What would you do if half your milking herd suddenly went dry, not from lack of nutrition or water, but from a silent bacterial invader spreading through the barn? For countless farmers, this is not an exaggerated fear. It is a reality that strikes without warning. Bacterial diseases in large ruminants don’t just harm the health of animals.
They derail production, threaten livelihoods, and leave farmers scrambling for solutions. Unlike feed shortages or visible injuries, these infections creep in unnoticed, only revealing themselves when losses are already mounting.
To help you protect your livelihood, I am listing the 15 common bacterial diseases of cattles and buffaloes you should watch out for.
15 Most Common Bacterial Diseases in Large Ruminants (Cattle and Buffaloes)
Bacterial diseases are among the biggest health challenges for cattle and buffalo owners. Unlike nutritional issues or parasitic infestations, bacterial infections often spread fast and cause severe losses in milk production, fertility, and even survival rates.
Some of these diseases strike suddenly, such as anthrax or black quarter, while others creep in slowly, like tuberculosis or Johne’s disease. The following are the 15 most common bacterial diseases of large ruminants that affect both cows and buffaloes.
1. Anthrax
- Causative agent: Bacillus anthracis
- Primary site of infection: Blood and multiple organs
Anthrax is a sudden and fatal bacterial disease in cattle and buffaloes. The spores remain in soil for decades and wait for the right conditions to infect grazing animals. Outbreaks often follow heavy rains or flooding. Death occurs rapidly, leaving little time for treatment, which makes preventive vaccination vital.
Symptoms of Anthrax
- Sudden death without prior illness
- Dark, unclotted blood oozing from body openings
- Rapid bloating of carcass
- Absence of rigor mortis
- High fever before death (if observed early)
Treatment of Anthrax
Treatment is rarely effective due to the rapid course of the disease. Early cases may respond to high-dose penicillin or oxytetracycline. The key is prevention through annual vaccination in endemic areas.
Carcasses must be properly disposed of (deep burial or burning) to prevent further spread of spores.
2. Hemorrhagic Septicemia (HS)
- Causative agent: Pasteurella multocida (serotypes B:2 and E:2)
- Primary site of infection: Respiratory tract and bloodstream
Hemorrhagic septicemia is one of the most devastating bacterial diseases in large ruminants, affecting both cattle and buffalo, especially in tropical regions. It spreads rapidly during hot and humid conditions. The disease strikes suddenly, causing high fever, swelling in the throat region, and severe breathing difficulty. Without quick treatment, death often occurs within 24 hours.
Symptoms of Hemorrhagic Septicemia
- High fever with depression and loss of appetite
- Painful swelling in the throat and neck region
- Severe respiratory distress with frothy discharge
- Profuse salivation and nasal discharge
- Sudden death in advanced cases
Treatment of Hemorrhagic Septicemia
Early treatment is critical. Broad-spectrum antibiotics like oxytetracycline, sulfonamides, or ceftiofur are commonly used. Anti-inflammatory drugs and supportive fluids help stabilize animals.
Preventive vaccination before seasonal outbreaks is the most effective control method, along with reducing stress factors such as transport or overcrowding.
3. Black Quarter (Blackleg)
- Causative agent: Clostridium chauvoei
- Primary site of infection: Skeletal muscles
Black quarter is a soil-borne bacterial disease that mainly affects young, healthy cattle and buffaloes. The bacteria remain dormant in muscle tissue until trauma triggers their growth. The disease causes swelling in large muscles, with gas formation producing a crackling sound when pressed. Death usually occurs within two days of onset.
Symptoms of Black Quarter
- Sudden lameness in one or more limbs
- Swelling in the thigh, shoulder, or hip regions
- Crepitation (crackling sound) when swelling is pressed
- High fever with loss of appetite
- Rapid death despite treatment attempts
Treatment of Black Quarter
Treatment is rarely successful once clinical signs appear. High doses of penicillin may help in the very early stages. Vaccination of young stock is the best preventive measure. Proper carcass disposal is essential to avoid soil contamination.
Good management practices that minimize injuries also reduce the risk of outbreaks.
4. Bovine Tuberculosis
- Causative agent: Mycobacterium bovis
- Primary site of infection: Lungs and lymph nodes
Bovine tuberculosis is a chronic bacterial disease that slowly spreads within herds. Animals may look healthy for months while silently shedding the bacteria. It primarily affects the respiratory system but can also involve lymph nodes and other organs. The disease causes significant economic losses due to poor productivity and is zoonotic.
Symptoms of Bovine Tuberculosis
- Chronic cough that worsens over time
- Progressive weight loss despite normal feeding
- Reduced milk yield in lactating animals
- Enlarged lymph nodes, especially around the neck
- Weakness and poor body condition in advanced stages
Treatment of Bovine Tuberculosis
There is no effective treatment for bovine tuberculosis. Control relies on regular testing, culling infected animals, and maintaining strict biosecurity. Pasteurization of milk is crucial to prevent human infection.
Vaccination is not commonly practiced in cattle and buffaloes, so prevention through herd health programs is the best strategy.
5. Brucellosis
- Causative agent: Brucella abortus
- Primary site of infection: Reproductive organs (uterus, placenta, testes)
Brucellosis is one of the most important reproductive diseases in cattle and buffaloes. It spreads through contaminated birth fluids, aborted fetuses, and raw milk. Farmers often first notice the disease when multiple animals abort late in pregnancy. It also poses a serious health risk to humans handling infected materials.
Symptoms of Brucellosis
- Abortion, usually in the last trimester
- Retained placenta and delayed recovery after abortion
- Infertility or repeated breeding failures
- Orchitis and swollen testes in bulls
- Reduced milk yield and overall productivity
Treatment of Brucellosis
There is no reliable treatment for brucellosis in large ruminants. Control depends on vaccination of young stock, strict hygiene during calving, and culling infected animals. Farmers must avoid consuming raw milk from suspected animals.
Eradication programs are the most effective way to reduce the disease at the herd or regional level.
6. Leptospirosis
- Causative agent: Leptospira species (especially L. interrogans)
- Primary site of infection: Kidneys, liver, and reproductive tract
Leptospirosis is a bacterial disease that thrives in wet and humid conditions. It spreads through contaminated water, urine, and direct animal contact. The disease can range from mild, unnoticed infections to severe outbreaks causing abortion, jaundice, and kidney damage. Buffaloes may carry the bacteria without obvious signs, making it harder to control.
Symptoms of Leptospirosis
- Sudden fever and depression
- Jaundice with yellow discoloration of mucous membranes
- Abortion and stillbirths in pregnant animals
- Reduced milk yield and “flabby udder” in dairy cows
- Blood-tinged urine or signs of kidney involvement
Treatment of Leptospirosis
Early treatment with antibiotics such as streptomycin or tetracyclines is effective. Supportive therapy, including fluids and vitamins, helps recovery. Vaccination is available in endemic areas and should be combined with good sanitation and control of standing water.
Farmers must handle suspected cases carefully due to the zoonotic risk.
7. Salmonellosis
- Causative agent: Salmonella species (commonly S. typhimurium and S. dublin)
- Primary site of infection: Intestines and bloodstream
Salmonellosis is a serious bacterial disease that affects both calves and adult ruminants. It spreads quickly in unhygienic environments through contaminated feed, water, and manure. Calves often develop diarrhea and septicemia, while adults may suffer from chronic diarrhea, poor performance, and abortions. It also poses a significant zoonotic risk to humans.
Symptoms of Salmonellosis
- Sudden onset of foul-smelling diarrhea, sometimes with blood
- High fever with rapid dehydration
- Weakness and loss of appetite
- Abortion in pregnant animals
- Septicemia and sudden death in calves
Treatment of Salmonellosis
Early treatment with antibiotics such as ampicillin, trimethoprim-sulfa, or fluoroquinolones may help, but resistance is common. Oral and intravenous fluids are critical to combat dehydration.
Strict hygiene, isolation of sick animals, and disinfection of housing are essential for prevention. Vaccination is available in certain regions for herd protection.
8. Colibacillosis (E. coli Infections)
- Causative agent: Pathogenic strains of Escherichia coli
- Primary site of infection: Intestinal tract of calves
Colibacillosis, often called calf scours, is one of the most common bacterial diseases in newborn calves. It strikes within the first week of life, especially in animals that did not receive enough good-quality colostrum. The rapid dehydration caused by diarrhea often kills calves within a short period if not managed promptly.
Symptoms of Colibacillosis
- Watery white or yellow diarrhea
- Severe dehydration with sunken eyes
- Weakness and reluctance to suckle
- Cold extremities and collapse in severe cases
- Rapid weight loss and poor growth in survivors
Treatment of Colibacillosis
Prompt fluid therapy with electrolytes is the most important treatment. Antibiotics such as amoxicillin or neomycin may help control secondary bacterial infections. Good colostrum management, strict hygiene in calf pens, and proper feeding practices are the best preventive measures. Vaccinating pregnant dams can boost calf immunity.
9. Mastitis (Bacterial Origin)
- Causative agent: Streptococcus agalactiae, Staphylococcus aureus, Escherichia coli, and others
- Primary site of infection: Udder (mammary gland)
Mastitis is one of the costliest bacterial diseases in large ruminants. It reduces milk yield, affects milk quality, and can lead to permanent udder damage. The infection spreads during milking, especially when hygiene practices are poor. It may be clinical, with visible signs, or subclinical, detected only through milk testing.
Symptoms of Mastitis
- Swelling and heat in one or more quarters of the udder
- Clots or flakes in the milk
- Pain during milking with reduced yield
- Fever and depression in severe systemic cases
- Fibrosis and hardening of udder tissue in chronic infections
Treatment of Mastitis
Treatment depends on the type and severity of infection. Intramammary and systemic antibiotics such as penicillin or cephalosporins are commonly used. Anti-inflammatory drugs and frequent milking help reduce bacterial load.
Prevention is crucial, involving teat dipping, clean milking practices, and dry cow therapy. Regular monitoring for subclinical cases saves production losses.
10. Actinomycosis (Lumpy Jaw)
- Causative agent: Actinomyces bovis
- Primary site of infection: Bones of the jaw and oral cavity
Actinomycosis, commonly called lumpy jaw, is a chronic bacterial infection that causes firm, immovable swellings on the jawbone. The bacteria usually enter through wounds in the mouth caused by rough feed or injuries. Over time, the lesions enlarge, making chewing difficult and leading to progressive weight loss in affected cattle and buffaloes.
Symptoms of Actinomycosis
- Hard, painless swelling on the jawbone
- Formation of draining sinuses with pus discharge
- Difficulty chewing and swallowing feed
- Loose teeth due to jawbone involvement
- Progressive weight loss and poor body condition
Treatment of Actinomycosis
Early cases may respond to prolonged antibiotic therapy with penicillin or tetracycline. Sodium iodide administered intravenously is also effective. Advanced cases with severe bone destruction have poor outcomes.
Preventive measures include avoiding rough feed and promptly treating oral wounds to stop bacterial entry.
11. Actinobacillosis (Wooden Tongue)
- Causative agent: Actinobacillus lignieresii
- Primary site of infection: Tongue and soft tissues of the mouth
Actinobacillosis, often called wooden tongue, is a bacterial disease affecting the soft tissues of the mouth, particularly the tongue. The tongue becomes swollen, firm, and painful, making eating and drinking extremely difficult. Nodules and ulcers may form, and saliva often dribbles continuously. Without treatment, the condition worsens rapidly.
Symptoms of Actinobacillosis
- Swollen, hard tongue with reduced movement
- Nodules or ulcers on the tongue surface
- Excessive salivation and drooling
- Difficulty chewing and swallowing feed
- Emaciation due to inability to eat properly
Treatment of Actinobacillosis
Sodium iodide given intravenously is the treatment of choice and usually produces rapid improvement. Antibiotics such as tetracycline or streptomycin may be used alongside. Good oral hygiene and early intervention are essential.
Avoiding rough feed and ensuring clean pastures can reduce the chances of infection.
12. Johne’s Disease (Paratuberculosis)
- Causative agent: Mycobacterium avium subspecies paratuberculosis
- Primary site of infection: Intestines and lymph nodes
Johne’s disease is a chronic, debilitating infection that slowly destroys productivity in cattle and buffaloes. Calves are usually infected at a young age but show signs only years later. The disease damages the intestines, leading to persistent diarrhea and weight loss despite normal feeding. It spreads through contaminated manure and milk.
Symptoms of Johne’s Disease
- Chronic, watery diarrhea that does not respond to treatment
- Progressive weight loss despite good appetite
- Swelling under the jaw (bottle jaw) due to protein loss
- Decreased milk production in dairy animals
- Weakness and poor body condition leading to culling
Treatment of Johne’s Disease
There is no effective treatment for Johne’s disease. Management focuses on prevention through testing and culling infected animals, strict hygiene in calf rearing, and avoiding manure contamination of feed and water. Vaccines may reduce severity but do not eliminate the infection. Biosecurity is the best defense against this disease.
13. Bovine Foot Rot
- Causative agent: Fusobacterium necrophorum and Dichelobacter nodosus
- Primary site of infection: Interdigital space of the hoof
Bovine foot rot is a painful bacterial infection of the hoof in cattle, usually occurring in wet and muddy conditions. It starts as an interdigital skin lesion that spreads rapidly, leading to lameness and reduced productivity. The disease spreads in herds through contaminated soil, manure, and unhygienic farm conditions.
Symptoms of Bovine Foot Rot
- Sudden onset of severe lameness
- Swelling between the claws
- Foul-smelling discharge from the lesion
- Reluctance to walk or graze
- Reduced milk yield and feed intake
Treatment of Bovine Foot Rot
Systemic antibiotics such as oxytetracycline or penicillin are effective. Cleaning and disinfecting the hoof with antiseptics is essential. Footbaths containing zinc sulfate or copper sulfate help control outbreaks. Preventive measures include improving drainage, keeping pens dry, and regular hoof trimming.
14. Tetanus
- Causative agent: Clostridium tetani
- Primary site of infection: Nervous system (via toxin released from contaminated wounds)
Tetanus is a fatal neurological disease of cattle caused by toxins from Clostridium tetani. Spores enter through deep wounds, particularly after castration, dehorning, or parturition injuries. The toxin interferes with nerve signaling, leading to uncontrolled muscle contractions. Cattle often succumb quickly if treatment is delayed.
Symptoms of Tetanus
- Stiffness of muscles (sawhorse stance)
- Difficulty chewing (lockjaw)
- Hypersensitivity to sound and light
- Rigid tail and erect ears
- Death due to respiratory failure
Treatment of Tetanus
High doses of penicillin can help eliminate the bacteria. Antitoxin serum is crucial to neutralize circulating toxin. Muscle relaxants and sedatives may be given for relief. Supportive care in a quiet, dark environment improves survival chances.
Vaccination with tetanus toxoid is the most reliable preventive measure.
15. Botulism
- Causative agent: Clostridium botulinum (toxin-producing bacterium)
- Primary site of infection: Nervous system (through ingestion of pre-formed toxin)
Botulism in cattle occurs after ingestion of feed or water contaminated with botulinum toxin, often from decomposing carcasses or spoiled silage. The toxin blocks nerve transmission, causing flaccid paralysis. The disease is highly fatal, and outbreaks can devastate herds if preventive measures are not in place.
Symptoms of Botulism
- Progressive weakness and paralysis
- Drooling and difficulty swallowing
- Inability to stand (downer cow)
- Loss of tongue tone (cannot retract tongue)
- Sudden death in severe cases
Treatment of Botulism
Specific antitoxin serum is rarely available but lifesaving if administered early. Supportive therapy includes fluid management and hand-feeding. Antibiotics are ineffective because the disease is toxin-mediated. Prevention involves proper disposal of carcasses, avoiding spoiled silage, and vaccinating animals in endemic regions.
Let’s Rewind
Bacterial diseases in large ruminants (cattle and buffaloes) are more than just health issues. They are direct threats to a farmer’s livelihood. From sudden killers like anthrax and hemorrhagic septicemia to chronic productivity drainers like tuberculosis and Johne’s disease, the spectrum of risk is wide.
The good news is that with timely vaccination, strict hygiene, and early veterinary intervention, most of these diseases can be prevented or controlled. As someone who works closely with farmers, I always encourage them to consult their veterinarian regularly and invest in preventive health plans.
