Use of ammonium chloride to prevent urolithiasis in sheep

F.C Navarro,J.R Peiró,F Bovino,F.L.F Feitosa,R.S Baptista,L.A.T Bentin,L.C.N Mendes

doi:10.1590/1678-4162-12082

Abstract

ABSTRACT Urolithiasis has a high incidence among confined sheep. It is multifactorial and may cause economic damage. Our aim was to determine the capacity of urinary acidification using ammonium chloride in sheep. Twenty-five 3-month-old male sheep were confined and randomly divided into three groups; the G200 and G500 groups received 200mg/kg/GW and 500mg/kg/GW of ammonium chloride daily for 56 consecutive days, respectively, whereas the CG group did not receive ammonium chloride. Sampling times and clinical evaluation were performed weekly, starting from the 14th day of confinement (M1 or immediately before administering ammonium chloride) until the 17th day (M9) of the feedlot. Hemogasometry, biochemical examination of serum urea and creatinine concentration and ultrasound evaluation of the urinary tract were performed. The urinalysis indicated a higher incidence of ammonium magnesium phosphate crystals at the beginning of the study, showing a migration to urate crystal formation, mainly in the G500 group because of urinary acidification. No hemogasometric, serum biochemistry, ruminal fluid, or ultrasonographic changes were observed. Urinary acidification was achieved and maintained after M7 during the administration of ammonium chloride in the G500 group, but not in the other study groups.

Highlights

The incidence of obstructive urolithiasis in sheep is high, mainly when they are confined
The urinalysis indicated a higher incidence of ammonium magnesium phosphate crystals at the beginning of the study, showing a migration to urate crystal formation, mainly in the G500 group because of urinary acidification
Several studies have investigated this multifactorial condition, which causes economic damage, affects sheep’s reproductive health, and may even lead to death (Guimarães et al, 2012), affecting primarily males because of anatomical reasons, whose complications may necessitate surgical treatment The main factors associated with lithogenesis are urinary stasis, dehydration, low fluid intake, alkaline urinary pH, decreased urinary protective factors, and increased excretion of minerals in the urine, mainly due to an imbalance in the concentration of calculogenic components in feed, such as diets rich in protein, calcium, magnesium, or phosphorus, or even the intake of certain oxalate or silica-rich plants (Stewart et al, 1990)

Summary

Introduction

The incidence of obstructive urolithiasis in sheep is high, mainly when they are confined. The formed nucleus promotes precipitation, aggregation, and concretion around it, increasing its volume and causing obstruction of the urinary tract (Radostits et al, 2000). Some authors, such as Ferreira (2009); Ferreira et al (2014) used ammonium chloride and vitamin C (ascorbic acid) for urinary acidification, leading to conflicting results and even inducing urinary calculus formation. The objective of this work was to evaluate the capacity of urinary acidification in sheep using ammonium chloride analyzed through urinalysis

Objectives

Methods

Results