Use of Blood, Urine and Milk Samples in the Diagnosis of Subclinical Ketosis and Negative Energy Balance in Grazing Dairy Cows

The objective of this study was to compare and associate plasma concentrations of beta-hidroxi-butyrate (beta HB) and subclinical ketosis with blood, urinary and milk indicators in dairy cow. Seventy four Holstein-Frisian cows were used from the third week pre-partum until the eighth week post-partum. Samples of blood, urine and milk were obtained weekly to determine the plasma concentrations of beta HB, non-esterified fatty acids (NEFA) and glucose. Rothera test reaction, excretion beta HB and pH were determined in urine samples. The concentrations of fat, protein and urea were determined on milk samples. The for subclinical ketosis were considered as beta HB > 1.0, > 1.2 and >1.4 mmol/L. Negative energetic balance (NEB) presentation was considered when NEFA >300 mu mol/L during pre-partum and when beta HB > 0.6 mmol/L during post-partum. The intensity in the reaction of Rothera test and the excretion of urinary beta HB were related with plasmatic concentrations of beta HB (r=0.57, P<0.05 and r= 0.42, P<0.5, respectively). The Rothera test associated with ketosis at the three desition limits (P<0.05), BEN (P<0.05). The relations between plasma beta HB with NEFA and glucose were lower (P<0.05), and not significant (P>0.05) with milk fat or protein content or urinary pH. In conclusion, slight and moderate reactions of the Rothera test are good indicators of NEB, while an intense test result indicates subclinical ketosis.