Early Signs of Illness in Lambs Raised for Meat

By Dr Duncan Houston

A lamb does not have to be lying in the corner of a paddock to be unwell. Sometimes the first clue is a quieter feeding response, a shorter stride or growth that has quietly stalled.

For meat lambs, these changes matter well before the planned sale date. A growing gap between lambs can point to problems with nutrition, parasites, infection or access to feed.

The aim is to notice a change from normal and investigate it early. Some diseases still develop rapidly or remain hidden, so observation works best alongside weighing, testing and a planned flock health programme.

Quick Answer

Early signs of illness in meat lambs include reduced suckling or feed intake, slower growth, isolation, altered droppings, stiffness and changes in breathing. Compare each lamb with its own previous performance and with similar lambs, then check feeding, water, movement and recent management changes. A newborn that is failing to suck needs prompt help, while collapse, difficult breathing, severe bloating or straining without passing urine require immediate veterinary attention.

1. Feeding changes before appetite disappears

Watch what lambs actually consume.

A lamb may still approach its ewe, feeder or trough while taking in much less than expected. Look for:

• Repeated attempts to suck without settling into a proper feed.

• Hanging back while other lambs eat.

• Picking at feed, then walking away.

• Dropping feed, drooling or showing soreness around the lips.

• A bottle-reared lamb taking less milk or sucking less strongly.

In suckling lambs, examine the ewe as well. Poor milk supply, mastitis, teat problems or rejection can leave a lamb hungry even when it appears to be with its mother. Twins and triplets need individual attention because one lamb feeding well does not confirm that its siblings are getting enough.

Scabby mouth can make sucking and eating painful, and affected teats may cause the ewe to resist feeding. Wear gloves when examining suspicious mouth lesions because orf can infect people. Do not pick off attached scabs.

In older lambs eating substantial solid feed, reduced cud chewing can support concern about reduced intake or digestive disease. This is not a useful adult-style health test for a newborn whose rumen is still developing.

2. Growth slows before the lamb looks thin

Regular liveweights are particularly valuable in growing lambs. A fluffy outline can hide a disappointing amount of lamb underneath.

Look for lambs that stop gaining, lose weight or progressively fall behind comparable animals. Assess tissue cover by hand as well, but prioritise growth records over adult ewe condition-score targets. MLA recommends growth-rate targets for lambs and weaners, with condition-score targets used for mature stock.

Calculate average daily gain:

Weight gained ÷ days between weighings.

For example, gaining 3 kg over 20 days equals 150 g per day. That is an example calculation, not a recommended target.

Compare similar ages, breeds, sexes and starting weights. Keep weighing conditions consistent because gut fill and fleece changes influence liveweight. Check individuals as well as the mob average, which can conceal a group of poor performers.

A growth check identifies a problem to investigate; it does not identify the cause.

3. The lamb becomes less involved with the group

Subtle changes include staying behind when others move, rising more slowly, spending longer lying down or standing hunched with little interest in feeding.

Observe before you approach. Mustering can temporarily make an unwell lamb move with the group and hide the behaviour that first caught your attention.

Some calling and searching can occur around weaning. However, persistent failure to eat, increasing dullness or worsening separation from the mob should not be dismissed as ordinary weaning stress.

4. Droppings change, or the tail becomes dirty

Watch for repeated soft droppings, watery scours, mucus, blood or increasing faecal staining beneath the tail.

In older suckling and weaned lambs, possible causes include intestinal worms, coccidiosis, dietary disturbance and bacterial infection. Grain-fed lambs also need assessment for grain overload. Appearance alone cannot reliably distinguish these problems.

Coccidiosis deserves particular attention in young lambs exposed to contaminated pens, feeding areas or heavily stocked ground. It can reduce growth and feed efficiency, sometimes without dramatic diarrhoea. Severe cases can cause painful straining, dehydration and bloody scours.

An ordinary worm drench should not be assumed to treat coccidiosis. Your vet may request specific faecal testing and interpret the findings alongside age, signs and management history.

5. Pale eyelids or swelling beneath the jaw

Barber’s pole worm feeds on blood and can cause anaemia without scouring. Warning signs include pale inner lower eyelids, reduced stamina, weakness and soft swelling beneath the jaw, often called bottle jaw.

These findings can mean disease is already significant. Seek veterinary advice promptly, and treat weakness or collapse as an emergency. Pallor and bottle jaw also have other causes, so neither confirms a worm diagnosis on its own.

Waiting for obvious signs misses part of the opportunity to prevent losses. Worm egg counts, interpreted through a regional parasite programme, can reveal a developing problem before the mob looks visibly affected.

6. Breathing changes while the lamb is resting

Observe breathing before handling, especially in warm weather.

Repeated coughing, nasal discharge, increased breathing effort or a lamb that tires unusually quickly deserve attention. Pneumonia can also present mainly as poor growth, with few obvious respiratory signs.

Dust, crowding, heat, transport and mixing groups can contribute to respiratory disease risk. A history of recent drenching matters because inhaled liquid can cause aspiration pneumonia.

Panting after movement in hot conditions has a different context from difficult breathing in a resting lamb. Provide shade and minimise disturbance, but do not assume that heat explains marked effort, open-mouth breathing or distress.

7. A shorter stride, stiffness or swollen joints

A lamb that repeatedly kneels to graze, trails behind or avoids bearing weight needs examination.

Foot problems and injuries are possible, but young lambs can also develop joint infections. Bacteria may enter through the navel or wounds, including around husbandry procedures. Arthritis can impair growth and lead to carcase trimming later.

Check the feet, joints and, in young lambs, the navel. Increasing swelling, heat, discharge or reluctance to move warrants prompt veterinary assessment. Do not wait for severe lameness before investigating.

8. Irritation, damp fleece or unusual attention to one spot

Tail flicking, stamping, repeated biting at the fleece or a dark, damp patch can indicate flystrike.

Part the fleece and inspect the skin promptly. A lamb can remain with the mob while a strike is developing. Confirmed flystrike needs immediate treatment under an appropriate treatment plan, with urgent veterinary help if the lamb is dull, weak, extensively affected or cannot be treated promptly.

Age changes how urgently you should act

Newborn lambs: Poor suckling, repeated crying, a hollow appearance, shivering or a fixed hunched stance can indicate inadequate intake or cold stress. Check the lamb and its ewe immediately. A weak, cold lamb may need a carefully sequenced warming and energy-support protocol based on age, temperature and swallowing ability. Simply putting it under a heat lamp may be insufficient.

Recently weaned lambs: Confirm that they can find water and are consuming enough suitable solid feed. Lightweight lambs often need separate nutritional management. Their requirements differ from those of heavier lambs, so one ration and one feeder arrangement may not suit the whole mob.

Finishing lambs: Pay particular attention after changes in grain access or ration composition. Reduced intake, diarrhoea, depression or unsteadiness following excess grain can signal acidosis and require urgent assessment.

How worried should you be?

What you notice	What to do
One mild change in an older lamb that remains bright, eating and moving normally	Check feed, water and the lamb now. Recheck during the next feeding or activity period that day. Seek advice if the change persists or worsens.
Repeated poor intake, declining growth, persistent scours, coughing, lameness or isolation	Contact your vet promptly, generally the same day when there are active illness signs. Arrange investigation rather than waiting for the next routine weighing.
A newborn failing to feed, or any lamb with pallor, painful swelling or marked dullness	Seek urgent assessment. Newborn weakness or coldness increases the urgency further.
Collapse, severe breathing difficulty, rapidly enlarging abdomen, neurological signs or inability to urinate	Contact a vet immediately. Minimise handling while help is arranged.

Several affected lambs, rapid deterioration or an unexpected death should trigger earlier investigation of the whole group.

What will your vet investigate?

The pattern helps narrow the possibilities.

One affected lamb may have a local injury, mouth lesion, feeding disadvantage or individual infection. Several lambs declining together raise concern about shared feed, water, parasites, infectious disease or environmental exposure.

Your vet may review weights, ration changes, vaccination and drench records, then examine affected lambs and suitable comparison animals. Faecal testing, blood tests, feed analysis or postmortem examination may be needed.

Trace-element deficiencies are possible in some regions, but poor growth alone is insufficient reason to give mineral injections. Diagnose the problem and assess the existing diet before supplementing; excessive supplementation can be harmful.

When is this an emergency?

Call your vet immediately for:

• A collapsed lamb, inability to stand or rapidly worsening weakness.

• A newborn that is cold, very weak or unable to suck.

• Severe breathing difficulty or open-mouth breathing at rest.

• Rapid abdominal swelling, severe pain or repeated grinding of the teeth with distress.

• Seizures, circling, apparent blindness or loss of coordination.

• Severe or bloody diarrhoea with weakness or dehydration.

• Repeated straining with little or no urine, particularly in ram and wether lambs.

Urinary obstruction can resemble constipation. Passing only a few drops does not exclude a dangerous blockage.

An unexpected death in a previously thriving lamb also warrants an immediate veterinary call about the remaining mob. Pulpy kidney disease can affect rapidly growing lambs on concentrates or lush pasture and may provide very little warning. Good appetite and rapid growth do not guarantee protection.

What should you do when a lamb seems slightly off?

1. Observe quietly. Note feeding, posture, breathing, movement and whether other lambs are affected. A short video before handling can help your vet.

2. Identify and record. Record the lamb’s identification, age, weight trend, onset of signs and recent changes in feed, paddock, weather or treatments.

3. Check access. Confirm that water is available, feeders work and the lamb can reach them. For suckling lambs, assess the ewe’s udder and actual nursing.

4. Examine safely. Check the mouth, feet, joints, skin and droppings. Take a rectal temperature if trained and equipped, then interpret it with your vet alongside the other findings.

5. Provide appropriate care. Use a clean, sheltered observation area when needed. Preserve the ewe-lamb bond where appropriate, and avoid unnecessary walking or stressful handling.

6. Set the next decision. Agree on treatment, sampling and a recheck time. Escalate immediately if feeding, alertness, breathing or mobility deteriorates.

Do not force milk or oral treatments into a weak lamb that cannot swallow safely. Stomach tubing requires training and an appropriate newborn protocol.

Common mistakes that delay recovery

• Calling every poor performer “wormy”. Drenching repeatedly can delay diagnosis of coccidiosis, pneumonia, pain or inadequate nutrition.

• Adding grain before investigating. A larger ration does not resolve every growth problem, and abrupt changes can create digestive disease.

• Judging by the mob average. The smallest or least competitive lambs can deteriorate while average growth looks acceptable.

• Assuming vaccination is complete after one dose. Follow the product’s primary course and booster requirements.

• Treating a sale date as a deadline for recovery. Assess the lamb’s welfare and fitness before planning transport.

Prevent setbacks before the finishing period

Build prevention around the stages when lambs are most vulnerable:

• Plan ewe nutrition, colostrum intake, lambing hygiene and shelter.

• Establish suitable solid-feed intake before weaning and support lighter lambs.

• Maintain clean water, adequate feeding space and gradual ration transitions.

• Use a regional worm-control programme, appropriate testing and treatments known to work on your property.

• Complete vaccinations according to the label and your veterinary plan.

• Reduce crowding, dust and unnecessary handling, and review purchased-lamb health information.

Use growth records alongside treatment outcomes and abattoir feedback. Findings such as pleurisy or arthritis may reveal problems that were difficult to detect in the paddock.

For broader management, see How to Optimise Lamb Production for Meat.

Before treated lambs leave the property

Check fitness for the entire intended journey. A lamb reaching its target weight does not make it fit to transport while ill or significantly lame.

Record treatments and confirm the applicable meat withholding period and export slaughter interval. These can differ. Clinical recovery does not mean the required interval has passed, and necessary treatment should not be delayed simply to preserve a sale date.

Can a lamb be sick while still eating?

Yes. Partial appetite and poor growth can accompany disease. Check how much the lamb consumes and whether its weight trend and behaviour have changed.

Does a lamb need to scour to have worms?

No. Barber’s pole worm can cause anaemia without diarrhoea, and other worm burdens can reduce performance before obvious signs develop.

Should I drench every lamb that is growing slowly?

Investigate first, unless your established veterinary parasite plan calls for immediate treatment. Review feed access, growth records, worm testing and drench effectiveness. Consider coccidiosis, respiratory disease and painful conditions as well.

Will a lamb catch up after being unwell?

Some recover and resume good growth, but catch-up is not guaranteed. The cause, severity and duration matter. Severe intestinal damage from coccidiosis, for example, can leave prolonged growth setbacks. Monitor recovery rather than assuming extra feed will restore the original sale schedule.

If you are unsure what a change in feeding, growth or behaviour means, ASK A VET™ can help you organise your observations and understand the next steps. For a weak newborn or a lamb showing emergency signs, contact your local vet immediately.