Experimental urolithiasis in goats: possible causes and prophylaxis

Abstract

The experiment was conducted at Centro Nacional de Pesquisas de Caprinos, Sobral, CE, Brazil, to find out possible causes of urolithiasis and plan prophylactic measures. Eight castrated bucks, divided in two equal groups (T₁ and T₂), were submitted to a diet of 59.5 g/day of corn meal and 40 g/day of cottonseed cake with ad libitum supplementation of elephant grass (Pennisetum purpureum, Schum.) for 180 days under confinement. The bucks in T₂ also recieved  0.5g of ammnonium chlorate per 100 g of ration. Seven bucks (87,5%), three T₁ and four T₂, showed urolithiasis. The first symptoms appeared after 92 days, but major part of animals showed symptoms around 120 days of the experimentation. Urine pH of T₁ and T₂ were comparable. Blood-serum examination of affected animals revealed a high concentration of magnesium and phosphorus. The post-mortem demonstrated presence of calculi in bladder, ureters and urethra. The calculi were composed of phosphates of ammonia, calcium and magnesium. The amount of ammonium chlorate used in the rations as a possible prophylaxis did not reduce the incidence of urolithiasis. The formation of calculi, therefore, may be due to a complexity of causes, such as composition of rations, confinament, and early castration or a combination of these factors.