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Proper use of dewormers

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Prepared for Delmarva Small Ruminant Conference: All Worms All Day. Delaware State University, Dover, Delaware. December 9, 2017.

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Proper use of dewormers

  1. 1. Sometimes you’ve got to shove a drug down their throats! Proper use of dewormers Susan Schoenian  Sheep & Goat Specialist  sschoen@umd.edu
  2. 2. Presentation outline 1. Anthelmintics (dewormers) 101 2. Anthelmintic (dewormer) resistance 3. Combination treatments 4. When deworming is not enough 5. Removal of tapeworms 6. Copper oxide wire particles 7. Anticoccidial medication 8. Treatment of meningeal worm 9. Extra label drug use (ELDU) 10. Veterinary-Client-Patient-Relationship (VCPR)
  3. 3. Acronyms used in presentation ▪ ELDU = Extra label drug use ▪ VCPR = Veterinary-Client-Patient-Relationship ▪ Vx = Veterinary ▪ Rx = Prescription ▪ Tx = Treatment ▪ OTC = Over-the-counter ▪ VFD = Veterinary Feed Directive
  4. 4. Anthelmintics (dewormers) 101
  5. 5. What is an anthelmintic (or dewormer)? ▪ A drug that expels parasitic worms (helminths) and other internal parasites from the body by either stunning or killing them. ▪ It must be selectively toxic to the parasite and not the host. ▪ It may be broad spectrum or targeted. ▪ It may contain single or multiple drug actives. Ivermectin was introduced in the early 1980’s
  6. 6. Anthelmintic (dewormer) classes for small ruminants GROUP 1 Benzimidazoles (BZ) GROUP 2 Macrocylic lactones (ML) GROUP 3 Nicotinic agonists Avermectins Milbemycins Imidazothiazoles Tetrahydropyrimidines THIABENDAZOLE TBZ® IVERMECTIN Ivomec® MOXIDECTIN Cydectin® Quest® LEVAMISOLE Prohibit® Leva-Med® Tramisol® Levasol® MORANTEL Rumatel® many trade namesFENBENDAZOLE SafeGuard® Panacur® DORAMECTIN Dectomax® PYRANTEL Strongid® ALBENDAZOLE Valbazen® EPRINOMECTIN Eprinex®OXFENDAZOLE Synanthic® Anthelmintics are separated into groups on the basis of similar chemical structure and mode of action.
  7. 7. Anthelmintics FDA-approved for sheep 1 Benzimidazoles VALBAZEN® sheep drench 2a Avermectins IVOMEC® sheep drench 2b Milbimycins CYDECTIN® sheep drench 3 Levamisole PROHIBIT® LEVA-MED® Adult worms     Larvae (L4)    Limited Hypobiotic larvae    Limited Lungworms     Tapeworms  Liver flukes Adult stage Coccidia External parasites Some labeled for bot control Some Not labeled Persistent activity   Safety 10x pregnancy restriction (first 30 days) 20x 5x 3x Labeled Dosage 3 ml/100 lbs. 3 ml/26 lbs. 1 ml/11 lbs. Depends on dilution 2 ml/50 lbs. (concentrated drench) Meat withdrawal 7 days 11 days 7 days 3 days Source: FDA animal drug database
  8. 8. Anthelmintics FDA-approved for goats 1 Benzimidazoles 3b Morantel Fenbendazole SAFEGUARD® Albendazole VALBAZEN® Feed premix RUMATEL® Adult worms  Not approved  Larvae (L4)  Not approved sporadic Hypobiotic larvae  Not approved Lungworms  Not approved Tapeworms Not labeled Not approved Liver flukes Adult stage Coccidia External parasites Persistent activity Safety wide 10x (sheep) pregnancy restriction ~20x (sheep) Labeled dosage 1.2 ml/50 lbs. 4 ml/100 lbs. Varies by product Meat withdrawal 6 days 7 days 30 days Milk withdrawal 0 days Source: FDA animal drug database
  9. 9. Extra-label anthelmintics for goats 1 Benzimidazoles 2a Avermectins IVOMEC® sheep drench 2b Milbimycins Moxidectin CYDEDTIN® sheep drench 3a Levamisole PROHIBIT® LEVA-MED® Fenbendazole SAFEGUARD® Albendazole VALBAZEN® Adult worms      Larvae (L4)     Limited Hypobiotic larvae     Limited Lungworms      Tapeworms Not labeled  Liver flukes Adult stage Coccidia External parasites Some label for bot control Some Not labeled Persistent activity   Safety wide 10x pregnancy restriction 20x 5x 3x ACSRPC recommended dosage 1.1 ml/25 lbs. 2 ml/25 lbs. 6 ml/25 lbs. 4.5 ml/25 lbs. Depends on dilution Meat withdrawal 16 days (1 day for each additional day used) 9 days 14 days 17 days 4 days Milk withdrawal 4 days (1 day for each additional day used) 7 days 9 days 8 days 3 days Source: FDA Animal Drug Database & www.wormx.info
  10. 10. Anthelmintic (Dewormer) Resistance
  11. 11. There are two kinds of resistance when we talk about internal parasites. IN WORM ▪ Worms develop resistance to drugs. ▪ Treatment doesn’t kill or expel them. ▪ Worms pass their resistant genes onto the next generation of worms. IN ANIMAL ▪ Some breeds and individual animals are more resistant to parasites. ▪ They have an ability to reduce establishment of parasites (animals have low fecal egg counts). ▪ They pass their resistance genes onto the next generation. My babies will be resistant. You won’t be able to kill them with your drugs. My babies won’t let your babies establish themselves.
  12. 12. What is anthelmintic resistance? ▪ Genetic ability of a worm to survive a dose of anthelmintic which would normally be effective. ▪ Only worms that survive treatment carry genes that confer resistance. ▪ Result of selection through exposure of worm population to an anthelmintic. ▪ When more than 5 percent of worms are “drug tolerant”; i.e. failure to reduce FEC by 95% or more (some say 90%). http://www.scops.org.uk/what-is-resistance.html
  13. 13. Documentation of anthelmintic resistance 0 10 20 30 40 50 60 70 80 90 100 Benzimidazoles Ivermectin Levamisole Moxidectin Maryland Virginia Georgia 2016-17 (ASI Let’s Grow Project)5-10 years ago
  14. 14. What practices accelerate dewormer resistance? 1. Frequent deworming, especially calendar-based treatments 2. Whole flock/herd treatments 3. Under-dosing of drugs 4. Treat and move: moving treated animals to a clean pasture 5. Rotating dewormers 6. Depositing drug in mouth instead of oral cavity 7. Use of persistent activity dewormers (macrocylic lactones) 8. Use of injectable dewormers 9. Use of pour-on dewormers 10. Feeding dewormers to groups of animals 11. Improper storage of dewormers
  15. 15. Two ways to test for dewormer resistance FECAL EGG COUNT REDUCTION TEST (FECRT) DRENCHRITE® TEST LARVAL DEVELOPMENT ASSAY (LDA)
  16. 16. Fecal egg count reduction test (FECRT) ▪ Compare before and after (10-14 days) fecal egg counts from same animals. ▪ Need ~15 animals to test a dewormer. 1-2 animals won’t tell you much. ▪ Need Minimum FEC of 250 epg*, preferably higher. ▪ Can use individual or pooled (composite) samples. ▪ Cost varies. Can learn to do yourself, have vet do, or send to a parasitology or diagnostic lab.
  17. 17. DrenchRite® larval development assay (LDA) ▪ Labor-intensive laboratory test that determines resistance to all dewormers and classes from a single pooled fecal sample (from ~10 animals). ▪ Test also identifies larvae: % Haemonchus Need to identify strongyle species from larvae. ▪ Need minimum FEC of 500 epg. ▪ Test done exclusively by Dr. Ray Kaplan’s lab at the University of Georgia (jscb@uga.edu) ▪ $450 per sample
  18. 18. Animal Before After % FECR 1 1000 100 90% 2 500 25 95% 3 6000 150 98% 4 4350 250 94% 5 3000 1000 67% 6 1200 400 67% 7 1500 200 87% 8 750 50 93% 9 1100 100 91% 10 3100 200 94% 11 2900 200 93% 12 475 200 58% 13 900 100 89% 14 1100 50 95% 15 300 0 100% Avg 1878 145 87% Fecal egg count reduction test (FECRT)
  19. 19. Combination treatments Using multiple drug actives to kill same types of worms
  20. 20. “There now is very strong evidence that using combination treatment is the best method for using dewormers and should be instituted on all farms immediately.” Dr. Ray Kaplan, University of Georgia (January 2017, www.wormx.info) https://www.wormx.info/combinations
  21. 21. Rationale for combination treatments ▪ Most farms have resistance to at least two of the four groups of dewormers; some have resistance to all. ▪ At first introduction, drug efficacy is over 99%. ▪ Once efficacy falls below 95%, drug resistance is present, though drug is still useful for treatment. ▪ As effectiveness of dewormer decreases (<95%), as it is used more, it provides less and less benefit to animals. ▪ Below 50%, it is no longer effective as the sole treatment. There is already resistance to Zolvix® in other countries. Zolvix® is not sold in US.
  22. 22. Why give combination treatments? ▪ Contrary to popular belief, rotating between dewormers will not prevent resistance from developing. In fact, it will allow worms to develop resistance to multiple drugs simultaneously. It is no longer recommended. ▪ Research done in New Zealand has shown that the best approach is to use several different dewormers at one time as a combination treatment. ▪ When combined with “best management practices” (that help to maintain refugia), combination treatments may improve drug efficacy and result in a reversion back toward susceptibility. Most dewormers sold in New Zealand and Australia are combination products (multiple drug actives in same product); No combination products are available for small ruminants in US.
  23. 23. Why (how) do combinations work? ▪ Unlike rotating drugs, there is an additive effect with each drug used in a combination treatment. ▪ When resistance is low, there may be a synergistic effect with a combination treatment. ▪ By achieving a higher efficacy, there are fewer resistant worms that survive treatment. ▪ The sooner you start using combination treatments the better, as you achieve the greatest difference in the percentage of resistant survivors when efficacy of dewormers is high. Drug 1 Drug 2 Drug 3 Combo12 Combo123 80% 80% 80% 96.00% 99.20% 90% 90% 90% 99.00% 99.90% 60% 95% 98.00% 98.00% 60% 60% 95% 84.00% 99.20% 99% 99% 99.99% 99.99% 60% 60% 60% 84.00% 93.60% 50% 50% 50% 75.00% 87.50% 40% 40% 40% 64.00% 78.40% 95% 80% 20% 99.00% 99.20%
  24. 24. Recommendations for using combination treatments ▪ Purchase and administer each dewormer singly in a separate syringe or drench gun. ▪ Do not mix dewormers. They are not chemically compatible. Only veterinarians have the right to compound medications. ▪ Administer each dewormer at full dose based on an accurate weight. ▪ Can give one drug immediately after the other. ▪ Observe withdrawal period of drug with longest withdrawal period.
  25. 25. Recommendations for using combination treatments Valbazen®* Cydectin® Prohibit®* Sheep 1.5 ml/50 lbs. [7 days] 4.5 ml/50 lbs. [7 days] Depends on dilution [3 days] Goats 4 ml/50 lbs. [9 days meat] [7 days milk] 9 ml/50 lbs. [17 days meat] [8 days milk] Depends on dilution [4 days meat] [3 days milk] Camelids 4 ml/50 lbs. 9 ml/50 lbs. Depends on dilution *Do not use first 30 days of pregnancy www.wormx.info
  26. 26. Recommendations continued ▪ Do not give combination treatments to all animals in a management group. ▪ Selective treat to maintain refugia. 1. FAMACHA© eye anemia system 2. Five Point Check© 3. Performance marker ▪ If you treat all animals, you will simultaneously develop resistant to all dewormer classes, eventually leaving you no drugs to effectively treat clinically-parasitized animals. ▪ Combination treatments require extra-label drug use in goats and camelids (VCPR). S S S S S S S S S S R S R R R R S S R Deworming
  27. 27. When deworming’s not enough Supportive therapy ▪ Remove from infected environment ▪ High protein feed or forage Powdered protein supplements ▪ Vitamin/mineral supplements Red Cell®, Iron Power®, Perktone® ▪ Electrolytes, supplemental energy Gatorade®, Powerade®, Pedilyte® ▪ B vitamins ▪ Injectable Iron (Fe) ▪ Vitamin K ▪ Kaopectate or Pepto-Bismal to slow diarrhea ▪ Probiotics to stimulate appetite https://www.wormx.info/wormnotenough
  28. 28. Removal of tapeworms (Moniezia spp.) There is little evidence that treatment for tapeworms is beneficial to lambs (goats?)
  29. 29. Removal of tapeworms in small ruminants ▪ Tapeworm removal requires specific drugs; not all dewormers are effective against tapeworms. ▪ Valbazen® (albendazole*) is labeled for treatment of tapeworms (heads and segments) in sheep. ▪ Extra label drug use (VCPR) is required to remove tapeworms in goats. 1. Valbazen® @ 10 mg/kg 2. Safeguard® (fenbendazole) @ 15 mg/kg *Albendazole should not be given during first 30 days of pregnancy.
  30. 30. Praziquantel is the drug of choice for tapeworms. ▪ Praziquantel is not approved for small ruminants in US. Its use requires extra label drug use (VCPR). ▪ Praziquantel is available in three combination deworming (gel) products for horses: 1. Equimax® (ivermectin + praziquantel) 2. Zimecterin Gold® (ivermectin + praziquantel) 3. Quest Plus® gel (moxidectin + praziquantel) ▪ Praziquantel is the active ingredient in Droncit® for cats and dogs. ▪ Internationally, praziquantel is available in various combination drenches: First Drench™, Firstmectin.
  31. 31. Copper oxide wire particles (COWPs)
  32. 32. What are copper oxide wire particles (COWPs)? ▪ Tiny needles of copper oxide. ▪ Slow release form of copper (Cu). ▪ Poorly absorbed form of copper vs. copper sulfate which has caused copper toxicity  when given to some sheep. ▪ COWPs have been shown to reduce barber pole worm infections in sheep and goats. Only “natural” substance with consistent proven efficacy against worms in animal. ▪ Available as a copper supplement for cattle (12, 25-g) and goats (2, 4-g). https://www.wormx.info/copper-oxide-wire-particles
  33. 33. Using COWPs to deworm sheep and goats 1. FIRST: assess copper status of flock (especially) or herd by submitting livers to a lab for a mineral panel. 2. REPACKAGE cattle and goat boluses into smaller doses for sheep and goats. 3. ALWAYS use lowest dose possible to achieve anthelmintic effect (more is not better!). ▪ 0.5 to 1 g for lambs and kids ▪ 1-2 g for mature animals MSU Veterinary Diagnostic Lab https://www.animalhealth.msu.edu/
  34. 34. Using COWPs to deworm sheep and goats 1. SELECTIVELY treat: FAMACHA© 3s, 4s, and 5s. 2. ADMINISTER using a bolus or balling gun; the gel cap is small, so you may need something sticky to hold capsule in the gun. 3. MINIMIZE the number of treatments given to the same sheep or goat. 4. PERIODICALLY check livers to see what copper levels are. https://www.wormx.info/cowp-safety
  35. 35. Another combination treatment proven effective COWPs + dewormer Treatment (10-23 lambs per Tx group) Efficacy (%FECR) No treatment (control) Increase Valbazen® (3 ml/50 lbs.) 20% COWP (2 g, Ultracruz™) 58% COWP (2 g, Copasure®) 12% Valbazen® + COWP 99% Burke, USDA-ARS, Booneville, Arkansas http://www.wormx.info/cowpcombo Similar results were obtained when COWPs were combined with levamisole (Prohibit®). (USDA, unpublished data)
  36. 36. Anticoccidial medication coccidiocidal - kills coccidia coccidiostatic - arrests development
  37. 37. Prevention of coccidiosis Active ingredient Tradename Administration Approved species Availability Withdrawal 1 Lasalocid (ionophore) BOVATEC® Feed Mineral Sheep OTC 0 days 2 Monensin (ionophore) RUMENSIN® Feed Mineral Goats OTC 0 days 3 Decoquinate (quinoline) DECCOX® Feed Mineral Sheep Goats OTC 0 days 4 Amprolium CORID® Water Cattle Poultry OTC ELDU 24 hours (cattle)
  38. 38. Use of coccidiostats ▪ Though ionophores (Bovatec® and Rumensin®) are coccidiocidal (kill coccidia), it is best begin feeding them before anticipated period of risk, usually from birth to 3-4 months. ▪ It is common to feed ionophores or Deccox® to females during late gestation to reduce shedding of coccidia oocysts into environment (ELDU) ▪ Last gestation feeding of ionophores or Deccox® may reduce abortion rate in flocks/herds with a history of toxoplasmosis (caused by cats) [ELDU].
  39. 39. Coccidiostats continued ▪ Coccidiostats can be fed free choice in mineral mix or incorporated into creep feed or ewe/doe ration. ▪ Corid® is usually added to drinking water (ELDU). ▪ Limitation of coccidiostats is adequate consumption, especially if offered free choice. ▪ Coccidiostats should not be fed year-round, as resistance can develop (is suspected).
  40. 40. Potential toxicity of coccidiostats ▪ Ionophores are particularly toxic to horses (< ½ g). ▪ Ionophores can also be deadly to dogs and pigs because they are monogastrics. ▪ Rumensin® is ten times more toxic than Bovatec® Toxicity is usually caused by feed mixing errors. ▪ Bovatec© toxicity in sheep is less uncommon, but can occur. ▪ Deccox® has a wide margin of safety.
  41. 41. Anticoccidial drugs for treatment of coccidiosis Active ingredient Tradename Administration Approved species Availability Withdrawal period 1 Amprolium CORID® Water Drench Cattle Poultry OTC ELDU 24 hours (cattle) 2 Sulfa drugs Sulfadimethoxine Sulfamethoxine Sulfaquinoxaline DI-METHOX® ALBON® SULMET® Feed additive Water Drench Cattle Swine Poultry ELDU Rx VFD variable
  42. 42. Use of anticoccidial drugs AMPROLIUM (CORID®) [ELDU] ▪ Kills coccidia late in life cycle, after damage has already been done. ▪ More effective as treatment than control. ▪ Mimics thiamine (vitamin B1), so prolonged use could cause polio. ▪ Individual animals should be drenched. ▪ Resistance has been reported (goats) SULFA DRUGS [Rx, ELDU] ▪ Water-soluble sulfa antibiotics: transitioned from OTC to Rx, as a result of new Veterinary Feed Directive (VFD) which became law in January 2017. ▪ Toxicity is a risk with overdosing and long-term use. ▪ Individual animals should be drenched. ▪ Resistance has been reported.
  43. 43. Other drugs that control coccidia Active ingredient Tradename Administration Approved species Availability Withdrawal Ponazuril MARQUIS® Paste Horses Rx NA Toltazuril TOLTRAZURIL® BAYCOX® Paste Drench Horses Not available in US 42 days meat withdrawal (sheep) Longer for goats Diclazuril VECOXAN® Drench Lambs Calves Not available in US 0 days
  44. 44. Other drugs that control coccidia TOLTRAZURIL - PONAZURIL ▪ Drench prior to the first expected onset of disease. ▪ Individual treat ALL animals. ▪ Persistency of drug should eliminate need for re-treatment. ▪ Goats may require higher dose DICLAZURIL (VECOXAN®) ▪ Give early in disease to prevent damage. ▪ Single or double administration 6-8 weeks or 3-4 weeks + 6-8 weeks
  45. 45. Treating meningeal worm deer or brain worm Sheep, goats, and camelids are abnormal hosts for parasite.
  46. 46. Treatment of meningeal worm ▪ Cornell University conducted a 3 year study comparing treatment protocols in naturally-infected sheep and goats on 14 farms near Ithaca, NY. Research project treatment protocol 1. SafeGuard® (Fenbendazole 10%) orally for 5 days @ 1.33 cc per 10 lbs. 2. Anti-inflammatory drug for 5 days a) If not pregnant: Dexamethasone (Rx) @ 0.5 cc per 10 lbs. for first 3 days, followed by 0.25 cc per 10 lbs. for next two days b) If pregnant: Banamine (Rx) @ 1 cc per 100 lbs. orally for 5 days. 3. Ivermectin injectable (ELDU) for 5 days 0.25 cc per 10 lbs. A placebo was given to some animals in study to determine efficacy of ivermectin.
  47. 47. Effectiveness of treatment protocol ▪ Treatment was effective for 11/13 goats and 9/14 sheep. ▪ Researchers have not determined whether ivermectin had any beneficial effect; however, it increased the meat withdrawal period substantially - to 96 days!. ▪ The treatment protocol requires veterinary involvement, as all drugs require extra-label drug use and some are only available via a veterinary prescription (Rx).
  48. 48. Extra label drug use (ELDU) ▪ While there is an FDA-approved dewormer in each class for sheep (all drenches), there is a general lack of FDA-approved dewormers for goats (and camelids); thus ELDU is usually required. ▪ No drugs are FDA-approved to treat coccidiosis in small ruminants. ▪ Extra label includes any use of a drug that is not specified on the label: species, class, indication (disease or condition), dosage, frequency, route of administration, or withdrawal period.
  49. 49. Extra label drug use (ELDU) ▪ Only a licensed veterinarian has a right to use or prescribe a drug extra label. ▪ Just because you can buy a drug over- the-counter or order it over the internet, doesn’t mean you are using it legally. ▪ Veterinarians can prescribe extra label drugs under specified circumstances, but only when a valid veterinarian-client- patient relationship (VCPR) exists.
  50. 50. Veterinary-Client-Patient Relationship (VCPR) A VCPR is present when all of the following requirements are met: 1. The veterinarian has assumed the responsibility for making clinical judgments regarding the health of the patient and the client has agreed to follow the veterinarians' instructions. 2. The veterinarian has sufficient knowledge of the patient to initiate at least a general or preliminary diagnosis of the medical condition of the patient. This means that the veterinarian is personally acquainted with the keeping and care of the patient by virtue of a timely examination of the patient by the veterinarian, or medically appropriate and timely visits by the veterinarian to the operation where the patient is managed. 3. The veterinarian is readily available for follow-up evaluation or has arranged for the following: veterinary emergency coverage, and continuing care and treatment. 4. The veterinarian provides oversight of treatment, compliance, and outcome. 5. Patient records are maintained. Source: AVMA
  51. 51. Drugs are a valuable, but limited resource. Use them wisely.
  52. 52. Thank you. Comments. Questions? SUSAN SCHOENIAN Sheep & Goat Specialist sschoen@umd.edu www.sheepandgoat.com www.sheep101.info www.wormx.info

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