Nephrolithiasis in Donkeys: Kidney Stones, Pain and Urinary Problems

Quick Answer
  • Nephrolithiasis means stones form in one or both kidneys. In donkeys, these stones may stay quiet for a while or trigger pain, blood in the urine, repeated straining, and poor urine flow.
  • Some donkeys show vague signs like colic, reduced appetite, weight loss, or standing stretched out to urinate. Males are at higher risk for urinary blockage because their urethra is narrower.
  • See your vet promptly if your donkey is dribbling urine, straining, acting painful, or not passing urine normally. A complete blockage can become an emergency.
  • Diagnosis often involves a physical exam, rectal exam when appropriate, urinalysis, bloodwork, and ultrasound. X-rays may help in some cases.
  • Treatment depends on stone size, location, kidney function, and whether there is obstruction or infection. Options range from pain control and fluids to referral surgery.
Estimated cost: $350–$8,500

What Is Nephrolithiasis in Donkeys?

Nephrolithiasis means kidney stones. These are hard mineral deposits that form inside the kidney, usually in the renal pelvis or collecting system. In equids, urinary stones are uncommon overall, but when they do occur they can form anywhere in the urinary tract, including the kidneys, ureters, bladder, or urethra. Donkeys are managed like other equids for this condition, but they may hide discomfort until the problem is advanced.

A kidney stone may irritate tissue, reduce urine flow, or move and partly block the ureter, which is the tube carrying urine from the kidney to the bladder. That can lead to pain, blood in the urine, infection, pressure build-up in the kidney, and over time, loss of kidney function. Some donkeys have stones in only one kidney and seem mildly affected at first. Others develop more serious urinary problems, especially if stones are present on both sides or if a stone causes obstruction.

For pet parents, the challenge is that signs are often subtle early on. A donkey may look dull, urinate more often in small amounts, stretch out repeatedly, or have episodes that seem like mild colic. Because urinary obstruction and kidney damage can worsen quickly, any change in urination deserves a call to your vet.

Symptoms of Nephrolithiasis in Donkeys

  • Repeated straining to urinate
  • Blood in the urine or discolored urine
  • Dribbling urine or weak urine stream
  • Standing stretched out to urinate for long periods
  • Colic signs such as restlessness, pawing, sweating, or flank watching
  • Reduced appetite, depression, or weight loss
  • Increased thirst and increased urination
  • Little to no urine passed

See your vet immediately if your donkey is not passing urine, is repeatedly straining, has severe colic signs, or suddenly becomes quiet and depressed after a painful episode. In severe obstruction, the bladder or urethra can rupture, and the donkey may briefly seem less painful before becoming much sicker.

Less dramatic signs still matter. Blood in the urine, urine scalding on the hind legs, dribbling, or repeated mild colic can all point to urinary stones. Because donkeys often mask pain, even subtle urinary changes are worth discussing with your vet.

What Causes Nephrolithiasis in Donkeys?

Kidney stones form when minerals in the urine clump together and gradually build into larger stones. In equids, the exact cause is not always clear. Veterinary sources note that high mineral content in feed or water may play a role, and urinary stones are thought to be influenced by urine chemistry, crystalluria, mucoprotein content, and how concentrated the urine becomes.

Several factors may increase risk. These include reduced water intake, urinary stasis, and bacterial infection somewhere in the urinary tract. Stones in the kidney may also develop in association with renal papillary necrosis, a condition where part of the kidney tissue is damaged. In practical terms, anything that promotes concentrated urine, chronic irritation, or poor urinary flow may make stone formation more likely.

Management matters too. Donkeys with limited access to clean water, heavy work in hot weather, or diets and water sources high in minerals may be at higher risk. Male equids are more likely to develop obstructive urinary signs because stones are harder to pass through the longer, narrower male urethra. That does not mean females cannot develop kidney stones, only that complete blockage is more common in males.

How Is Nephrolithiasis in Donkeys Diagnosed?

Your vet will start with a history and physical exam, paying close attention to urination, pain, hydration, and signs of colic. In some cases, a rectal exam may help assess bladder size or detect complications linked to obstruction. If your donkey is male, your vet may also examine the penis and urethral opening to rule out other causes of straining, including urethral concretions or distal obstruction.

Testing usually includes urinalysis to look for blood, crystals, inflammation, and signs of infection. Bloodwork can help assess kidney values, hydration status, and electrolyte changes. Ultrasound is often one of the most useful tools for suspected nephrolithiasis because it can help identify stones, kidney enlargement, hydronephrosis, or changes in the urinary tract. X-rays may also help confirm some stones, depending on their size and mineral makeup.

If there is concern for blockage, your vet may carefully pass a urinary catheter to check urine flow or confirm an obstruction. This must be done gently because excessive force can damage the urethra. When stones are removed, stone analysis can be helpful for planning prevention, since long-term management depends in part on what the stone is made of.

Treatment Options for Nephrolithiasis in Donkeys

Spectrum of Care means you have options. Here are treatment tiers at different price points.

Budget-Conscious Care

$350–$1,200
Best for: Stable donkeys with mild signs, uncertain diagnosis, or pet parents needing an evidence-based first step before referral
  • Farm call or clinic exam
  • Pain control and anti-inflammatory medication as directed by your vet
  • Sedation if needed for exam
  • Urinalysis and basic bloodwork
  • Hydration support with oral, nasogastric, or IV fluids when appropriate
  • Monitoring urine output and comfort
  • Referral discussion if obstruction, infection, or kidney compromise is suspected
Expected outcome: Fair to guarded. Some donkeys improve temporarily if irritation is mild and urine flow remains adequate, but kidney stones rarely resolve on their own.
Consider: This approach may control pain and support hydration, but it usually does not remove the stone. Ongoing obstruction, recurrent pain, infection, or kidney damage can still develop.
Most Common

Recommended Standard Treatment

$1,200–$3,500
Best for: Most donkeys with confirmed or strongly suspected nephrolithiasis that need a fuller workup and active medical stabilization
  • Complete exam and repeat monitoring
  • CBC, chemistry panel, and urinalysis
  • Ultrasound and, when useful, radiographs
  • Urinary catheterization if indicated
  • IV fluids and hospital observation
  • Targeted antimicrobials only if infection is documented or strongly suspected by your vet
  • Referral planning for stone removal if the stone is causing obstruction, recurrent pain, or kidney damage
Expected outcome: Variable. Better when one kidney is affected and urine flow is maintained. More guarded if both kidneys are involved, infection is present, or there is prolonged obstruction.
Consider: This tier improves diagnostic clarity and stabilization, but definitive treatment may still require referral surgery or advanced procedures.

Advanced / Critical Care

$3,500–$8,500
Best for: Donkeys with obstruction, severe pain, recurrent episodes, infection, hydronephrosis, worsening kidney values, or pet parents pursuing the full range of available options
  • Referral hospital care
  • Advanced imaging and repeated kidney monitoring
  • Continuous IV fluid therapy and intensive pain management
  • Management of electrolyte or kidney complications
  • Surgical or specialized stone removal when feasible based on location
  • Possible nephrectomy in select unilateral end-stage cases, at your vet's discretion and referral surgeon assessment
  • Stone analysis and tailored prevention plan after recovery
Expected outcome: Guarded to fair, depending on whether the stone can be removed, how much kidney function remains, and whether one or both kidneys are affected.
Consider: This tier offers the most information and intervention, but it requires referral access, transport, anesthesia or standing procedures in some cases, and a higher cost range.

Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.

Questions to Ask Your Vet About Nephrolithiasis in Donkeys

Bring these questions to your vet appointment to get the most out of your visit.

  1. Based on the exam, do you think the stone is in the kidney, ureter, bladder, or urethra?
  2. Is my donkey still passing enough urine, or are you worried about a partial or complete blockage?
  3. What tests do you recommend first: urinalysis, bloodwork, ultrasound, x-rays, or catheterization?
  4. Are there signs of kidney damage, infection, or hydronephrosis right now?
  5. What conservative care can we start today while we decide whether referral is needed?
  6. What are the realistic treatment options for this stone's location and size?
  7. If surgery or referral is recommended, what is the expected cost range and prognosis?
  8. After treatment, what changes in water access, diet, or monitoring may help reduce recurrence?

How to Prevent Nephrolithiasis in Donkeys

Prevention focuses on keeping urine dilute and reducing conditions that favor stone formation. The most practical step is making sure your donkey always has access to clean, palatable water. Donkeys that work, travel, sweat heavily, or live in hot climates may need extra attention to hydration. If your water source is very hard or mineral-rich, ask your vet whether testing the water or changing the source makes sense.

Diet review matters too. Because equine urinary stones may be influenced by mineral intake and urine chemistry, your vet may want to look closely at forage, concentrates, supplements, and treats. Avoid making major diet changes on your own, especially if your donkey has other health issues. If a stone is removed, stone analysis can help guide a more specific prevention plan.

Prompt care for urinary tract infections, regular observation of urination habits, and follow-up imaging in donkeys with a history of stones can all help catch recurrence earlier. Call your vet if you notice blood in the urine, repeated straining, dribbling, or changes in thirst and urination. Early action often gives you more treatment options.

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