CASE REPORT Report of urinary bladder rupture following obstructive urolithiasis in rams of Romanov sheep flock Farshid Davoodi 1 & Amir Zakian 1 & Abbas Raisi 1 & Alireza Rocky 1 & Ghasem FarjaniKish 2 Received: 18 March 2020 /Accepted: 10 September 2020 # Springer-Verlag London Ltd., part of Springer Nature 2020 Abstract A 4-year old Romanov ram with a history of anorexia, severe depression, and anuria for 4 days was referred to the Veterinary Teaching Hospital of Lorestan University. In the clinical examinations of the ram, no penile protrusion from prepuce, pain, straining; decreased body temperature; and increased heart rate and respiration rate were observed. For further evaluation, the blood sample was taken, and ultrasound of the abdominal area and ultrasound-guided cystocentesis were performed. The results indicated dehydration; leukocytosis; increased serum urea, creatinine, magnesium, and cholesterol; and decreased serum calcium concentrations. The ultra-sonographic findings demonstrated that the bladder was swollen and full of urine, however, without rupture. Despite the treatment, the ram was culled after 5 days and necropsy for investigating macroscopic changes, and tissue sampling was done. Macroscopic examination indicated a fibrinopurulent layer around the right kidney, and jagged stones with various sizes and shapes in the kidney and urinary tract were observed. Microscopic results showed atrophy and degeneration of renal tubules, destruction of tubules and glomeruli, fibrosis of the kidney, and increase in the thickness of the bladder wall. Keywords Obstructive urolithiasis . Ram . Uroliths . Romanov Introduction Obstructive urolithiasis is a severe and approximately com- mon complication in male ruminants (Floeck 2009). The mor- tality rate from uroliths is low; however, it has a high epidemic in the flock. Therefore, it can cause economic damage due to bladder and ureteral rupture and results in death (Constable et al. 2017). The Romanov sheep are native to Russia’s Volga region and originate from a village with the same name. This breed is a high-yield breed with a record lamb production of nine lambs per year and a lambing rate of 250% for ewes (Ricordeau et al. 1990). Common types of urinary stones in- clude silica, struvite (magnesium ammonium phosphate), cal- cium carbonate, calcium phosphate (apatite), oxalate, and clo- ver stones (Gardiner 1965). Many parameters are involved in the type of urinary stones including nutritional, physiological, and management issues. Veterinarians who encounter animals with urinary tract obstruction should find out the structure and type of the stones so that they can find appropriate solutions to prevent and minimize disease damage to the herd (Jones et al. 2017). Increased or imbalanced mineral intake is recognized as one of the most important factors in the formation of urinary calculi (Floeck 2009; Mohamed and El-Deeb 2015). An effective way to prevent the formation of struvite stones is to change the diet to acidify the urine (Stratton-Phelps and House 2004). Increasing the ratio of calcium to phosphorus in the diet can also be effective in preventing the formation of phosphate stones (Emerick and Embry 1963; Gardiner 1965). Urinary acidification with anionic salts and increased calcium in the diet may increase urinary calcium excretion and in- crease the risk of calcium calculi formation (Mavangira et al. 2010). In 2018, Alimi et al. reported a case of urethral obstruc- tion due to oxalate, phosphate, silicate, and a combination of the stones in a male Ouda–Yankasa ram and performed clin- ical examinations, autopsy, and histopathology (Alimi et al. 2018). Al-Lugami and Sickinger, in a study in 2018, intro- duced ultrasonography as a choice technique to diagnose uri- nary tract obstruction disorders in lambs (AlLugami and Sickinger 2018). Surgery is the only treatment available in * Farshid Davoodi davoodi.fa@fv.lu.ac.ir; farshiddavoodi620@yahoo.com 1 Department of Clinical Sciences, Faculty of Veterinary Medicine, Lorestan University, Khorramabad, Iran 2 Department of Pathobiology, Faculty of Veterinary Medicine, Lorestan University, Khorramabad, Iran Comparative Clinical Pathology https://doi.org/10.1007/s00580-020-03165-1