Abstract

GALVIS GOEZ, Rubén Darío; CORREA CARDONA, Héctor Jairo; BARRIENTOS GRAJALES, Sorany Milena  and  CASTANO, Yised Muñoz. Effect of Increasing Levels of non Protein Nitrogen in Dairy Cows on Nitrogen Metabolites Concentrations in Urine, Blood and Milk. Rev. Fac. Nac. Agron. Medellín [online]. 2011, vol.64, n.2, pp.6191-6198. ISSN 0304-2847.

In order to test the effect of growing levels of dietary non nitrogen protein in lactating cows on urine, blood and milk nitrogen metabolites concentrations, fifteen cows Holstein in their first one hundred post calving days were used. They were three different experimental treatments assigned at random, which consisted on the supply a commercial feeding supplement without any addition of urea as a source of NNP (T0); the second treatment (T1) consisted on the supply of the same supplement with an addition of urea, so that the supply of PDR was increased 10% approximately to the requirements; finally, in the third treatment, (T2) consisted on the supply of the same supplement which was added with enough urea so that the supply of PDR was increased 15% approximately to the requirements. In these cows were determined concentrations of ureic nitrogen in blood (UNB), urine (UNU), milk (UNM), ammonium in blood (AB) and urine (AU), and glycemia; through spectrophotometric analysis. Finding positive correlations between UNB and AB and UNM, while that correlation between UNU and AU was negative. The other correlations weren't relevant. In addition, it was made a balance of degradable protein in rumen (PDR) where relevant differences were found among the treatments for the tested variables.

Keywords : Ammonia; nitrogen metabolism; milk urea nitrogen.

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