F09 - D,L Methionine and Ammonium Chloride Effect on Urine pH and Excretion of Calcium in Goats

Abstract: Background: Urinary acidification with ammonium chloride (NH4Cl) for urolith dissolution is a common treatment for goats with urolithiasis. Studies have reported increased fractional excretion of calcium (FECa) following NH4Cl administration, which could increase calcium-based urolithiasis. D,L methionine may result in similar acidification with less calcium excretion.

Objectives: To compare effects of orally administered D,L methionine and NH4Cl on urine and blood pH, FECa, and blood HCO3- concentrations in male goats.

Animals: Twelve healthy 4-6 month old Boer-cross wethers

Methods: Prospective, randomized, cross over study. Wethers were administered 200mg/kg of NH4Cl or D,L methionine orally for 14 days with a 7 day washout period between trials. Venous blood and urine samples were collected every 2 days. The effects of treatment and treatment day on urine and blood pH, FECa, and HCO3- was assessed using linear mixed models.

Results: In models with treatment and day, mean urine pH on day 6 (µ = 7.49, P < 0.001), 8 (µ = 7.78, P= 0.008, and 10 (µ = 7.53, P < 0.001) was significantly lower than on day 0 (µ= 8.23). A significant treatment effect was not detected on urine pH (P= 0.1158), blood pH (P= 0.7683), FECa (P= 0.4038), and blood HCO3- (P= 0.1422).

Conclusion and Clinical Importance: Urine pH was decreased on days 6, 8, and 10 however, values were not low enough to dissolve uroliths. Under the conditions of this study, there was no difference in FECa between treatments. Further studies should investigate effects of higher doses of these drugs.