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Dairy cow ketosis
After calving, a dairy cow produces a lot of milk while she still eats little: she expends more energy than she swallows. To make up for this deficit, it draws on its fat reserves. These fats are transformed by the liver, but when they arri...
What is it?
After calving, a dairy cow produces a lot of milk while she still eats little: she expends more energy than she swallows.
To make up for this deficit, it draws on its fat reserves. These fats are transformed by the liver, but when they arrive in too large quantities, the liver no longer burns them completely and produces ketone bodies, including acetone. They are what give the cow its characteristic smell.
Ketosis is therefore an energy disease, not a microbe. It mainly affects the first month and a half of lactation.
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:
Decrease in milk production, often the first sign, in a cow at the beginning of lactation.
Capricious appetite: the cow sorts its ration, shuns the concentrates and turns to roughage.
Rapid weight loss, hollowness on the flanks and hips, dull, pitted hair.
Dung more rare, dry and firm.
Distinctive, sweetish odor, reminiscent of nail polish or overripe apple, perceptible in the breath, on the skin and sometimes in milk.
Despondency, fewer ruminations, cow which stays lying down longer than its peers.
A less common nervous form exists: the cow compulsively licks walls and barriers, salivates, walks staggering, appears blind or becomes unusually agitated. These crises come and go.
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 basic cause is an energy deficit at the start of lactation: production increases quickly, ingestion follows too slowly.
A cow that is too fat at calving eats even less and mobilizes more fat: it enters ketosis more easily.
Any disease at the beginning of lactation which reduces the appetite also leads to it: mastitis, infection of the uterus, displacement of the abomasum, lameness, milk fever.
An unbalanced ration, a lack of space at the trough, unpalatable forage or poorly preserved silage reduce intake and create the same deficit.
Some poorly stored silages contain compounds that directly fuel the production of ketone bodies.
High producing cows, in the first weeks after calving.
Excessive body condition at calving: a cow fattened during drying off is the typical candidate.
Conversely, thin cows, poorly fed at the end of gestation.
Abrupt dietary transition between the drying ration and the lactation ration.
Poor quality fodder, overheated or moldy silage, lack of clean water.
Overloaded building, trough too short, dominated cows which do not access the ration.
History of ketosis or milk fever, calving of twins.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The veterinarian assesses body condition, appetite, production and looks for an illness that may have reduced appetite: this is the key point, because ketosis is often secondary to something else.
It can detect ketone bodies using a rapid test on blood, milk or urine. The blood test is the most reliable.
Palpation and auscultation of the flank make it possible to look for displacement of the abomasum, which is very often associated.
In herds, screening of freshly calved cows makes it possible to identify silent forms before they become complicated: it is a herd approach, to be organized with the veterinarian.
An examination of the uterus, udder and feet completes the assessment.
Treatment
The objective is to make sugar available to the cow and make it eat again.
The veterinarian administers glucose intravenously for an immediate effect, and prescribes sugar precursors orally, including propylene glycol, for a prolonged effect.
Corticosteroids or other medications may be used depending on the case; they are subject to prescription and waiting periods for milk and meat which must be strictly respected.
The associated disease, when there is one, is treated at the same time: treating ketosis without treating the mastitis or the displacement of the abomasum which triggered it is of no use.
On the management side, offer the cow very good quality forage, palatable, as much as you like, clean and fresh water, and easy access to the trough without competition.
Do not suddenly increase concentrates to compensate: you risk pushing the cow into acidosis and making the situation worse.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Everything is prepared during the dry-off and transition.
Arrive at calving with cows that are neither fat nor thin: scoring body condition, done regularly, is the simplest and most effective breeding tool.
Make the dietary transition gradually over the weeks before and after calving, so that the rumen and its flora have time to adapt.
Feed after calving a ration that is energy dense but balanced in fiber, with good quality forage to support intake.
Take care of access to the trough: enough space for all the cows, ration distributed several times, refusals pushed back regularly, clean water in quantity.
Eliminate overheated, moldy or poorly stored forage from the freshly calved lot.
Limit stress around calving: stable flocks, no changing of buildings at the last moment, clean bedding.
Monitor each freshly calved cow individually during the first month: appetite, production, dung, general condition. An unexplained drop in milk is a red flag.
Possible complications
The liver overloaded with fat functions less well, which aggravates the vicious cycle and further weakens the appetite.
Movement of the abomasum: ketosis and this movement mutually support each other.
Decrease in immune defenses, with more mastitis and uterine infections.
Delay in resumption of cyclicity, discreet heat, difficulty in obtaining a new pregnancy.
Loss of production throughout lactation, even after apparent recovery.
In nervous forms, the cow can injure itself or a worker during seizures.
When to see a veterinarian
A freshly calved cow produces significantly less milk for no obvious reason.
She avoids concentrates and loses weight quickly despite a correct ration.
His breath smells like acetone or overripe apples.
She licks the walls, salivates, staggers or seems to no longer see: consult without delay, the nervous form is impressive and can be dangerous.
She is lying down and does not get up.
Several freshly calved cows show the same signs: it is a ration problem, to be treated at herd level.
Prognosis
Taken early and treated, the cow eats again in a few days and returns to correct production, without always making up for the lost lactation peak.
Relapses are common as long as the energy deficit is not remedied or the associated illness is not treated.
The prognosis is more guarded when the liver is already very loaded with fat, in cows which were very fat at calving.
The nervous form generally responds well to treatment, but requires close monitoring.
Frequently asked questions
Is milk from a cow in ketosis edible?
Milk from a cow in ketosis may have an abnormal taste and odor, making it unsuitable for collection. Above all, as soon as a treatment is administered, the waiting times indicated by the veterinarian must be respected before putting the milk back into the tank.
Why do my fattest cows get sick first?
Because a cow that is too fat eats less around calving and mobilizes more fat. It therefore combines the two factors: less energy input and more fat sent to an already loaded liver.
Can I just increase the concentrate ration?
No, not brutally. A rapid increase in concentrates pushes the rumen into acidosis and further reduces intake. The increase must be gradual and compensated by quality fibers.
Can a cow that looks like nothing be in ketosis?
Yes, and this is even the most frequent case. The silent form cannot be seen with the naked eye: it results in a little less milk, a difficult recovery and more mastitis or reproductive problems. Only a test can identify it.
References
FAO — Organisation des Nations unies pour l'alimentation et l'agriculture
Content reviewed by the TunisieVet editorial team · Updated 09 August 2026
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