Nitrogen excretion and utilization on grassland dairy cows

NITROGEN EXCRETION AND UTILIZATION ON GRASSLAND DAIRY COWS

SALCEDO G.¹ and L MARTINEZ-SULLER.²

¹I.E.S., Dept. Techonology Agricultural, Heras,Cantabria,  Spain

²Cantabria University, Water and Environmental Science and Techonolgy Department, Cantabria, Spain

22^nd General Meeting of the European Grassland Federation, Uppsala, Sweden 9-12 Junio 2008, 855-857.

ABSTRACT

Between 1991 and 2005 nitrogen (N) excretion and utilization have been studied in Friesan dairy cows offered (Lolium perenne and Trifolium pratense) with a minimum concentrate supplementation (2.63 ± 1.62 kg dry matter per cow and day). Daily N excretion in faeces, urine and milk was 120 ± 1.25, 188 ± 2.13 and 101 ± 0.74 g, respectively. Variance analysis results show that the 64, 46 and 21% of N intake was excreted in faeces, urine and milk, respectively. Statistically, the best relationship was observed between N intake and N in milk.