Internal Parasite Evaluation and Control

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Internal Parasite Evaluation and Control

• Steve Hart
• American Institute for Goat Research
• Langston University

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E. Kika De la Garza American Institute for Goat
Research

• Research Program
• Nutrition
• Vegetation Mgt.
• Parasites
• Economics
• Carcass Quality

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Extension Program

• Field Day April 29, 2007 at Langston University
• Mini Field Day February in NE and SW OK
• Buck Test with OMGA May-Aug

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Extension Workshops

• Nutrition
• Birthing
• Goat Management
• Parasites
• Artificial Insemination
• Contact your county agent

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Fencing Garden
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Web Site WWW2.luresext.edu
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Topics

• Parasite life cycle
• Management to prevent parasites
• Dewormer resistance
• Developing a workable parasite control program

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Roundworms

• Barber pole worm, Haemonchus contortus- feeds on
  blood in abomasum, causes anemia, poor
  performance and death

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Barberpole Worm
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• Barber pole worms in the abomasum

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Roundworms

• Bankrupt worm, Trichostrongylus colubriformis,
  feeds on mucus in small intestine, diarrhea,
  reduced appetite, poor performance
• Brown stomach worm, Teledorsagia circumcincta or
  Ostertagia, feeds on gastric glands, causes
  diarrhea, reduced appetite, poor performance

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Worm life cycle

• Life cycle is very important to understand so you
  know some actions to take to reduce worm problems
  and also, why some environmental conditions or
  management practices increase worm problems so
  that you can be alert for parasite problems

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Life Cycle 2

• Egg in feces from animal falls to ground
• Requires warmth 50F and humidity to hatch to
  first stage larvae, abbreviated L-1 in 1-6 days
• Winter parasites are less of a problem
• Dry hot summer parasites are less of a problem

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• Roundworm egg

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Life Cycle 3

• Direct sunlight can heat fecal pellet to
• 155 F and sterilize pellet
• Diatomaceous earth helps pellet to dry out?
• Shade trees and tall, dense grass increase
  humidity and shade fecal pellets from the sun

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Life Cycle 4

• L-1 eats bacteria in feces and grows, molts
  (sheds skin like a snake) and becomes L-2
• L-1 and L2 are subject to dying by drying out.
  Heat and low humidity will kill them in the pellet

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Life Cycle

• L-2 eats bacteria in feces and grows and molts to
  L-3. However, the cuticle (skin) is not shed, so
  the L-3 has 2 layers of cuticle. This makes the
  L-3 much more resistant to drying out.

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• Note how the old cuticle is surrounding the L3
  stage
• This means the L3 cant feed and must rely on
  stored metabolites or energy to survive

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Life Cycle 5

• However, the L-3 cannot eat, because his mouth is
  covered. He must live off his stored reserves.
  He can only live about 30-60 days in hot weather
  or 120-240 days in cool weather.

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Life Cycle 6

• Takes about 6-14 days from fresh fecal pellet to
  L-3
• The L-3 must escape from the fecal pellet to
  infect an animal
• The L-3 can only live a few weeks inside a fecal
  pellet

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Life Cycle 7

• Pellet must be broken up by rain (2 inches in a
  months time) and then the larva scoots on a film
  of water (from rain or dew) 2-3 inches up forage
  or he may scoot under a fallen leaf or other
  debris.
• Close grazing or goats picking up debris infects
  goats. Browsing goats pick up few larvae

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• L3 larvae caught in a dew droplet on a stem of
  grass

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Life Cycle 8

• Maybe only 3-10 of eggs end up as L-3 larvae on
  forage.
• L-3 must be eaten by goat or sheep to continue
  development
• L-3 inside goat leaves its sheath and molts to
  L-4.
• L-4 can enter suspended animation called
  hypobiosis or arrested form

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Life Cycle 9

• Arrested form of L-4 does not stimulate animals
  immune system and often requires a higher dose of
  dewormer
• Barber pole worm eggs and larvae are killed by
  freezing it overwinters as arrested L-4 and
  survives hot dry summers as an L-4 in the goat
• Otherwise L-4 molts to L-5 which is adolescent
  which develops ovaries and uterus and then molts
  to an adult which lays thousands of eggs per day

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Immune Response

• Good nutrition stimulates immune system
• Can select goats for low fecal egg counts
• Other diseases which depress immune system (e.g.
  coccidiosis) can cause increased worm problems

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Life Cycle 11

• When goat are lactating, immune system is
  suppressed and does not fight parasites.
  Arrested L-4 larvae acquired during the fall all
  mature simultaneously in the spring during
  lactation. Rationale for deworming before kidding

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Barber Pole Worm

• Dominant species in warm climates
• Produces 1-6,000 eggs/day
• Develops dewormer resistance more rapidly than
  other species because of 3 wk generation interval.

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Symptoms of Barber Pole Worm

• Barber pole worm consumes 1-5 drops of blood per
  day. 1,000 nearly a pint of blood in a week.
• Causes anemia (low red blood cell number),
  hypoproteinemia (low blood protein), edema and
  ultimately death
• Blood is normally 36 red blood cells
• Deworm when 20 red blood cells
• Goat is at deaths door at 8 red blood cells
• Coccidiosis, liver flukes, and lice can cause
  anemia

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Symptoms of Barber Pole Worm

• Look at color of mucous membranes-under lower
  eyelid, gums, inside vulva. Dark pink color is
  good, pale watery color indicates anemia
• Make a habit of noticing animals with white
  around eyes
• Bottle jaw, a collection of fluid (edema) under
  the lower jaw

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Symptom of Barber Pole Worm

• Fecal egg counts are the best measure of barber
  pole worm infection, reflecting the number of
  mature worms in the goat. Takes 1-3 weeks from
  L-3 to egg laying adult-it is possible to
  accumulate enough worms to have anemia and fecal
  egg count not yet increased. Is rare.

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Dewormer Action Families

• All members of an action family share the same
  mode of action despite there being several
  members in the same family
• Only 3 broad spectrum families available
• Benzamidoles
• Levamisole and Morantel/Pyrantel
• Avermectins/Milbemycins

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Benzamidoles

• fenbendazole (Panacur, Safeguard) oxfendazole
  (Synanthic)
• albendazole (Valbazen) also kills flukes
• All kill eggs, lungworms and tapeworms
• Greatest level of dewormer resistance because of
  long history of use

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Levamisole Morantel/Pyrantel

• Levamisole (Tramisol, Levasole,Prohibit)
• Morantel/Pyrantel (Rumatel, Positive Pellet
  Dewormer)
• Basically only effective against roundworms

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Avermectins/Milbemycins

• Ivermectin (Ivomec)
• Dormectrin (Dectomax)
• Eprinomectin (Eprinex)
• Moxidectin (Cydectin) long residual effect
• Effective against roundworms, sucking lice and
  mange

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Use of Dewormers

• Few are approved for use in goats
• Use 1.5 times the sheep dose because goats have
  faster rate of passage and larger livers to
  metabolize the drug
• Administer orally back behind tongue so they go
  to the rumen

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Use of Dewormers

• Do not return to same pasture but send to new
  uncontaminated pasture
• Observe withdrawal period before selling goat
• Pour-on works poorly in goats
• Dewormers should not be injected

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Dewormer Resistance

• An effective dewormer will reduce fecal egg
  counts by 95 7-14 days after giving the
  dewormer
• Fecal Egg Count before deworming 1,000 eggs per
  gram
• 10 days after deworming 200 eggs per gram 80
  fecal egg count reduction

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Langston -ivermectin
Reduction 43
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Oklahoma Farm FECR

• Farm IVM VAL LEV CYD
• 1 12 87 98
• 2 37 88 99
• 3 7 67 99
• 4 63 85 92
• 5 55 99 100
• 6 46 42 98
• 7 41 91
• 8 0 97
• 9 69 74 94

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Dewormer Resistance

• Biggest threat to the goat industry in the near
  future 3-5 years
• Means we will have to rely on techniques other
  than dewormers to control worms
• Knowledge about dewormer resistance and
  management to control parsites has doubled in the
  last 10 years and your vet may not be up to date

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Management to Reduce Parasite Problems

• 1. Stocking rates lt 2 hd/ acre
• 2. Grazing cattle or horses with goats
• 3. Dont graze close to ground
• 4. Haymaking or tillage
• 5. Pasture rotation with 6 or more weeks rest
• 6. Browse or animals eating off ground

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Concept for Selective Treatment

• All goats do not carry the same worm burden.
  Some goats are more resistant to worms than
  others. We should deworm only those goats that
  need it. The goats that didnt get dewormed will
  have susceptible worms to dilute the resistant
  worms of the animals that were dewormed.

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Distribution of FEC in Goat Herds
33 of Goats 80 of Eggs
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Selective Treatment Protocol

• Examine each goat individually every 3 weeks
  during the warm season.
• Use eye color chart to determine those that are
  anemic and need dewormed.
• Deworm and record the animals number.
• Requires training to understand and implement
  concept.
• Method is called FAMACHA

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Consequences of Selective Treatment

• Reduces rate of development of dewormer
  resistance
• Culling goats that need dewormed the most
  increases resistance of goat herd to parasites
  and reduces number of infective larvae on a
  pasture (from eggs hatching)

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Alternative Dewormer Research

• With the development of dewormer resistance, the
  goat industry may find itself without an
  effective drug dewormer. There is an increasing
  amount of dewormer research on alternatives so
  that we do have some way to control worms when
  this happens.
• Two studies at Langston have shown that Sericia
  lespedeza is effective at controlling worms in
  goats.

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Effect of Sericea lespedeza on FEC (egg/g) in
Spanish wether goats
Pasture
Pasture
Lespedeza
Lespedeza
10 Oct. 15 Oct. 20 Oct. 25
Oct. 1 Nov. 5 Nov. 10 Nov.
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Effect of Sericea lespedeza on Egg Production and
Development

• Item Grass Sericea
• __________________________________
• FEC 2722 956
• Eggs/d, 1000 1730 450
• Hatch 99 58
• Larvae/10g feces 2518 126

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Alternative Dewormer Research

• Capsules of copper wires
• Protein supplementation
• Trace mineral boluses
• Herbal dewormers
• Garlic, wormwood fennel, ginger

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Risk Factors for Parasites

• 1. Warm weather
• 2. Two inches of rain in a month
• 3. Grazing pastures short
• 4. High stocking rates
• 5. Thin animals
• 6. Animals in lactation
• 7. Long residence on a pasture

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Planning a Parasite Control Program

• 1. Monitor parasite problems with fecal egg
  counts or eye scores
• 2. When you have a parasite problem determine
  why and change parts of management that you can
• 3. Only use dewormer when necessary
• 4. Deworm only animals that need it
• 5. Cull wormy animals

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Planning a Parasite Control Program

• 6. Deworm new animals coming on your place with 2
  classes of dewormer
• 7. Notice eye mucous membrane color when you
  check animals
• 8. Use good nutrition

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Langston Parasite Workshop

• Parasite life cycle and management
• Dewormers, resistance and proper use
• Eye color scores (includes hands-on)
• How to do your own fecal egg counts
• Schedule one in your area by working with your
  County Agent to contact me

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Conclusion

• If you plan to stay in the goat business for the
  long term, you need to put more thought into how
  we raise our goats so we can reduce worm problems
  with management and only use dewormers when
  necessary.