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Potential Sheep Health Challenges

Two sheep standing in a field

Updated June 15, 2021

When it comes to sheep, if you want to ensure that you treat any health challenges as early as possible, you’ll have to spend a lot of time with the herd, so slight changes and symptoms are more apparent to you. By conducting regular full body health examinations, you’ll be able to know what healthy looks and feels (and smells!) like, and when you should be concerned.

Animal Healthcare Disclaimer

This is not an exhaustive list of everything that can happen to a sheep, but can help you get a sense of what challenges a sheep under your care may face in their lifetime. If you believe a sheep is facing a health issue, always discuss with a qualified veterinarian as soon as possible. Reading about health issues does not qualify you to diagnose your residents!

Issues By Afflicted Area

Appetite/Drinking Changes: Anaplasmosis, Anemia, Bloat, Caseous Lymphadenitis (CL), Clostridial Disease (Enterotoxemia, Struck, Necrotic Enteritis, Overeating Disease, Pulpy Kidney, Tetanus), Coccidiosis, Grain Overload (Rumen Acidosis, Lactic Acidosis)Internal Parasites, Listeriosis, Upper Respiratory Infection, Urinary Calculi

Blood: Anaplasmosis, Anemia, Anthrax, Barber Pole, Coccidiosis, Copper Toxicity, Internal Parasites

Breathing/Mouth: Abscesses, Anaplasmosis, Barber Pole, BluetongueBottle JawClostridial Disease (Enterotoxemia, Struck, Necrotic Enteritis, Overeating Disease, Pulpy Kidney, Tetanus)Copper Toxicity, Listeriosis, Lungworms, OPP, Sheep Nasal Bot Fly (Oestrus ovis), Sore Mouth, Upper Respiratory Infection, White Muscle Disease

Droppings: Anaplasmosis, Clostridial Disease (Enterotoxemia, Struck, Necrotic Enteritis, Overeating Disease, Pulpy Kidney, Tetanus), Coccidiosis, Copper Toxicity, Internal Parasites, Johne’s Disease, Pizzle End RotTapeworms, Urinary Calculi

Energy/Movement: Anaplasmosis, Anemia, Anthrax, Arthritis, Barber Pole, Bent Leg, Bloat, Caseous Lymphadenitis (CL), Clostridial Disease (Enterotoxemia, Struck, Necrotic Enteritis, Overeating Disease, Pulpy Kidney, Tetanus)Coccidiosis, Copper Toxicity, Grain Overload (Rumen Acidosis, Lactic Acidosis), Infectious Foot Rot (Contagious Hoof Rot), Interdigital Dermatitis (Foot Scald), Internal Parasites, Laminitis, Listeriosis, Mastitis, OPP, Overgrown Hooves, Parelaphostrongylus Tenuis (Meningeal Worm, Deer Worm, Brain Worm), Pizzle End RotTapeworms, Thiamine DeficiencyUpper Respiratory Infection, Urinary Calculi, White Muscle Disease

Eyes: Anemia, Barber Pole, Clostridial Disease (Enterotoxemia, Struck, Necrotic Enteritis, Overeating Disease, Pulpy Kidney, Tetanus)Entropion, Fly StrikePink Eye (Infectious Keratoconjunctivitis), Thiamine Deficiency

Feet/Hooves: Arthritis, Bluetongue, Fly Strike, Infectious Foot Rot (Contagious Hoof Rot), Interdigital Dermatitis (Foot Scald), Laminitis, Mastitis, Overgrown Hooves

Head/Neck: Abscesses, Caseous Lymphadenitis (CL), Listeriosis, Sore Mouth

Legs/Joints: Arthritis, Bent Leg, Bluetongue, Infectious Foot Rot (Contagious Hoof Rot), Interdigital Dermatitis (Foot Scald), Laminitis, Mastitis, Overgrown Hooves, Parelaphostrongylus Tenuis (Meningeal Worm, Deer Worm, Brain Worm)

Skin/Coat: Abscesses, Anemia, Arthritis, Caseous Lymphadenitis (CL), Copper Toxicity, Fly Strike, Lice, Mange, Parelaphostrongylus Tenuis (Meningeal Worm, Deer Worm, Brain Worm), Sore Mouth

Social Changes: Anaplasmosis, Anemia, Anthrax, Arthritis, Barber Pole, Bloat, Copper Toxicity, Grain Overload (Rumen Acidosis, Lactic Acidosis)Listeriosis, Mastitis, OPPPizzle End Rot, Sheep Nasal Bot Fly (Oestrus ovis), Tapeworms, Thiamine DeficiencyUpper Respiratory Infection, White Muscle Disease

Udder: Abscesses, Caseous Lymphadenitis (CL), Lice, Mastitis, Sore Mouth

Weight: Anaplasmosis, Anemia, Arthritis, Barber Pole, Caseous Lymphadenitis (CL), Coccidiosis, Copper Toxicity, Internal Parasites, Johne’s Disease, Listeriosis, Tapeworms


Abscesses are pockets of pus that can develop internally or externally. They can develop in any area of the body, but some common sites for sheep include their feet, face, and neck. Abscesses can form for a variety of reasons, including infections, poor wound management, and benign reactions to vaccinations or injectable medications. Abscesses can also form as a result of Caseous Lymphadenitis (more below), a highly contagious condition that can cause internal and external abscesses. This disease is spread through contact with the pus, so separating individuals with external abscesses is typically recommended. In the event of a suspected abscess, it should be first evaluated by a veterinarian or experienced caregiver- they can aspirate the lump to determine if it is an abscess or not. Depending on the location, size, and whether or not the sheep is displaying other signs of concern, your veterinarian may decide to lance the abscess. In most cases, a culture will be recommended to determine the best course of action. Your veterinarian will be able to advise you about any necessary treatments based on the cause of the abscess. If you have not been trained to identify and lance an abscess, you must work closely with your veterinarian. Not all external lumps are abscesses, and cutting into tumors or other masses could result in serious issues. Also be aware that any abscess on the neck or near major blood vessels should always be evaluated by a veterinarian. In these instances, it may be too dangerous to lance the abscess due to the risk of major bleeding. Back To Top


Anaplasmosis in sheep is caused by the bacterium Anaplasma ovis, which parasitizes red blood cells. While many infected sheep will remain asymptomatic, it can cause severe disease, especially in older sheep. Anaplasmosis is an infectious disease that is typically transmitted by insects such as ticks and biting flies, but can also be spread through any practices that may expose sheep to infected red blood cells (such as by reusing needles or not sterilizing surgical equipment). It may be possible to also transmit the disease in the womb. Signs of anaplasmosis include fever, pale mucous membranes, weakness, and dark urine. Infected individuals may exhibit additional signs such as depression, constipation, an elevated respiratory rate, and inappetence. Be sure to contact your veterinarian immediately if one of your residents is showing signs of anaplasmosis. They can diagnose the issue and recommend treatment, which may include intravenous antibiotics (typically a tetracycline drug) and possibly a blood transfusion. Back To Top


Anemia in sheep is characterized by pale mucous membranes, especially the mucous membranes of the lower eyelid. An anemic sheep might be more lethargic, have a dull or shabby coat, and lose weight. Anemic individuals may also develop Bottle Jaw. In addition to treating the anemia, it is imperative to identify the cause, which could be due to parasitic disease (especially Barber Pole worm), ingestion of a toxin, or trauma. In areas where Barber Pole worms are common, this will likely be the most common cause of anemia in sheep and goats. Be sure to work closely with your veterinarian if one of your residents appears to be anemic. They can help determine the cause of the anemia and offer treatment recommendations. Depending on the severity of the anemia, they may also recommend a blood transfusion. If you have not already done so, talk to your veterinarian about using the FAMACHA system to regularly evaluate residents for signs of anemia. Back To Top


Anthrax is caused by Bacillus anthracis spores, which can lie dormant in soil for many years. The bacteria is more common in temperate climates and can come to the surface after heavy rains, especially after periods of drought. Animals who graze are susceptible to the disease after eating contaminated grass. Symptoms include depression, incoordination, staggering, trembling, convulsions, excitement, high fever, bleeding, and unfortunately, typically death. If you suspect a sheep has anthrax, you must contact your veterinarian immediately. The infected sheep can quickly spread the disease to other animals, including humans. Confirmations of anthrax must be reported to government officials. If it is treated very early on with antibiotics, it is possible for sheep to survive. There is also a vaccine available for anthrax. Back To Top


There are many types of arthritis with different causes (including septic arthritis, which can be quite in lambs who did not receive colostrum), but like most animals, degenerative arthritis (osteoarthritis) tends to be quite common in sheep as they age. Sheep may also develop arthritis due to Ovine Progressive Pneumonia (OPP). Symptoms of arthritis will vary depending on the affected area and cause, but typically includes abnormal gait, shifting of weight, lameness, and reduced activity. Sheep with arthritis may spend more time laying down. Individuals with mobility issues should be evaluated by a veterinarian to determine the underlying cause. They will be able to recommend a treatment plan based on the specific cause, which should include some sort of pain management. Your veterinarian may recommend a non-steroidal anti-inflammatory drug (NSAID), such as Meloxicam, Phenylbutazone, or Banamine and may suggest a Chondroprotective agent such as Adequan to help repair joint cartilage and soothe inflammation. For more information on managing arthritis in older sheep, check out our resource here. Back To Top

Barber Pole

Barber pole worm (Haemonchus contortus, sometimes called wireworm) is a gastrointestinal roundworm that can cause serious disease in sheep, goats, llamas, and alpacas. While other gastrointestinal parasites can cause illness in small ruminants and camelids, barber pole worm is especially dangerous because it is a blood-sucking parasite that has the potential to cause life-threatening anemia. To further complicate things, anthelmintic resistance (resistance to dewormers) is a serious and growing issue, though the degree of resistance and to which drugs worms are resistant will vary region by region and also property to property. For more information on barber pole worm, including ways to slow the development of anthelmintic resistance, check out our in depth resource, here. Back To Top

Bent Leg

Bent leg refers to a form of rickets that can affect young, rapidly growing sheep (usually between 6-12 months old). The most common symptom of bent leg is when a sheep’s leg or legs ceases to grow straightly. It is a result of an imbalance of nutrition, especially too much high protein or high energy food. You can prevent bent leg by providing an appropriate calcium to phosphorus ratio, appropriate amounts of Vitamin D, magnesium, and providing good exposure to sunlight throughout the winter. Back To Top


In ruminants, a significant amount of gas is produced during the digestive process and is naturally released through eructation (belching). Bloat occurs if this gas is not able to be released for some reason. The build-up of gas causes the rumen to expand, which will displace and put pressure on internal organs and can make it difficult for the individual to breathe. Bloat should be considered a health emergency and must be addressed immediately. There are two types of bloat that affect mature sheep- frothy bloat (or primary ruminal tympany) and free-gas bloat (or secondary ruminal tympany). Though they have different causes and require different responses, the signs of frothy bloat and free-gas bloat are vastly similar. The most obvious sign of bloat is distention of the left side of the abdomen, though their entire abdomen may be enlarged. In some cases, the rumen may be so distended that their left side bulges above the level of the spine, creating a hump. The left side of their abdomen will feel tight and, when tapped, may produce a sound like a kettle drum. Bloated individuals often develop labored breathing and may be observed grunting, open-mouth breathing with their tongue out, and extending their neck. Frequent urination and signs of discomfort and distress are commonly seen, and as the condition progresses, individuals may become recumbent. If not addressed, bloat can be fatal. Regardless of the type, be sure to contact your veterinarian immediately if you suspect a resident is suffering from bloat. Encourage the individual to walk, or at least remain standing while waiting for treatments to be administered.

Frothy Bloat is the more common of the two types and occurs when a stable foam develops on top of the rumen liquid, preventing the gas from being released normally. This type of bloat is diet-related. Grazing on lush pastures containing large quantities of certain legumes (especially alfalfa and red and white clover) is one of the main causes of frothy bloat. Frothy bloat caused by pasture is most likely to occur in the spring and fall. When pasture is the cause, multiple residents are typically affected, though some individuals may be more prone to bloat, especially new residents who may not be accustomed to lush pastures (which is why they should be slowly introduced to pastures). If a resident shows signs of bloat, it is important to immediately prevent them from further grazing on the pasture. In the case of established residents developing bloat, be sure to remove all members of the flock from the pasture, even if not everyone is showing concerning signs. Frothy bloat can also be caused by high-grain diets (which we do not recommend for a variety of reasons), especially if the grain is finely ground.

In addition to removing everyone from the pasture (if that appears to be the cause), talk to your veterinarian about administering an anti-foaming agent such as vegetable oil or products containing dioctyl sodium sulfosuccinate (DSS) or polaxolene. These can be drenched or administered via stomach tube (which must be done by an experienced caregiver, as incorrect placement of the tube could have dire consequences). Placement of a stomach tube alone will not release gas build-up in individuals suffering from frothy bloat. Prevention is key- when introducing residents to new pasture types, be sure to do so gradually, over a period of a few weeks, with a small amount of grazing time per day until their bodies adjust, avoid giving residents access to high-risk pastures (such as those heavy on legumes), do not allow sheep to graze on rich pastures when they are wet, and don’t put very hungry individuals on rich pastures- feed them hay first so they don’t gorge themselves on pasture. If you must supplement a resident’s diet with grain, be sure to talk to your veterinarian about the safest way to do so and avoid finely ground grains (including pelleted food made from finely ground grains).

Free-gas bloat is much less common and can have a variety of causes. Anything that creates an obstruction or interferes with belching will result in the build-up of free-gas in the rumen. Potential causes include obstruction of the esophagus due to choking, lesions of the esophageal groove, or pressure from a mass or enlarged lymph node. Certain health conditions, such as grain overload or anaphylaxis, can cause secondary free-gas bloat. Individuals can also develop free-gas bloat if they become stuck in a position that prevents them from belching. This can occur if they stay in a laterally recumbent position (flat on their side) for extended periods of time (or worse, if they get stuck on their back). Bloat caused by a sheep’s position is most likely to occur if they become stuck in a dangerous position, such as falling into a ditch or lying down on an incline that makes rising difficult, or if they are injured and, therefore, unable to rise. This type of bloat is also a concern when an individual is sedated for a medical procedure. Sedated individuals should be propped up to keep them in a sternal position (hay or straw bales can be used to do this) and should be monitored closely to ensure they do not end up in a dangerous position. Unlike frothy bloat, free-gas bloat typically only affects one individual rather than multiple members of the herd. Removal of gas is imperative and is typically done with a stomach tube, though in some cases, more aggressive steps may need to be taken, such as trocharization (inserting a trochar or cannula into the rumen through the abdominal wall). After alleviating the gas, be sure to investigate the underlying cause of the free-gas bloat.

Talk to your veterinarian about the emergency supplies you should have on hand to respond to both types of bloat. By having the right supplies on hand and a basic understanding of how to use them, in the event that your veterinarian cannot make it to the sanctuary in time, they may at least be able to talk you through certain life-saving interventions. Back To Top


Bluetongue is a viral infection that can affect both domesticated and wild ruminant species. Of the domesticated species, sheep are the most severely affected. Transmission of bluetongue virus (BTV) occurs primarily via biting midges (Culicoides spp.), though not all species of Culicoides act as vectors of BTV. While some other bloodsucking insects may be able to act as mechanical vectors, according to the Merck Veterinary Manual, they are of minor significance. In many parts of the world, BTV infections are often subclinical. However, BTV infection can cause serious and potentially fatal illness. Initial signs of BTV infection include fever and lethargy, which may be followed in a few days by edema (fluid build-up) of the mouth, lower jaw (bottle jaw), eyelids, or ears. Other signs include lameness, depression, excessive salivation, and congestion of the nose, mouth, conjunctiva, or coronary band. Individuals often have profuse nasal discharge which is initially thin and clear and then becomes mucopurulent. BTV can cause small hemorrhages of the nasal and oral mucous membranes as well as ulceration of the mouth. In some cases, the individual’s tongue will swell and become a blueish color (hence the name ‘bluetongue’). BTV can also cause reproductive issues. Secondary bacterial infections are possible, and in severe cases, pulmonary edema may result in difficulty breathing or even asphyxiation. Be sure to contact your veterinarian immediately if one of your residents is showing signs of bluetongue. In areas where the disease is endemic, your veterinarian may be able to make a diagnosis based on clinical signs alone. However, there are diagnostic tests they may recommend to confirm. Treatment typically includes supportive care and possibly antibiotics to address secondary infections. Because oral lesions often make eating painful, individuals may need encouragement to eat and may benefit from soft food such as soaked timothy pellets. Your veterinarian can recommend specific interventions based on the needs of the individual. Vaccination may be advisable if you are in an area where this disease is endemic, but you should consult with an experienced veterinarian to establish an appropriate protocol for your sanctuary and to determine which of the available vaccines will offer the best protection based on the virus strains in your area. Back To Top

Bottle Jaw

Bottle Jaw is the term commonly used to describe edema in the lower jaw which manifests as a visibly swollen area under the jaw. Bottle jaw is a symptom of numerous health challenges, and while it can have other causes, most often bottle jaw develops because of reduced oncotic pressure resulting from anemia or hypoproteinemia (low protein levels in the blood). Be sure to work with your veterinarian if one of your residents is showing signs of bottle jaw- it is important to diagnose the underlying cause in order to make treatment decisions. In sheep, bottle jaw is most often associated with barber pole worm infections, though it can be caused by other internal parasites or other health challenges, such as Johne’s disease. Back To Top

Caseous Lymphadenitis (CL)

Caseous lymphadenitis is a contagious and chronic disease that causes abscesses in sheep and goats and is caused by the bacterium Corynebacterium pseudotuberculosis. For more information, on this disease, check out our resource Caseous Lymphadenitis In Small Ruminants. Back To Top

Clostridial Disease

There are many clostridial organisms that can live in the soil and even in the gastrointestinal tract of healthy animals. While there are a host of clostridial organisms that can cause disease in sheep, the most common are Clostridium perfringens types C and D and Clostridium tetani. Because of the prevalence of these pathogens and the fact that they produce toxins that often cause fatal disease, vaccination is universally recommended in North America. There is a three-way vaccine, referred to as CDT, that protects against all three of these pathogens and the diseases they cause, as well as an eight-way vaccine that protects against additional clostridial diseases as well. Talk to your veterinarian about which vaccine makes the most sense for your residents, as additional clostridial diseases may be a concern in certain regions.

C. perfringens type C most often affects young lambs, causing hemorrhagic enterotoxemia or necrotic enteritis, but can also affect adults causing a disease called “struck”. Lambs may die without showing signs of illness, but more often they will develop diarrhea that is yellow, and they may have streaks of blood in their feces. Affected lambs will not want to eat, will show signs of colic, and will tense their abdominal muscles, especially when being handled. Unfortunately, this disease is often fatal, ending in convulsions and coma. Adult sheep with “struck” may die suddenly or may show signs of toxemia. If C. perfringens type C infection is recognized early, treatment with antibiotics, Clostridium antitoxin, and supportive care may help, but often once there are clinical signs of disease, treatment is not successful.

C. perfringens type D causes classic enterotoxemia in sheep and is also referred to as “overeating disease” and “pulpy kidney disease”. This disease is often associated with over ingestion of grain, but can also result from over ingestion of milk or lush pasture, and can also be caused by an abrupt change in diet (such as sudden introduction of lush pasture or increase in grain). As a result of over ingestion or sudden diet changes, C. perfringens type D proliferates and produces toxins. While it occurs most often in lambs, unvaccinated adults can also be affected. Some sheep may die before or soon after showing signs of illness. Signs of enterotoxemia caused by C. perfringens type D include an elevated respiratory rate, elevated heart rate, fever, and inappetance. Individuals will show signs of colic, such as laying flat on their side and tensing their abdominal muscles, and develop neurologic signs that progress to seizures or coma. In the final stages of disease, lambs may develop watery, yellow diarrhea. If caught early, treatment with antibiotics, Clostridium antitoxin, and supportive care, as well as adjustments to their diet may help. 

C. tetani is found in the soil and causes tetanus when introduced to the tissue via a wound, surgical procedure, or even intramuscular injection. The incubation period varies, with signs of tetanus developing anywhere between 1 and 60 days after introduction of C. tetani. Tetanus is a progressive disease. Though often missed, the first sign of tetanus is often a tensing of the muscles in the head and neck. Within the first 24 hours, individuals often develop gas bloat. As the condition progresses, the individual will develop more generalized stiffness that involves their head, neck, limbs, and tail. Affected sheep may lay on their side and be unable to rise or stand in a “sawhorse” stance. Treatment involves high doses of antibiotics, administration of tetanus antitoxin, medications to relieve muscle spasms, supportive care, and if there is a necrotic wound present, debridement of the wound. The individual should be kept in a quiet, dark space with ample bedding and minimal stimulation while they recover. Unfortunately, death due to respiratory paralysis is common. If a young or new resident has not yet been vaccinated and requires surgery (such as neutering) or becomes wounded, your veterinarian can administer tetanus antitoxin to provide temporary protection.

Your best course of action is to prevent the above diseases by establishing an appropriate vaccination program with your veterinarian, such as administration of the three-way CDT vaccine. Generally, newly rescued adult sheep with unknown vaccination status should be vaccinated soon after arrival, so long as they are healthy enough. Lambs fed an appropriate amount of colostrum from a vaccinated individual receive passive immunity to these clostridial diseases. This immunity is temporary and will begin to fade when lambs are about 6 weeks old. Vaccinating these lambs when they are about 6-8 weeks old will ensure continued protection against these dangerous diseases. Lambs who did not receive colostrum from a vaccinated individual (and therefore did not receive passive immunity) should be vaccinated for clostridial diseases at an earlier age, typically when they are between 3-4 weeks old. Lambs with unknown immunity or vaccination status should also be vaccinated between 3-4 weeks of age. Be sure to administer subsequent boosters following the manufacturer’s instructions or your veterinarian’s recommendations. Back To Top


Coccidia are parasites which can damage a sheep’s small intestinal lining. Most adult sheep are infected and immune, but one to six month-old sheep are at risk of fatal infestations. An acute infection can lead to anemia, dehydration, fever, hair loss, weight loss, stunted growth, and bloody, mucus-filled diarrhea. Usually Coccidiosis is a result of overcrowding, stress, and poor sanitation. The best prevention is keeping a sheep’s living space clean and uncrowded! There are medicines available to treat infections. As a preventative measure, you should have a lab perform a fecal test on sheep every three months to ensure that they are not facing a dangerous parasitic infection. Back To Top

Copper Toxicity

Copper toxicity is especially dangerous in sheep because their liver accumulates copper much more readily than in other animals. Although copper is essential for sheep, too much copper can cause anemia, lack of appetite, lethargy, teeth grinding, increased thirst, jaundice, dark red-colored urine, and diarrhea. Copper can accumulate in a sheep’s liver for up to a year without any symptoms until the liver releases a large amount at once, causing damage to their red blood cells. In addition to copper intake levels that are too high, copper toxicity can also be caused by liver damage or a lack of dietary molybdenum, sulfur, zinc, or calcium. Left untreated, copper toxicity can be fatal in only a few days after presenting symptoms. Unfortunately, the prognosis is poor in severely affected individuals. If you suspect copper toxicity in one of your sheep residents, contact a veterinarian immediately. They can recommend appropriate treatments based on the situation such as those that reduce copper absorption, enhance copper elimination, and reduce damage to red blood cells, and they can also provide supportive care as needed. It’s also imperative you determine the cause of the copper toxicity to avoid toxicity in other residents. Your veterinarian may recommend treatment for flockmates even if they are not showing clinical signs of toxicity. The best prevention includes ensuring that the sheep are not getting too much copper in their diet and that their diet is properly balanced. Make sure that sheep are not given access to minerals or food formulas not explicitly approved for sheep, as even goat minerals have too much copper for a sheep’s body. Also consider other potential sources of copper such as foot baths containing copper or even water sources. Back To Top

Entropion (Or, Inverted Eyelid)

Entropion is a condition in which the eyelid rolls inward causing eyelashes and the hair around the eye to come into contact with the eye, resulting in irritation. This condition can be congenital and is one of the most common eye issues in neonatal lambs. Congenital entropion usually affects the lower eyelids of both eyes. Non-congenital entropion can affect individuals of any age and typically affects only one eye, but may affect either the top or bottom eyelid. This type of entropion can develop as a result of trauma or secondary to certain eye conditions. It can also develop in individuals who are emaciated or severely dehydrated and can also affect elderly individuals due to a loss of retrobulbar fat. Individuals with entropion will show signs of eye irritation such as squinting or rubbing of the eye, as well as tearing and eye discharge. Upon closer inspection, you will be able to see that the eyelid is inverted. Your veterinarian can recommend treatment based on the severity of the case and the cause. Treatment may include eye ointments, skin sutures to evert the eyelid, or surgical correction. Congenital entropion tends to improve over time, so it’s often recommended to hold off on surgical correction to see if the condition revolves, in the meantime using non-surgical interventions to evert the eyelid and treat the eye. Left untreated, entropion can cause corneal scarring and ulceration. Back To Top

Fly Strike

Fly strike refers to a maggot infestation. There are numerous species of blowfly that commonly cause fly strike in sheep, and species of concern vary by region. Some fly species will attack living tissue, while others will only infest wounds with necrotic tissue. While anyone can suffer from fly strike, sheep are especially vulnerable because flies are attracted to soiled wool. Another challenge with wooly sheep is that their wool can easily hide wounds that attract flies. In addition to soiled wool and wounds, foot rot can attract flies and result in fly strike. In a sanctuary setting where individuals are regularly observed and evaluated, fly strike is far less common than on a commercial farm. However, you should be sure to clean up individuals with soiled wool (which is especially common on their bums). Keep a close eye out for wounds or other conditions that could lead to fly strike, and be sure to protect these areas from flies and monitor them regularly. Daily observation, cleaning or partially shearing wool that is soaked with urine or matted with feces, implementing fly mitigation strategies, and close monitoring of anyone who has a condition that makes them more vulnerable to fly strike will help prevent this issue and ensure that if someone does develop fly strike, you will be more likely catch it early. If you find that one of your residents has fly strike, consult with your veterinarian for guidance. In addition to eradicating the maggots, your veterinarian may recommend other treatments depending on the severity. Back To Top

Grain Overload (Rumen Acidosis, Lactic Acidosis)

Grain overload, or grain poisoning, occurs when a sheep eats large quantities of carbohydrate-rich foods when they are not used to eating such diets. In a sanctuary setting, it is most often caused by residents accidentally gaining access to grain storage areas, but could also occur if residents who require grain supplementation are fed too much or are not slowly transitioned onto this diet. Despite commonly being called grain overload, grain is not the only food source that can cause lactic acidosis, though many of the other problematic foods would not typically be available to sanctuary residents in the amount needed to cause an issue. Fruits, including apples and grapes, as well as sugar beets, potatoes, and bread products can also cause acidosis. How much of a particular carbohydrate-rich food is needed to cause illness is dependent on the type of food, what the individual is used to eating, and other factors. Ingestion of grains with a smaller particle size typically results in more severe illness (compared to the same amount of grain of a larger particle size) because it will be broken down more quickly. 

Ingestion of large quantities of carbohydrate-rich foods by individuals who are not used to such diets will result in a change in the rumen microflora and a lower than normal pH (more acidic). These changes result in certain acid-tolerant bacteria to increase, which in turn results in more lactic acid being produced. Rumen motility slows, resulting in stasis and mild bloat. Lactic acidosis can be fatal- prompt intervention is imperative. Be sure to contact your veterinarian if a resident is showing signs of lactic acidosis or if they got into large amounts of grain (or other concerning foods), even if they are not showing signs of illness yet. If you have activated charcoal products such as Universal Animal Antidote, ask if administration is advised. 

Early signs of grain overload include restlessness and colic (including kicking at their abdomen). Affected individuals may develop ataxia and have trouble rising due to weakness. Individuals will not want to eat and may extend their neck, grind their teeth, and have a distended abdomen. Breathing is often shallow and rapid. At first they may have an elevated rectal temperature, but as the condition progresses their temperature will drop below normal. While they may show no sign of diarrhea for the first 12-24 hours, profuse diarrhea, often with a sweet- sour odor, often develops after this point. In some cases, removal of rumen contents through rumenotomy (surgical incision into the rumen) or lavage (using a stomach tube) will be required. Both carry risk and your veterinarian will determine the best course of action given the specifics of the situation. Transfaunation (ruminal fluid transfer) to restore healthy microflora, and fluid therapy to address dehydration and metabolic acidosis are important. Your veterinarian may also prescribe antibiotics (Penicillin is commonly used) and thiamine or multivitamin injections depending on the severity of the illness. Prevention is key. Make sure all grain is stored out of reach and secured from residents, and talk to your veterinarian about safely introducing supplemental grain to a resident’s diet if needed. Also be aware of other risks on your property such as large numbers of apple trees in or overhanging resident pastures. Back To Top

Infectious Foot Rot (Contagious Hoof Rot)

Infectious foot rot (sometimes spelled “footrot” or used interchangeably with the term “hoof rot”) is a bacterial infection that affects both sheep and goats but tends to be more severe in sheep. Though there are often multiple bacteria involved, Dichelobacter nodosus (formerly Bacteroides nodosus) must be present to be considered true foot rot. The other bacteria most often associated with foot rot, but which is the absence of D. nodosus does not cause true foot rot, is Fusobacterium necrophorum. On its own, F. necrophorum causes interdigital dermatitis (sometimes referred to as “scald”) but can make the foot vulnerable to infection with D. nodosus. There are numerous strains of D. nodosus with varying degrees of virulence. Differentiating between benign foot rot and interdigital dermatitis is difficult, and people sometimes refer to both as “foot scald”. In benign cases, sheep will develop inflammation and necrosis of the tissue between their claws and mild lameness. Benign foot rot typically only affects a few individuals in a flock, whereas virulent strains typically affect numerous individuals. Virulent foot rot often causes severe lameness, separation of the hoof wall, a foul odor, and a black tarry appearance. Individuals with virulent strains may also develop a fever and have a reduced appetite, resulting in weight loss. Foot rot can lead to secondary bacterial infections and flystrike.

Foot rot typically occurs in areas with periods of warm, wet weather- with spring and fall being common times for transmission. In addition to wet conditions, overgrown hooves can also make foot rot infections more likely. Some breeds of sheep, such as Merinos, are more susceptible to foot rot than other breeds. Sheep and goats with foot rot contaminate the environment with D. nodosus which can then infect other residents. D. nodosus can only survive for between a few days and a few weeks in the environment, but infected sheep and goats can be carriers for years. 

If you suspect a resident has foot rot, be sure to get your veterinarian out to examine the individual(s). Foot rot is usually diagnosed based on clinical signs, though, as mentioned above, benign strains may be difficult to differentiate from interdigital dermatitis. Treatment typically involves trimming of the hoof, application of a topical antibiotic treatment (tetracycline is a common one) or medicated foot baths, and possibly systemic antibiotics. Please note, there is conflicting information regarding whether or not hoof trimming assists in the healing process or not. Be sure to work with your veterinarian for specific recommendations. Depending on the situation, they may also recommend fully isolating the affected individual or taking measures to prevent the spread to other groups of sheep and goats that have not yet had contact with the individual. In severe cases, you may be advised to remove all sheep and goats from certain living spaces temporarily, in order to prevent reinfection. Prevention is key- be sure to regularly trim your residents’ hooves, keep indoor living spaces dry and clean, and make sure outdoor areas have adequate drainage. Back To Top

Interdigital Dermatitis (Foot Scald)

Ovine Interdigital Dermatitis (OID) is sometimes referred to as “foot scald” but that term can be confusing because it is occasionally used to describe benign strains of foot rot. Interdigital dermatitis is caused by the bacteria Fusobacterium necrophorum (this bacteria is typically seen in combination with Dichelobacter nodosus, the bacteria that causes infectious foot rot), and often occurs in warm, wet conditions. If the foot is exposed to wet conditions for prolonged periods of time, it can become vulnerable to damage, especially between the claws, which allows bacteria to enter. Sheep with interdigital dermatitis usually develop only mild lameness. Affected sheep will have inflammation of the tissue between the claws, and the skin may be discolored, moist, raw, and sensitive. Individuals with this condition are vulnerable to infectious foot rot. Treatment typically involves limiting their exposure to wet areas and a topical treatment of zinc sulfate. Though sometimes recommended as a treatment, copper sulfate should be avoided due to the possibility of copper toxicity if ingested. In some cases, trimming the wool around the hoof can help the foot to dry out more quickly. Back To Top

Internal Parasites

There are a number of internal parasites that can affect a sheep’s quality of life, and unfortunately a number of internal parasites that are resistant to common treatments. Some internal parasites, such as LungwormsBarber Pole, and Coccidia, can cause severe illness depending on the severity of the infection. Common parasite symptoms can include lethargy, diarrhea, clumped stools, weight loss, and anemia. As a preventative measure, you should have a lab perform a fecal test on sheep every three months to ensure that they are not facing a dangerous parasitic infection and have appropriate treatment policies in place for infected sheep. Back To Top

Johne’s Disease

Also known as paratuberculosis, Johne’s disease is a fatal contagious gastrointestinal disease caused by the bacteria Mycobacterium avium paratuberculosis. It can affect goats, sheep, cows, and other ruminants. It is usually transmitted when a sheep incidentally eats fecal-infected material or while a lamb is in their mother’s womb. An infected sheep loses a large amount of weight and generally gets worse and worse off over time, and may have a large amount of diarrhea before death. There is unfortunately no reliable medication to treat Johne’s Disease. Back To Top

Joint Infections

If a sheep has a swollen, reddened, or hot joint, have a veterinarian evaluate them immediately, and never tap a swollen joint yourself. There are a number of different diseases and illness that could cause joint infections, including OPP or Joint or Navel Ill if young. If untreated, the infection can spread to the bone or cause permanent damage and death. Back To Top


Sheep keds (Melophagus ovinus) are a blood-sucking external parasite of sheep, though they can occasionally affect other species as well, including goats. This parasite is sometimes called “sheep tick” though it is actually a wingless fly. Keds are about 7mm long- large enough to be seen easily with the naked eye, but may be concealed by the sheep’s wool, making observation difficult without looking through their wool. Common feeding areas include the neck, shoulders, chest, sides, and bum, but not typically the back. Keds are spread through direct contact with infected individuals. Sheep with keds will be itchy, so watch for any biting, scratching, or rubbing. Wool will also become discolored from the keds’ excrement. Severe infestations can result in anemia and weight loss, and can keds can transmit certain diseases such as bluetongue. Treatment typically involves shearing, which will remove a large percentage of keds, and a sheep-safe topical treatment. If shearing is not an option due to weather concerns, you can still treat with a topical or pour-on treatment, but you’ll need to make sure to part their wool and get the treatment down to the skin. Permethrin-based products are typically effective, but your veterinarian should be able to recommend an appropriate product that is safe for your residents and can also make recommendations about follow-up treatments depending on the product. Back To Top


Laminitis can be extremely painful to sheep and cause lameness. Symptoms include fever, heat in the feet, lowered mobility, enlarged feet, overgrown hooves, and a reluctance to stand. Laminitis is typically a secondary disease to digestion issues (sometimes from bloat or grain poisoning) or from eating too much grain, or from infection. A recovered sheep might end up with permanently inhibited motion. There are other diseases that present similar symptoms to laminitis, such as hoof rot.  Back To Top


There are multiple species of sheep lice, including Bovicola ovis, a chewing louse which feeds on skin cells and debris, and Linognathus pedalis and L. ovillus, which are sucking lice that feed on blood. While lice tend to be species-specific, it is possible for sheep who live with goats to become infected with some types of goat lice and vice versa. In regions with cold winters, lice infestations tend to be more of a cold weather issue. Different lice species affect different areas of the body (though as infestations become more severe, lice may spread to other areas). For example, B. ovis is typically found on woolen parts of the sheep, especially their back; L. pedalis (sheep foot louse) typically affects hair-covered areas of the foot and leg, but can spread to the abdomen and scrotal area; and L. ovillus (sheep face louse) typically affects the face and other hair-covered areas. Early signs of lice infestations include itching and rubbing, which is often noticed before lice can be easily found during an examination. Sheep with lice infestations may have damaged, raggedy, or missing wool/ hair due to itching and rubbing. Foot lice infestations can also cause lameness. Severe sucking lice infestations can result in anemia. Lice are transmitted via direct contact with infected animals and via infected fomites. While it is possible to see lice with the naked eye, it can be very difficult to find them in the wool until there are many lice present. Individuals with compromised immune systems may be more severely impacted than other residents, but even if you can only find lice on one member of the flock, you should plan on treating the entire flock. Treatment typically includes shearing (if the weather permits), as this will reduce lice populations and will also make topical treatments more effective. Your veterinarian can recommend a treatment based on the type of lice and also the specifics of your region; insecticide-resistance is becoming an issue in some parts of the world and may impact the recommended treatment plan. Back To Top


Listeriosis is most often the result of an infection caused by the bacteria Listeria monocytogenes, though in sheep disease from L. ivanovii infection is also possible. This bacteria can be found in soil, water, and vegetation. Many species of animals can be affected by this disease and can shed the bacteria in their feces, even if they are not showing clinical signs of disease. This disease occurs more frequently in the winter and spring, and sheep typically become exposed by ingesting plants contaminated with infective soil or feces. Listeriosis is often associated with feeding poor-quality silage (partially fermented forage), but can also be caused by ingesting moldy hay or rotting vegetation. Not all individuals carrying this bacteria will show clinical signs of disease, but when clinical signs are present, they typically manifest in one of the following ways: encephalitis, which is the most common manifestation, abortion, septicemia, mastitis, or ophthalmitis. Initial signs of the encephalitic form include depression and inappetence. Individuals often appear disoriented and may walk in circles towards their affected side (which is why listeriosis is sometimes called “circling disease”). They may develop facial paralysis on the affected side with a droopy ear and eyelid and loose lips. They may drool excessively and there may be food stuck in their cheek on the affected side because chewing is difficult. In severe cases, the individual may show more severe neurological signs, in which case the prognosis may be poor even with treatment. If you think a sheep is suffering from listeriosis, it’s critical that you get a veterinary evaluation, as prompt, aggressive antibiotic treatment is imperative for successful recovery. If the individual is unable to eat or drink normally, supportive care will also be necessary. Individuals with listeriosis should be isolated from other residents. Listeriosis is a zoonotic disease, though most healthy humans do not become seriously ill. Humans most at risk of listeriosis are newborns, the elderly, and those who are pregnant or immunocompromised. Back To Top


There are multiple lungworm species that can affect sheep and goats- the most important being Dictyocaulus filaria, Muellerius capillaris, and Protostrongylus rufescens

D. filaria is the most pathogenic of the lungworm species that can affect sheep. Unlike the other two species, it has a direct life cycle. Infection most often occurs in sheep who are 2-18 months old but adults can also be affected. Female D. filaria lay eggs containing larvae in the lungs which are then coughed up, swallowed, and hatch into first-stage larvae before being passed in feces. Larvae develop into infective third-stage larvae on the pasture- how quickly this occurs depends on environmental factors. Infection occurs when infective larvae are consumed while animals graze. The larvae continue their development inside the host and travel to the lungs to start the process again. Signs of D. filaria infection include cough, nasal discharge, elevated respiratory rate, labored breathing, chronic fever, poor appetite, and weight loss. 

M. capillaris is the most common lungworm species to affect sheep and is also the least pathogenic. In fact, many infections do not cause clinical disease in sheep (goats are typically more severely affected). Both M. capillaris and P. rufescens have an indirect life cycle and require an intermediate snail or slug host. Female M. capillaris lay eggs in the lungs that hatch into first-stage larvae. These larvae are coughed up, swallowed, and passed in the feces. Larvae can survive for months in the environment. They penetrate their intermediate host and develop into infective third-stage larvae. Infection occurs when snails or slugs containing infective larva are ingested while sheep graze. The larva continues to develop and travels back to the lungs to start the cycle again. 

P. rufescens infections are typically subclinical or mild, but serious illness is possible. P. rufescens is rare in North America. This parasite has a similar life cycle to M. capillaris. Infection can cause diarrhea, weight loss, mucopurulent nasal discharge, elevated respiratory rate, and increased respiratory sounds.

Diagnosis of lungworm infections can be difficult. In addition to looking at clinical signs, a fresh fecal sample can be evaluated using the Baermann technique to identify larvae. Fecal samples should be fresh, and it’s best to collect it directly from the rectum. Damage from lungworm infections can lead to secondary infections. Your veterinarian can recommend an appropriate treatment based on the species of lungworm and also your sanctuary’s overall parasite management plan. M. capillaris may require higher doses or repeat treatment in order to kill immature worms. Back To Top


Mange is a skin condition caused by a number of species of very small mites, one of the most common types being Demodectic mange, which can be tough to eliminate, causing nodules filled with whitish material on their face, body, and udders. Mange presents as flaky and scruffy dandruff-like material on the skin as well as irritation. In more advanced cases, a sheep may lose some hair and the underlying skin might become thick and hard. Chorioptic mange is common in sheep, which begins behind their dewclaws and can spread up their legs and infect an entire flock quickly. Any suspected mange must be dealt with quickly. There are a number of medications available for mange, but you must make sure that they are sheep-safe, as some treatments could cause dangerous or lethal reactions. Treatments usually must be repeated over a long period of time in order to be effective, and topical treatments don’t work very well if a sheep hasn’t been very recently shorn.  Back To Top


Also known as acute pasteurella, hard bag, or blue bag, mastitis presents as inflammation to a bacterial udder infection, typically of Staphylococcus aureus or Pasteurella hemolytica. A ewe can have either acute mastitis or chronic mastitis, the latter typically undetected throughout a ewe’s life. Acute mastitis presents itself as discolored, dark, swollen, painful, and hot udders. An afflicted sheep will likely not want to walk, keep a rear foot held up, and might not be able to nurse any lambs. Mastitis can also be a secondary infection to sore mouth or OPP. Have a veterinarian evaluate the disease to determine appropriate treatment. It is treatable with antibiotics and anti-inflammatory drugs. Back To Top

Overgrown Hooves

While some sheep may naturally wear down their hooves through regular activity, many sanctuary sheep residents will need their hooves trimmed to prevent them from becoming overgrown. Typically, a sheep needs their hooves trimmed once every six to ten weeks, although older sheep and less active individuals (including those with Arthritis or OPP) may need more frequent trimming. Without regular trimming, the hoof wall will grow past the soft sole of the sheep’s foot and begin to curl over on their toe, which can create painful walking conditions and trap dirt tightly against the area between the sole and hoof wall. It will also begin to grow on the heel, creating an uneven surface for the sheep to walk on. If a sheep seems to have difficulty or reluctance walking, check out their feet. You might be far past due for a trimming by that point! If their hooves are significantly overgrown due to a lack of hoof maintenance, such as in the event of a newly rescued sheep, you may need to spread trimming out over a couple sessions. During the first trimming you can work to bring the hooves closer to a reasonable length and shape, and then come back a few days or a week later to do the finishing touches. If hooves are significantly overgrown or misshapen and you are unsure of how to address them, be sure to consult with your veterinarian for assistance. For more information on hoof trimming, check out our resource here. Back To Top

Ovine Progressive Pneumonia (OPP)

OPP is a slow-developing retroviral disease. Afflicted sheep will have difficulty breathing, lose weight, difficulty walking, paralysis, or mastitis. There are no treatments available for OPP beyond supportive measures to symptoms. Check out our article on OPP here. Back To Top

Parelaphostrongylus Tenuis (Meningeal Worm, Deer Worm, Brain Worm)

Parelaphostrongylus Tenuis (P. tenuis) is a parasitic worm whose natural host is the white-tailed deer. Goats, sheep, and camelids living in areas with white-tailed deer populations can also become infected by this parasite but are considered aberrant, or unnatural hosts. In these species, the parasite can cause significant issues not typically seen in white-tailed deer. There are two common manifestations of this parasitic infection- one presents as neurological issues and the other presents as skin issues. Neurological symptoms typically start with slight weakness or dragging of one or both hind legs, which can then develop into more severe ataxia and even hind limb paralysis. When presenting as a skin issue, symptoms include excessive itching and hair loss- typically in vertical stripes on the body. In rare instances an affected individual may develop a head tilt, walk in circles, have rapid eye movements, and have a hard time chewing. Presumptive diagnoses are made based on clinical signs and exposure risk- a fecal test will not detect P. tenuis in unnatural hosts. In some cases, examination of the cerebrospinal fluid may be recommended to help support the presumptive diagnosis, but this requires anesthesia and will not result in a definitive diagnosis. Absolute confirmation of P. tenuis can only be made during a post-mortem examination. Treatment typically includes a combination of multiple dewormers (often at higher and/or more frequent doses than when treating other parasites) and an anti-inflammatory medication. With prompt treatment, even sheep with more severe symptoms can make a full recovery, though some may have residual weakness for the remainder of their lives. If left untreated, paralysis and other neurological symptoms can become permanent. Back To Top

Pink Eye

The term “pink eye” is often used to describe infectious keratoconjunctivitis (IKC), but is sometimes used to describe non-infectious eye irritation resulting from dust, wind, hay, grass, or even intense sunlight. Infectious keratoconjunctivitis can be caused by various microorganisms, but the most common are Mycoplasma and Chlamydophila, especially Mycoplasma conjunctivae and Chlamydophila pecorum. Initial signs of infectious keratoconjunctivitis typically include squinting, watery eyes, and sensitivity to light. The affected eye(s) will be red and inflamed. As the condition progresses, they may develop thick discharge from the eye and the eye will become cloudy. In some cases, individuals may develop  a corneal ulcer or become temporarily or even permanently blind. Be sure to contact your veterinarian if one of your residents is showing signs of an eye issue, as prompt treatment is imperative. Because of the contagious nature of infectious keratoconjunctivitis, individuals showing signs of this disease, as well as those who have had direct contact with them, should be isolated from residents who have not been exposed. The disease can be spread via direct contact with infectious eye discharge but can also be spread via fomites and flies. Most causes of infectious keratoconjunctivitis in sheep and goats are bacterial and typically respond to treatment with tetracycline drugs. Your veterinarian will likely recommend treatment with an antibiotic eye ointment, after cleaning away any discharge or crusts, and may also prescribe systemic antibiotic treatment. In some cases your veterinarian may determine that more advanced treatments are necessary. While individuals are healing, it is important to protect them from eye irritants such as flies, wind, dust, and rough hay or pasture and to house them in a shady area. If the affected individual has become blind, they may need additional accommodations to keep them calm and comfortable, and you will want to make sure they are easily able to find food and water. Depending on the underlying cause, individuals can continue to spread infection for months after they have stopped showing signs of illness. Your veterinarian can recommend diagnostics to determine the cause and can make specific recommendations based on the results. Back To Top

Pizzle End Rot

Pizzle end rot, or ulcerative posthitis (sometimes also called “sheath rot”) mostly affects neutered males. It can be the result of a high protein diet, such as from grazing on lush pastures, but can also have a non-dietary cause. High protein intake causes the concentration of urea in the urine to increase. Bacteria that are part of the local flora, such as Corynebacterium renale, break down the urea, releasing excess ammonia. The ammonia then leads to irritation and ulceration of the prepuce. Once the skin is ulcerated, it is vulnerable to bacteria. Alternatively, if an individual’s hair or wool is long and covers their prepuce, it will become soaked with urine, resulting in irritation and an environment that is conducive to bacteria growth. Pizzle end rot manifests as inflammation and scabbing of the prepuce which can range from mild to severe, and in severe cases, the inflammation or scabbing can interfere with urination. Treatment of mild cases of pizzle end rot may only require cleaning and application of an antibacterial ointment. More severe cases may require veterinary involvement to evaluate the extent of the infection, debride the area, and prescribe systemic antibiotics and pain medication. During fly season, pizzle end rot can attract flies, resulting in fly strike, so be sure to monitor the area closely and take steps to protect the area from flies. It’s important to identify the underlying cause and consider what changes can be implemented to prevent the issue from recurring. If caused by long hair or wool, regularly shaving the area around the prepuce or frequently monitoring for signs of urine build-up and cleaning the area as needed can help prevent future issues. Back To Top

Sheep Nasal Bot Fly

Oestrus ovis, often called the sheep nasal bot, sheep nose bot, or simply the sheep bot, is found worldwide, but is most common in warm climates. The female fly deposits small (less than 2mm long), clear-white larvae in the host’s nostrils. These larvae then travel into the nasal cavities and sinuses where they develop over a period of 1-10 months before returning to the host’s nostrils. The host sneezes the mature larvae out of their nostrils, and larvae then drop to the ground to pupate in the soil. Adult flies attempting to deposit larvae will cause agitation in sheep who may be seen running in an attempt to get away from them or may keep their nose close to the ground. When flies are very active, sheep may huddle together in a circle with their heads facing inward and their noses down in an attempt to protect themselves. Other signs of agitation from adult O. ovis flies include head shaking, head rubbing, and foot stomping. The presence of larvae causes irritation to nasal passages and sinuses resulting in profuse nasal discharge which starts out as clear mucus and then becomes mucopurulent and may be tinged with blood. Other symptoms include sneezing fits, nose rubbing, and reduced airflow through the nares. O. ovis infestations can lead to bacterial rhinitis or sinusitis and, less often, interstitial pneumonia. Often, clinical signs are enough for your veterinarian to make a presumptive diagnosis, and response to treatment can help confirm. Ivermectin is effective against all stages of O. ovis larvae. Back To Top

Sore Mouth (Or, Orf)

Sore mouth is a highly contagious viral disease caused by a poxvirus that can affect both sheep and goats. It enters an individual through cuts or abrasions of their skin, and a nursing lamb with sore mouth could also spread the disease to their mother’s udder. Sore mouth symptoms include blister-like lesions in less hairy parts of the sheep’s body, often on their lips and mouth, with the blisters eventually becoming scabs. While adults with sore mouth typically continue eating, lambs with severe lesions may be reluctant to eat, in which case tube feeding may be necessary (this must be performed by a veterinarian or experienced caregiver to avoid potentially fatal consequences). There is no treatment for sore mouth, but the condition will usually resolve within 3-6 weeks barring any complications. In some cases, topical or systemic antibiotics may be recommended to address secondary bacterial infections. While this disease is most common in younger sheep and goats, adults can also become infected. Immunity after infection typically lasts 2-3 years, though after the initial infection, any subsequent infections tend to be less severe. Sore mouth can be spread to humans (though it manifests differently in humans, resulting in a single lesion, often on the hand), so it is imperative that anyone interacting with an individual with sore mouth wears gloves and other protective coverings. Sheep and goats with sore mouth could continue to spread the disease for weeks after lesions have healed, and individuals can be carriers of the disease (and spread it to others) without ever showing symptoms. Back To Top


One of many parasites that affect sheep, tapeworms can be diagnosed by finding yellow to white segments in a sheep’s feces. Sheep can become resistant to tapeworms relatively early on in life, so they do not pose too great of a health risk. Symptoms can include weight loss, sluggishness, and stomach discomfort. As a preventative measure, you should have a lab perform a fecal test on sheep every three months to ensure that they are not facing a dangerous parasitic infection and have appropriate treatment policies in place for infected sheep. Back To Top

Thiamine Deficiency

Thiamine deficiency is the most common cause of Polioencephalomalacia (PEM) in sheep and goats, though PEM can be caused by other factors such as sulfur toxicosis, salt poisoning, or lead poisoning. While kids and lambs who have not yet begun to ruminante rely on dietary thiamine (vitamin B1), once they start ruminating, healthy rumen microflora produce necessary levels of this vitamin. Because it is water soluble, long-term storage of thiamine in the body is not possible. Therefore, if something occurs that disrupts the normal production of thiamine or causes an individual to require higher levels of thiamine than normal, individuals can quickly become deficient. Rumen acidosis, certain plants, and some medications can put an individual at an increased risk of developing a thiamine deficiency. Symptoms develop quickly and include behavioral changes, blindness, incoordination, head pressing, backward arching of the neck so that the head is held high or bent towards their back, muscle tremors, seizures, and rapid eye movements. Thiamine deficiency is often diagnosed based on clinical signs, consideration of the specifics of the situation, and response to thiamine replacement therapy (though response to thiamine can not rule out another cause of PEM, so be sure to talk about this possibility with your veterinarian). Using diagnostic testing to confirm thiamine deficiency is difficult, and most labs are not equipped to run the specialized tests necessary. Be sure to contact your veterinarian immediately if one of your residents is showing signs of thiamine deficiency- prompt intervention is imperative. Concentrated thiamine injectable formulas are prescription only- we recommend you talk to your veterinarian about keeping some in stock at your sanctuary. B complex formulas that are available at supply stores contain much lower concentrations of thiamine. Even if you have access to thiamine, it’s still important to consult with your veterinarian to have the individual evaluated and discuss the best course of action. Depending on the severity of symptoms, your veterinarian may recommend the first dose of thiamine be administered intravenously, but adverse reactions are possible, so this should be done by your veterinarian. They may also recommend an NSAID or steroid treatment, and supportive care may also be necessary. Back To Top

Upper Respiratory Infection

There can be a variety of different illnesses and parasites that can affect a sheep’s breathing, nose, windpipe, and lungs. Symptoms of an upper respiratory infection include coughing, sneezing, nasal discharge, increased body temperature or fever, and loss of appetite. If you suspect a sheep may have an upper respiratory infection, it’s important to get an immediate veterinary consultation to determine its cause as some infections are considerably more dangerous and harder to treat than others. Back To Top

Urinary Calculi

Urolithiasis, or the formation of urinary calculi (stones or crystals) in the urinary tract, tends to be more common in goats, but can affect sheep as well. While both males and females can develop urinary calculi, males are more likely to develop urinary blockages as a result. Urinary calculi often form as a result of dietary issues. Struvite and apatite stones are most commonly seen in sheep eating diets high in grain concentrates, while calcium carbonate stones are more common in sheep eating diets containing lots of legumes. Be sure to talk with your veterinarian about the risks associated with your region and pasture/ forage make-up, because there are other types of stones that can be caused by eating plants containing high levels of certain compounds (such as silica) that may be common in your region. One of the more common causes of urinary calculi is an imbalance of calcium-to-phosphorus in their diet. Your veterinarian may have specific recommendations regarding what ratio is best for your residents, but generally, you should strive for a 2:1 calcium-to-phosphorus ratio. To help prevent urinary calculi, avoid feeding cereal grains (for example oats and corn), legumes (alfalfa and clover), and grain concentrates as much as possible.

While urinary calculi can develop anywhere in the urinary tract, they can result in a full or partial obstruction when located in the urethra. Male sheep neutered at a very young age have narrower urethras than those neutered when they are closer to 5 months old and are, therefore, more prone to urinary obstruction if they develop stones. We recommend having a discussion with your veterinarian regarding the best age at which to neuter your male sheep residents, specifically asking about the increased risk of urinary blockages in lambs neutered at a younger age.

Signs of a urinary blockage include straining to urinate, posturing as if to urinate but not actually doing so, head pressing, lethargy, inappetance, and signs of pain such as vocalizing, kicking at their belly, and teeth grinding. This is a very painful condition, but some individuals will mask their pain until they are no longer able to do so; therefore, it is important to catch the more subtle signs of concern. If you ever have concerns that a resident may have a urinary blockage, as long as they are currently stable and alert, you can spend time watching to see if they are able to urinate. If they seem to struggle or strain to urinate, have bloody urine, are seen dribbling only a small amount of urine at a time, or have crystals or sandy deposits on the hair around their prepuce, these are signs of concern. If you suspect a urinary blockage, contact your veterinarian immediately- if left untreated, urinary blockages can result in bladder rupture and, ultimately, death. Because surgical intervention is often required, we strongly recommend a sheep with a suspected urinary blockage be hospitalized as soon as possible. However, in the case of a partial obstruction, if the individual is still passing some urine and is up and alert, your veterinarian may recommend evaluating the individual on-site to determine if hospitalization is necessary.

In addition to avoiding foods that are known to cause urinary calculi, make sure the minerals you provide offer the proper ratio of calcium-to-phosphorus and consider having your water analyzed so you know the mineral composition. Be sure to look at their food sources, minerals, supplements, and water make-up holistically, working closely with your veterinarian to determine if changes need to be made. If an individual develops urinary calculi, be sure to have the stone analyzed so you know what type of stone you are dealing with and can take appropriate measures to prevent future issues, both for the individual and their flockmates. Back To Top

White Muscle Disease

White muscle disease is a degenerative disease that can be found in sheep and goats as well as other large mammals. It is caused by a nutritional deficiency of selenium, Vitamin E, or both and can affect heart muscle, skeletal muscle, or both. When the skeletal muscle is affected, a sheep may have an arched back, appear to be hunched over, and move very stiffly, though signs can be less obvious with the individual only having minor stiffness. Sheep with severe white muscle disease may not be able to stand or even sit upright. Lambs with white muscle disease may be too weak to nurse. When the heart is affected, the individual may have a fever, nasal discharge that is frothy and possibly blood-tinged, and will have difficulty breathing. Individuals with white muscle disease may also have a weakened immune system, making them vulnerable to other diseases. Selenium deficiency tends to be a regional issue with some areas having selenium deficient soil, which results in forages that are low in selenium. Adequate levels of vitamin E are typically found in fresh grass and legumes, but in dried hay vitamin E levels are low. Therefore, sheep who do not have ample opportunities to graze and are primarily fed hay are more at risk of developing a vitamin E deficiency. If you suspect one of your residents has white muscle disease, contact your veterinarian for evaluation and to discuss treatment options. Selenium and vitamin E levels can be assessed through blood testing, and treatment involves appropriate selenium and/ or vitamin E supplementation based on your veterinarian’s recommendations. While commercial products containing both vitamin E and selenium are available, additional vitamin E supplementation is usually necessary to treat a vitamin E deficiency because of the low levels found in many of these products. Follow your veterinarian’s recommendations. The best prevention is to ensure that sheep have access to nutritional sources that provide appropriate amounts of vitamin E and selenium throughout the year, routinely monitor your residents’ vitamin E and selenium levels through blood testing, and to provide appropriate supplementation as needed! Back To Top


Sheep Care | Farm Sanctuary

Sheep Diseases | University Of Minnesota

Anaplasmosis | Purdue University College Of Veterinary Medicine

Anaplasmosis | Merck Veterinary Manual

Overview of CAE | Merck Veterinary Manual

Meningeal Worm – Deer Worm – Brain Worm | Maryland Small Ruminant Page

UAA (Universal Animal Antidote) Gel | Drugs

Footrot | Veterinary Handbook For Sheep, Goats, And Cattle

Bloat In Small Ruminants | University Of Arkansas At Pine Bluff

Bottle Jaw | Veterinary Handbook For Cattle, Sheep & Goats

White Eyes And Bottle Jaw:  Are There Zebras? | American Consortium for Small Ruminant Parasite Control

Overview Of Copper Poisoning | Merck Manual Veterinary Manual

Eyelids | Merck Veterinary Manual

Polioencephalomalacia in Ruminants | Merck Veterinary Manual

Sheep Nose Bot | Merck Veterinary Manual

Overview Of Lungworm Infection | Merck Veterinary Manual

Lungworm | Worm Boss

Overview of Listeriosis | Merck Veterinary Manual

Listeriosis In Sheep And Goats | Michigan State University Extension

White Muscle Disease In Sheep And Goats | Michigan State University Extension

White Muscle Disease In Small Ruminants | Ohio State University

Sheep And Goat Medicine, Second Edition (Non-Compassionate Source)

Common Diseases And Health Problems In Sheep And Goats | Purdue University (Non-Compassionate Source)

List Of Sheep Diseases | Sheep 101 (Non-Compassionate Source)

Some Diseases That Affect Sheep | Maryland Small Ruminant (Non-Compassionate Source)

Sheep Diseases | Raising Sheep (Non-Compassionate Source)

Barber’s Pole Worm | Worm Boss (Non-Compassionate Source)

Caseous Lymphadenitis Of Sheep And Goats | Merck Veterinary Manual (Non-Compassionate Source)

Bloat In Ruminants | Merck Veterinary Manual (Non-Compassionate Source)

Johne’s Disease | American Dairy Goat Association (Non-Compassionate Source)

Copper Toxicity In Sheep | Sheep & Goat (Non-Compassionate Source)

Deer Worm Factsheet | Cornell Sheep & Goat Program and Cornell Ambulatory Veterinary Services (Non-Compassionate Source)

Contagious Ecthyma – Commonly Known As Orf | Ontario Ministry Of Agriculture, Food, And Rural Affairs (Non-Compassionate Source)

Urolithiasis in Large Animals | Merck Veterinary Manual (Non-Compassionate Source)

Urolithiasis in Small Ruminants | American College Of Veterinary Surgeons (Non-Compassionate Source)

Grain Overload In Ruminants | Merck Veterinary Manual (Non-Compassionate Source)

Footrot In Sheep And Goats | Purdue Extension (Non-Compassionate Source)

Foot Rot Or Scald: Which Is It? | University Of Maine Cooperative Extension (Non-Compassionate Source)

Contagious Footrot In Sheep | Merck Veterinary Manual (Non-Compassionate Source)

Aetiology, Risk Factors, Diagnosis and Control of Foot-Related Lameness in Dairy Sheep (Non-Compassionate Source)

Sheep Keds | Merck Veterinary Manual (Non-Compassionate Source)

Copper Toxicity In Sheep | Maryland Small Ruminant Page (Non-Compassionate Source)

Contagious Keratoconjunctivitis (Pinkeye) | Maryland Small Ruminant Page (Non-Compassionate Source)

Blowfly Strike (Cutaneous Myiasis, Maggots) | NADIS Animal Health (Non-Compassionate Source)

Polioencephalomalacia | Michigan State University (Non-Compassionate Source)

Pizzle Rot In Sheep | Ontario Ministry Of Agriculture, Food, And Rural Affairs (Non-Compassionate Source)

Enzootic Posthitis And Vulvitis In Sheep And Goats | Merck Veterinary Manual (Non-Compassionate Source)

Large Animal Internal Medicine 5th Edition | Bradford P. Smith (Non-Compassionate Source)

Overview of Bluetongue | Merck Veterinary Manual (Non-Compassionate Source)

Sheep Lice | Prime Facts (Non-Compassionate Source)

Lice | Sustainable Control Of Parasites (Non-Compassionate Source)

Sheep Lice Spread And Detection | Government Of Western Australia (Non-Compassionate Source)

Lice In Sheep And Goats | Merck Veterinary Manual (Non-Compassionate Source)

Biology Of Sheep Lice (Bovicola ovis) | Lice Boss (Non-Compassionate Source)

Sheep Lice | Parasitipedia (Non-Compassionate Source)

Clostridial Diseases | Cornell University College Of Veterinary Medicine (Non-Compassionate Source)

CDT Vaccinations | Maryland Small Ruminant Page (Non-Compassionate Source)

Enterotoxemias | Merck Veterinary Manual (Non-Compassionate Source)

Listeriosis In Ruminants And Human Risk | Purdue University College Of Veterinary Medicine (Non-Compassionate Source)

Non-Compassionate Source?

If a source includes the (Non-Compassionate Source) tag, it means that we do not endorse that particular source’s views about animals, even if some of their insights are valuable from a care perspective. See a more detailed explanation here.

Updated on June 15, 2021

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