Pericarditis in Sheep: Inflammation Around the Heart

Pericarditis is inflammation of the pericardium, the thin sac that surrounds the heart. When that sac becomes inflamed, fluid, fibrin, or infectious material can build up around the heart. That pressure can make it harder for the heart to fill and pump normally, which may lead to weakness, poor exercise tolerance, breathing effort, and signs of right-sided heart failure.

In sheep, pericarditis is uncommon but serious. It may develop after bacteria spread through the bloodstream, extend from nearby chest infection, or follow penetrating trauma or a migrating foreign body. Merck notes that traumatic reticuloperitonitis is much less common in sheep than cattle because sheep are more selective eaters, but severe complications in ruminants can include pericarditis when a sharp object penetrates tissues and infection spreads.

Some sheep decline gradually over days to weeks. Others look sick very quickly, especially if infection is severe or fluid around the heart builds up fast. Because outward signs can resemble pneumonia or generalized illness, early veterinary assessment matters.

Pericarditis in sheep is usually caused by infection or inflammation spreading to the tissues around the heart. Bacteria may reach the pericardium through the bloodstream during septicemia, from a nearby lung or pleural infection, or from penetrating trauma to the chest. In lambs and adults, severe bacterial disease can sometimes seed multiple body sites, including the heart sac.

A less common but important cause is a migrating sharp foreign body. Merck describes traumatic reticuloperitonitis in ruminants as a condition caused by swallowed metal objects such as wire or nails that can penetrate the reticulum and, in severe cases, lead to peritonitis, pleuritis, or pericarditis. This pathway is much less common in sheep than in cattle, but it remains possible, especially in environments with baling wire, fencing fragments, or contaminated feed.

Other contributors can include chest wounds, extension from abscesses, and severe inflammatory disease in the thorax. In some cases, the exact source is not confirmed until necropsy. That is one reason your vet may recommend a broader workup rather than assuming the problem is only respiratory.

Diagnosis starts with a careful farm or hospital exam. Your vet will assess heart rate, breathing effort, temperature, hydration, mucous membranes, jugular veins, and whether heart sounds are muffled. They will also look for signs of pain, brisket edema, poor rumen fill, or concurrent pneumonia. In ruminants with penetrating foreign-body disease, Merck notes that decreased feed intake, pain, fever, and reduced rumen motility may be part of the picture.

Ultrasound is often the most useful next step because it can help identify pericardial fluid, fibrin, reduced heart motion, pleural effusion, or nearby inflammatory changes. Depending on the case, your vet may also recommend bloodwork, thoracic radiographs where practical, and sometimes fluid sampling or culture. If a foreign body is suspected, imaging and the history of exposure to wire or metal become especially important.

In some sheep, diagnosis is presumptive rather than absolute. That means your vet combines exam findings, imaging, response to treatment, and herd or environmental history to decide the most likely cause. If a sheep dies or is euthanized, necropsy can be very valuable for confirming the diagnosis and protecting the rest of the flock.

Prevention focuses on reducing the conditions that let infection or penetrating injury reach the heart. Keep feed areas, bedding, and pastures free of wire, nails, and metal fragments. Merck specifically notes that swallowed metallic objects in ruminants can come from fencing, cut tires used on silage covers, and damaged equipment. Even though sheep are less likely than cattle to ingest these items, environmental cleanup still matters.

Good flock health practices also help. Promptly address pneumonia, abscesses, wounds, and severe systemic illness so infection is less likely to spread. Isolate and examine sheep that are weak, losing weight, limping, or behaving abnormally. Merck’s sheep management guidance emphasizes removing abnormal animals from the flock for evaluation and investigating deaths whenever possible.

Work with your vet on practical prevention steps for your setup. That may include safer feed storage, regular fence and equipment checks, wound care protocols, and necropsy of unexplained deaths. In many flocks, the most effective prevention is not one single measure but a combination of cleaner environments, earlier detection, and faster response when a sheep looks off.