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Cow ovarian cysts
Each cycle, a follicle matures on the ovary and releases an egg: this is ovulation. An ovarian cyst forms when this follicle does not ovulate and persists, swollen with fluid, instead of disappearing. The ovary then continues to send abnorm...
What is it?
Each cycle, a follicle matures on the ovary and releases an egg: this is ovulation. An ovarian cyst forms when this follicle does not ovulate and persists, swollen with fluid, instead of disappearing.
The ovary then continues to send abnormal hormonal messages, and the cow's cycle becomes disrupted. Depending on the type of cyst, the cow may constantly ask for the bull or, on the contrary, no longer show any heat.
It is a common disorder in high-producing dairy cows, especially in the first weeks of lactation. It does not make the cow sick but costs a lot in unproductive days.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
Absence of pregnancy despite repeated inseminations.
Abnormal heat: either repeated and close together, or very long, or completely absent for several weeks.
Male-like behavior in certain cows: they try to ride their peers, become agitated, moo, sometimes aggressive.
Flow of clear mucus outside of normal heat periods.
In cows affected for a long time, relaxation of the ligaments of the pelvis which gives the appearance of a sagging rump, and sometimes a raised tail base.
Possible weight loss in very agitated cows who eat less.
Some cows show no visible signs: the cyst is only discovered during the reproductive examination.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
The central mechanism is a fault in the hormonal control between the brain and the ovary: the signal that triggers ovulation is not given, or not at the right time.
The energy deficit at the start of lactation is the best established factor: the cow produces a lot of milk, eats less than its needs, mobilizes its reserves, and its reproduction goes into hibernation.
The stress, pain and illnesses of early lactation — metritis, lameness, milk fever, ketosis — disrupt the same hormonal order.
A hereditary component exists: certain lines are more prone to it.
Ration imbalances, particularly in energy, proteins and minerals, are also to blame.
Strong producers at the start of lactation, a period when the energy deficit is maximum.
Cows that are too fat at calving, which eat less afterwards.
Postpartum diseases: metritis, retained placenta, milk fever, acetonemia.
Lameness and anything that limits access to the trough.
Heat stress and poorly ventilated buildings.
Family history of cysts.
Season: cycle disorders are more common during periods of high heat.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The diagnosis cannot be made by eye: it is based on the examination of the genital tract by the veterinarian.
Rectal palpation allows one to feel an abnormally large fluid structure on the ovary.
Ultrasound specifies the size of the cyst, the thickness of its wall and the number of cysts; it is this which distinguishes the follicular cyst from the luteal cyst, a decisive distinction for the treatment.
A hormonal dosage can complete the examination in difficult cases.
The veterinarian checks at the same time the condition of the uterus and the body condition of the cow, and makes the link with the feeding behavior of the herd.
Treatment
The treatment is hormonal and depends exclusively on veterinary prescription: the product chosen depends on the type of cyst, and a bad choice is ineffective, or even counterproductive.
Manual emptying of the cyst by crushing should be avoided: it causes bleeding and adhesions around the ovary, which can make the cow permanently sterile.
Hormonal treatment is often associated with a synchronization protocol to regain control of the cycle and schedule insemination.
Correcting the diet is part of the treatment: without restoring the energy balance, the cysts reform.
Some cysts disappear spontaneously, particularly those that appear very soon after calving: this is why the veterinarian does not always treat immediately.
If drug treatment is administered, respect the milk and meat withdrawal period indicated by the veterinarian.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Control the energy deficit at the start of lactation: well-balanced ration, gradual food transition, easy and permanent access to a clean trough.
Avoid cows that are too fat when drying off.
Treat postpartum illnesses and lameness, which disrupt the cycle, without delay.
Implement regular reproductive monitoring: an examination of cows not seen in heat or that have returned several times allows cysts to be detected early.
Keep a record of heat and inseminations: this is the best tool for spotting a cow that is going off the rails.
Limit heat stress and ensure abundant watering in summer.
Consider background when choosing breeding stock.
Possible complications
Significant lengthening of the interval between two calvings and economic loss linked to unproductive days.
Reform for infertility.
Adhesions and permanent damage to the ovary in case of rough handling of the cyst.
Frequent association with uterine infections, each fueling the other.
When to see a veterinarian
Your cow comes into heat repeatedly without being fertilized.
She has not been seen in heat for several weeks after calving.
She rides her peers constantly, becomes agitated or aggressive.
Her heat is abnormally long or irregular.
Its rump sags and its tail appears raised.
Several cows in the herd have cycle disorders: have the ration and breeding management analyzed.
Prognosis
If diagnosed and treated correctly, most cysts resolve and the cow becomes pregnant again.
The time taken to return to fertility varies: several weeks are often necessary after treatment.
Recurrences are common as long as the underlying cause – energy deficit, associated illness – is not corrected.
Cows with repeated cysts over several lactations often end up culled for infertility.
Frequently asked questions
Can you recognize an ovarian cyst without a veterinarian?
No. Behavioral signs only make one suspect the problem, and many affected cows show nothing. Only an examination of the ovary, by palpation and especially by ultrasound, can confirm it and specify its type.
Does a cow that rides other cows necessarily have a cyst?
No. A cow in normal heat also mounts her fellow cows. What should raise alarm is behavior of this type which lasts or returns constantly, without any insemination taking place.
Should the cyst be pierced?
No. Crushing or blindly puncturing the cyst can cause bleeding and adhesions that permanently compromise fertility. Modern treatment is hormonal, on prescription.
Do cysts come back after treatment?
This is possible, especially if the cow remains in energy deficit or suffers from another illness. Correcting the diet and treating associated conditions is as important as the hormonal treatment itself.
References
Content reviewed by the TunisieVet editorial team · Updated 09 August 2026
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