Internal Parasites in Sheep and Goats: Signs, FAMACHA and Dewormer Resistance

By Dr Duncan Houston

A sheep or goat can be dangerously anaemic from barber-pole worm while still passing firm, apparently normal faeces.

That is one reason internal parasites remain such a serious threat. The first visible signs may be pale eyelids, slower growth, bottle jaw, weakness or an animal lagging behind the group. In hyperacute infections, death may occur before prolonged weight loss or obvious diarrhoea is noticed.

The other major danger is treatment failure. Giving a dewormer does not prove that the animal has received an effective treatment. The product must be appropriate, given accurately and still capable of killing the parasites on that particular farm.

Quick Answer

Internal parasite control in sheep and goats should be based on individual clinical monitoring, quantitative faecal egg counts, farm-specific dewormer-efficacy testing, refugia, pasture management, nutrition and genetic selection.

FAMACHA© is designed mainly to identify anaemia associated with Haemonchus contortus, the barber-pole worm. Scores 4 and 5 generally require prompt treatment with a product known to work, while score 3 must be interpreted alongside age, species, pregnancy or lactation, body condition, growth, bottle jaw and diarrhoea. Animals with nearly white eyelids, collapse, severe weakness or laboured breathing need immediate veterinary care. (wormx)

Parasite Control at a Glance

Tool or finding	What it tells you	Main limitation
FAMACHA©	Estimates anaemia in an individual sheep or goat	Mainly useful for blood-feeding barber-pole worm
Five Point Check©	Assesses anaemia, bottle jaw, condition, diarrhoea and nasal signs	Findings are not specific to parasites
Quantitative faecal egg count	Estimates egg shedding and pasture contamination	Does not perfectly equal adult worm burden or clinical severity
Larval culture or molecular testing	Helps identify which strongyle species are present	Requires specialised laboratory testing
Packed cell volume and protein testing	Measures anaemia and protein loss	Does not identify the cause by itself
Faecal egg count reduction test	Tests whether a dewormer remains effective	Requires correct design, dosing, timing and analysis
Weight and body-condition records	Shows whether an animal is maintaining performance	Trends are more useful than one isolated measurement
Necropsy and worm counts	May directly confirm parasite species and burden	Requires a suitable recently dead or euthanased animal

A strong programme combines several of these tools. One eyelid score, one pooled faecal sample or one treatment response cannot answer every parasite question.

Which Internal Parasites Cause Disease?

“Worms” are not one diagnosis. Different parasites live in different areas of the gastrointestinal tract and cause different clinical patterns.

Parasite	Main location	Common clinical pattern
Haemonchus contortus	Abomasum	Anaemia, bottle jaw, weakness, weight loss and sudden death
Teladorsagia circumcincta	Abomasum	Reduced appetite, poor growth, diarrhoea and protein loss
Trichostrongylus species	Abomasum or small intestine	Dark diarrhoea, weight loss and protein-losing enteropathy
Nematodirus species	Small intestine	Sudden severe diarrhoea and dehydration, especially in lambs
Oesophagostomum species	Large intestine	Diarrhoea, weight loss and intestinal inflammation
Chabertia ovina	Large intestine	Soft faeces, mucus, blood streaks and poor condition
Coccidia	Intestine	Diarrhoea, straining, blood or mucus and poor growth in young stock
Liver fluke	Liver and bile ducts	Anaemia, bottle jaw, weight loss and sometimes sudden death

Coccidia are protozoa rather than worms, and ordinary gastrointestinal nematode treatments do not control them. Liver fluke also requires a different diagnostic and treatment strategy. (Merck Veterinary Manual)

Why Is Barber-Pole Worm So Dangerous?

Haemonchus contortus is a highly pathogenic blood-feeding worm that lives in the abomasum, the true stomach of sheep and goats.

Heavy infection removes red blood cells and plasma protein, causing:

• Progressive anaemia

• Weakness and exercise intolerance

• Reduced growth and production

• Submandibular oedema, known as bottle jaw

• Cardiovascular compromise

• Collapse

• Death

Female barber-pole worms are exceptionally fecund and may produce up to approximately 10,000 eggs each day. This allows pasture contamination to increase rapidly during suitable warm and moist conditions. (Merck Veterinary Manual)

Does Barber-Pole Worm Cause Diarrhoea?

Usually not when it is the only major parasite involved.

Pure Haemonchus infection commonly causes anaemia, oedema and weight loss without significant diarrhoea. If a pale animal is also scouring, consider a mixed worm burden, coccidiosis, enteric infection, dietary disease or another intestinal problem. (Merck Veterinary Manual)

This is a clinically important distinction. Waiting for diarrhoea before checking for barber-pole worm may mean waiting until the animal is already severely anaemic.

How Quickly Can It Become Fatal?

Haemonchosis may be hyperacute, acute or chronic.

After a very heavy challenge, an animal may die within approximately one week without a long period of obvious illness. Acute cases develop severe anaemia and oedema, while chronic cases progressively lose weight and condition. Late pregnancy and early lactation are important risk periods because immunity may temporarily weaken and dormant larvae can resume development. (Merck Veterinary Manual)

Are Goats More Susceptible Than Sheep?

Goats often require closer monitoring, particularly when forced to graze close to the ground instead of browsing.

A controlled 2024 comparison using the same H. contortus challenge found that infected goats developed higher faecal egg counts, lower packed cell volumes and greater worm establishment than infected sheep from the same local breed population. The result should not be converted into a universal rule for every goat and sheep breed, but it supports the practical observation that goats may struggle to develop and maintain effective immunity against gastrointestinal nematodes. (Nature)

Risk is particularly high in:

• Growing kids

• Pregnant and lactating does

• Goats maintained on short pasture

• Nutritionally compromised animals

• High-density grazing systems

• Warm, wet conditions

• Herds with multidrug-resistant parasites

A goat herd should not automatically inherit the sheep flock’s monitoring interval, treatment threshold or dose plan.

What Signs Should Producers Watch For?

Signs Associated With Barber-Pole Worm

Watch for:

• Pale pink or white conjunctivae

• Weakness

• Falling behind the group

• Reduced exercise tolerance

• Faster breathing

• Faster heart rate

• Poor growth

• Reduced milk production

• Bottle jaw

• Weight loss

• Collapse

• Sudden death

Signs Associated With Other Gastrointestinal Parasites

Possible signs include:

• Persistent diarrhoea

• Dark or loose faeces

• Faecal staining around the tail

• Poor growth

• Progressive weight loss

• Rough wool or coat

• Reduced appetite

• Low milk production

• Abdominal discomfort

• Protein loss

• Bottle jaw

Signs in Lambs and Kids

Young animals may develop:

• Sudden growth checks

• Profuse diarrhoea

• Dehydration

• Weakness

• Straining

• Rectal prolapse

• Dullness

• Rapid death

Nematodirus, coccidiosis, cryptosporidiosis, bacterial enteritis and nutritional disease should all be considered when young stock develop diarrhoea. (Merck Veterinary Manual)

How Worried Should You Be?

Lower Risk

The animal has:

• FAMACHA© score 1 or 2

• Normal appetite

• Expected growth

• Stable body condition

• Normal faeces

• No bottle jaw

• Normal behaviour

Action: Do not treat solely because other animals are being treated. Record the result and continue risk-based monitoring.

Moderate Concern

The animal has:

• FAMACHA© score 3

• A worsening score since the previous check

• Mild loss of body condition

• Slower weight gain

• Mild faecal staining

• A rougher coat

• A high-risk age or production stage

Action: Assess the whole animal. Treatment is more likely to be appropriate in lambs, kids, goats, pregnant or lactating animals and any animal losing weight, developing bottle jaw or showing diarrhoea. If treatment is deferred, recheck promptly, commonly within one week during high-risk conditions.

High Concern

The animal has:

• FAMACHA© score 4

• Bottle jaw

• Marked weight loss

• Reduced appetite

• Persistent diarrhoea

• Significant weakness

• Poor milk production

• Failure to respond to a previous treatment

Action: Treat promptly using a veterinarian-directed product or combination known to be effective on the farm. Assess hydration, nutrition and the possibility of another diagnosis.

Critical

The animal has:

• FAMACHA© score 5

• Nearly white conjunctivae

• Inability to stand

• Collapse

• Severe weakness

• Rapid or laboured breathing

• Very rapid heart rate

• Cold ears or limbs

• Severe dehydration

• Minimal responsiveness

• A rapid increase in group deaths

Action: Seek immediate veterinary care. Killing the worms does not instantly replace the blood already lost. Severely affected animals may require intensive supportive treatment as well as effective parasite control. (wormx)

What Is FAMACHA© Scoring?

FAMACHA© compares the colour of the lower conjunctival mucous membrane with a standardised five-colour card.

Score	Eyelid colour	General interpretation
1	Red	No visible anaemia
2	Red-pink	Acceptable colour
3	Pink	Borderline or moderate anaemia
4	Pink-white	Marked anaemia
5	Nearly white	Severe anaemia

The system allows producers to identify animals likely to benefit from treatment while leaving healthier animals untreated. This supports refugia and reduces unnecessary exposure of parasites to dewormers. (wormx)

Does Every Score of 3 Need Deworming?

No.

Score 3 is a clinical decision point rather than an automatic treatment instruction.

Treatment becomes more appropriate when the score-3 animal is:

• A lamb or kid

• A goat

• Pregnant or heavily lactating

• Losing weight

• Failing to meet growth targets

• Developing bottle jaw

• Scouring

• Weak or dull

• Progressing rapidly from a previous score

• Grazing during a period of intense barber-pole transmission

A strong mature animal maintaining body condition and performance may sometimes remain untreated and be rescored soon under a farm-specific protocol.

The mistake I would avoid is treating every score of 3 simply because it feels safer. That approach removes much of the refugia benefit that makes selective treatment useful.

How Should FAMACHA© Be Performed?

Producers should complete approved training and use an authentic card.

Correct technique includes:

1. Examine the animal in good natural daylight.

2. Roll the upper eyelid over the eyeball.

3. Apply gentle pressure to the closed upper lid.

4. Pull the lower eyelid down to expose the conjunctival bed.

5. Compare the tissue directly with the card.

6. Check both eyes.

7. Use the more severe score if the eyes differ.

8. Round borderline results upwards rather than inventing half-scores.

Do not use a phone screenshot or a home-printed card. Screen brightness, printer ink and paper colour can materially alter the comparison. (wormx)

How Often Should FAMACHA© Scoring Be Performed?

Monthly scoring may be far too infrequent during peak transmission.

Current ACSRPC guidance recommends:

• Every two weeks during peak transmission when fewer than 10% of animals are scores 4 or 5

• Weekly when more than 10% of the flock or herd are scores 4 or 5

• Every three to four weeks outside the main transmission period when local risk is lower

• More frequent checks around lambing, kidding and other periods of increased susceptibility

The interval should shorten when rainfall, warmth, previous farm history or worsening group scores indicate rising risk. (wormx)

Calendar dates are a poor substitute for current conditions. Changing temperature and rainfall patterns may shift the timing and duration of transmission seasons, while extreme heat or drought can reduce free-living larval survival in other settings. The practical response is local monitoring, not assuming every farm now has identical year-round risk. (PubMed Central (PMC))

What Can FAMACHA© Not Tell You?

FAMACHA© does not:

• Diagnose every gastrointestinal worm

• Detect coccidiosis

• Diagnose liver fluke

• Measure egg shedding

• Measure pasture contamination

• Identify the exact worm species

• Determine whether the selected dewormer works

• Distinguish barber-pole anaemia from every other cause of anaemia

• Identify clinically resilient animals that shed large numbers of eggs

Animals with Teladorsagia, Trichostrongylus or Nematodirus may remain at FAMACHA© scores 1 or 2 while developing diarrhoea, weight loss or reduced production.

A clinically healthy animal with red eyelids may also have a high faecal egg count. That animal is resilient, meaning it tolerates infection, but it is not necessarily resistant, meaning it suppresses worm establishment and egg output.

What Is the Five Point Check©?

The Five Point Check© expands the clinical assessment beyond eyelid colour.

It evaluates:

1. Eye: FAMACHA© score and anaemia

2. Jaw: bottle jaw or submandibular oedema

3. Back: body condition

4. Tail: diarrhoea and faecal staining

5. Nose: nasal discharge, including possible nasal bots or respiratory disease

This framework helps detect animals that may require investigation or treatment despite a reasonable FAMACHA© score. It also highlights non-parasitic disease that may otherwise be mistaken for worms.

What Else Can Look Like a Parasite Problem?

Finding	Important alternative explanations
Pale eyelids	Liver fluke, external blood loss, sucking lice, coccidiosis, chronic inflammation or nutritional disease
Bottle jaw	Barber-pole worm, liver fluke, Johne’s disease, malnutrition or another protein-losing condition
Diarrhoea	Coccidiosis, Nematodirus, bacterial enteritis, cryptosporidiosis, dietary disease or toxins
Poor growth	Inadequate nutrition, coccidiosis, respiratory disease, dental problems or social competition
Progressive weight loss in goats	Parasites, Johne’s disease, dental disease, chronic infection or cancer
Persistent anaemia after treatment	Resistance, underdosing, reinfection, liver fluke, lice or another blood-loss disorder
Coughing	Lungworm, bacterial pneumonia, viral disease or environmental irritation
Poor milk production	Parasites, inadequate nutrition, mastitis, systemic disease or poor water access

Repeatedly deworming an animal that remains anaemic or unthrifty may delay the correct diagnosis while applying further resistance pressure.

What Is the Role of Faecal Egg Counts?

Quantitative faecal egg counts can answer several different questions.

How Much Egg Contamination Is the Group Producing?

A group or pooled count estimates egg shedding onto pasture.

It does not perfectly measure disease severity. Worm species vary substantially in egg production, and immature worms may cause disease before they begin laying eggs.

Which Animals May Be More Resistant?

Individual counts help identify persistent high and low egg shedders within comparable management groups.

This information can support:

• Replacement selection

• Breeding decisions

• Identification of highly susceptible animals

• Estimation of pasture contamination

• Development of faecal egg count estimated breeding values

Parasite resistance has a moderately heritable component. Selecting animals with consistently lower faecal egg counts and acceptable performance can reduce long-term reliance on medication. (wormx)

Did the Dewormer Work?

A faecal egg count reduction test compares egg counts before and after treatment in the same identified animals.

Field protocols often collect post-treatment samples approximately 10 to 14 days later, but the correct interval depends on the drug, parasite population and laboratory protocol. AASRP recommends testing an adequate group, commonly at least 10 animals, rather than judging farm resistance from one animal.

The old shortcut of declaring resistance whenever reduction is below 95% is too simplistic. The current WAAVP guideline considers test design, counting method, sample size, statistical uncertainty and confidence intervals when classifying a parasite population as susceptible, resistant or inconclusive. (waavp)

When Is This an Emergency?

Seek immediate veterinary care when a sheep or goat has:

• Nearly white conjunctivae

• Collapse

• Recumbency

• Severe weakness

• Open-mouth or markedly laboured breathing

• A very rapid heart rate

• Cold ears or limbs

• Inability to eat or drink

• Severe dehydration

• Major bottle jaw combined with weakness

• Profuse or bloody diarrhoea in a lamb or kid

• Sudden deterioration after treatment

• Multiple deaths or down animals within the group

Do not force an oral drench into an animal that cannot hold its head up or swallow normally. Aspiration can add severe pneumonia to an already critical condition.

What To Do Right Now

1. Examine the Whole Group

Do not assess only the most visibly affected animal.

Record:

• Individual identification

• FAMACHA© score

• Body condition

• Body weight or growth

• Bottle jaw

• Faecal consistency

• Appetite

• Production stage

• Previous treatments

A cluster of worsening scores changes the required monitoring interval and may indicate that the entire pasture group is under increasing challenge.

2. Decide Which Clinical Pattern Fits

Ask:

• Is anaemia the dominant sign?

• Is diarrhoea the dominant sign?

• Are only lambs or kids affected?

• Are pregnant or lactating females involved?

• Did the problem follow warm rain?

• Has the group recently changed pasture?

• Did the current drug work the last time it was formally tested?

• Could liver fluke or coccidiosis be involved?

3. Collect Diagnostic Samples Before Treatment Where Practical

Pre-treatment samples are valuable when planning a faecal egg count reduction test.

Do not delay life-saving treatment in a collapsed or severely anaemic animal merely to produce a perfect research-quality sample.

4. Weigh Before Dosing

Do not estimate weight by looking across the pen.

Use accurate scales and:

• Weigh individual animals or divide them into suitable weight groups

• Dose according to veterinary and product guidance

• Calibrate the drench gun

• Confirm the product concentration

• Use the correct route

• Ensure the full dose is swallowed

• Record meat and milk withdrawal periods

Do not automatically copy sheep instructions into goats. Product approval, dose requirements and withdrawal implications vary between species, drugs and jurisdictions.

5. Support Severely Affected Animals

A weak, anaemic animal should not be forced to walk long distances or compete aggressively for food.

Provide:

• Protection from extreme weather

• Easy access to water

• Palatable forage

• An appropriate nutritional ration

• Minimal handling stress

• Veterinary-directed supportive treatment

• Frequent reassessment

An animal may remain pale after effective treatment because replacing lost red blood cells takes time. Continued deterioration should trigger investigation for resistance, reinfection, poor nutrition or another diagnosis.

6. Confirm Efficacy

Arrange post-treatment faecal egg counts according to the drug-specific protocol.

Do not continue repeating the same treatment merely because the product has been used successfully in previous years.

How Are Internal Parasites Treated?

Treatment should target animals likely to benefit and use a drug or drug combination expected to remain effective on that farm.

The plan should consider:

• Parasite species

• Disease severity

• Previous efficacy testing

• Animal species

• Age and production stage

• Body weight

• Product approval

• Route of administration

• Meat and milk withdrawal

• Local resistance patterns

In areas with substantial multidrug resistance, full-dose combination treatment using more than one active class may be appropriate under veterinary direction. Do not mix commercial products in one container unless the combination is specifically formulated and authorised. Each component must be dosed correctly, and efficacy still needs to be checked afterwards.

Anthelmintics are only one part of treatment. Severe anaemia, dehydration, hypoproteinaemia, diarrhoea and malnutrition require their own supportive management.

Why Is Dewormer Resistance So Serious?

Resistance occurs in the parasite population, not in the sheep or goat.

Worms carrying resistance traits survive treatment and reproduce. Repeated exposure increases the proportion of resistant worms in later generations.

Selection pressure becomes stronger when:

• Every animal is treated repeatedly

• Animals are underdosed

• Products are given incorrectly

• The same ineffective product continues to be used

• Treatments are given when parasite challenge is low

• Animals are treated before moving to low-contamination pasture

• Resistant worms are imported with new stock

• Long-acting products expose several larval generations to declining drug concentrations

Anthelmintic resistance is now widespread in small-ruminant nematodes, and selective treatment strategies are recommended to slow further loss of efficacy. (Merck Veterinary Manual)

What Is Refugia?

Refugia is the part of the parasite population not exposed to the dewormer.

It includes:

• Worms inside untreated animals

• Eggs and larvae already on pasture

• Developmental stages not affected by the chosen treatment

These susceptible parasites can breed with resistant survivors, reducing the proportion of resistance genes in the next generation.

Treating every animal and immediately placing the group onto pasture with very few susceptible larvae can create intense selection pressure. Most of the eggs subsequently deposited may come from resistant worms that survived treatment.

Preserving refugia does not mean leaving sick animals untreated. It means identifying healthy, productive animals that do not currently need medication. (Merck Veterinary Manual)

Should Dewormer Classes Be Rotated?

Do not rotate classes according to an arbitrary calendar.

Blind rotation may expose the parasite population to several partially effective classes without identifying which product actually works.

Drug selection should be based on:

• Farm efficacy results

• Parasite species

• Clinical disease

• Previous treatment history

• Product approval

• Withdrawal periods

• Veterinary advice

Strategic combinations may be valuable in some resistant populations. They should not be used as a substitute for diagnosis, accurate dosing or post-treatment testing.

How Can Pasture Management Reduce Parasite Exposure?

Pasture management can lower exposure, but it rarely eliminates internal parasites by itself.

Avoid Grazing Too Close

Most infective larvae remain within the lower portion of the pasture canopy.

Preventing sheep and goats from repeatedly grazing below roughly 4 to 6 inches can reduce larval ingestion. Goats allowed to browse taller vegetation may encounter fewer infective larvae than goats forced onto short, heavily contaminated pasture. (University of Minnesota Extension)

Do Not Rely on One Fixed Rest Period

A rule such as “rest every pasture for three months” is too rigid.

Larval survival depends on:

• Temperature

• Rainfall

• Humidity

• Shade

• Forage density

• Parasite species

• Season

• Soil and pasture conditions

A 90 or 120-day rest may reduce risk in one climate while remaining inadequate or unnecessarily long in another. Use local conditions, pasture history and monitoring rather than one universal number. (University of Missouri Extension)

Use Lower-Risk Pasture for Vulnerable Animals

Reserve the safest grazing for:

• Young lambs and kids

• Lactating females

• Recently weaned animals

• Animals recovering from parasitism

• Groups with known susceptibility

Lower-risk options may include:

• Hay or silage regrowth

• Annual forage crops

• Browse

• Newly established pasture

• Land previously grazed by cattle or horses

Use Multispecies Grazing Correctly

Cattle and horses do not share most of the important sheep and goat gastrointestinal nematodes. Grazing them together or sequentially may reduce the density of small-ruminant infective larvae.

Sheep and goats do share many important parasites, including H. contortus. Alternating sheep and goats does not provide the same parasite break and may increase pressure on susceptible goats. (University of Minnesota Extension)

Manage High-Risk Congregation Areas

Larval exposure may be particularly intense around:

• Water troughs

• Feeders

• Shade trees

• Shelters

• Gateways

• Small handling pens

• Damp, overgrazed areas

Move feeders and water points where practical, avoid severe overstocking and prevent animals from grazing contaminated forage immediately around these areas.

Does Better Nutrition Help?

Adequate energy, protein and minerals support:

• Immune function

• Red-cell production

• Tissue repair

• Albumin production

• Growth

• Lactation

• Recovery from blood loss

Good nutrition improves resilience, meaning an animal can maintain health and performance more effectively during parasite challenge.

It does not reliably remove an established adult worm burden. Protein supplementation cannot replace an effective dewormer in a severely anaemic animal.

Review:

• Forage quality

• Energy balance

• Protein supply

• Trace-mineral status

• Pregnancy and lactation demands

• Stocking density

• Access to feed

• Competition within the group

Do not begin high-dose copper or iron simply because an animal appears pale. Sheep are particularly susceptible to copper toxicity, and anaemia has several possible causes.

Can Tannin-Rich Forages Reduce Parasites?

Certain condensed-tannin forages can contribute to an integrated control programme.

Sericea lespedeza has reduced faecal egg shedding and other parasite measures in several sheep and goat studies. Results vary with:

• Tannin concentration

• Plant form

• Proportion of the diet

• Intake

• Parasite species

• Animal class

• The rest of the ration

Tannin-rich forage should be considered an adjunct rather than a replacement for monitoring or clinically necessary treatment. Excessive tannin can also reduce palatability and nutrient availability. (wormx)

What About Nematode-Trapping Fungi?

Duddingtonia flagrans spores can pass through the gastrointestinal tract and germinate in fresh faeces.

The fungus produces structures that trap and kill developing nematode larvae before they migrate from the faecal mass onto pasture. This may substantially reduce future pasture contamination when animals consume the product consistently under suitable conditions.

It has no direct anthelmintic effect on the adult worms already living inside the sheep or goat. An anaemic animal still requires appropriate assessment and treatment. (Goats and Sheep)

Can Genetic Selection Reduce Reliance on Dewormers?

Yes.

Resistance to gastrointestinal nematode infection is moderately heritable. Animals with consistently lower faecal egg counts can pass some of that advantage to their offspring.

Useful selection information includes:

• Individual faecal egg counts

• FAMACHA© history

• Number of treatments required

• Growth under parasite challenge

• Body condition

• Reproductive performance

• Faecal egg count estimated breeding values

Breed averages can provide useful context, and some hair-sheep populations perform favourably under parasite challenge. Individual records remain more important than breed labels. Susceptible animals exist in every breed. (wormx)

How Should New Animals Be Quarantined?

Purchased sheep and goats may introduce resistant worms even when they look healthy.

A veterinarian-designed quarantine programme may include:

• Separate housing and grazing

• Pre-treatment faecal egg counts

• Strategically selected treatment or combinations

• Correct dosing

• Holding animals off the home pasture temporarily

• Post-treatment efficacy testing

• Investigation for liver fluke and other regional parasites

• Continued monitoring before joining the main group

SCOPS advises that every incoming sheep or animal returning from grazing away should be considered a potential source of resistant parasites and other infectious disease. (SCOPS)

Common Internal-Parasite Mistakes

Treating Every Animal on a Calendar

This removes refugia and exposes the entire parasite population to selection pressure.

Using FAMACHA© for Every Parasite

Red eyelids do not exclude worms that cause diarrhoea, protein loss and poor growth.

Scoring Only Monthly During Peak Transmission

Susceptible animals may deteriorate before the next scheduled check.

Treating Every Score of 3 Automatically

Score 3 requires interpretation of the whole animal and current farm risk.

Estimating Body Weight

Underdosing increases the chance that resistant parasites survive. Overdosing certain products can be unsafe.

Rotating Drugs Blindly

Changing classes without efficacy testing is not resistance management.

Assuming a High Egg Count Always Means Severe Disease

Egg output and clinical impact are related imperfectly.

Assuming a Low Egg Count Excludes Disease

Immature worms and some low-fecundity parasites may cause serious illness before or without a high count.

Alternating Sheep and Goats To Break the Cycle

They share many of the same economically important worms.

Treating Every Animal and Moving Immediately to Clean Pasture

This may allow resistant survivors to dominate contamination of the new pasture.

Assuming Nutrition, Tannin Forage or Fungi Are Dewormers

These tools can support resilience or reduce future pasture contamination. They do not replace emergency treatment of a clinically affected animal.

Continuing a Product Because It Worked Last Year

Resistance status changes. Test it.

A Practical Farm Parasite-Control Plan

Before the Main Risk Period

1. Review previous faecal egg counts and treatment results.

2. Identify which products still work.

3. Train staff in FAMACHA© and the Five Point Check©.

4. Calibrate scales and drench equipment.

5. Identify high-risk pasture and vulnerable groups.

6. Review nutrition and stocking density.

7. Confirm the farm’s emergency veterinary plan.

During High-Risk Conditions

1. FAMACHA-score at least every one to two weeks.

2. Record body condition and growth.

3. Check for bottle jaw and diarrhoea.

4. Treat only animals meeting the farm’s clinical thresholds.

5. Investigate unexpected diarrhoea rather than assuming barber-pole worm.

6. Recheck clinically affected animals after treatment.

7. Shorten the monitoring interval if group scores worsen.

After Treatment

1. Confirm clinical improvement.

2. Perform post-treatment faecal egg counts.

3. Investigate inadequate reduction.

4. Do not repeat an ineffective treatment automatically.

5. Review reinfection and pasture exposure.

6. Record withdrawal dates.

At the End of the Season

1. Identify animals requiring repeated treatment.

2. Compare faecal egg counts within appropriate contemporary groups.

3. Review sires and replacement selection.

4. Analyse mortality, growth and treatment costs.

5. Adjust the next grazing and monitoring programme.

Frequently Asked Questions

How often should sheep and goats be FAMACHA-scored?

During peak barber-pole worm transmission, check approximately every two weeks. Recheck weekly when more than 10% of the group are scores 4 or 5. Lower-risk periods may allow intervals of three to four weeks. (wormx)

Does every FAMACHA score of 3 require deworming?

No. Score 3 is conditional. Consider age, species, pregnancy, lactation, growth, body condition, bottle jaw, diarrhoea and recent score progression.

Can FAMACHA© replace faecal egg counts?

No. FAMACHA© detects anaemia associated mainly with barber-pole worm. Faecal egg counts help assess egg shedding, pasture contamination, genetic resistance and treatment efficacy.

Should dewormers be rotated every few months?

No. Calendar rotation without efficacy testing may accelerate resistance to several classes. Select products using farm-specific results and veterinary guidance.

Does pasture rotation eliminate internal parasites?

No. Rotation can reduce exposure, but larval survival varies with climate, pasture and parasite species. It works best as one component of an integrated programme.

Final Thoughts

Internal parasites remain one of the most important threats to grazing sheep and goats, but routine blanket deworming is no longer a sustainable answer.

The most important points are:

1. Barber-pole worm causes anaemia and bottle jaw, often without diarrhoea.

2. Other gastrointestinal parasites commonly cause scouring and poor growth.

3. FAMACHA© is designed mainly for barber-pole worm.

4. Scores 4 and 5 require prompt treatment.

5. Score 3 requires clinical judgement.

6. Monthly scoring may be too infrequent during peak transmission.

7. Faecal egg counts do not replace clinical assessment.

8. A properly designed reduction test determines whether a drug still works.

9. Refugia helps preserve susceptible parasite genes.

10. Calendar deworming and blind drug rotation accelerate resistance.

11. Sheep and goats share many of the same parasites.

12. Cattle and horses are more useful alternative grazers.

13. Nutrition improves resilience but is not a dewormer.

14. Tannin-rich forages and nematode-trapping fungi are supplementary tools.

15. Genetic selection can reduce long-term dependence on medication.

16. Severe anaemia requires urgent supportive care as well as effective parasite treatment.

The most expensive mistake is assuming that administering a dewormer means treatment succeeded. The only useful product is one that reaches the animal at the correct dose and still kills the relevant parasites on that farm.

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ASK A VET™ can help organise FAMACHA© records, body weights, treatment dates, faecal egg counts, efficacy-test results and pasture history while producers work directly with their attending livestock veterinarian. A sheep or goat with white eyelids, collapse, severe weakness, profuse diarrhoea or breathing difficulty still requires immediate hands-on veterinary care.