Anaplasmosis in Cows: Signs, Tick Transmission, and Treatment
- See your vet immediately if a cow has weakness, pale or yellow mucous membranes, fever, rapid breathing, or sudden drop in milk production.
- Bovine anaplasmosis is usually caused by Anaplasma marginale, a blood-borne bacterium that infects red blood cells and can cause severe anemia.
- Ticks are important biological vectors, and the infection can also spread mechanically through blood on needles, dehorners, castration tools, tattoo equipment, and biting flies.
- Disease severity is strongly age-related. Calves under 1 year often have mild or no signs, while adult cattle are more likely to become seriously ill or die.
- Treatment often involves tetracycline-class antibiotics, supportive care, and herd-level management. Your vet may also recommend testing herd mates and tightening tick control.
- Typical 2025-2026 U.S. cost range for exam, testing, and treatment planning is about $150-$600 per affected cow, with hospitalization, transfusion, or intensive care increasing total costs substantially.
What Is Anaplasmosis in Cows?
Bovine anaplasmosis is an infectious disease of cattle most commonly caused by Anaplasma marginale. This organism infects red blood cells, so the main problem is progressive anemia rather than diarrhea or pneumonia. As red blood cells are removed from circulation, affected cows can become weak, feverish, short of breath, and pale or yellow around the eyes, gums, and vulva.
This disease is often described as tick-borne, and that is true, but ticks are not the only route. Blood transfer also matters. A single contaminated needle, surgical instrument, or other blood-contaminated equipment can move infection between animals. Because of that, anaplasmosis is both an individual-cow problem and a herd-management problem.
Age matters a lot. Young calves often have mild or even unnoticed infection, while older cattle are more likely to develop severe disease. Adult cows may show marked production losses, abortion risk, collapse, or death if treatment is delayed. Even animals that recover can remain carriers, which is one reason your vet may recommend herd testing and a longer-term prevention plan.
Symptoms of Anaplasmosis in Cows
- Fever
- Pale gums, eyelids, or vulva
- Yellowing of the eyes or mucous membranes
- Weakness, lagging behind, or reluctance to move
- Rapid breathing or increased heart rate
- Loss of appetite and weight loss
- Drop in milk production
- Abortion or reproductive setback
- Collapse or sudden death after stress or exertion
See your vet immediately if a cow looks weak, breathes hard, has pale or yellow tissues, or goes down. Adult cattle can worsen fast, and moving a severely anemic cow may increase the risk of collapse. Calves may show milder signs, but any herd with suspected anaplasmosis deserves prompt veterinary guidance because carrier animals can keep infection circulating.
What Causes Anaplasmosis in Cows?
The usual cause of bovine anaplasmosis is Anaplasma marginale, a bacterium that lives in red blood cells. In the United States, several tick species can transmit it, and Dermacentor ticks are considered important vectors. Ticks spread the organism biologically when they feed on an infected animal and later feed on another cow.
Mechanical blood transfer is also a major cause. Reusing needles between animals, or using blood-contaminated dehorning, castration, tagging, tattoo, or surgical equipment without proper sanitation, can spread infection. Biting flies may also move small amounts of infected blood between cattle.
Herd introductions can create problems too. A healthy-looking carrier animal may bring infection into a naïve herd. Because recovered cattle may remain persistently infected, your vet may think beyond the sick cow and look at pasture exposure, vector pressure, recent purchases, and handling practices across the whole group.
How Is Anaplasmosis in Cows Diagnosed?
Your vet usually starts with the pattern of illness: fever, anemia, jaundice, weakness, and age of the affected cattle. A blood smear can sometimes show the organism on red blood cells, especially during active infection. This can be a useful same-day clue in the field or through a diagnostic lab.
Serologic testing is often used to support the diagnosis and to screen herd mates. Laboratories such as Cornell list an anaplasmosis cELISA for bovine samples, and state animal health programs also use serology in herd investigations. Your vet may pair test results with packed cell volume, total protein, and other bloodwork to judge how severe the anemia is.
Diagnosis also means ruling out look-alike problems. Depending on region and season, your vet may consider babesiosis, theileriosis, leptospirosis, copper toxicity, post-partum blood loss, or other causes of anemia and jaundice. In a herd outbreak, your vet may recommend testing additional animals so treatment and prevention decisions match the real level of risk.
Treatment Options for Anaplasmosis in Cows
Spectrum of Care means you have options. Here are treatment tiers at different price points.
Budget-Conscious Care
- Farm call or herd consultation with your vet
- Focused physical exam and anemia assessment
- Basic confirmation with blood smear or targeted herd history
- Tetracycline-class treatment plan when appropriate under veterinary direction
- Strict rest, minimal handling, shade, water access, and reduced stress
- Immediate stop to shared needles and improved equipment sanitation
Recommended Standard Treatment
- Complete veterinary exam
- CBC or packed cell volume and blood smear
- Serologic testing such as cELISA or lab confirmation
- Prescription treatment plan, often using tetracycline-class antibiotics as directed by your vet
- Supportive care and close follow-up for hydration, appetite, and exertion risk
- Testing or monitoring selected herd mates
- Tick-control plan and biosecurity review for needles, instruments, and animal movement
Advanced / Critical Care
- Emergency assessment for down, severely weak, or heavily pregnant cattle
- Hospitalization or intensive on-farm monitoring when available
- Expanded bloodwork and confirmatory testing
- Blood transfusion in selected life-threatening anemia cases
- Aggressive supportive care, oxygenation support where feasible, and careful movement restriction
- Detailed herd outbreak investigation with broader testing and prevention planning
Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.
Questions to Ask Your Vet About Anaplasmosis in Cows
Bring these questions to your vet appointment to get the most out of your visit.
- How severe is this cow's anemia right now, and is she safe to move?
- Which tests do you recommend for this cow, and should we also test herd mates?
- Is tetracycline treatment appropriate here, and what meat or milk withdrawal times apply to the products you choose?
- Could this be another cause of anemia or jaundice in our area, such as babesiosis or theileriosis?
- Do you think this herd has carrier animals, and how should we manage new additions or replacements?
- What tick-control products and pasture strategies make the most sense for our region and production system?
- Which handling practices on our farm could be spreading blood between cattle?
- What signs mean a sick cow needs emergency care or a higher level of support?
How to Prevent Anaplasmosis in Cows
Prevention starts with vector control and blood-borne biosecurity. Work with your vet on a tick-control plan that fits your region, season, and grazing system. That may include pour-ons, sprays, ear tags, pasture management, and closer surveillance during higher-risk months. In areas with cattle fever tick concerns, state and federal animal health rules may also affect movement and treatment requirements.
Do not share needles between animals. Clean and disinfect dehorning, castration, tattoo, tagging, and surgical equipment between uses, and review fly control if biting insects are a problem. These steps are practical, affordable, and often overlooked.
Herd additions deserve caution. Ask your vet whether purchased or returning cattle should be tested before mixing with the herd. In endemic areas, prevention may also include age-based management and strategic herd planning, because young animals usually handle infection better than older naïve adults. The best prevention program is the one your vet can tailor to your cattle, geography, and production goals.