Broken Mouth in Sheep

Broken mouth is the livestock term for a sheep with worn, shortened, loose, broken, or missing lower incisor teeth. Sheep do not have upper front incisors. Instead, the lower incisors press against a firm dental pad on the upper jaw to crop forage. When those lower teeth no longer line up well or are missing, grazing becomes much less efficient.

This problem is most common in older ewes, especially after they become full-mouthed adults. Over time, the incisors can spread, angle forward, wear down, or fall out. Some sheep can maintain weight for a while, especially on soft feed or lush pasture. Others lose condition quickly when pasture is short, stemmy, or dry.

Broken mouth is not always an emergency, but it matters because it affects how well a sheep can eat. In severe cases, poor intake can lead to weight loss, weak milk production, poor lamb performance, and reduced overall thrift. A mouth exam is also important because not every sheep with eating trouble has age-related dental wear.

The most common cause is normal age-related wear of the lower incisors. Sheep use these teeth every day to crop forage against the upper dental pad. As they age, the teeth can become elongated, spread apart, slant forward, loosen, chip, or fall out. This is why broken mouth is seen most often in older sheep rather than lambs or yearlings.

Forage conditions also matter. Sheep grazing short, coarse, sandy, stemmy, or drought-stressed pasture may wear their incisors faster. Breed, genetics, and individual mouth structure can also influence how long teeth stay functional. Some sheep keep useful teeth longer than others under the same management.

Not every abnormal mouth is true broken mouth. During tooth eruption, a younger sheep can briefly look uneven in the front teeth. Mouth lesions from contagious ecthyma, trauma, jaw misalignment, abscesses, or other oral disease can also interfere with eating. That is why a hands-on exam matters before assuming the problem is only old age.

Your vet usually diagnoses broken mouth with a physical exam and an oral exam. They will look at the lower incisors for wear, spacing, looseness, fractures, and missing teeth. They may also assess whether the incisors still meet the upper dental pad well enough for effective grazing.

A full evaluation often includes body condition scoring, feed history, age estimation from dentition, and a check for other reasons a sheep may be thin. That can include parasites, chronic disease, lameness, poor-quality forage, or oral lesions. In flock settings, your vet may recommend checking several animals to see whether the issue is isolated or part of a broader nutrition or management problem.

If the mouth looks abnormal in a way that does not fit routine wear, your vet may look for sores, swelling, jaw asymmetry, or infection. Additional testing is not always needed for straightforward cases, but it may be recommended if weight loss is severe or another disease is suspected.

You cannot fully prevent age-related dental wear, but you can reduce its impact with regular flock checks. Mouth and body-condition evaluation are especially helpful in older ewes before breeding, before lambing, and when pasture quality drops. Catching dental decline early gives you more options.

Good nutrition and pasture management matter. Sheep with access to appropriate forage and timely supplementation are more likely to hold condition even as teeth age. When possible, avoid forcing older sheep to rely on very short, coarse, or poor-quality pasture for long periods.

Selection and culling decisions also play a role. Sheep that lose dental function early may be less suitable to keep in the breeding flock. Many producers use dentition, body condition, and productivity together when deciding whether an older ewe should stay, receive special feeding, or leave the flock.

If a sheep suddenly has mouth pain, sores, swelling, or rapid weight loss, do not assume it is broken mouth. Have your vet examine the sheep so contagious or painful oral conditions are not missed.