Use of acid-base indicators to predict the risk of milk fever in dairy cows
2012
Rérat, M. | Hess, H. D., Forschungsanstalt Agroscope Liebefeld-Posieux ALP, Posieux (Switzerland)
The aim of this study was to investigate a possible relationship between acid-base parameters in urine before parturition and the calcium level in blood shortly after parturition. Hundred dairy cows kept under identical feeding and housing conditions were monitored. The diet was based on grass and corn silage and hay ad libitum. Urine samples were taken on day 14, 7, and 3 before the estimated calving (day 285 of gestation) for the determination of pH, net acid-base excretion (NABE) and base-acid quotient (BAQ). Blood samples were taken within the first 12 h after calving for theanalysis of total calcium. During the period before parturition, the mean values of urinary pH, NABE, and BAQ were 8,63 ± 0,02, 232 ± 4 mEq/kg DM, and 4,75 ± 0,09, respectively. The pH and NABE values indicated a state of metabolic alkalosis of the cows resulting from the distribution of a diet with a high positive dietary cation-anion difference value (+ 474 mEq/kg DM). No significant correlations were observed between total calcium concentration in blood (1,92 ± 0,04 mmol/L) and mean values of urinary pH (r = 0,08; P = 0,416), NABE (r = 0,04, P = 0,719), or BAQ (r = -0,12, P = 0,234). The measurement of acid-base parameters in urine prior to parturition cannot be used to predict the level of blood calcium after parturition in cows under alkalotic condition. The determination of the NABE and BAQ parameters revealed similar information on the acid-base status of dairy cows as the measurement of the urinary pH.
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