Sheep Diseases

Symptoms & Diagnosis for Common Diseases of Sheep

Whether you have a sick sheep, a sick flock or are simply trying to learn about sheep health so that you can avoid common illnesses, our list of common sheep diseases is a useful resource which will help you identify symptoms and diagnose problems with the health of your flock.

We have several “featured” sheep diseases and illnesses linked at the top of this page, and we’ve recently added a long alphabetical list of some of the most common diseases in sheep as well. 

Sick Sheep

If we don’t have what you’re looking for today please bookmark this page and check back often to see if we’ve added the sheep disease you’re looking for. We also have a very in-depth guide to sheep medication and antibiotics that you may find helpful and informative.

As always this list of sheep diseases is intended to inform and be helpful to our visitors so if there’s a sheep disease that isn’t listed which you’re interested in learning about please email us and we’ll make an effort to add that as quickly as we can.

Featured Sheep Diseases

Detailed Information About Common Sheep Diseases and Disorders

(Alphabetical, Click to Navigate)


Abortion occurs when a ewe’s pregnancy is terminated suddenly and the lambs she delivers are lost due to premature birth. The birth of weak or deformed lambs which are alive, but die shortly after birth can also technically be labeled as abortion. The causes of abortion can be both physical or infectious.


The three most frequently observed infectious causes of abortion in ewes in the United States are Toxoplasmosis (Toxoplasma gondii), Enzootic Abortion (Chlamydia), and Vibrio (Campylobacter). You may have heard of these organisms before as they can also cause abortion (miscarriage) in women. It’s important that pregnant women avoid handling lamb fetuses or placental fluids from aborted or miscarried lambs.

Physical trauma or stress can cause early-delivery or abortion of lambs in ewes, which is why it’s important to take care in handling pregnant ewes and to avoid loud noises or sudden movements which could spook them and result in physical injury.


Acidosis, also called lactic acidosis, ruminal acidosis, grain overload, or grain poisoning, is the result of excessive consumption of concentrated food (grain), which produces elevated acid levels in the sheep’s rumen. Symptoms include depression or listlessness as well as abdominal pain (though this is typically harder to observe).


Acidosis in sheep can be a life-threatening condition and action should be taken immediately to drench affected sheep with an antacid such as carmalax, baking soda, or similar products containing magnesium carbonate or magnesium hydroxide.

It’s important to know that Acidosis is generally caused by poor feeding management practices and it can be avoided by introducing grain to sheep’s diet gradually, ramping up consumption to the desired level over time. This will allow the sheep’s digestive system to acclimate properly and you’ll provide the sheep’s rumen with time to adjust to the concentrated food source.


Similar to humans, arthritis in sheep is an inflammation of the sheep’s joints – typically leg joints – which can cause a loss of production, conditioning, and death. In sheep the primary cause of arthritis is bacteria which can enter the sheep’s body through any break in the sheep’s skin.


Sheep are susceptible to bacteria which cause arthritis after birth (umbilical cord), during docking, castration, and ear tagging. Other moments when sheep are at risk are when they sustain wounds from shearing, nails, or other sharp objects in their environment.

Erysipelothix rhusiopathiae is the bacteria which most commonly causes arthritis in sheep, but there are several others which can also cause this sheep disease. You will typically observe swollen, hot or painful joints anywhere from 2 days to 2 weeks after infection occurs. Administering antibiotics is the proper treatment of arthritis in sheep, but this disease can be avoided if proper sanitation and hygiene practices are observed on your farm.

Bent Leg or Rickets

You may have heard of Rickets before, and in sheep, “Bent Leg” is a form of this disease which is caused by errant bone metabolism during growth. Bent Leg typically will occur during the period in which sheep experience their most rapid growth rate (between 6 and 12 months). You’ll typically observe Bent Leg in rams most of the time, but it can also occur in ewes (though it is less common). The Rambouillet sheep breed is one in which Bent Leg is most frequently observed.


Prevention of Bent Leg is a matter of observing proper feeding and management practices on your farm. Feed balanced rations and avoid pushing animals to consume high-levels of high-protein feed. Ensure that lambs are provided with a calcium to phosphorus ration of at least 1.5 to 1 in their food, and consider supplementing their diet with at least 300 IU of vitamin D per day for every 100 pounds of body weight. In addition to vitamin D supplementation, it’s considered a good practice to shear young rams in the fall, which can help with vitamin D conversion (more skin surface is exposed to the sun). You should also try to provide housing for your sheep which provides plenty of exposure to the sun during winter months when sunlight is at a premium.

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Bloat is a sheep disease caused when the rate at which gas is produced in the rumen (stomach) exceeds the rate at which gas is eliminated. This produces a condition where gas accumulates within your sheep’s abdomen, resulting in distention or swelling of the rumen.


Bloat is typically observed when the skin behind your sheep’s last rib is distended and/or swollen. This condition can be a medical emergency and intervening in a timely manner can be necessary to prevent the sheep’s death. Bloat in sheep is a common cause of sudden death and is typically caused by something in the sheep’s nutrition.

The two common causes of bloat in sheep are Pasture Bloat (Frothy Bloat) and Feed Lot Bloat (Free Gas Bloat).

  • Pasture Bloat earned its name due to its association with sheep consuming leguminous forages, cereal grain pastures or wet grass pastures, though it can also be caused by consuming grain which is ground too finely. Cooking oil, mineral oil or a product like Poloxalene can be administered orally as treatment.
  • Feed Lot Bloat is commonly the result of heavy grain feeding and often results when your sheep weren’t allowed a long enough period to acclimate and adjust to a diet of heavy grain consumption. Passing a stomach tube down the sheep’s throat and into the sheep’s stomach can help to relieve bloat, and a last-resort (life-saving measure) can be to insert a trochar needle into the abdomen of the sheep. This should only be a last-resort and you should ask a veterinarian to perform this procedure if possible.


Transmitted by insects, Bluetongue is a viral disease which affects most domestic and wild ruminants, including sheep. For shepherds, a case of Bluetongue is serious as it’s possible for half of the sheep in an infected flock to die. Bluetongue earned its name due to the symptoms of the disease, which are inflamed, swollen or hemorrhaging mucous membranes of a sheep’s mouth, nose and/or tongue.


It’s important to know that soreness of the feet are also associated with Bluetongue, and this may be a symptom. More commonly, though, you should look for swollen or hemorrhagic membranes in the mouth or tongue which can present as a dull blue color. Biting gnats spread the disease from one animal to the next, and in the United States the disease is much more common in the southern or southwestern regions, where these insects are most prevalent.

Animals with the disease cannot spread it to other animals (only insects can spread it), so there’s no need to separate infected members of your flock. There is a vaccine, but it is only effective against certain strains and may cause adverse reactions, so many shepherds choose not to vaccinate. Pregnant ewes should never be vaccinated for Bluetongue.

Border Disease

Sometimes referred to as hairy shaker disease or fuzzy-lamb syndrome, Border Disease afflicts newborn lambs. Affected lambs will typically have a hairy coat and will tremble uncontrollably. This viral sheep disease will present with a range of symptoms depending upon when the ewe is affected by the virus, ranging from abortion of mummified lambs to the symptoms mentioned above which are observed in lambs after delivery.


The way most sheep contract border disease is if they are kept in close proximity to cattle or new additions are made to a flock from a farm where sheep were kept with cattle which have bovine viral diarrhea. There is no treatment for sheep affected with border disease and sheep with the disease won’t respond to antibiotics.

Caseous Lymphadenitis

A contagious and infectious disease, Caseous Lymphadenitis (also referred to as CLA, CL, boils, abscesses, cheesy glands) primarily affects the lymphatic system in sheep. Corynebacterium pseudotuberculosis is the bacteria which causes CLA – a disease which is typically observed when an abscess forms in the lymph nodes of a sheep. When this abscess is cut or ruptured, pus containing the bacteria will discharge. As Caseous Lymphadenitis spreads internally, ewes affected with this disease will lose weight dramatically.


CL is one of the leading causes of sheep causes getting condemned in the United States. Controlling the disease is a matter of culling visibly infected sheep from your flock and ensuring that hygienic practices are followed when your flock is sheared each year.

There is a CL vaccine for sheep, and it has been shown to decrease the number of sheep affected by Caseous Lymphadenitis and to diminish the number of affected lymph nodes in sheep that have CL, making it a good investment for shepherds.

Clostridial Diseases

There are several different types of clostridial disease common in sheep which are caused by clostridial organisms found in the soil where sheep live and graze. Most clostridial disease in sheep can occur naturally in the gut of sheep, passing to other sheep through bowel movements which are absorbed into the soil. Black leg, botulism, red water disease and malignant edema are some forms of Clostridial disease which can occur in sheep, but by far the most common forms of clostridial disease are enterotoxemia types C & D (overeating disease) and tetanus, also known as lockjaw.


Copper Toxicity

You may not be aware, but sheep are 10 times as likely to get copper toxicity than are cattle, and many salt licks and mineral supplements sold at your local grain and feed store are likely formulated primarily for cattle. This may cause them to have dangerous levels of copper which can cause copper toxicity in sheep.


When the levels of copper in a sheep become toxic the destruction of red blood cells occurs. Symptoms of copper toxicity in sheep include weakness and animals that suddenly go off their feed. Examine the sheep’s mucous membranes and white skin … if a yellowish brown color is present, and if urine is a red-brown color, your sheep may be suffering from copper toxicity. Treating copper toxicity in sheep involves the use of ammonium molybdate and sulfate compounds to bring copper levels back to a normal level.


While it may sound mundane compared to the less-familiar sheep illnesses listed on this page, diarrhea can be one of the most deadly sheep diseases if left untreated and unattended. The causes of diarrhea in sheep are varied and can range from bacterial and viral infections, parasites, poor diet, and stress. The only way to accurately identify the cause of diarrhea in your sheep is to have a sample submitted to a lab for microbiological analysis, but shepherds can generally address it without lab work by doing some blanket treatments. These include isolating the animal that’s affected, de-worm them, monitor their diet, and provide plenty of fluids. If diarrhea continues it’s likely that the problem is bacterial or viral and antibiotics can be administered.


While diarrhea in sheep is less of an illness and more of a symptom of a more serious health condition, quick treatment and support of animals with diarrhea can play a major role in maintaining the animal’s health and conditioning. Diarrhea in sheep is not always a reason to panic, but continued diarrhea can lead to dehydration, weight loss, and put your sheep at risk of flystrike.


Dystocia in sheep is a blanket term which refers to any form of lambing difficulty. Difficult births can be caused by abnormal presentation of lambs, atypically large lambs, obese ewes, small pelvic areas or disease.

E. Coli Scours

The majority of time, E.Coli Scours is completely avoidable in your flock of sheep. It’s usually associated with a messy environment where your sheep are housed and poor sanitation in the barn. E. Coli Scours typically presents in 2-4 day old lambs which have diarrhea, produce excess saliva, and have a cold mouth when you insert your finger into it. “Watery mouth” is a common nickname for E. Coli Scours in sheep.


Due to the age of lambs affected by this disease, responding rapidly and aggressively is the best chance your lambs will have of survival. Rehydrate the lamb with oral fluids and nutrients like Nutri-Drench. Subcutaneous fluids may be administered in extreme cases to rehydrate the lamb quickly. Treat your lambs with the proper dosage of antibiotics as well.

Maintaining a clean, dry environment for your lambs is critical to avoiding this dangerous lamb disease.


Entropion or “inverted eyelid” is a congenital condition which affects lambs. Lambs with Entropion will have the eyelashes of the lower eyelid roll in against the eye, causing the hairs and eyelashes to rub against the eye. Initially this will result in irritation which presents as your lamb having teary eyes. If left untreated, serious condition such as corneal ulceration, scarring and, ultimately, blindness will occur. Inverted eyelid can present in one or both eyes of lambs, and if you notice it in one lamb, it’s in your best interest to check the other lambs sired by their father … it’s common for the sire to pass this on to most of his offspring.


Treating entropion can be done in a couple of different ways, depending upon the severity. For less severe cases which are caught very early on in a lamb’s life, the most effective method is to use a fine needle to inject long-acting antibiotic under the skin of the affected eyelid. By injecting antibiotic between the layers of skin of the eyelid, the eyelid will expand and swell to accommodate the fluid, which forces the hairs and eyelashes to roll out normally and no longer irritate the lamb’s eye. Often, by the time the antibiotic fades later that week and the swelling goes away, the lamb’s eyelid muscles have corrected, and it will no longer be an issue.

For more serious cases of Entropion in lambs, staples, sutures or veterinary clips like those found in this inexpensive medical-grade stapler kit on Amazon can be applied to roll the eyelid away from the eye, holding it there while the lamb’s eyelid muscles acclimate to this new position. It goes without saying that treating Entropion is a labor-intensive task which can be avoided by culling rams with the disease, and rams which sire lambs with the disease.


This venereal disease in rams is caused by the Brucella Ovis bacteria. Inflammation of the epididymis on the testicles is how this presents and severely affected rams will have at least one enlarged epididymis and may exhibit pain when their testicle is manipulated. Epididymitis may cause infertility in affected rams, and it’s the top cause of infertility in the sheep industry. It is a contagious disease and can be transmitted between rams during homosexual activity, or during breeding season via the ewes.


Damage from Epididymitis is typically permanent in rams, and only about half of rams respond to treatment with antibiotics. Affected rams should be culled to avoid a permanent and ongoing problem which can affect your flock.

External Parasites

Ectoparasites, or external parasites in sheep, include flies, lice, mites, ticks and keds. Mange in sheep is rare in the United States, and any cases should be reported.


  • Sheep Keds — Keds are wingless, reddish-brown biting flies which closely resemble ticks. They’re often called ticks by those who don’t look closely. Like ticks, keds feed on blood and high ked populations can cause emaciation in your flock and make animals susceptible to other sheep diseases. Keds can only survive off of the animal for about a week, and treatment with insecticide immediately after shearing is recommended to knock down any ked population in your flock.
  • Lice — Sheep lice are small and difficult to detect since they spend most of their time on sheep right next to the skin. There are three species of lice which can be found on sheep, and while they’re difficult to see, you can sometimes become aware that you have a lice problem with your sheep when you notice excessive itching. Insecticides are the best treatment.
  • Fly Strike — If your sheep has scours for several days during fly season, be aware of the risk of fly strike. Flies will lay their eggs in the dirty, wet wool of your sheep’s posterior and when the eggs hatch, the blowfly maggots will burrow into your sheep’s wool and skin and live within the flesh of your sheep. Sheep are the most at-risk of fly strike of all domesticated mammals due to their wool. During fly season it’s recommended to keep your sheep clean and their back-end shorn to reduce the risk of wool contaminated with feces. If you notice one of your sheep has diarrhea which is on their wool, you should wash that sheep or shear it to prevent fly strike during the warm months when flies are present.
  • Nasal Bots or Flies — The Sheep bot fly deposits small larvae on the muzzles of sheep in or around their nose, and as the larvae develop they will migrate into your sheep’s nose and sinuses. Nasal bots presents in sheep as a very snotty nose. If you notice sheep with a snotty nose which hold their head down and seek out corners to escape flies then that animal may have nasal bots. Treating with insecticide which contains ivermectin is typically the best treatment.
  • Scabies or Mange — Sheep scabies or mange is an extremely contagious disease which is the result of small mites feeding on the surface of your sheep’s skin. Scabs develop due to the damage they cause, itching leads to hair or wool loss, with wool typically falling out in patches. Dipping your sheep in an insecticide bath is the preferred method of treating scabies or mange … but if you live in the United States the good news is your flock is likely safe as it has been eliminated here.

Facial Eczema

Fungal spores from perennial ryegrass and other dead vegetative material in pastures can cause liver damage which presents as facial eczema — a condition of severe dermatitis in sheep and cattle. This is a common sheep disease in New Zealand, Australia and South Africa. Oregon in the United States where irrigated perennial ryegrass fields exist, is another location where this condition can be observed. Treat affected sheep by removing them from the pasture, providing them with shade, plenty of water, and a good diet. The addition of zinc to their grain can help as well.

Foot and Mouth Disease

Foot and Mouth Disease in sheep (FMD) is a viral, severe and highly contagious disease which affects sheep, cattle, swine, goats and other cloven-hoofed animals. This sheep disease presents with a fever and lesions which resemble blisters on the animal’s mouth and lips. Subsequently erosions of the tongue, lips, mouth, teats and between the animal’s hooves may be observed.


While the effects of Foot and Mouth Disease on adult sheep is typically minimal (you may not even notice it), young sheep affected by this disease are at risk of death. While it’s typically not harmful to humans, it is highly contagious and one case in your flock will likely  mean that your entire flock will contract this disease. If you catch it early – try to isolate infected animals and remove and clean feed-pans and water buckets to try to prevent it spreading to the rest of your flock. Wash them in a diluted bleach solution.


Footrot or Hoof Rot in sheep is an infection of the hoof caused by two types of bacteria. We have an in-depth article on footrot in sheep which covers the causes, symptoms and treatment of this disease as well as foot scald in sheep. We also have a useful article on how to trim sheep hooves, which can help prevent diseases like hoof rot which cause lameness.

Dr. Naylor’s Hoof n’ Heel is the recommended product for topical treatment of footrot in sheep.

Grass Tetany

All ruminants are at risk of Grass Tetany – a disease which results from magnesium deficiency. Ewes are usually the members of your flock to be affected, and it’s likely that you’ll observe symptoms within 4-6 weeks of lambing. Symptoms include sensitivity to touch and trembling — most typically observed in the ewe’s facial muscles. Some ewes will be suddenly unable to move, or they may hobble and move stiffly about your barn or pasture. The most extreme cases of grass tetany in sheep will present when a ewe collapses and spasms with all four legs extended straight out.


Low blood magnesium levels which result in Grass Tetany are the result of low levels of magnesium in the ewe’s diet. The demands of lactation, a lush spring-grass diet which features low levels of magnesium or other mineral imbalances in their diet will be the culprit. Usually if a ewe has reduced magnesium levels, she’ll also have low calcium levels and treatment with calcium borogluconate and magnesium hypophosphite are the best path to recovery. Magnesium oxide is typically the cheapest supplement, and many producers will supplement their ewe’s food with 10-20 grams of commercial or homemade magnesium to prevent Grass Tetany in their flock.

Internal Parasites

Like external parasites, the list of internal parasites which can cause health issues in sheep is long. Each internal parasite can cause significant (and different) health concerns for sheep. In the broadest sense sheep internal parasites can be classified as worms, flukes, and protozoa. Here’s a short list of some of the most common types of internal parasites in sheep (you can read our sheep wormer guide for more information):


  • Cryptosporidiosis — This species of tiny protozoan parasites are related to coccidia and one of its major species can infect both humans and farm animals. This species, Cryptosporidium Parvum (or C. Parvum for short) has a rapid life cycle and infection occurs when oocysts are ingested. This most commonly occurs in lambs which are under a month old, though lambs as young as three days old can become infected. Symptoms of Cryptosporidiosis are a lack of sucking, diarrhea, and dehydration which can quickly be deadly if left untended. Illness from C. Parvum can last up to 10 days and relapses (even after your lamb appears to have recovered) are common.
  • Coccidiosis — Coccidia are single-cell protozoa, and what you may not know is that this form of internal parasite in sheep is commonly found in a sheep’s digestive system. These protozoa damage the lining of the small intestine which can prevent the absorption of nutrients for affected lambs. The most common symptom of Coccidiosis in sheep is diarrhea which could be bloody or smeared with mucous. This sheep disease is typically considered a management-related disease and results when sheep are housed in overcrowded areas or poor barn hygiene practices are observed. Include Lasolocid (Bovatec), Monensin (Rumensin), or Decoquinate (Deccox) in the grain you feed to prevent coccidiosis in your flock. If your lambs are affected treat Coccidiosis with Amprolium or Sulfa medications.
  • Stomach Worms in Sheep — Stomach worms are the most common type of internal parasites in sheep, and there are several different varieties which can infect your flock. The barber pole worm (Haemonchus Contortus) is the most common type of stomach worm in sheep with the small brown stomach worm being the next most likely culprit. These blood-sucking parasites pierce the mucosa of the abomasum (one of a sheep’s four stomach compartments), which causes blood and protein loss. As a result Anemia is a common condition affecting sheep infected with barber pole worms. An easy way to diagnose anemia in sheep is to take a look at the sheep’s lower eyelid. The eyelid will appear whiter in affected animals. An accumulation of fluid under the jaw (called “bottle jaw”) is another symptom. Diarrhea may also be observed, and you may also see worms in the stools of infected animals.

Several types of de-worming medications (like Ivermectin and Safeguard) are available, but some types of sheep wormers may not have an impact on the unique type of stomach worms present in your flock. This is why many shepherds use two or more brands of de-wormer, rotating them every month or every two months, so there’s regular, prophylactic coverage against all types of stomach worms which could affect your flock of sheep.

  • Nematodirus — This type of internal parasite differs from other worms in that it has a very short life-cycle and cannot survive for long outside of animals during warm, dry  months. It’s therefore unlikely to occur in your flock during the summer. During cooler, damp months, however, Nematodirus larvae can survive in the pasture long enough to infect grazing animals. Scours and weight-loss are the early symptoms of this parasite.
  • Tapeworms (Moniezia) — If you see worms in the stools of your lambs or sheep, it’s likely that your sheep has tapeworms. There’s some disagreement among producers about the degree of impact tapeworms can have on your flock, but heavy infestations can cause diarrhea, weight-loss, and even intestinal blockages which can result in death. Suckling lambs are the most at-risk for tapeworms and benzimidazoles and Praziquantel (Zimectrin Gold) are the only anthelmintics which have been proven to be effective against tapeworms.
  • Lungworms in Sheep — If you’re treating your sheep proactively for stomach worms, the good news is that you’re also covered against lungworms in sheep. Infestation from lungworms is difficult to diagnose, and the only sure way to do it is during necropsy. Lungworms earned their name because they affect the respiratory system, though they’re passed from animal to animal through feces. As with all internal parasites, pasture rotation, providing clean water, and not overcrowding your flock are all key farm management practices which can reduce the likelihood of infestation.
  • Liver Flukes — Snails and slugs spread liver flukes in sheep, and the problem is much more common to flocks residing in low, wet areas. The affected animal will suffer liver damage, blood loss, diarrhea, and (ultimately) death. Clorsulon (contained in Ivomec Plus) and Albendazole (Valbazan) are the only two drugs which are known to successfully treat liver flukes, so it’s recommended that you use one of these as part of your flock de-worming program.
  • Meningeal Worms — This internal parasite is passed from white-tailed deer to sheep and other farm animals, even though domestic farm animals are not the standard hosts for this dangerous parasite. Infection occurs when grazing sheep ingest the Meningeal Worm larvae, at which point the larvae migrate to the animal’s spinal cord. Your sheep will have trouble walking and other neurological symptoms which could include paralysis. Sadly, when this deadly parasite reaches your sheep’s brain, it will kill its host.

There is no accurate way to diagnose Meningeal worm infection in a live animal, though when symptoms like those described above are observed you can suspect that this may be the cause. If you suspect your sheep has been infected with Meningeal worms treat it immediately with high doses of anthelmintics (de-worming medication) and anti-inflammatory drugs. The best way to prevent death due to meningeal worms is to have secure perimeter fencing (often we think of fencing as a means to keep sheep in a pasture, but you should also think of it as a means to keep deer and sheep predators out). If preventing deer from entering your pastures is not possible, try to control the snail population in low areas of your pasture, as the Meningeal worm requires snails to complete its life cycle. The absence of snails will prevent larvae from infecting your flock.

Joint or Naval Ill

Joint Ill or Naval Ill in sheep commonly occurs in lambs that are 30 days old or younger. Affected lambs will be lame in several of their joints, most commonly joints in their legs. These joints will be hot to the touch and your lambs will act depressed, and they may be feverish as well. This sheep disease is caused when certain strains of streptococci enter its body, most commonly from an under-treated umbilicus, which is why treating the umbilical cord with a betadine or diluted iodine solution at birth is so important.


Lameness is the first symptom  you’ll observe in cases of Laminitis, and the cause in this case is poor blood flow to the foot. If you handle the foot your sheep is favoring and it is warm to the touch, your sheep could have Laminitis. The cause of laminitis is an intake of grain which is too high (grain overload or acidosis). It’s important to know that if your sheep is limping that Laminitis may not be the only sheep disease which could cause these symptoms … in fact, it’s usually true that sheep affected by Laminitis die before the feet become involved. Proper nutrition and feedlot management is the key to preventing laminitis in sheep, and if your sheep is affected and you make changes in time, it is not uncommon for recovered animals to display abnormally large feet or permanent lameness.


Listeriosis is caused by Listeria Monocytogenes, a bacteria which is widely available in nature and can be found in the soil, food sources, and even the feces of healthy animals. Most commonly, this sheep disease is observed as a result of feeding moldy or spoiled hay or silage, but even if you don’t feed silage or wet hay, it’s possible for your sheep to be infected as it is occasionally found in the environment.


This disease presents as inflammation of your sheep’s brain, and depression and disorientation are the first observable symptoms of this sheep disease. Listeriosis (sometimes called circling disease in sheep) can present as your sheep walking in circles, with its head tilted and part of your sheep’s face may appear paralyzed. The only way to treat this disease is with high doses of antibiotics, but generally treatment is not effective and the mortality rate for sheep with circling disease is very high.


An inflammation or infection of the mammary gland (udder) in ewes, Mastitis is sometimes also called “hard bag” or “blue bag” locally. Mastitis is caused by a bacterial infection – usually either Staphyloccus Aureus and/or Pasteurella Hemolytica. Mastitis in sheep is categorized either as acute or chronic. Ewes with acute mastitis will have mammary glands which could appear darker than normal, and the udder will also be quite warm to the touch. Ewes with acute mastitis may exhibit symptoms such as a hesitancy to walk, or they may hold up one rear foot due to the discomfort. It’s also not unusual that they balk at allowing their lambs to nurse due to the intense discomfort they are experiencing. On the other hand ewes with Chronic Mastitis may go undetected in your flock, as they don’t usually exhibit these telling symptoms.


Treatments for mastitis in sheep usually involves a regimen of antibiotics which can be administered intra-muscularly, or in some cases a veterinarian may administer intra-mammary infusions of antibiotics. There is no vaccine for mastitis and the best way to prevent ewes from contracting mastitis is to focus on effective flock management including good hygiene in your barn. Keep the bedding for lactating ewes clean and dry. It’s often the heaviest milking ewes which are more at risk for developing mastitis, and there may be a genetic component at play as well. Treating affected ewes with antibiotics and milking them to help clear the infection and keep them producing milk is usually the best method to treat sheep with Mastitis.

Measles in Sheep

Cysticercus Ovis, or measles in sheep, is a sheep disease associated with tapeworms which are in their intermediate or larval stage of development. There are no clinical signs of Cysticerosis or measles in sheep, and the only current method of diagnosing this sheep disease is at slaughter, when the cysts which result from this disease are evident. The risk of sheep measles is that farm dogs can develop tapeworms passed to them from the sheep by consuming droppings or sheep carcases. It’s very important that any dogs who have access to sheep farms are dewormed for tapeworms regularly.

Milk Fever

Milk Fever is a sheep disease which affects pregnant ewes which are approaching their delivery date. This is a time when calcium demands are highest for ewes as their lambs are developing their bone structure. Milk Fever results from inadequate intake of calcium in your ewe’s diet and symptoms of this disease are similar to what is observed in sheep which have pregnancy toxemia. The one difference which can help you determine that your ewe has milk fever and not toxemia is that sheep with milk fever will generally respond well (and quickly) to increasing the amount of calcium in their diet or administered subcutaneously (calcium gluconate). Milk fever is a sheep disease which is easy to prevent in your flock by ensuring that your pregnant ewes have access to plenty of calcium in their diet throughout their pregnancy, but particularly in the final months leading up to delivery.

Ovine Progressive Pneumonia (OPP)

Ovine Progressive Pneumonia or OPP in sheep is a viral disease which develops slowly. Sheep with OPP will exhibit weight loss, difficulty breathing, and sometimes lameness, paralysis or even Mastitis could be symptoms of OPP in sheep. Ovine Progressive Pneumonia in sheep is caused by a retrovirus and is transmitted to offspring through infected milk or colostrum, and while there is no treatment for this disease, it can be eliminated from your flock by participating in annual blood tests to identify infected animals which can then be culled.


At present it is estimated that over 50% of sheep flocks in the United States have an OPP infections, with anywhere from 1% up to 70% of flocks suffering from OPP infections. The majority of these infected sheep won’t be symptomatic, but identifying and culling sheep is the only way to prevent lambs or other members of your flock from contracting this potentially devastating disease. Veterinary lab testing is the only way to identify the disease with 100% accuracy.

Pink Eye

Pink Eye is a sheep infection which is important to be aware of and to watch out for – especially if you buy a new sheep from another farm, or regularly bring your sheep to county and state fairs where they share fencing with animals from other flocks, or are housed in pens that have been used by sheep and goats from other farms. Pink Eye is very contagious and affects the eyes of sheep. Once infected, the sheep with pink eye will be affected for approximately three weeks before the disease fully runs its course, and it’s critical that that animal be separated from your flock during this period so that your entire flock (and all of your sheep feeders, barn, and equipment) doesn’t become contaminated.


There are no vaccines which are effective for preventing pink eye, and there is a risk of transmitting pink eye to humans from sheep and goats, so care should be taken when handling these animals to prevent developing pinkeye yourself. Eye medications containing antibiotics may accelerate the time-table for this infection in some cases, but results of this treatment aren’t consistent … usually this sheep disease simply has to run its course.

Pizzle Rot

Sheath rot or pizzle rot is a disease affecting rams, and it is an infection of the sheath of your ram’s penis. Corynebacterium Renale or a similar bacteria is the cause of pizzle rot in sheep. Rams who consume a high-protein diet (usually a diet which consists of over 16% protein) are at higher risk for developing pizzle rot. Once rams develop this infection, the ammonia in their urine can cause very painful irritation and ulceration of the skin and debris from this ulceration can sometimes form a crust which blocks the opening of their sheath. Pizzle rot in rams can affect the desire of rams to breed ewes as the act will become very painful. Treatment with intramuscular antibiotics is effective.


Polioencephalomalacia, also called PEM, CCN, or Polio in sheep, is a disease which affects your sheep’s central nervous system. Polio in sheep is caused by a deficiency in vitamin B1 … though it’s typically not the product of dietary deficiencies, rather the inability of the sheep’s body to utilize thiamine produced by the sheep’s rumen. If your sheep appears to be blind, or to gaze up at the sky blindly, your sheep may have polio.


The most common group of sheep to have Polioencephalomalacia are lambs which are consuming high concentrate diets in their creep, but it can also occur in any pasture sheep which consume plants which contain a thiaminase inhibitor (this can prevent proper metabolization of Vitamin B1. While the symptoms of polio in sheep will be similar to those observed with some other disease affecting your sheep’s central nervous system, diagnosis can usually be made following treatment with injections of vitamin B1. If your sheep responds to this treatment, you’ll know that they were suffering from polio.

Pregnancy Toxemia

Pregnancy Toxemia in sheep is a dangerous disease of pregnant ewes and you  may have heard it called Ketosis, Twin Lamb Disease, Lambing Paralysis or Hypoglycemia locally. Toxemia in sheep is a disease which affects ewes late in their pregnancy and it’s a metabolic disease which will most commonly be observed in either thin ewes, fat ewes, older ewes, and ewes which are carrying two or more lambs. The cause of pregnancy toxemia in sheep is an inadequate intake of energy during the final stages of sheep gestation — a time when the bulk of fetal growth is occurring and the ewes need more nutrition to accommodate this fetal development.


Symptoms of Pregnancy Toxemia are usually listlessness, lack of energy, and eventually a lack of strength to stand and move around the barn. Treatment should be made right away, or you risk the health of the ewe and/or lambs as she will lack the strength to deliver her lambs. Treat ketosis in sheep by increasing the blood sugar supply of the affected ewe. This can be done by intravenous injections of glucose, and/or administering propylene glycol or molasses orally to the ewe with toxemia.

You can prevent pregnancy toxemia in your ewes by making sure late-term pregnant ewes are receiving sufficient food. Feed late term ewes at least  ½ to 1 full pound of grain per day, and more may be required in large, high-producing ewes which have a history of delivering multiple lambs during each pregnancy. You should also ensure that each pen with pregnant ewes has adequate feeder space so that every ewe has easy access to the grain … otherwise smaller ewes may regularly be pushed aside and they might not be getting the nutrition they require.

The most common treatment for ewes with pregnancy toxemia or ketosis is to drench them daily with Propylene Glycol to meet the energy (glucose) needs of the ewe. Early detection combined with 2-3 ounces administered orally 3 times daily can help to spike their caloric intake to balance the nutritional demands of their late-term pregnancy.


A viral disease which can affect sheep, Rabies is spread after contact is made between your sheep and saliva from an infected animal. Rabies is a central nervous system disease in sheep and usually results from bites or scratches, or when sheep have open wounds which come into contact with saliva from an animal with rabies.


Symptoms of rabies in sheep include when your sheep vigorously pulls at their wool. While there are vaccinations available for rabies, most flocks do not vaccinate for this disease because the risk of infection is low relative to the annual cost of vaccination. If you have a flock which contains very valuable animals (say you invested a lot of money in a stud ram), then you  may choose to vaccinate those animals as a way to protect your investment. If you exhibit your animals publicly, your state may require that those animals receive a rabies vaccination as well.

Rectal Prolapse

If you notice that your sheep’s rectal tissue is protruding from their body, this is an ailment called rectal prolapse in sheep. Early signs of rectal prolapse may appear to not be serious … these include a small round area which sticks out of your sheep’s backside when it coughs or lies down. In more extreme cases of rectal prolapse, the entire rectum may be pushed out of your sheep’s backside, and the sheep’s intestines may also pass through the opening. If this is the case, the disease may be fatal.


Factors which can lead to rectal prolapse in sheep include genetics, docking tails too short, chronic cough, stress, and sheep which consume high-concentrate diets are more at risk than others. Ewe lambs seem to be at higher risk than ram or wether lambs, and black-faced sheep seem to suffer rectal prolapse more frequently than their white-faced counterparts. Club lambs are at higher risk for rectal prolapse due to the extremely short tail docking and high-concentrate diet fed to most club lambs.

Ringed Cervix

A ringed cervix is generally the result of a traumatic delivery of lambs the year prior. Scar tissue develops on the cervix as a result of that delivery and the next time the ewe becomes pregnant this scar tissue prevents the cervix from fully dilating, which leads to difficulty lambing. Sometimes lambs can only be delivered via c-section as a result of a ringed cervix in sheep.


Ringworm in sheep is also called club lamb fungus or wool rot, and it is a highly contagious fungal infections of the sheep’s skin. While the name may lead you to believe ringworm is a type of parasite, it’s not … it is instead a fungal infection, and ringworm in sheep is primarily found on show lambs which are frequently slick-shorn. Infection is transmitted via fungal spores which are usually carried on contaminated sheep shears, blankets, combs or bedding, and while the ringworm lesions can appear anywhere on the animal, you’ll often observe them on the sheep’s head, neck or back. Antifungal agents applied topically can treat ringworm in sheep, but care should be taken when handling the animal, clippers used on the animal, sheep blankets, bedding or farm panels used to house sheep with ringworm, as club lamb fungus can cause an equally bad ringworm infection in people.

Ryegrass Staggers

Grazing animals who have access to perennial ryegrass are at risk of developing a sheep disease called ryegrass staggers. Ryegrass Staggers is a sheep disease which produces symptoms which range from muscle spasm to paralysis in sheep, and sheep contract this disease after metabolizing a specific group of toxins known to accumulate within the leaves of perennial ryegrass. These toxins are produced by ryegrass endophyte, a native fungus which frequently grows within the leaves, stems and seeds of perennial ryegrass.


If your flock has access to perennial ryegrass in their pasture and you notice animals with a stiff gait, or who develop difficulty walking (or become unable to walk), there’s a good chance they may have this sheep disease. Symptoms generally begin 1-2 weeks after your sheep has grazed on this plant, and extended exposure to this food source will likely produce permanent neurological damage to the animal. Younger sheep are considered to be more at risk than older animals which may have learned to avoid perennial ryegrass.

Scrapie in Sheep

Scrapie in sheep is a fatal neurological sheep disease which can also affect and be transmitted by goats. Scrapie is passed to lambs via their mother when the lambs come into contact with her placenta or the fluids associated with lambing. Bedding which has been wet with these fluids can also transmit the disease. There is no known treatment for Scrapie in sheep, and animals which have Scrapie will always die.


Thankfully, the occurrence of Scrapie in sheep flocks within the United States is low, but the disease is of regulatory concern to the US Department of Agriculture as it’s a member of a family of diseases referred to as TGE’s (Transmissible Spongiform Encephalopathies). Other disease in this family include Mad Cow Disease, Chronic Wasting Disease, and Creutzfeldt-Jacob’s Disease (in humans).

If you raise sheep it is recommended that you enroll your flock in the voluntary scrapie flock certification program. This program allows you to have your flock certified “Scrapie Free” after five years in the program, which consists of annual veterinary checks, and places limitations on what new animals you can or should bring onto your farm to add to your flock (encouraging producers to purchase breeding stock from other farms enrolled in the program). Having a certified scrapie-free flock is a great marketing tool for your flock, in addition to being a way to contribute to the national effort to combat this deadly sheep disease. Sheep can be genetically tested for scrapie resistance, though Scrapie is not strictly a genetic disease in sheep.

Spider Lamb Syndrome

Spider Lamb Syndrome (SLS) in sheep is a genetic condition which will result in severe skeletal malformations in lambs. Sheep will only have Spider Lamb Syndrome when they inherit the recessive gene from both parents, and when that happens their bone will be extremely fine. Usually these sheep will have deformed and crooked legs, which are weak enough so that they can break under their own weight as the lambs grow heavier. Generally sheep with spider lamb syndrome do not survive to full maturity.


SLS in sheep is predominantly observed in black-faced sheep. It originated from a genetic mutation in the Suffolk sheep breed, and it spread rapidly due to the unique nature of this genetic disease. In most diseases like this, carriers (those with a dominant normal gene and the recessive gene of the disease) display no symptoms, but with carriers of Spider Lamb Syndrome, those who carried a single recessive gene often displayed rapid growth and larger bone structure than those who had two normal genes. As a result, SLS carriers often excelled in the show ring and were selected for breeding stock … which resulted in the spread of the disease within the Suffolk breed, and to other black-faced sheep breeds through crossbreeding programs.

There is a DNA test for the disease, and today animals with two normal (resistant) genes are favored by breeders, as having a flock without any carriers eliminates any risk for having spider lamb syndrome sheep born on your farm. Today, it’s nearly impossible to market your flock as free of the SLS gene if you sell breeding stock.

Urinary Calculi

Urinary Calculi in sheep refers to a metabolic sheep disease which affects rams and wether sheep. Rams with urinary calculi develop stones within the urinary tract which can be painful when passed during urination and (in serious cases) can result in a blockage of the urethra. This can result in retained urine, abdominal pain, and even rupture of the urethra or bladder … which will cause the ram to die.


Usually, the condition of urinary calculi or stones in rams will present when rams and wethers are fed grains with especially high phosphorus levels. The natural diet of sheep (forages, particularly leguminous plants), has a desirable ratio of phosphorus to calcium, whereas manufactured sheep food (grains), tend to have a very high level of phosphorus relative to calcium levels.

While some shepherds attempt to combat this discrepancy by offering free-choice mineral supplements to their rams as a method to prevent urinary calculi, this is not the recommended method, as there are no guarantees that rams will eat the available mineral supplements. Instead, shepherds should ensure that the ratio of calcium to phosphorus in the grain ration fed to their rams is at least 2:1. An additional step you can take to prevent urinary calculi in your rams is to add ammonium chloride to their diet and to ensure that rams always have access to an abundance of clean water. You can also add salt to their feed, which will increase thirst and ensure that your rams are consuming plenty of water.

Shepherds who invest a lot of money in high-quality stud rams should be especially diligent when it comes to managing the diet and water supply of these rams, as failing to do so can result in the death of an expensive stud at an early age. With proper diet and management, it’s likely that you can avoid having a ram with urinary stones.

Uterine Prolapse

A ewe may prolapse her uterus immediately after lambing. Uterine prolapse in sheep occurs when a ewe’s womb (uterus) is turned inside out and pushed through the birth canal due to the intense abdominal strainings of the ewe following labor. This is a life-threatening condition, so if this occurs to your ewe it’s critical that you (or your veterinarian) act swiftly to save the ewe.


If your ewe prolapses her uterus what you need to do is to push the uterus back inside of her — a challenging job since she will be straining against you the entire time, trying to expel it again. Before you begin there are several steps you should take:

  • First, you should raise the ewe’s hindquarters. This can be accomplished by stacking one or two bales of hay, and forcing the ewe onto her front knees and lifting her back end up onto the hay bales so her feet don’t touch the ground. With someone holding her head and placing some gentle weight on her shoulders this will keep the ewe stationary, and it also allows gravity to assist you when you return her uterus through the birth canal.
  • Second, it’s important that the uterus is clean before returning it to its rightful position. This will help reduce the risk of infection. You can use a disinfectant solution of warm, soapy water. Washing the uterus with this solution should be done before the uterus becomes dried out from exposure to the air, and before cold weather has the chance to damage the tissues.
  • Once the uterus is clean and the ewe’s hindquarters are raised, work to push the uterus back through the birth canal so it is inside her again. Since it will be inside out after she pushes it out, be aware that you’ll be pushing the side exposed to you in so that is the inside part of the organ again when it’s properly positioned inside her.
  • Finally,  you’ll want to ensure that the ewe doesn’t simply prolapse again. This is a common risk, as the more trauma a ewe endures, the more likely it is that her body will send the signal that she needs to keep pushing. You can purchase a prolapse retainer (a small plastic device which is inserted into the ewe’s vagina and is secured around her torso with string to prevent her from prolapsing her uterus again). Be sure to wash the retainer with warm, soapy disinfectant before placing it into her body. After the uterus is returned to her and the retainer is secured, administer antibiotics to proactively knock down any resulting infection and you may also administer oxytocin. Ensure that she has plenty to eat and drink. It’s a good idea to add some molasses or propylene glycol to her water to ensure that she’s getting plenty of calories from her water to help her recover.

If you discover a uterine prolapse late, it’s not uncommon that the uterus will swell up considerably, which can make it difficult to return to the ewe’s abdomen. One home remedy which can help with this is that after you have disinfected the uterus with warm, soapy water, you can sprinkle some granulated sugar onto the uterus, which will help the tissues shrink back to nearly normal size. It’s not ideal to do this, but if you find that you are unable to return the uterus to her vagina at its current size, this is an option to make the process easier.

If you call a veterinarian to assist you, he or she may take one or two additional steps to ease the process of returning her uterus to its proper position, and to ensure that she does not prolapse again. Your veterinarian may give the ewe a shot in or near the spine to numb her so that she doesn’t push while he or she returns the uterus to the ewe. Your veterinarian may also use sutures to close the opening to the ewe’s vagina and prevent her from pushing the uterus out again after leaving your farm. Your ewe will still be able to urinate, but this is generally a more fail-safe way of preventing re-prolapse.

If handled and treated promptly, ewes who have prolapsed their uterus can often be kept in your flock and can deliver lambs again.

Vaginal Prolapse

In sheep, vaginal prolapses are commonly observed in pregnant ewes during the final months of pregnancy. Occasionally, you’ll see a ewe prolapse her vagina shortly after lambing. There are several common causes of vaginal prolapse in sheep, which can include hormonal or metabolic imbalances, a lack of exercise, sheep that are too fat or too thin, lambing difficulties during previous pregnancies, or an above-average amount of abdominal pressure due to large lambs. It’s not uncommon to observe vaginal prolapse repeatedly in the same ewe, during subsequent pregnancies.


When your ewe has a vaginal prolapse you should take some of the same treatment steps described above with uterine prolapse. Wash the exposed vagina with warm soapy disinfectant water and force it back into her vagina, using a prolapse retainer to prevent further prolapsing. If your ewe has already lambed, sutures are the preferred method to prevent re-prolapse.

Vaginal prolapse tends to be a hereditary issue, and while you may decide to keep a ewe after one vaginal prolapse to see if it recurs, if it does reoccur then you should cull that ewe and her offspring to prevent having to deal with this problem every year.

White Muscle Disease

White Muscle Disease (also called stiff lamb disease or WMD), is a disease which affects lambs and is the result of a deficiency of selenium or Vitamin E. This is a life-threatening disease if left untreated, so if you have a lamb exhibiting the symptoms of White Muscle Disease, you should treat it promptly with an injection of selenium and vitamin E.


It’s good practice to evaluate the feed rations of what you’re feeding your pregnant ewes to ensure that you are providing adequate levels of selenium and vitamin E to your flock. If your ewes aren’t getting enough of these minerals, it’s likely that you’ll see a number of lambs with stiff lamb disease. Supplementing the diet of your pregnant ewes is the preferred method of preventing white muscle disease, but you can also give them injections during pregnancy, or you can administer the appropriate dose to all of your lambs at birth if your flock has a history of white muscle disease. This can be given as a shot or (safer) an oral gel.

Generally flocks in the Northeastern United States are most at risk, as there tends to be a lack of these minerals in forages in this part of the country.