Urolithiasis in Pigs

Urolithiasis means stones made of minerals and crystals have formed somewhere in the urinary tract. In pigs, those stones may develop in the bladder or urethra and can irritate the lining, cause pain, trigger infection, or block urine flow. In miniature pet pigs, Merck notes that cystitis and urolithiasis are common urinary problems.

This becomes an emergency when a stone blocks the urethra and your pig cannot urinate normally. A blocked pig can develop a painfully enlarged bladder, kidney damage, electrolyte problems, and in severe cases bladder rupture. Male pigs are often at greater risk of obstruction because the urethra is narrower and more difficult for stones to pass through.

Some pigs show mild signs at first, like frequent squatting or dribbling urine. Others decline quickly. Because the signs can look similar to cystitis or other urinary disease, your vet usually needs testing to confirm whether stones are present and where they are located.

Urinary stones form when minerals in the urine precipitate into crystals and then clump together. This usually happens because of a mix of factors, not one single cause. Important contributors can include urine pH, mineral balance in the diet, low water intake, concentrated urine, urinary tract infection, and how long urine sits in the bladder.

Diet matters. VCA notes that balanced nutrition is important for mini pigs, and large amounts of foods that disrupt calcium and phosphorus balance are not ideal. More broadly, veterinary nutrition guidance shows that water intake is one of the biggest factors in reducing stone risk because dilute urine is less likely to form crystals. In pigs, Merck also notes that routine urinalysis can help catch urinary disease early.

In some pigs, infection and inflammation may play a role alongside stone formation. Stones can also recur, especially if the underlying diet, hydration, or urinary environment does not change. Your vet may recommend stone analysis after removal when possible, because prevention depends in part on what the stone is made of.

Diagnosis starts with a physical exam and a careful history. Your vet will want to know how often your pig is trying to urinate, whether any urine is coming out, what the urine looks like, what your pig eats, and how much water your pig drinks. In a blocked pig, the first priority is stabilizing the patient and relieving pressure on the bladder.

Merck lists urinalysis, urine culture, CBC, serum biochemistry, radiography, and ultrasonography as important diagnostic tools for miniature pet pigs with suspected urinary disease. A sterile urine sample may be collected by cystocentesis for culture. Bloodwork helps assess kidney values and hydration status, while imaging helps your vet locate stones in the bladder or urethra and look for complications.

Not every pig needs every test on day one. A stable pig with mild signs may start with exam, urinalysis, and imaging. A pig that cannot urinate, is painful, or seems systemically ill often needs same-day imaging, bloodwork, sedation, and urgent decompression. Your vet may also recommend stone analysis after surgery to guide long-term prevention.

Prevention focuses on hydration, balanced nutrition, and early monitoring. Fresh water should always be available, and water should never be restricted. Merck notes that pigs have unusual drinking behavior, so your vet may ask detailed questions about feeding practices and water intake when urinary problems keep happening.

Feed a nutritionally balanced mini-pig diet rather than a patchwork of treats, cereal, or table foods. VCA advises using a commercially balanced pelleted mini-pig chow as the base diet, and warns that large amounts of foods that disrupt calcium and phosphorus balance are not ideal. If your pig has had stones before, your vet may suggest more specific diet adjustments based on urine testing or stone analysis.

Routine checkups matter. Merck specifically recommends routine urinalysis as part of annual examinations in miniature pet pigs because it may allow early diagnosis and prevention of serious urinary tract disease. If your pig has a history of urinary issues, your vet may recommend recheck urinalysis, culture, or imaging sooner than once a year.

At home, watch for subtle changes: more frequent squatting, dribbling, blood in the urine, or new accidents. Catching those signs early can make treatment less invasive and may reduce the chance of a true urinary blockage.