White Muscle Disease in Sheep: Selenium Deficiency, Stiffness, and Sudden Weakness

Quick Answer
  • White muscle disease is a nutritional muscle disorder linked to low selenium, often with low vitamin E, and it affects both skeletal muscle and the heart.
  • Young lambs are most often affected. Signs can include stiffness, weakness, trouble standing, poor nursing, fast breathing, and sudden collapse or death.
  • See your vet immediately if a lamb is weak, cannot rise, breathes hard, or dies suddenly in a flock with known mineral deficiency risk.
  • Diagnosis often involves a physical exam, flock diet review, and bloodwork such as selenium status and muscle enzymes like AST, CK, or LDH.
  • Early treatment may help some lambs, but severe heart muscle damage can carry a guarded prognosis even with prompt care.
Estimated cost: $120–$900

What Is White Muscle Disease in Sheep?

White muscle disease, also called nutritional myodegeneration or stiff lamb disease, is a muscle disorder seen most often in lambs when selenium is too low and vitamin E may also be inadequate. These nutrients help protect muscle cells from oxidative damage. When levels are too low, muscle fibers can degenerate, especially in fast-growing young animals.

In sheep, the disease can affect skeletal muscles used for standing and walking, or cardiac muscle in the heart. That is why some lambs show gradual stiffness and weakness, while others may collapse or die suddenly. Merck notes that hind-end stiffness, an arched back, tucked-up flanks, pneumonia, and acute death can all occur.

Some lambs are born weak or fail to nurse well. Others look normal at birth and become affected over the next days to months. The exact pattern often depends on how deficient the ewe was during pregnancy, the selenium content of local soil and forage, and whether the flock receives an appropriate sheep-specific mineral program.

Symptoms of White Muscle Disease in Sheep

  • Stiff gait, especially in the hind limbs
  • Weakness or reluctance to stand and walk
  • Arched back and tucked-up flanks
  • Poor nursing or trouble suckling in newborn lambs
  • Muscle tremors, exercise intolerance, or rapid tiring
  • Fast breathing or respiratory distress if chest muscles are affected
  • Sudden collapse or sudden death from heart involvement

Mild cases may start as a stiff, awkward walk or a lamb that tires quickly. More serious cases can progress to inability to rise, poor nursing, breathing difficulty, or sudden death. See your vet immediately if a lamb is down, weak after birth, breathing hard, or if more than one lamb in the flock shows similar signs. White muscle disease can look like trauma, starvation, pneumonia, or other metabolic problems, so a veterinary exam matters.

What Causes White Muscle Disease in Sheep?

The main cause is selenium deficiency, sometimes combined with vitamin E deficiency. Selenium content in forage depends heavily on local soil, so some regions produce feeds that are naturally low in selenium. If pregnant ewes do not get enough selenium, their lambs may be born with low stores and develop disease early in life.

Vitamin E and selenium work together in muscle protection. A lamb may show signs when selenium is low, when vitamin E intake is poor, or when both are marginal. Merck describes white muscle disease as a degenerative disease of skeletal and cardiac muscle caused by deficiency of selenium and/or vitamin E.

Risk is often highest in newborn and fast-growing lambs, especially when the flock relies on unsupplemented hay, pasture, or home-mixed rations without a balanced sheep mineral. Flocks in deficient areas may see repeated cases unless the ewe nutrition program is corrected before lambing. Because too much selenium can also be toxic, supplementation should be planned with your vet or a flock nutrition advisor rather than guessed.

How Is White Muscle Disease in Sheep Diagnosed?

Your vet will usually start with the lamb's age, clinical signs, and flock history. A weak or stiff lamb from a flock in a selenium-deficient area raises concern, but diagnosis should not rely on appearance alone. Other problems, including starvation, joint infection, pneumonia, trauma, copper issues, and other nutritional or neurologic diseases, can look similar.

Testing often includes bloodwork to look for muscle damage and low selenium status. Merck notes that muscle enzymes such as AST and LDH increase with muscle injury, and nutritional myopathy references also include CK as a useful marker. Whole blood selenium or glutathione peroxidase activity can support the diagnosis, and liver testing may be used in some cases.

If a lamb dies, necropsy can be very helpful. White or pale streaking in skeletal muscle, diaphragm, or heart muscle is classic for this disease. A flock-level diagnosis may also involve reviewing the mineral program, feed sources, and whether ewes received appropriate supplementation before lambing.

Treatment Options for White Muscle Disease in Sheep

Spectrum of Care means you have options. Here are treatment tiers at different price points.

Budget-Conscious Care

$120–$250
Best for: Mild early cases in stable lambs that are still standing, nursing with help, and not showing major breathing or heart-related signs.
  • Farm-call or clinic exam
  • Assessment of lamb strength, hydration, nursing ability, and breathing
  • Targeted selenium-vitamin E treatment if your vet feels it is appropriate
  • Basic supportive care such as warming, assisted feeding, and reduced exertion
  • Review of current sheep mineral access and ewe ration
Expected outcome: Fair if caught early and muscle damage is limited. Response is less predictable if the disease has been present for several days.
Consider: Lower upfront cost, but limited testing means another condition could be missed. This approach may be less helpful in flocks with repeated losses or in lambs with severe weakness.
Most Common

Recommended Standard Treatment

$250–$500
Best for: Most suspected cases, especially when the diagnosis is uncertain, more than one lamb is affected, or the flock has a history of deficiency.
  • Full veterinary exam
  • Selenium and vitamin E treatment plan directed by your vet
  • Bloodwork for selenium status and muscle enzymes such as CK, AST, or LDH
  • Supportive care including fluids, nursing support, anti-inflammatory guidance when appropriate, and activity restriction
  • Flock-level nutrition review with a prevention plan for ewes and lambs
Expected outcome: Good to guarded depending on whether skeletal muscle alone is affected or the heart is involved. Lambs treated before they become recumbent often do better.
Consider: More complete and practical for flock management, but costs more than symptom-based care alone. Some lambs still have lasting weakness if muscle damage is advanced.

Advanced / Critical Care

$500–$900
Best for: Critically ill lambs, lambs with respiratory distress or suspected cardiac involvement, and flocks with sudden deaths or ongoing losses.
  • Emergency evaluation for down lambs or sudden severe weakness
  • Intensive supportive care such as IV or SQ fluids, oxygen support if available, and repeated monitoring
  • Expanded diagnostics to rule out pneumonia, septicemia, trauma, or other metabolic disease
  • Necropsy and flock investigation if deaths have occurred
  • Detailed ration and mineral reformulation for the flock with follow-up testing
Expected outcome: Guarded to poor in severe cardiac cases or when lambs are unable to rise. Flock prognosis improves when the underlying mineral program is corrected quickly.
Consider: Most intensive and informative option, but requires higher cost and may still not save lambs with major heart muscle damage.

Cost estimates as of 2026-03. Actual costs vary by location, clinic, and individual case.

Questions to Ask Your Vet About White Muscle Disease in Sheep

Bring these questions to your vet appointment to get the most out of your visit.

  1. Does this lamb's exam fit white muscle disease, or do you think another problem is more likely?
  2. Should we test whole blood selenium, glutathione peroxidase, or muscle enzymes in this lamb or in flock mates?
  3. Is the heart likely involved, and what signs would make this an emergency?
  4. What selenium and vitamin E products are safe for sheep, and what dose is appropriate for this lamb?
  5. Should pregnant ewes in this flock receive a different mineral or supplementation plan before lambing?
  6. Would you recommend testing feed, forage, or liver samples to confirm a flock-level deficiency?
  7. How can we prevent selenium deficiency without risking selenium toxicity?
  8. Which lambs or ewes in the flock should be monitored or treated next?

How to Prevent White Muscle Disease in Sheep

Prevention focuses on giving sheep the right amount of selenium and vitamin E for your region, forage base, and stage of production. Merck emphasizes that prevention is preferred because treatment may not fully reverse clinical signs once muscle damage has occurred. In many flocks, the most important step is a sheep-specific trace mineral program offered consistently, not an occasional block or a product designed for another species.

Pregnant ewes deserve special attention because lambs depend on maternal selenium status before birth. In deficient areas, your vet may recommend a pre-lambing supplementation plan, newborn lamb support, or both. Merck also notes that injectable vitamin E-selenium products may be used shortly after birth in deficient areas and that selenium-supplemented trace mineral mixtures can be useful when fed correctly.

Work with your vet to review feed tags, mineral labels, and local deficiency patterns. Cornell notes that sheep generally require about 0.10-0.20 mg/kg selenium in the diet, but more is not safer. Excess selenium can be toxic, so avoid mixing your own supplements unless your flock nutrition plan has been professionally reviewed. If your flock has had previous cases, ask about periodic testing of blood, liver, or feed so prevention is based on data rather than guesswork.

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