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Lamb Rickets
Rickets is a disease of the growing bone. In lamb, the bone does not mineralize properly: instead of hardening, it remains soft, deforms under the weight of the animal and becomes painful. Three elements work together to build bone: vitamin...
What is it?
Rickets is a disease of the growing bone. In lamb, the bone does not mineralize properly: instead of hardening, it remains soft, deforms under the weight of the animal and becomes painful.
Three elements work together to build bone: vitamin D, calcium and phosphorus. It only takes one lack, or their ratio is unbalanced, for mineralization to fail.
Vitamin D deserves special mention, because it is produced in the skin under the action of the sun. A lamb raised in a closed sheepfold, without ever going outside, is deprived of this source, whatever the quality of its ration. This is why rickets mainly affects lambs fattened in buildings and much less those who live outside, including in regions where there is no shortage of sun.
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:
Lameness that changes limbs from one day to the next, or general stiffness of gait.
Lambs that have difficulty getting up, that lie down longer than the others, that refuse to follow the crowd.
Lambs eating on their knees, on the carpals of the forelimbs.
Joints that appear large, especially at the knees and hocks, with enlarged ends of bones.
Limbs that curve: arched front legs, abnormal balance which worsens with time.
Arched back, cautious gait, animal that growls or grinds its teeth while moving.
Slowed growth, lambs which clearly lag behind their contemporaries despite an apparently correct ration.
Dull, poor quality wool.
In advanced forms, fractures occurring during routine handling, or the lamb remaining permanently lying down.
Several lambs from the same batch are generally affected to varying degrees: this is an important sign, isolated lameness rather points towards another cause.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
Lack of vitamin D, most often due to lack of exposure to the sun in lambs raised in closed buildings, sometimes due to a poor ration or fodder.
Lack of phosphorus, common when the ration is based on poor quality roughage and without supplementation.
Lack of calcium, or more often imbalance between calcium and phosphorus: an excess of one blocks the use of the other. A ration very rich in cereals or, conversely, in legumes can create this imbalance without either element being absent.
Fodder harvested late, hay washed out by rain, straw used as a basis for the ration.
Mineral supplement absent, unsuitable or inaccessible to some animals.
Rapid growth: the lambs that grow the fastest have the highest needs and are the first to be affected.
Certain chronic diseases, notably digestive parasitoses, reduce absorption and worsen the situation even when the ration is correct.
Lambs for fattening in a closed sheepfold, without access to daylight or outside access.
Ration based on roughage, straw or poor quality hay.
Unbalanced ration in calcium and phosphorus, especially when a lot of cereals are distributed without suitable supplements.
Absence of mineral and vitamin supplement, or supplement poorly distributed in the batch.
Fast growing lambs, early weaned lambs.
Lambs born to poorly nourished ewes at the end of gestation, which leave with low reserves.
Associated digestive parasitism.
Dark buildings, prolonged winter, animals never out.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The veterinarian examines several lambs in the group, not just the most lame: the collective nature of the attack is a key element of the diagnosis.
He palpates the joints and the ends of the long bones in search of enlargement, assesses the plumbness and deformation of the limbs.
Radiographs, when accessible, show the mineralization defect very well.
Blood tests evaluate calcium, phosphorus and bone health.
Analysis of the ration and fodder is essential: it provides the cause and therefore the solution.
The veterinarian rules out other causes of lameness in several lambs in the same flock, in particular joint infection, foot rot, selenium-related white muscle disease and trauma. These situations require different responses and some are urgent.
He also checks the parasitic status, which often worsens the picture.
Treatment
Correcting the ration is the basic treatment: rebalancing calcium and phosphorus, improving the quality of the fodder, providing a mineral and vitamin supplement suitable for sheep. This plan is created with the veterinarian based on the analysis of the food actually distributed.
Vitamin D intake can be prescribed by the veterinarian, who chooses the form and route. This intake should not be improvised: excess vitamin D is toxic and causes calcium deposits in the organs, with serious consequences. It is a vitamin that you never double on your own initiative.
Providing access to daylight is a treatment in its own right and costs nothing: take the lambs out, open the building, set up an outdoor exercise area.
Lambs in pain can be given a prescription anti-inflammatory, and should be housed on thick bedding, with water and the trough within immediate reach so they do not have to move.
Treat digestive parasitism at the same time if it is present, because it cancels out the efforts made on the ration.
Bone deformities already established do not straighten out: the treatment stops the worsening, it does not erase what has been done.
No mineral supplement intended for cattle should be used in sheep, due to its copper content which is dangerous for this species.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Provide growing lambs with a balanced ration of calcium and phosphorus, with a mineral and vitamin supplement formulated for sheep.
Providing access to daylight and an outdoor path: this is the simplest and most effective measure, and it is free in sunny regions.
Use good quality forage, harvested at the right stage, and avoid basing the ration on straw or faded hay.
Feed ewes correctly at the end of gestation, so that the lambs are born with reserves.
Distribute the distribution points of the mineral so that the dominated lambs also have access to them.
Control digestive parasitism in young people, which compromises the absorption of minerals.
Monitor the growth of groups by weighing: a collective dropout is often the first signal, even before lameness.
Have the fodder analyzed when fattening lambs in barns over several months.
Possible complications
Permanent deformities of the limbs, with animals with ruined limbs impossible to keep for reproduction.
Fractures occurring during ordinary handling, restraint or loading.
Chronic pain and immobility, with permanently lying lambs and bedsores.
Growth delay that cannot be recovered, light carcasses and heterogeneous batches.
Increased susceptibility to other diseases in weakened and immobile animals.
In affected females kept for reproduction, deformed pelvis and difficult births later.
When to see a veterinarian
Several lambs in the same flock are limping or walking stiffly without visible injury.
Lambs eat on their knees or refuse to move.
Joints appear large or limbs become deformed.
The growth of a batch stalls even though the ration seems correct.
A lamb fractures a limb during ordinary handling: this is a warning signal for the entire flock.
You have been fattening lambs in a closed building for several weeks without outside access: have the ration checked before lameness appears.
Prognosis
Good when the problem is caught early: correcting the diet and access to the sun allows growth to resume and pain to disappear.
Reserved when the limbs are already deformed: the twisted bones remain so, and the animal cannot be preserved for reproduction.
Bad in very advanced forms with fractures and lying animal.
At the flock level, the prognosis is excellent as soon as the ration is corrected and the animals go out: new cases stop quickly.
Frequently asked questions
Several of my lambs are lame without being injured, what to think about?
A lameness that affects several lambs from the same batch points to a common cause: unbalanced ration, lack of vitamin D, joint infection or foot rot. Rickets is one of the hypotheses, especially in lambs raised in buildings. The veterinarian will make the difference, because the actions to take are very different.
My lambs are in the fold, is this really a problem for their bones?
Yes, and it is often underestimated. Vitamin D is produced in the skin under the action of the sun. Lambs that never go out are deprived of this, even in a very sunny region. Giving them access to daylight is a free and very effective measure.
Can I give my lambs vitamin D for peace of mind?
Not on your own initiative. Excess vitamin D is toxic and causes calcium deposits in the organs. Its intake, form and frequency are subject to veterinary prescription, after examination of the ration actually distributed.
Will the twisted limbs straighten out once the ration is corrected?
No. Treatment stops the worsening and eliminates the pain, but an already deformed bone remains so. This is why we must react from the first lameness and not wait to see abnormal postures, especially in animals intended for reproduction.
References
FAO — Organisation des Nations unies pour l'alimentation et l'agriculture
Content reviewed by the TunisieVet editorial team · Updated 11 August 2026
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