Pyelonephritis in Cattle: Kidney Infection Signs, Causes, and Treatment
- Pyelonephritis is a bacterial kidney infection that usually starts as an ascending urinary tract infection and is seen most often in adult cows, especially after calving-related trauma or uterine infection.
- Common signs include blood-tinged urine, straining to urinate, frequent urination, reduced appetite, lower milk production, fever, weight loss, and signs of abdominal discomfort or colic.
- This condition needs veterinary attention promptly because delayed care can lead to kidney damage, dehydration, chronic poor performance, or death in severe cases.
- 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 with your vet, plus supportive care and follow-up testing to confirm the infection has cleared.
What Is Pyelonephritis in Cattle?
Pyelonephritis is a bacterial infection of the kidney and renal pelvis in cattle. In many cows, the infection starts lower in the urinary tract, such as the bladder, then travels upward through the ureters into one or both kidneys. It is considered one of the more important urinary tract diseases in adult cattle and is seen far more often in cows than in bulls.
This problem can develop suddenly or smolder for weeks. Early on, a cow may only show subtle signs like blood-stained urine, reduced appetite, or a drop in milk production. As the infection progresses, inflammation and pus can damage kidney tissue, which can affect hydration, comfort, and overall productivity.
Pyelonephritis is especially important around the postpartum period. Cows that have recently calved, had dystocia, abortion, uterine infection, or urinary tract trauma are at higher risk. Because chronic cases are common and signs can be easy to miss at first, early veterinary evaluation matters.
Symptoms of Pyelonephritis in Cattle
- Blood in the urine
- Frequent attempts to urinate
- Straining or discomfort while urinating
- Reduced appetite
- Drop in milk production or poor performance
- Fever
- Colic-like behavior or abdominal pain
- Weight loss, poor hair coat, or anemia
- Excessive urination and drinking
Call your vet promptly if you notice blood in the urine, repeated straining, fever, or a fresh cow that suddenly drops in milk and seems uncomfortable. Pyelonephritis can look mild at first, but chronic kidney damage can develop if treatment is delayed.
See your vet immediately if the cow is weak, dehydrated, not passing normal amounts of urine, has severe pain, or seems systemically ill. Those signs raise concern for advanced infection, kidney dysfunction, or another urgent urinary problem.
What Causes Pyelonephritis in Cattle?
Most cases of pyelonephritis in cattle are caused by bacteria that move upward from the lower urinary tract. Historically, the Corynebacterium renale group was the classic cause, but modern reports also identify Escherichia coli, Trueperella pyogenes, Staphylococcus, Streptococcus, Proteus, Klebsiella, Enterococcus, and Pseudomonas species in some cows.
The infection often takes hold after the urinary tract's normal defenses have been disrupted. Common risk factors include recent calving, dystocia, abortion, puerperal infection, trauma to the reproductive or urinary tract, and bladder dysfunction that prevents complete emptying. Multiparous cows are affected more often than younger females, and the condition is uncommon in male cattle.
Management factors can matter too. Nonsterile urinary catheterization can spread bacteria between cows, and anything that increases contamination around the vulva or urinary opening may raise risk. In some herds, high-protein diets have also been discussed as a contributing factor because more alkaline urine may favor colonization by certain bacteria.
How Is Pyelonephritis in Cattle Diagnosed?
Your vet usually starts with the history and physical exam. Recent calving problems, uterine disease, blood in the urine, straining, reduced production, and chronic weight loss can all raise suspicion. In adult cows, rectal palpation may help your vet assess the left kidney and ureters for enlargement, pain, or loss of normal shape.
Urine testing is a key next step. A urinalysis may show blood, protein, white blood cells, bacteria, or pus. A catheterized urine sample for culture and susceptibility testing is especially helpful because it identifies the organism and helps your vet choose the most appropriate antimicrobial plan.
Ultrasound can add useful detail, especially when the diagnosis is unclear or the cow is not improving as expected. It may show changes in the kidneys, ureters, or bladder that support pyelonephritis or cystitis. Depending on the case, your vet may also recommend bloodwork to assess dehydration, inflammation, and kidney function, and to help rule out other causes of hematuria or poor performance.
Treatment Options for Pyelonephritis in Cattle
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Farm call or clinic exam
- Basic urinalysis or urine dipstick screening
- Empirical antimicrobial plan chosen by your vet based on likely organisms and herd context
- Monitoring of appetite, urine appearance, hydration, temperature, and milk production
- Recheck to assess response
Recommended Standard Treatment
- Farm exam with rectal palpation and full history review
- Urinalysis plus catheterized urine culture and susceptibility testing
- Targeted prolonged antimicrobial treatment, often for 2-4 weeks depending on response and your vet's plan
- Supportive care such as fluids, anti-inflammatory treatment if appropriate, and management changes to reduce contamination and stress
- Follow-up urine testing after treatment to help confirm clearance
Advanced / Critical Care
- Everything in the standard tier
- Ultrasound of kidneys, ureters, and bladder
- CBC and chemistry testing to assess inflammation, dehydration, and kidney function
- More intensive fluid therapy and close monitoring for systemic illness
- Referral-level care or surgical discussion in select unilateral, nonresponsive cases
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Pyelonephritis in Cattle
Bring these questions to your vet appointment to get the most out of your visit.
- Does this cow's history after calving make pyelonephritis more likely?
- Should we collect a catheterized urine sample for culture before starting or changing antimicrobials?
- Do you suspect one kidney or both kidneys are involved?
- Would ultrasound or bloodwork change the treatment plan or prognosis in this case?
- What signs would tell us the cow is improving versus getting worse?
- How long should treatment continue, and when should we recheck urine?
- Are there milk or meat withdrawal considerations with the medications you are choosing?
- Could bladder dysfunction, calving injury, or uterine infection be causing this to recur?
How to Prevent Pyelonephritis in Cattle
Prevention focuses on reducing ascending urinary tract infection and protecting cows during the high-risk postpartum period. Good calving management matters. Prompt attention to dystocia, retained placenta, metritis, and vulvar or vaginal trauma may lower the chance that bacteria move into the urinary tract. Clean maternity areas and careful hygiene around fresh cows are practical steps that support this goal.
Avoid unnecessary urinary catheterization, and if catheterization is needed, sterile technique is important. Historically, nonsterile catheter use has been linked with spread of urinary pathogens between cows. Cows with poor urine flow, suspected bladder paralysis, or repeated urinary signs should be evaluated early because incomplete bladder emptying can set the stage for recurrent infection.
Daily observation also helps. Fresh cows that show blood in the urine, repeated straining, reduced appetite, or a sudden drop in milk should be checked promptly. Early treatment offers the best chance of recovery before chronic kidney damage develops.
If pyelonephritis has shown up in your herd more than once, ask your vet to review calving protocols, hygiene, catheter practices, and any herd-level postpartum disease patterns. Small management changes can make a meaningful difference.