content according to the months and the
areas. Milk urea concentration changed according to the months owing to the diet: the
summer diets, mainly composed by grass in many farms, were characterized by higher
nitrogen content which as result an increase in milk urea concentration. The geographic areas
can also influence milk urea concentration due to dietary difference. For example, in the
Hesbaye area, beet and cereals are produced while in the Ardennes, grasslands are dominant.
The urea content in milk can be an useful measurement for the diet calculations in order to
decrease nitrogen waste and to reduce the feed costs.