Bacterial Nephritis in Cattle: Kidney Inflammation and Infection

Quick Answer
  • Bacterial nephritis in cattle usually develops when a lower urinary tract infection ascends to the kidneys, causing pyelonephritis and kidney inflammation.
  • Common signs include blood-stained urine, straining to urinate, frequent urination, reduced appetite, fever, drop in milk production, abdominal discomfort, and sometimes pus in the urine.
  • Recently fresh cows and multiparous cows are at higher risk, especially after calving trauma or urinary tract irritation.
  • Diagnosis often includes a farm exam, rectal palpation, urinalysis, urine culture, and sometimes ultrasound to check the kidneys, ureters, and bladder.
  • Treatment usually requires a prolonged course of antimicrobials chosen by your vet, plus supportive care and monitoring for kidney damage or dehydration.
Estimated cost: $250–$1,800

What Is Bacterial Nephritis in Cattle?

Bacterial nephritis in cattle is a bacterial infection and inflammation of the kidneys. In practice, this problem is often discussed as bovine pyelonephritis, because the infection commonly starts in the lower urinary tract and then travels upward through the ureters into the kidney. Merck Veterinary Manual describes it as an ascending urinary infection that can involve the bladder, ureters, and kidney tissue, with blood, white blood cells, and bacteria often present in the urine.

This condition is uncommon overall, but it can become serious when it does occur. Merck notes that prevalence is generally low, under about 1% to 2%, yet affected cattle may develop pain, reduced feed intake, lower production, fever, and progressive kidney damage if treatment is delayed.

Many cases are seen in adult cows after parturition, and multiparous cows appear to be at higher risk than first-calf heifers. Early recognition matters. A cow with blood in the urine or repeated straining to urinate should not be watched for days at home without guidance. Your vet can help determine whether the problem is limited to the bladder or has already reached the kidneys.

Symptoms of Bacterial Nephritis in Cattle

  • Blood-stained urine
  • Frequent attempts to urinate
  • Straining or painful urination
  • Pus or cloudy urine
  • Reduced appetite
  • Drop in milk production or general performance
  • Fever
  • Abdominal pain, restlessness, or tail switching
  • Increased thirst and urination
  • Weight loss, anemia, or chronic poor thrift

Blood in the urine is never a sign to ignore in cattle. Merck Veterinary Manual lists hematuria, pyuria, frequent urination, anorexia, mild fever, colic-like discomfort, and production loss among the common signs of bovine cystitis and pyelonephritis. Chronic cases may also show diarrhea, increased water intake, anemia, and ongoing straining.

See your vet promptly if your cow has blood in the urine, repeated straining, fever, reduced appetite, or a noticeable drop in milk production. See your vet immediately if the cow seems weak, dehydrated, stops eating, has severe pain, or may be pregnant and systemically ill, because kidney infection can progress and may affect both welfare and herd productivity.

What Causes Bacterial Nephritis in Cattle?

Most bacterial kidney infections in cattle happen when bacteria move upward from the bladder into the ureters and kidneys. Merck Veterinary Manual reports that E. coli, Staphylococcus spp, Proteus spp, Streptococcus spp, and Trueperella pyogenes are now commonly isolated from cows with pyelonephritis, while the Corynebacterium renale group remains a classic cause.

These bacteria are often environmental or part of the normal flora of the reproductive tract. Infection becomes more likely when the urinary tract's normal defenses are disrupted. Important risk factors include recent calving, trauma to the urinary or reproductive tract, peak lactation stress, and urinary tract irritation. Merck also notes that high-protein diets can raise urine pH, which may favor colonization by Corynebacterium species.

Management factors matter too. Nonsterile urinary catheterization can spread bacteria between cows, and reduced use of catheterization has been associated with lower prevalence of Corynebacterium-related disease. In many herds, the condition is sporadic rather than contagious in the everyday sense, but hygiene around calving, reproductive procedures, and urinary handling still plays a major role.

How Is Bacterial Nephritis in Cattle Diagnosed?

Diagnosis starts with a careful history and physical exam. Your vet will usually ask about calving date, milk drop, appetite, urine changes, breeding history, and whether the cow has had recent urinary or reproductive procedures. Merck Veterinary Manual says diagnosis is based on clinical signs, hematuria, recent parturition history, rectal palpation of the left kidney for enlargement or pain, urinalysis, and urine culture.

A urine sample is especially important. Microscopic urine evaluation may show white blood cells and bacteria, while dipstick or chemistry testing may detect blood and protein. A catheterized urine sample for culture and susceptibility testing helps identify the organism and guides antimicrobial selection. Merck specifically recommends culture and susceptibility testing before or early in treatment when possible.

Ultrasound can add useful detail, especially in more advanced or unclear cases. Published clinical reports in cows with pyelonephritis describe ultrasonographic findings such as dilated ureters, cystic or abscess-like kidney changes, and dilation of the renal sinus. In some cases, your vet may also recommend bloodwork to assess dehydration, inflammation, anemia, and kidney function, or necropsy if a cow dies unexpectedly and herd-level prevention decisions are needed.

Treatment Options for Bacterial Nephritis in Cattle

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

Budget-Conscious Care

$250–$500
Best for: Stable cows with mild to moderate signs, early disease, or situations where herd budget limits testing.
  • Farm exam and rectal palpation
  • Basic urinalysis or urine sediment evaluation
  • Empiric antimicrobial plan chosen by your vet when culture is not feasible
  • Hydration support and nursing care on-farm
  • Milk and meat withdrawal discussion
Expected outcome: Fair if caught early and the cow is still eating, hydrated, and likely has one kidney affected.
Consider: Lower upfront cost, but less diagnostic certainty. Without culture or imaging, treatment may be less targeted and relapse risk may be higher.
Most Common

Recommended Standard Treatment

$500–$1,000
Best for: Most cows with suspected pyelonephritis that are stable enough for on-farm treatment but need a more confident diagnosis and targeted plan.
  • Farm exam plus rectal urinary tract assessment
  • Urinalysis and catheterized urine culture with susceptibility testing
  • Targeted prolonged antimicrobial treatment directed by your vet
  • Bloodwork such as CBC and chemistry to assess inflammation and kidney impact
  • Recheck exam and repeat urine testing if signs persist
Expected outcome: Fair to good when treatment starts early and infection is unilateral. Long-term recovery is less likely if disease is chronic or kidney damage is advanced.
Consider: More complete information and better antimicrobial stewardship, but higher cost range and more handling time.

Advanced / Critical Care

$1,000–$1,800
Best for: High-value cattle, severe illness, uncertain diagnosis, poor response to initial treatment, or cases where preserving breeding or production value is especially important.
  • Everything in the standard tier
  • Ultrasound of kidneys, ureters, and bladder
  • More intensive fluid therapy and close monitoring
  • Referral or hospital-level care when available
  • Discussion of salvage, culling, or rare surgical options such as unilateral nephrectomy in selected nonresponsive cases
Expected outcome: Guarded to fair. Outcome depends on whether one or both kidneys are involved, how long the infection has been present, and the cow's overall condition.
Consider: Provides the most information and monitoring, but requires the highest cost range and may not be practical for every herd or every cow.

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

Questions to Ask Your Vet About Bacterial Nephritis in Cattle

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

  1. You can ask your vet whether this looks more like bladder infection alone or kidney involvement.
  2. You can ask your vet which bacteria are most likely in this cow and whether a urine culture is worth doing before treatment.
  3. You can ask your vet if bloodwork or ultrasound would change the treatment plan or prognosis.
  4. You can ask your vet whether one kidney or both kidneys may be affected.
  5. You can ask your vet how long treatment usually needs to continue and what signs show that it is working.
  6. You can ask your vet about milk and meat withdrawal times for any medications used.
  7. You can ask your vet whether this cow should stay in the herd, be dried off, or be considered for culling if recovery is incomplete.
  8. You can ask your vet what calving, catheter, or hygiene changes could reduce future cases in the herd.

How to Prevent Bacterial Nephritis in Cattle

Prevention focuses on reducing opportunities for bacteria to enter and ascend the urinary tract. Good calving hygiene, careful postpartum monitoring, and prompt treatment of reproductive tract disease can all help. Because many cases occur after parturition, cows that have had difficult calving, trauma, or postpartum illness deserve closer observation for urine changes and appetite loss.

Avoid unnecessary urinary catheterization, and when catheterization is needed, use strict sterile technique. Merck Veterinary Manual notes that nonsterile catheter use can facilitate transmission of Corynebacterium species from cow to cow, and reduced catheter use has been linked with lower prevalence of Corynebacterium-associated pyelonephritis.

Herd-level prevention also includes clean housing, dry bedding, sensible nutrition, and minimizing stress around freshening and peak lactation. If your herd has repeated urinary cases, your vet may want to review transition-cow management, calving assistance practices, and whether urine culture from affected cows could identify a pattern. Early recognition is one of the best preventive tools, because treating lower urinary tract infection before it reaches the kidneys may reduce long-term damage.

Find a Vet Near You