Small Ruminant Parasite Management Dr. Niki Whitley The Cooperative Extension Program at North Carolina Agricultural and Technical State University [email protected]; 336-285-4684

Mention of products/services in this presentation is not an endorsement

Internal parasites • Internal parasites (mostly “gut” worms) are the primary health problem in goats/sheep • Goats and sheep are the most susceptible farm livestock to worms. • Worms are rapidly becoming resistant („immune‟) to dewormers. • We need to use every method we can to control worms not just dewormers alone

The worst one (for sheep and goats): Barberpole worm (Haemonchus contortus)

Female worm

Barberpole worms in a goat stomach

Pale eyelids in a sheep caused by a barberpole worm infection

Although there are other worms that can cause problems, the barberpole worm sucks blood and can kill sheep and goats very quickly. These worms cause anemia (blood loss) that can be seen as very pale eyelids (and bottle jaw – swelling under the jaw from loss of blood proteins). Barberpole worms do not normally cause scours/diarrhea.

Other worms Stomach and intestinal – scours, weight loss, poor doers •Trichostryonglus (Hair worm) •Nemtodirus (Thin-necked int. worm •Oesophagostomum (Nodular worm) •Trichuris (Whip worm) •Trichostrongylus axei •Ostertagia/Teledorsagia (Brown stomach worm) •Tape worms (only ones can “see” in feces) Others: liver fluke Not a lot in our area Deer worm – Meningeal worm

A parasite but not a worm - coccidia Coccidia

are different for each species (goats vs sheep vs cattle vs chickens, etc.) Eimeria Cause

spp.

scouring

Damage

lining of small intestines; can be permanent.

Treat

with amprolium (Corid) or sulfa drugs.

Prevent Be

with coccidiostats

careful with most drugs to treat or prevent this – they can be dangerous for horses (read labels!)

“Whole farm” approach to parasite management

• Understand parasites • Manage animals for their problem level • Create clean or safe pastures • Consider multi-species grazing • Use pasture rest and rotation • Consider alternative forages • Understand the role of nutrition • Could use zero grazing • Use genetic selection • Manage refugia (worms that will die when treated) • Use multiple measures of worm infection to decide who to deworm

Barberpole worm life cycle • Eggs hatch and grow inside manure to the infective stage larvae (L3) which comes out of the manure and can migrate up grass in dew drops/water. • Goats/sheep eat the grass with the L3 on it; In the stomach, the L3 mature (L4 and then to adults – both suck blood). Adult worms lay eggs and the eggs exit the animal in feces. •The L4 can go into a dormant (“sleeping”) state and survive in the animal a long time; the L3 outside on the pastures have a tough sheath (“skin”) and can live a long time (months). •They like to develop in warm (above 60 degrees F) and moist weather; pastures have lower worm problems in very cold and very hot/dry periods.

Most likely to get worms (more susceptible) • Just weaned up to yearlings • Orphans/bottle babies • Late-born (in worm season) • High-producing females • Just before/after giving birth • Thin animals • Geriatric sheep • Stressed/sick animals • Some breeds/not adapted • Goats

Less likely (more resistant) • Mature (adults) • Dry (not milking), open or early pregnant • Pets (“babied”/well fed) • Ones in good body condition (fat) • Some breeds or adapted/selected animals

Management • Clean areas, especially where eat; use feeders • Clean water • Avoid overgrazing • Do not graze below 2 inches (4+ best). • Time birthing to minimize parasite infections.

Pasture or forage management •

Rotate pastures to keep grazing height up and reduce worms on pasture

•

Rest 2-4 months for a pasture to be “cleaner”; 6 months best or use adult cattle or horses to clean pasture (they eat and kill goat/sheep worms but the worms do not hurt the horses or adult cattle)

•

New pastures, those rotated with crops/tilled or those “burned” are “clean”

•

Allow access to browse (like woods); 80% of worms are in the first 2 inches of forage

•

Forages with high tannin (like sericea lespedeza) have been shown to lower worm egg counts in feces of goats and sheep

Nutritional management Animals fed well and in better body condition are better able to handle or resist worms; this is especially important in late pregnancy Higher protein has been shown to reduce problems with worms; feeding some grain on pasture helps them fight worms Animals raised in confinement (barns) or dry lots with no access to grazing have few worm problems but could have coccidia problems if the feeders, waterers and barn areas are not kept clean.

Genetic selection •

Breeds vary in their resistance to gastro-intestinal parasites.

•

– Ability of host to resist infection – Measured by fecal egg counts

– Resistant breeds: Spanish, Myotonic, Kiko?

•

There is as much difference within breeds (“lines” of animals) as between breeds. – The 20-80 rule: around 20 percent of the herd/flock sheds 80 percent of the eggs onto pasture. – Parasite traits are moderately heritable (inherited); you can select for it! – Selection for parasite resistance will not adversely affect the growth of lambs or fertility of ewes.

Resistance

•

Resilience – Ability of host to withstand challenge and/or infection.

Slow down worm immunity to dewormers Refugia are worms that have not been exposed to deworming treatment. •

Do not deworm on a regular schedule.

•

Do not deworm all animals in a group.

•

Do not return treated animals to a clean pasture.

•

Give all anthelmintics orally at the proper dose (1.5-2x labeled dose for goats; talk to vet though).

•

Do not underdose.

•

Deworm new animals with anthelmintics Without refugia, worms will eventually be from at least two different chemical resistant to all anthelmintics. classes (one from all three for goats).

How do we decide who to deworm? Can use the FAMACHA© eyelid color scoring system to estimate anemia in sheep and goats (works for Barberpole worm only – maybe liver fluke)

1 2 3 4 5

Eye lid color

Packed cell volume

Treatment recommendation

Red

> 28

Optimal

No

Red-Pink

23-27

Acceptable

No

Pink

18-22

Borderline

?

Pink-White

13-17

Dangerous

Yes

White

< 12

Fatal

Yes

Body condition score can help decide if should deworm Spine

Transverse processes Fingers easily pass underneath

Muscle

Fat

Very little

No

1

Individually clearly felt, sharp, obvious

2

Form a smooth line with deep undulations

Smooth round edges

Concave

Very thin

3

Only slightly detectable undulations

Well covered have to push firmly to get fingers underneath

Not concave Not convex

Moderate

Cannot be felt at all

Maximally developed Convex

4 5

Only detectable with firm pressure Not detectable

Score:

1

2

3

4

Thick Very thick

5

Dag Scores (“Dingle-berries”, Dirty butts) Description

Treatment recommendation

0

No fecal soiling

No indication for treatment

1

Very slight soiling on edge of tail

No treatment

2

Slight soiling on edge of tail and on each side

Usually no treatment

3

Moderate soiling of tail and wool Dag formation

Consider treatment

4

Severe soiling extending far into wool/hair Severe dag formation

Treatment, crutching (trimming hair if long) recommended

5

Very severe watery diarrhea extending to hocks

Treatment and crutching (trimming hair if long) essential

Dag score

Other – bottle jaw, hair coat, energy level (?)

Fecal egg counts eggs per gram of feces • Indicate “potential” parasite burden in animal. • Indicate potential parasite problems on the pasture. • Use to determine if dewormers still work (fecal egg count reduction test). • Use to determine genetic differences (who to breed or who to sell).

Fecal egg counts-what do they mean?

Cautions with FEC • Many eggs look alike; normal regular fluctuations in output; output varies by season; eggs not evenly distributed in feces; species vary in output of eggs; inhibited larvae and L4‟s do not lay eggs; total eggs are often a mixture of species; diarrhea increases fecal moisture (may dilute eggs); not all parasites are pathogenic; possibility of human error

Three drug classes (in US) Look for the DRUG name on the label, not the name brand

1) Benzimidazoles Chemical name ends in '..dazole Fenbendazole, Albendazole, Oxybendazole

2) Nicotinics Levamisole, Morantel, Pyrantel

3) Macrocyclic lactones Chemical name ends in “ectin” a) Avermectins Ivermectin, Doramectin, Eprinomectin

b) Milbemycins Moxidectin

When using dewormers for goats Works best if given orally and at 1.5 to 2X the labeled dose (see deworming chart at www.acsrpc.org). Use sheep products first, then cattle or horse Consult your vet if the dewormer you want to use is not labeled for your animal species or if you are using more than the labeled dose

Benzimidazoles (BZD) Characteristics • • • • • •

White dewormers Water soluble Broad spectrum Wide margin of safety Efficacy against tapeworms Efficacy against liver flukes (albendazole) • Widespread resistance • Resistance is caused by dominant gene

Products

1) Fenbendazole SafeGuard®, Panacur® 2) Albendazole Valbazen® 3) Oxfendazole Synanthic®

Nicotinic agonists Characteristics

Products

• Levamisole

1)

– – – –

Clear drench Water soluble Broad spectrum of activity Not effective against arrested larvae – Narrower margin of safety – Resistance reported – Resistance is caused by a recessive gene

• Morantel and Pyrantel – Not effective against larval stages

Imidazothiaoles (IMID) a) Levamisole Prohibit®, Levasol®

2) Tetrahydropyrimidines (TETR) a) Morantel Goat Care 2X Positive Pellet b) Rumatel® c) Pyrantel Strongid®

Macrocylic lactones (ML) Characteristics • Broad spectrum • Wide margin of safety • Works against external parasites (ticks, flies, etc) • Lasts longer than other types • Widespread resistance/immunity, especially ivermectin

Products 1) Avermectins a) Ivermectin Ivomec® b) Doramectin Dectomax® c) Eprinomectin Eprinex ® LongRange™

2) Milbemycins a) Moxidecin Cydectin® Quest®

Keep your dewormers working • • •

•

•

Weigh animals to determine proper dose (or guess HIGH). Do not under-dose. Use proper oral dosing (drench) technique – give on top of tongue at the back of the mouth; make sure they swallow it. Fast animals prior to treatment. Give multiple anthelmintics (with vet input) –

•

Often they work together even if they do not work when given alone

Manage for refugia

How do you know if you have dewormer resistance (immunity) on your farm? 1) DrenchRite® Larval Development Assay • An in vitro test for the detection of resistance to all anthelmintic groups. – Need pooled fecal sample from 10 or more animals (minimum of 6); at least > 350 epg, >500 epg preferred • Animals with FAMACHA© scores of 3, 4, or 5 are more likely to have higher egg counts if barber pole worm is the primary parasite.

2) Fecal Egg Count Reduction Test (FECRT) • Comparison of before and after fecal egg counts – Benzimidizoles 7 days post-treatment – Levamisole 7 days post-treatment – Avermectins 14 days post-treatment

• Should include “control” (untreated) animals in testing.

The future of parasite control “natural” anthelmintics? • •     • • •

Copper oxide wire particles Copper sulfate (?) Garlic Pumpkin seed (variable) Diatomaceous earth Papaya Pine bark Sericea lespedeza (leaf meal) Others (commercial herbals)?

• Vaccine development – They are testing a promising vaccine in Australia – Likely will not come to US

• New anthelmintics – Zolvix® Monepantel (may be approved soon for sheep in US) – Startect® derquantel + abamectin

• EPDs/DNA tests

Parasite control requires an integrated/whole farm approach. Clean Pastures

Mixed species grazing

Proper Anthelmintic Use

Genetic selection Strategic deworming

Good management

Fecal egg counts FAMACHA©/ Selective Deworming

Good nutrition

Pasture Rest and Rotation Resistant breeds Zero grazing

Browsing

Manage anthelmintic resistance Alternative forages

Questions?