The Use of Additives to Prevent Urolithiasis in Lambs Fed Diets with a High Proportion of Concentrate

SIMPLE SUMMARY: Urolithiasis is the formation of salt crystals in the kidney and can be caused by several factors, one of which is the use of unbalanced diets for feeding animals. This study aims to evaluate the effectiveness of different additives in preventing urolithiasis in lambs fed a high-concentrate diet. Thirty-two noncastrated male lambs were divided into four treatments, three including additives in the diet and one group without additives (CON), and fed for 56 days in a feedlot. The additives used were ammonium chloride (ACL), calcium chloride (CCL), and benzoic acid (BZA), and each was added to a diet composed of 6% Cynodon ssp. hay and 94% concentrate. The use of additives in the diet did not affect the performance of the lambs. Regarding urine pH, inclusion of ACL and CCL in the diet acidified the urine, but none of the additives prevented urolithiasis. However, the formation of these crystals did not show obstruction of the urinary tract or affect the lambs’ health. ABSTRACT: This study aimed to evaluate the effectiveness of different additives in preventing urolithiasis in lambs fed a diet rich in concentrate and their impact on performance and blood and urinary parameters. Thirty-two noncastrated male lambs, crossbred Dorper × Santa Inês, with initial body weights (BWs) of 23 ± 0.1 kg and ages of 50 ± 5 days, were kept in individual pens and fed a diet composed of 6% Cynodon ssp. hay and 94% concentrate and subjected to four treatments: CON without inclusion of additives, addition of ACL 5 g/kg of dry matter (DM), addition of CCL 6.3 g/kg of DM, and addition of BZA 5 g/kg of DM. There was no effect of treatment or interaction with time on blood parameters (p > 0.050), and performance characteristics, morphometry of ruminal papillae, and scores of cecum and rumen lesions were not affected by the addition of additives to the diet (p > 0.050). Greater urinary acidification was observed in animals from CCL and ACL treatments (p = 0.033). Calcium chloride acidified the urinary pH and can be used instead of ammonium chloride at a concentration of 0.63% based on DM, when this is the objective.