Parasite Management in Goats & Sheep
Internal Parasites - Specific focus on Barberpole worm
Notes from OSU Parasitology Seminars - August 2011
Finding a vet who specializes in small ruminants is stressed.
You can use the Find A Vet option at www.aasrp.org (American Association of Small Ruminant Practitioners)
Parasite Management = Pasture Management
All parasites are local. This means that every farm is different...every city or state is different - and you must understand that.
Life of the worm:
Eggs in manure can live for a few weeks under favorable conditions.
Moisture is required for egg survival - so extremely dry conditions can kill it.
Eggs also don't do well in freezing conditions (especially freeze - thaw - freeze)
Eggs can hatch as early as in as early as 48 hours and last as long as they don't have "killing" conditions.
Rain is often the "release" factor that causes a hatch.
Stage 1 & 2 larvae aren't very hardy and can die easily.
Stage 3 (L-3) larvae keep their stage 2 shell and gain their stage 3 shell as well and are therefore very hardy and therefore harder to kill.
Stage 3 (L-3) larvae are the INFECTIVE stage...this is when they climb a stalk to seek a host to eat them (2-4 inches off the ground max)
In good conditions the egg can hatch in 48 hours and go to stage 3 larvae (L-3) at a 4 day minimum.
What worms:
Nematodirus, Cooperia, Trichostrongylus, Telodorsagia (Ostertagia) - These worms will cause a goat / sheep to be unthrifty, a poor doer and cause diarrhea. They are not blood suckers and do not cause death.
Hemonchus Contortus (Barberpole) - This is the worst worm that we are dealing with. It is a voracious bloodsucker and can kill the animal. It is very small only about 1/2 inch long as "adult". A heavy infestation can remove 1/5 of the animal's blood in 24 hours.
Dewomers:
In sheep there are 3 classes of dewormer available by label:
Macrocyclic lactones - Ivermectin (Ivomec) and moxidectin (Cydectin)
Benzimidazoles - Valbazen
Levamisole
For goats were have by label:
Fenbendazole (Safeguard & Pancur) approved for non-lactating goats
Rumatel Medicated Premix 88 for lactating and non-lactating goats
Use of any other labeled for cattle or sheep is extra label and should not be used without vet prescription
Dewormers by Class
Avermectins
Brand Name: Ivomec, Double Impact, Top-line, Phoenectin Pour-on
Active Ingredient(s): ivermectin 1% (injectable) ivermectin 0.5% (pour-on)
Availability: OTC
Withdrawal: 35 days before slaughter
Indications: Control of internal and external parasites
Brand Name: Ivomec Plus
Active Ingredient(s): ivermectin 1% and clorsulon 10%
Availability: OTC
Withdrawal: 56 days before slaughter
Indications: Control of internal and external parasites including adult liver flukes
Brand Name: Dectomax
Active Ingredient(s): doramectin 1% injectable; doramectin 0.5% pour-on
Availability: OTC
Withdrawal: 35 days before slaughter for injectable; 42 days before slaughter for pour-on
Indications: Control of internal and external parasites
Brand Name: Eprinex (Ivomec)
Active Ingredient(s): eprinomectin 5mg
Availability: OTC
Withdrawal: No slaughter or milk withdrawal on cattle
Indications: Control of internal and external parasites
Notes: Used frequently in dairy goats(No milk withdrawal)
Milbymycin
Brand Name: Cydectin, Quest Equine Wormer
Active Ingredient(s): moxidectin
Availability: OTC
Withdrawal: No slaughter withdrawal on cattle
Indications: Control of internal and external parasites
Notes: Cydectin - this is the most effective wormer we have right now.
Benzimidazole (white dewormers)
Brand Name: Safe-guard, Panacur, Benzelmin
Active Ingredient(s): fenbendazole
Availability: OTC
Withdrawal: 8 days before slaughter
Indications: Control of internal parasites - Tapeworms
Notes: Most stomach and intestinal worms show resistance to fenbendazole products.
Extremely high safety margin.
Brand Name: Synanthic
Active Ingredient(s): oxfendazole
Availability: OTC
Withdrawal: 11 days before slaughter
Indications: Control of internal parasites
Brand Name: Valbazen
Active Ingredient(s): albendazole
Availability: OTC
Withdrawal: days before slaughter
Indications: Use Valbazen to control of internal parasites including adult liver flukes.
Notes: Do not use on does of breeding age that have been exposed to a buck, or those that are
bred. May cause abortion or birth defects.
From here on we will talk only of the Barberpole...
When are they worst (in OHIO):
From March to October
2 weeks prekid / lamb to 6 weeks post kid/ lamb
Worms start to become a problem for kids / lambs at approximately 6 weeks of age.
Around 7-9 months of age kids / lambs will begin to develop some immunity to some worms.
Just because your animals aren't sick and/or dying doesn't mean you don't have a worm problem.
Dewormer Resistance:
All programs that rely strictly on the use of chemical dewormers will eventually fail as a result of development of resistance.
The question is how soon it will happen to YOUR farm.
REFUGIA = That portion of a worm population that escapes treatment of a dewormer when used. This is a NEED to have for this worm. You want a certain % of worms left in the pasture (10-20%) while you treat the 80-90% that are in the animals...allowing for only unresistant worms to be ingested. Remember that your dewormer will not kill them all. You are not going to eliminate the worms - you must learn to live with them and treat them appropriately and treat only those that truly need it.
Once resistance is present on your farm it is likely to be a permanent situation. Resistance happens when worms have a frequent exposure to a drug.
A frequent cause of resistance is UNDER dosing.
How?
under estimating on weight (a scale is recommended to avoid this...weight tapes are not always accurate for all animals)
incorrect dose calculation
incorrect dilution of product
improperly calibrated or faulty equipment (always check dosing syringes...a leaking gasket on a drenching syringe can cause an underdose)
Remember that goats metabolize faster and therefor require a higher dosage to work - DO NOT UNDERDOSE!
Another problem is treating all animals and then moving them to a "safe" or "clean" pasture...as this allows them to carry resistant worms to the new pasture.
Unless you use one of the following methods that method won't work.
Options when using "clean" pasture method:
Pastures previously grazed by horses or cattle
Hayfield regrowth
Spring Planted annuals (tilling of soil will bury and kill the egg / larvae)
Crop aftermath (cornfield or other crop after harvest)
Please remember that if you have a resistance to ivermectin that the worms have the gene potential to develop resistance to moxidectin (Cydectin) too. So while Cydectin is more potent than Ivomec you need to be careful not to underdose.
Alternatives to preserve a REFUGIA:
Treat selectively with FAMACHA and body condition score; then move to rotational graze / browse
Leave heaviest 10-15% untreated, then move to rotational graze / browse
Treat all animals with a non-persistent dewormer and leave on contaminated pasture for 3-5 days
Treat lambs / kids, but not dams, if lambs / kids are not weaned
Treat thin and twin / triplet bearing dams only (this is the best option for dam treating)
Persistent Dewormers:
Ivomec (injected)
Dectomax (injected)
Cydectin (more persistent than Ivomec and Dectomax)
What does persistent dewormer mean?
It means that the drug stays in the tissue a longer time when it is injected. The drug settles into the fat of the animal.
Cydectin will stay in the tissues for 35 days post administration when given orally.
Things needed to UN-learn:
Treating of adult animals when there is no real need. DO NOT DO THIS....it causes resistance.
Need to implement a SMART DRENCHING PROGRAM
more info at http://scsrpc.org
Know the resistance status of the herd or flock
Sound pasture management
Keep resistant worms off the farm
Administer the proper dose
Utilize host physiology
Selective treatment - FAMACHA
Make sure when drenching that your drench pipe is in the BACK of the mouth to ensure the drug goes into the proper part of the stomach. Administering in the front of the mouth can lead to drug resistance due to the dewormer going into the wrong part of the stomach first.
DON'T BUY RESISTANT WORMS!
Quarantine new arrivals for 30-60 days
Deworm with 2 or even 3 classes of dewormers (make Cydectin one of them)
Perform a FEC to confirm no eggs are being passed
Expose to your farms worms post quarantine - put onto a contaminated field
Concept behind Selective Treatment:
Parasite numbers are not equally distributed in groups of animals.
20-30% of your animals are producing 75% of your worms
FAMACHA is highly recommended for selective treatment and is ONLY effective for Barberpole worm.
A note on bottle jaw:
If your sheep or goat has bottle jaw - diagnosis can be confirmed by pressing your thumb into the swollen area. If it is indeed bottle jaw the imprint will stay for 8-10 seconds. Bottle jaw is often a symptom of Barberpole infestation.
Body condition scoring was also discussed and may be an indicator of animals that may be harboring worms.
The Five Point Check for targeted selective treatment of internal parasites in small ruminants has been developed but is not yet available in the US. There is a score card much like the FAMACHA for this as well.
Here's a power point presentation that explains both FAMACHA and The Five Point Check
*When to begin using FAMACHA in OHIO (and other states with a like climate)
~Parasite life cycle ramps up in May (around planting time)
~Begin scoring animals in May
~IF FAMACHA is the ONLY strategy that you are using it MUST be done at LEAST every 14 days or WEEKLY
by mid June
~Helps you reduce the selection pressure of the worm to develop resistance
~Helps you keep costs down (you use less dewormer)
~May be necessary to continue scoring through early September (depending on outdoor temperatures)
~Lambs / kids can be difficult to score (use caution)
*due to size of the eye and their eye lid membrane tends to be paler than that of an adult
Approaches to control:
1)Conquer [chemical dewormers]
Since we don't have a new chemical coming out every 5 years this is impossible. The reality is that nature will continue evolving and the parasite will always win if this
is your strategy.
2)Co-Exist
Understand the biology and lifecycle of the parasite and manage your farm accordingly
Minimize lamb/kid time on pasture
Maximize dry ewe / doe time on pastures
Genetics - breed for parasite resistence
3)Avoidance
Non-pasture systems
Off season lambing / kidding in the FALL
Conclusion:
*There are no easy answers
*Each farm must use various tools and put together an integrated control strategy for their farm
*Management on your farm depends on your goals, your market and the size of your flock / herd
*Recognize economic factors: pasture is cheap feed - grains are expensive
*Worms will adapt - you must co-exist because they are not going away
*Lambs / kids are the weak link...most susceptible
*Dry ewes / does have a good level of resistance
Full discussion can be found here: http://www.backyardherds.com/forum/viewtopic.php?id=12553&p=1
Fecal testing via mail: http://www.midamericaagresearch.net/instructions.php
OSU Extension Information on dewormers: http://www.extension.org/pages/19651/goat-dewormers
Langston University Parasite Article: http://www2.luresext.edu/goats/training/parasites.html#ip
Internal Parasites - Specific focus on Barberpole worm
Notes from OSU Parasitology Seminars - August 2011
Finding a vet who specializes in small ruminants is stressed.
You can use the Find A Vet option at www.aasrp.org (American Association of Small Ruminant Practitioners)
Parasite Management = Pasture Management
All parasites are local. This means that every farm is different...every city or state is different - and you must understand that.
Life of the worm:
Eggs in manure can live for a few weeks under favorable conditions.
Moisture is required for egg survival - so extremely dry conditions can kill it.
Eggs also don't do well in freezing conditions (especially freeze - thaw - freeze)
Eggs can hatch as early as in as early as 48 hours and last as long as they don't have "killing" conditions.
Rain is often the "release" factor that causes a hatch.
Stage 1 & 2 larvae aren't very hardy and can die easily.
Stage 3 (L-3) larvae keep their stage 2 shell and gain their stage 3 shell as well and are therefore very hardy and therefore harder to kill.
Stage 3 (L-3) larvae are the INFECTIVE stage...this is when they climb a stalk to seek a host to eat them (2-4 inches off the ground max)
In good conditions the egg can hatch in 48 hours and go to stage 3 larvae (L-3) at a 4 day minimum.
What worms:
Nematodirus, Cooperia, Trichostrongylus, Telodorsagia (Ostertagia) - These worms will cause a goat / sheep to be unthrifty, a poor doer and cause diarrhea. They are not blood suckers and do not cause death.
Hemonchus Contortus (Barberpole) - This is the worst worm that we are dealing with. It is a voracious bloodsucker and can kill the animal. It is very small only about 1/2 inch long as "adult". A heavy infestation can remove 1/5 of the animal's blood in 24 hours.
Dewomers:
In sheep there are 3 classes of dewormer available by label:
Macrocyclic lactones - Ivermectin (Ivomec) and moxidectin (Cydectin)
Benzimidazoles - Valbazen
Levamisole
For goats were have by label:
Fenbendazole (Safeguard & Pancur) approved for non-lactating goats
Rumatel Medicated Premix 88 for lactating and non-lactating goats
Use of any other labeled for cattle or sheep is extra label and should not be used without vet prescription
Dewormers by Class
Avermectins
Brand Name: Ivomec, Double Impact, Top-line, Phoenectin Pour-on
Active Ingredient(s): ivermectin 1% (injectable) ivermectin 0.5% (pour-on)
Availability: OTC
Withdrawal: 35 days before slaughter
Indications: Control of internal and external parasites
Brand Name: Ivomec Plus
Active Ingredient(s): ivermectin 1% and clorsulon 10%
Availability: OTC
Withdrawal: 56 days before slaughter
Indications: Control of internal and external parasites including adult liver flukes
Brand Name: Dectomax
Active Ingredient(s): doramectin 1% injectable; doramectin 0.5% pour-on
Availability: OTC
Withdrawal: 35 days before slaughter for injectable; 42 days before slaughter for pour-on
Indications: Control of internal and external parasites
Brand Name: Eprinex (Ivomec)
Active Ingredient(s): eprinomectin 5mg
Availability: OTC
Withdrawal: No slaughter or milk withdrawal on cattle
Indications: Control of internal and external parasites
Notes: Used frequently in dairy goats(No milk withdrawal)
Milbymycin
Brand Name: Cydectin, Quest Equine Wormer
Active Ingredient(s): moxidectin
Availability: OTC
Withdrawal: No slaughter withdrawal on cattle
Indications: Control of internal and external parasites
Notes: Cydectin - this is the most effective wormer we have right now.
Benzimidazole (white dewormers)
Brand Name: Safe-guard, Panacur, Benzelmin
Active Ingredient(s): fenbendazole
Availability: OTC
Withdrawal: 8 days before slaughter
Indications: Control of internal parasites - Tapeworms
Notes: Most stomach and intestinal worms show resistance to fenbendazole products.
Extremely high safety margin.
Brand Name: Synanthic
Active Ingredient(s): oxfendazole
Availability: OTC
Withdrawal: 11 days before slaughter
Indications: Control of internal parasites
Brand Name: Valbazen
Active Ingredient(s): albendazole
Availability: OTC
Withdrawal: days before slaughter
Indications: Use Valbazen to control of internal parasites including adult liver flukes.
Notes: Do not use on does of breeding age that have been exposed to a buck, or those that are
bred. May cause abortion or birth defects.
From here on we will talk only of the Barberpole...
When are they worst (in OHIO):
From March to October
2 weeks prekid / lamb to 6 weeks post kid/ lamb
Worms start to become a problem for kids / lambs at approximately 6 weeks of age.
Around 7-9 months of age kids / lambs will begin to develop some immunity to some worms.
Just because your animals aren't sick and/or dying doesn't mean you don't have a worm problem.
Dewormer Resistance:
All programs that rely strictly on the use of chemical dewormers will eventually fail as a result of development of resistance.
The question is how soon it will happen to YOUR farm.
REFUGIA = That portion of a worm population that escapes treatment of a dewormer when used. This is a NEED to have for this worm. You want a certain % of worms left in the pasture (10-20%) while you treat the 80-90% that are in the animals...allowing for only unresistant worms to be ingested. Remember that your dewormer will not kill them all. You are not going to eliminate the worms - you must learn to live with them and treat them appropriately and treat only those that truly need it.
Once resistance is present on your farm it is likely to be a permanent situation. Resistance happens when worms have a frequent exposure to a drug.
A frequent cause of resistance is UNDER dosing.
How?
under estimating on weight (a scale is recommended to avoid this...weight tapes are not always accurate for all animals)
incorrect dose calculation
incorrect dilution of product
improperly calibrated or faulty equipment (always check dosing syringes...a leaking gasket on a drenching syringe can cause an underdose)
Remember that goats metabolize faster and therefor require a higher dosage to work - DO NOT UNDERDOSE!
Another problem is treating all animals and then moving them to a "safe" or "clean" pasture...as this allows them to carry resistant worms to the new pasture.
Unless you use one of the following methods that method won't work.
Options when using "clean" pasture method:
Pastures previously grazed by horses or cattle
Hayfield regrowth
Spring Planted annuals (tilling of soil will bury and kill the egg / larvae)
Crop aftermath (cornfield or other crop after harvest)
Please remember that if you have a resistance to ivermectin that the worms have the gene potential to develop resistance to moxidectin (Cydectin) too. So while Cydectin is more potent than Ivomec you need to be careful not to underdose.
Alternatives to preserve a REFUGIA:
Treat selectively with FAMACHA and body condition score; then move to rotational graze / browse
Leave heaviest 10-15% untreated, then move to rotational graze / browse
Treat all animals with a non-persistent dewormer and leave on contaminated pasture for 3-5 days
Treat lambs / kids, but not dams, if lambs / kids are not weaned
Treat thin and twin / triplet bearing dams only (this is the best option for dam treating)
Persistent Dewormers:
Ivomec (injected)
Dectomax (injected)
Cydectin (more persistent than Ivomec and Dectomax)
What does persistent dewormer mean?
It means that the drug stays in the tissue a longer time when it is injected. The drug settles into the fat of the animal.
Cydectin will stay in the tissues for 35 days post administration when given orally.
Things needed to UN-learn:
Treating of adult animals when there is no real need. DO NOT DO THIS....it causes resistance.
Need to implement a SMART DRENCHING PROGRAM
more info at http://scsrpc.org
Know the resistance status of the herd or flock
Sound pasture management
Keep resistant worms off the farm
Administer the proper dose
Utilize host physiology
Selective treatment - FAMACHA
Make sure when drenching that your drench pipe is in the BACK of the mouth to ensure the drug goes into the proper part of the stomach. Administering in the front of the mouth can lead to drug resistance due to the dewormer going into the wrong part of the stomach first.
DON'T BUY RESISTANT WORMS!
Quarantine new arrivals for 30-60 days
Deworm with 2 or even 3 classes of dewormers (make Cydectin one of them)
Perform a FEC to confirm no eggs are being passed
Expose to your farms worms post quarantine - put onto a contaminated field
Concept behind Selective Treatment:
Parasite numbers are not equally distributed in groups of animals.
20-30% of your animals are producing 75% of your worms
FAMACHA is highly recommended for selective treatment and is ONLY effective for Barberpole worm.
A note on bottle jaw:
If your sheep or goat has bottle jaw - diagnosis can be confirmed by pressing your thumb into the swollen area. If it is indeed bottle jaw the imprint will stay for 8-10 seconds. Bottle jaw is often a symptom of Barberpole infestation.
Body condition scoring was also discussed and may be an indicator of animals that may be harboring worms.
The Five Point Check for targeted selective treatment of internal parasites in small ruminants has been developed but is not yet available in the US. There is a score card much like the FAMACHA for this as well.
Here's a power point presentation that explains both FAMACHA and The Five Point Check
*When to begin using FAMACHA in OHIO (and other states with a like climate)
~Parasite life cycle ramps up in May (around planting time)
~Begin scoring animals in May
~IF FAMACHA is the ONLY strategy that you are using it MUST be done at LEAST every 14 days or WEEKLY
by mid June
~Helps you reduce the selection pressure of the worm to develop resistance
~Helps you keep costs down (you use less dewormer)
~May be necessary to continue scoring through early September (depending on outdoor temperatures)
~Lambs / kids can be difficult to score (use caution)
*due to size of the eye and their eye lid membrane tends to be paler than that of an adult
Approaches to control:
1)Conquer [chemical dewormers]
Since we don't have a new chemical coming out every 5 years this is impossible. The reality is that nature will continue evolving and the parasite will always win if this
is your strategy.
2)Co-Exist
Understand the biology and lifecycle of the parasite and manage your farm accordingly
Minimize lamb/kid time on pasture
Maximize dry ewe / doe time on pastures
Genetics - breed for parasite resistence
3)Avoidance
Non-pasture systems
Off season lambing / kidding in the FALL
Conclusion:
*There are no easy answers
*Each farm must use various tools and put together an integrated control strategy for their farm
*Management on your farm depends on your goals, your market and the size of your flock / herd
*Recognize economic factors: pasture is cheap feed - grains are expensive
*Worms will adapt - you must co-exist because they are not going away
*Lambs / kids are the weak link...most susceptible
*Dry ewes / does have a good level of resistance
Full discussion can be found here: http://www.backyardherds.com/forum/viewtopic.php?id=12553&p=1
Fecal testing via mail: http://www.midamericaagresearch.net/instructions.php
OSU Extension Information on dewormers: http://www.extension.org/pages/19651/goat-dewormers
Langston University Parasite Article: http://www2.luresext.edu/goats/training/parasites.html#ip