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Contagious epididymitis of rams
Contagious epididymitis is an infection of the reproductive organs of rams caused by a bacteria, Brucella ovis. It settles in the epididymis, the small bead-shaped organ attached to the testicle where the sperm complete their maturation and...
What is it?
Contagious epididymitis is an infection of the reproductive organs of rams caused by a bacteria, Brucella ovis. It settles in the epididymis, the small bead-shaped organ attached to the testicle where the sperm complete their maturation and are stored.
The infection gradually damages this duct, then the testicle itself. The ram continues to breed normally, mounts the ewes, behaves as usual, but his semen no longer fertilizes.
This is the treachery of the disease: nothing is seen in the animal's behavior. The problem only appears at the time of lambing, when the farmer notices that half of his ewes are empty or that they have lambed over an interminable period. The wrestling season is then lost and it is too late to make up for anything.
Key point
An infected ram doesn't look sick at all: he rides, he eats, he looks superb. The price is paid five months later, in empty sheep. It is a disease that is fought by control before the fight, never by treatment after the fact.
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:
The most reliable sign is found by palpation, not by eye: the tail of the epididymis, located at the bottom of the testicle, becomes hard, large and bumpy. A healthy testicle ends in a small, soft mass; here you feel a firm lump, sometimes the size of a walnut or more.
Only one side is often affected at first, which makes the comparison between the two testicles very telling.
Over time, the affected testicle shrivels and becomes smaller and softer than the other: this is atrophy. The ram can then have a huge side and a tiny side.
In the beginning phase, some rams show a hot, swollen and painful bursa, a sideways gait, a little fever and temporary depression. This phase is brief and almost always goes unnoticed in pasture.
The vast majority of infected rams have no visible signs and behave completely normally.
To the flock, it is the results that speak: falling fertilization rates, lambings spread over weeks instead of being grouped, ewes returning to heat, unusual number of empty ewes on ultrasound.
In sheep, the infection is generally silent; it can occasionally cause abortion or the birth of weak lambs that do not survive.
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 disease is caused by a bacteria, Brucella ovis, which only infects sheep and is mainly transmitted between rams.
It lodges in the epididymis and the sexual glands, causes chronic inflammation, then a blockage of the ducts through which the sperm circulate. The pressure bursts these ducts and the seminal fluid spreads into the tissues, where it in turn triggers an inflammatory reaction that destroys the testicle from the inside.
This process is slow, silent and irreversible: once the lesion is established, the lost fertility never returns.
An infected ram sheds the bacteria in its semen, often for years, including long periods when it appears perfectly healthy.
Buying or borrowing a ram without prior examination or analysis: this is by far the first factor.
Adult rams, which are more often carriers than young ones.
Parking of rams together all year round, without monitoring of breeding between males.
Natural breeding in batches, with several rams for the same group of ewes: a single infected contaminates the others.
Ram loans between farms, participation in fairs and competitions.
Absence of palpation of the bursae before the wrestling season.
Replacement of rams purchased without quarantine.
Transmission
Transmission occurs mainly between rams, by direct contact when they mount each other, which they do naturally when they are herded together outside of the fighting season, and by semen deposited on the fleece or the ground.
The ewe plays the role of intermediary: mated by an infected ram, it can carry the bacteria in its genital tract and transmit it to the next ram who will breed it, without ever appearing ill itself.
A purchased ram is the classic gateway to disease on a healthy farm. A single animal introduced without control is enough to contaminate all the other rams in the flock in one season.
Loans and exchanges of rams between neighbors, fairs, groups of males grouped together on a common route spread the disease from one herd to another.
There is no transmission through grass, water or air.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
The examination begins with the palpation of both testicles and both epididymis, ram by ram, before each wrestling season. The veterinarian compares the two sides, assesses flexibility, symmetry and volume, and identifies the hardened epididymis tails. This simple gesture is the first filter and the breeder can learn to do it himself under the guidance of the veterinarian.
However, palpation is not enough: many infected rams have perfectly normal bursae to the touch. This is why a blood test for antibodies is necessary to detect silent carriers. It is practiced on all rams in the herd, not just those that appear abnormal.
Examining the semen under a microscope makes it possible to directly measure the quality and mobility of the spermatozoa; the presence of inflammatory cells strongly indicates an infection.
The veterinarian rules out other causes of a large bursa in the ram: trauma, abscess, hernia, other bacteria, and especially brucellosis of small ruminants, which is a regulated disease and transmissible to humans, and whose behavior is radically different.
A large purse in a ram should therefore never be handled without veterinary advice until the origin is established.
Treatment
There is no reliable treatment. Antibiotics have difficulty reaching the bacteria, which take refuge in poorly irrigated tissue, and in no way erase the lesions already established in the epididymis and the testicle.
Even if an apparent improvement is obtained, the animal remains a carrier and continues to eliminate the bacteria in its semen: it constitutes a time bomb for the other rams in the herd.
The action recommended by the veterinarian is therefore the elimination of rams recognized as infected from the breeding circuit, and not their treatment. A confirmed positive ram should never be sold as a breeding stock to another breeder: the disease would simply move from one farm to another.
In affected farms, the strategy consists of testing all the rams, removing the positive ones, retesting the others after a time limit set by the veterinarian, and only keeping tested males for breeding.
A ram suffering from a large painful bursa of still uncertain origin receives comfort care in the meantime, on prescription: anti-inflammatory, rest, shade, absence of transport. This care never replaces the diagnosis.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Quarantine of any ram purchased is the number one measure: keep it away from other males, have it palpated and analyzed by the veterinarian, and only include it in the batch after a favorable result. No ram should enter a sheepfold without this control.
Palpate the bursae of all rams before each wrestling season, and exclude those with hardened epididymis while awaiting veterinary advice.
Buy only from breeders who test their rams, and ask for the analysis results rather than relying on the appearance of the animal.
Avoid ram loans between neighbors; if it is essential, have the animal checked before and after.
Limit the number of rams per batch of ewes and avoid mixing males of different origins.
Without hesitation culling a ram whose offspring have been poor two seasons in a row rather than keeping it out of attachment or purchase value.
A complete examination of the aptitude for reproduction, carried out by the veterinarian a few weeks before the fight, remains the best investment of the year for a sheep flock.
Vaccination
No vaccine for this disease is routinely available in most countries, and prevention relies entirely on screening and management of rams.
Vaccinations against brucellosis in small ruminants target another bacteria and another disease; their possible use is subject to a precise regulatory framework and the decision of the veterinary services. Ask your veterinarian before taking any action.
Possible complications
Permanent sterility of the affected ram, with no possibility of recovery.
Lost season of struggle: empty ewes, lambings spread out, batch of lambs heterogeneous and unsaleable in a single flock.
Silent diffusion to all other rams in the herd within one or two seasons.
Increased mortality of lambs born to ewes bred by an infected ram, with weak newborns not holding up.
Occasional abortions in sheep.
Reputation of the breeder damaged if it sells breeding stock.
When to see a veterinarian
You feel a hard lump at the bottom of a testicle when feeling a ram.
One testicle is significantly larger or significantly smaller than the other.
A ram's bursa is hot, swollen and painful: have the animal examined without delay.
Many ewes come back into heat after being bred.
Lambings are spread over weeks instead of in groups, or the number of empty ewes is abnormally high.
You have just bought a ram: have it checked before putting it with the others, even if it looks magnificent.
Abortions occur in the herd: the cause can be quite different and some are transmissible to humans, veterinary advice is essential.
Prognosis
For the affected ram, the fertility prognosis is poor: the lesions are irreversible and the animal no longer has a future as a breeder.
For the herd, on the other hand, the prognosis is good as long as the breeder agrees to detect and eliminate the carriers: the disease is not transmitted through the external environment, it disappears when the infected rams leave the circuit.
Farms that systematically check purchased rams remain unharmed for the long term.
Frequently asked questions
My ram breeds normally, can he still be sterile?
Yes, and this is the most common case. Libido and fertility are two different things: a ram can mount all the ewes with enthusiasm and no longer produce a single fertilizing sperm. Only palpation and veterinary examination can tell before it is too late.
Is it brucellosis? Is my family at risk?
This is a different bacteria, specific to sheep, which does not make people sick. Be careful, however, not to confuse it with brucellosis of small ruminants, another very real disease in the Mediterranean, this one transmissible to humans, which mainly causes abortions in sheep. Only the veterinarian can tell the difference, and this justifies never handling an abortion with bare hands.
Can I treat my ram with an antibiotic and keep him?
No. Antibiotics do not eliminate the bacteria from the epididymis and do not repair the lesions. A treated ram remains carrier, contaminates other males and remains sterile. The vet will recommend taking him out of breeding.
Should I palpate all my rams every year?
Yes, before each wrestling season, and this is something the veterinarian can teach you. It takes a few minutes per animal and allows you to identify a hardened epididymis tail. But as many carriers have normal bursae, palpation must be supplemented by a blood test from all males.
References
WOAH — Organisation mondiale de la santé animale (ex-OIE)
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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