Urinary excretion of purine derivatives in dry buffalo and Fresian cows

Aim of this paper was to compare urinary purine derivatives (PD) excretion in Italian Mediterranean dairy buffaloes and Fresian dairy cows during dry period. Six buffalo and six dairy cows at about 60 days to delivery were housed in individual cages and fed the same diet. Feed intake was monitored daily. After a period of adaptation, total daily urine was collected, weighed, sampled in test-tubes and frozen up to HPLC analysis. During the urine recovery period the daily feed intake was higher for dairy cows (kg/DM 9.0 vs 7.6) even if differences were not significant due to the high individual variability. Urine excretion was significantly (P<0.01) higher in buffaloes than in cow. Total urinary excretion of PD in buffalo was 11% of that of dairy cow (23.707 mmol/l vs 2.711 mmo/l in dairy and buffalo cows, respectively), however the incidence of uric acid was similar in both species. In order to explain the low concentrations of PD in the urine of buffaloes, we investigated also the presence of allantoic acid, final product of purine degradation in several fish species. However it was not detected.