Volume 44 Supplement 1
Influence of Acidogenic Salts and Sodium Bicarbonate as Feeding Components on Urine Composition
© The Author(s); licensee BioMed Central Ltd. 2003
Published: 31 March 2003
Rumen acidosis and rumen alkalosis are among the most frequent diseases caused by a faulty diet in dairy cattle husbandry. The economic losses are caused more by subclinical or chronic cases than by acute acidosis. Recent research has shown that sampling of urine is the best way to diagnose disturbances in the acid-base equilibrium. Acidogenic salts and sodium bicarbonate are additives often used in dairy cattle feed rations in order to prevent both parturient paresis as well as rumen acidosis. Since they interfere with the acid-base equilibrium, they may also change the urine composition which complicates diagnosis. The purpose of the following studies was to investigate the influence of both feeding additives on urine composition.
The studies took place on eight high producing dairy cattle farms in East Germany. The milk production ranged from 7000 l (FCM) to 11000 l/FCM), the herd size ranged from 150 to 1300 cattle. The farms were visited once a month. On these visits urine samples were taken from ten apparent healthy cows during each of five different stages of lactation The urine samples were pooled from each group and stored at -20°C until laboratory testing. The concentrations of the following parameters were measured in the pooled samples: pH, Netto-acid-base-excretion (NABE), Acids, Bases, Ammonium (NH4+), Sodium, Potassium, Chloride, Calcium, Phosphorus.
The mean pH for all groups showed a basic response within or above the physiological ranges. Only the cows sampled during the transit period fed acidogenic salts had pH-values below the physiological ranges on certain times. The NABE showed an acidic response in the majority of the samples of group 2. Dependent on the quantity of the acidogenic salts feed the NABE could reach values below zero. The cows fed sodium bicarbonate had higher NABE than the animals tested during the same stage of lactation without this feed additive. The concentrations of acids showed only little variation among the nine groups. The excretion of bases in group 2 was reduced compared to group 6 and had increased in groups 3, 4 and 5 compared to groups 7, 8 and 9. Among the six groups post partum, there were no differences in the concentrations of calcium in the urine. Groups 1 and 6 showed a slightly increased excretion of calcium with concentrations around 1,5 mmol/l. Cows of group 2 had the highest excretion of calcium and the measured concentrations had been above the physiological ranges. The cows fed acidogenic salts (group 2) had the highest mean concentration of magnesium with a mean concentration above the physiological ranges. The other groups showed mean concentrations mostly within the normal ranges. The mean concentrations of potassium were above the normal ranges for the three groups ante partum. The six groups post partum had mean concentrations within the normal ranges. The cows fed sodium bicarbonate had higher concentrations than the corresponding animals of the groups without sodium bicarbonate. The cows fed sodium bicarbonate had the lowest mean concentration of chloride reaching the inferior physiological range.
Acidogenic salts and sodium bicarbonate have an influence on the composition of urine causing changes in acids, bases and major elements that is not to neglect.
Feeding acidogenic salts produces alkaline urine. Concentrations of bases decrease, which results in a low value of NABE. The concentrations of calcium clearly increase.
Sodium bicarbonate produces basic urine. The concentration of bases and the NSBA increase, chloride concentrations decrease. For there are no signs of acidosis the decrease of NH4+ and phosphorus are difficult to interpret.
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