Some of the most common health problems in commercial sow herds are Urinary tract infections (UTI). Prevalence of UTIs ranges from 4 to 40% in sow herds and at least 15% of all sow deaths are generally attributed to cystitis-pyelonephritis (Wegemann, 1993). Examinations of reproductive organs showed a correlation between sow infertility and UTIs. Infections of the urinary tract are known as predisposing factors for inflammations of the uterus. An endogenous mechanism of the sow as protection against bacterial infections in the urogenital tract is the urinary pH, which can be manipulated by dietary means affecting the dietary anion-cation balance (Beker, 1999). The objective of this experiment was to evaluate the effect of a dietary urine acidifier based on a blend of anionic substances, inorganic acids and plant extracts from vaccinium species on urinary and reproductive parameters in sows.