Efficacy of pour-on dewormers on weight gain and fecal egg count in Hawaiian stocker cattle

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Efficacy of pour-on dewormers on weight gain and
fecal egg count in Hawaiian stocker cattle

• Jonathon Beckett1, Tim Richards2, Craig
  Reinemeyer3
• 1Animal Science Department, Cal Poly State
  University, Kahua Ranch2, East Tennessee Clinical
  Research3

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What is a Parasite?

• The Random House Dictionary defines it as an
  organism that lives on or within a plant or
  animal of a different species, from which it
  obtains nutrients.

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Parasites of Concern

• Bunostomum phlebotomum (Cattle Hookworm)
• Causes itching of the leg and feet
• Irritate stomach and intestines
• Feed on blood in the intestinal wall
• Causes bloody, tar colored diarrhea

• Fasciola hepatica (Common Liver Fluke)
• Live in the bile ducts of the liver, and
  gallbladder
• Animals experience anemia and decreased growth
• Usually results in condemnation of the liver at
  slaughter

• Strongyloides papillosus (Intestinal threadworm)
• Most common in young calves
• Causes intermittent diarrhea, loss of appetite,
  and weight

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Parasites of Concern

• Cooperia spp (Cattle Bankrupt worm)
• Lives in the Small Intestine
• Animals exhibit poor utilization of feed, taking
  a long time to reach market weight

• Ostertagia ostertagia (Brown Stomach Worm)
• Affected cattle not only lose weight but often
  die
• Cells damaged by the parasite are replaced by
  rapidly dividing cells that lack function
• The most commonly found and economically
  important internal parasite

• Toxocara vitulorum (Large Roundworm)
• Live in the Small Intestine
• Found especially in warm climates
• can travel through the lung and cause pneumonia
• Compete with host for food , causing diarrhea
  and weight loss

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Clinical Parasitism

• Diarrhea
• Anemia
• Rough hair coat
• Pot bellied appearance
• Bottle jaw
• Less common

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Subclinical Parasitism

• Decreased milk production
• Poor performance
• More susceptible to disease
• Infertility
• Unthrifty

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We Deworm Cattle For Only One Reason

• FOR THE MONEY

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Parasitism

• Economics of Parasite Control
• Calves
• More efficient
• Less susceptible to disease
• Cows
• Increased milk production
• Better body condition
• Better breeding efficiency
• Less susceptible to disease

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Benefits of Deworming

• Increased productivity
• Increased efficiency
• Better immune status
• Increased breeding efficiency
• Reduced pasture contamination

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Importance of fecal egg counts?

• Most commonly used technique
• Usefulness depends on its precision and accuracy
• Requires knowledge of parasite biology in area,
  experience with levels that are indicative of
  economic impact in a given situation

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EPGs (Eggs Per Gram) importance?

• An indicator, but only tell you that you have at
  least one female worm laying eggs
• Can be used to determine potential parasite
  transmission levels in groups of animals, but not
  individual animals
• Poor indicator of number of worms in an
  individual animal
• Should not be used to measure production losses

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Importance of Larval Cultures

• Very few parasitologist are able to differentiate
  between different genera of the parasite eggs
• Nematodirus is only easy one
• Larval cultures let eggs hatch then the worms are
  identified

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Macrocyclic Lactones

• Avermectins
• Ivermectin (Ivomec)
• Doramectin (Dectomax)
• Eprinomectin (Eprinex
• Look alikes
• Generic
• Milbemycins
• Moxidectin (Cydectin)

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Macrocyclic Lactones
Doramectin
Ivermectin
Moxidectin
Eprinomectin
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Types of Administration

• Injectable
• Advantage Easy to administer
• Disadvantage Can create problems in the meat
• Disadvantage Must be re-dosed every 60 days
• Pour-On
• Advantage Very quick to administer
• Advantage Noninvasive administration
• Disadvantage Must be re-dosed every 60 days

• Drench
• Advantage Very quick to administer (not as
  quick as Pour-On)
• Disadvantage Must be re-dosed every 60 days
• Disadvantage Cow can spit out most of the
  product
• Bolus
• Advantage Dosed only once in the cows life
• Disadvantage Much longer administration time
• Disadvantage Administration requires training

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Just Some More Facts

• Worms die after 5-8 wks in adult stage
• Some products kill most of the worms present in
  the digestive tract at time of treatment
• Some control only external parasites
• Some control both internal external
• A few also kill the inhibited stages
• A few offer persistence of several weeks

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Hypothesis

• The effective drug in pour-on dewormers will
  affect growth and parasite infection throughout
  the grazing season in stocker cattle.

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Protocol
Transported to Feedyard, Bruneau, ID
Harvested at IBP, Boise, ID
A
Cydectin
Dectomax
B
Eprinex
C
D
Ivomec
Control
E
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Days
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Average Daily GainDay 0-105
a
a
a
a
b
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Average Body WeightDay 105
36.1
32.8
31.6
27.6
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Fecal Egg Counts
Redewormed
Dewormed
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Carcass Weights
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Yield Grade
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Backfat
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Ribeye Area
a
ab
ab
ab
b
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Marbling Score
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Yield Grade 1 2s
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What does this mean?

• It is important to deworm
• Eprinex and Cydectin equally resulted in maximal
  growth
• Ivomec is the weakest against internal parasites
• Without adequate forage, no dewormer is fully
  effective

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What does this mean?

• Effect of dewormer during stocker phase is not
  significant at slaughter but effects are visible
• Take advantage of cheap gain during stocker phase
  rather than pay more for the gain in the feedyard

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What does this mean?

• Other factors must be considered when selecting a
  dewormer
• Cost
• Persistency of Protection
• Ease of Administration
• Rain Fastness
• Flame Resistance
• Customer Service

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Acknowledgements

• Kahua Ranch Thank you for allowing Cal Poly to
  conduct the trial on their cattle
• Bruneau Cattle Company Accommodating the
  feedlot phase
• 2001 Swanton Pacific Stocker Enterprise group for
  participating in the data collection and
  organization of the trial
• Brian Wetzel Cal Poly Alumni for initiating
  this line of research as his senior project