03070nas a2200157   4500000000100000000000100001008004100002260007000043100001600113700001800129245011800147300001200265490000800277520261300285022001402898       2008                            d  c07/2008bSchlütersche Verlagsgesellschaft mbH & Co. KGaHannover1 aC-C Gelfert1 aR Staufenbiel00aThe role of dietary calcium concentration in the use of anionic salts to prevent parturient paresis in dairy cows  a256-2620 v1213 aThe role of dietary calcium concentration during the feeding of anionic salts (AS)was reviewed. Hypocalcaemia is still the major cause of parturient paresis in dairycows. Feeding AS is an established method for preventing severe hypocalcaemiaby activating the calcium metabolism in the last two to three weeks beforeparturition by inducing a metabolic acidosis. In compensation for this acidosis,the organism increases the concentrations of ionised Ca [Ca2+] in the blood. Thisincrease leads to an increasing excretion of calcium via the urine, which is ensuedby an increased calcium absorption in the intestine. The ongoing metabolicacidosis changed the flux of Ca. The size of the Ca pool, however, remainedunchanged. As the calcium metabolism is activated by AS, it seems necessary toincrease the amount of calcium that is fed to the cows. Several studies examinedthe impact of different dietary calcium concentrations on the acid-base balanceand the calcium metabolism in cows fed anionic salts. The study designs varyconcerning the amounts of calcium fed and the use of pregnant or non-pregnantcows. Only one study combined the feeding of AS with a very low amountof calcium, which fell below the daily requirements of pregnant cows in the lastthree weeks before parturition. In this study, the calcium balance post partumwas better in the cows that were administered AS and a high calcium diet. In theother studies, the amount of calcium in the different experimental groups andthe difference between the amounts of calcium fed varied greatly. As far as it wasmonitored in the studies, the calcium concentration of the diet did not have asignificant impact on the degree of acidosis induced by AS. In pregnant cows, nosignificant differences in the calcium concentration in serum or urine occurredbefore parturition. Some of the researchers found a lower incidence of parturientparesis when cows were fed a combination of AS and a higher amount ofcalcium, but some other researches did not. Interestingly, the parameters of bonemetabolism did not change between experimental groups. According to what iscurrently known, the feeding of AS to transition cows should not be combinedwith a dietary calcium concentration that falls below the requirement of cowsin this stage of lactation. On the other hand, there is no need to increase the Caconcentration. When AS are used the dietary calcium concentration should bebetween 9 g and 12 g/kg dry matter. Further research is needed to investigatethe role of dietary calcium regarding the use of AS for improving Ca metabolismin dairy cows around parturition.  a0005-9366