Bovine Reproduction. Группа авторов

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Bovine Reproduction - Группа авторов


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20.1 Urethral calculi visible on preputial hairs.

Photo depicts subcutaneous peripenile swelling typically extends from the base of the scrotum cranially and involves the entire ventrum.

      Urolithiasis can typically be diagnosed utilizing historical data and clinical signs. Additionally, rectal palpation and careful palpation of the penis can typically locate the site of obstruction and the presence or absence of a urethral or bladder rupture. For feedlot steers or economically constrained cases, treatment is implemented based on physical examination. However, for valuable individuals a complete diagnostic picture includes a complete blood count (CBC), biochemistry profile, and ultrasound.

      The abnormalities observed with a CBC will typically coincide with the severity and duration of disease. Typical findings include a neutrophilia and possible hemoconcentration depending on the degree of dehydration. Cases with urethral rupture may have increased fibrinogen with excessive subcutaneous tissue necrosis. Common biochemical abnormalities include azotemia, hyponatremia, and hypochloremia. In ruminants, potassium can be normal or elevated in individuals with obstructive urolithiasis. When hyperkalemia is present, the degree of elevation is typically mild. One study experimentally induced uroabdomen and demonstrated increased salivary potassium excretion, possibly explaining the less severe hyperkalemia observed in ruminants with urolithiasis [11]. In small ruminants, Ewoldt et al. found individuals with no free abdominal fluid and a serum potassium less than 5.2 meq/l more likely to survive [12]. Individuals with urolithiasis may have a metabolic alkalosis, acidosis, or normal blood pH. When acidosis occurs, individuals are often severely dehydrated and suffering from lactic acidosis [13]. With prolonged obstructions, hyperphosphatemia and hypomagnesemia can occur and concerns of secondary renal failure should be considered. One study stated the best prognostic indicator was excessive serum phosphate being associated with increased likelihood of death [14]. In absence of hydronephrosis, 48 hours of fluid diuresis should be administered before diagnosing an individual in secondary renal failure. In individuals with uroabdomen, the degree of azotemia, hyponatremia, hypochloremia, and hyperkalemia can be severe due to the osmotic gradient across the abdominal wall pulling sodium and chloride into the abdomen, potassium and blood urea nitrogen intravascularly, with creatinine staying mostly intra‐abdominally, since it diffuses at a slower rate being a larger molecule.

Photo depicts severe hydronephrosis in a mature bull.

      Immediate Care

      Prior to initiating treatment for urolithiasis, the intended use of the animal, economics, site of obstruction, and integrity of the urinary tract should be considered. For acute cases, medical management can be attempted or immediate slaughter if uremia is not present. Most cases of urolithiasis will require surgical intervention. For breeding bulls, maintaining a patent urethra is paramount for successful outcome and breeding career. Surgical procedures utilized in breeding individuals include tube cystostomy, cystotomy, ischial urethrostomy, and urethrotomy. Surgical procedures utilized in salvage bulls and steers include ischial urethrostomy, perineal urethrostomy, and urethrotomy.

      Before sedation or anesthesia, any severe electrolyte derangement should be corrected. For severe hyperkalemia, a bolus of 50% dextrose can be


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