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Pasture management to control internal parasites

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Presentation for 2020 Texas Sheep & Goat Expo

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Pasture management to control internal parasites

  1. 1. PASTURE MANAGEMENT TO CONTROL INTERNAL PARASITES SUSAN SCHOENIAN Sheep & Goat Specialist University of Maryland Extension sschoen@umd.edu wormx.info sheepandgoat.com
  2. 2. CURRENT SITUATION Internal parasites are the primary health problem affecting small ruminants in warm, moist climates and/or times of warmth and moisture. In the past, internal parasite control relied mostly on treatments with dewormers. This approach eventually led to high levels of drug resistance. Integrated approaches which rely less on drugs are now needed.
  3. 3. DEWORMERS Proper use of dewormers Targeted selective treatment Combination treatments Refugia Testing for resistance MANAGEMENT OPTIONS Pasture and grazing management Nutritional management Genetic selection Management / husbandry practices
  4. 4. Weather dependen L3 L4 L 3 A A = adult L = larvae https://www.agric.wa.gov.au/livestock-parasites/barbers-pole- L 2 L1 Host Animal Pastur e Manure
  5. 5. Factor Time or conditions Number of eggs deposited daily Up to 10,000 per day for barber pole worm Much less for other worm species Maximum time worm eggs can live waiting for suitable hatching conditions 5 days for barber pole worm Longer for other worms Minimum time for egg to develop into infective third stage larvae (L3) 3-4 days (4 to 10 days) Conditions required for significant numbers of worm eggs to hatch and become infective larvae. Daily maximum >64.4°F (50-96°F) Moisture 0.4-0.6 inches rainfall Minimum time for L3 to develop into adult worms “prepatent period” 18 days for most sheep roundworms Adult worm life span 4-6 months Time for 90% of larvae to die Weeks to months Temperature dependent Longer for non-barber pole worms IT’S MOSTLY A NUMBER’S GAME!
  6. 6. REFUGIAWORMS NOT EXPOSED TO THE DEWORMERS Internal parasite control is a conflict between controlling worms and slowing dewormer resistance Refugia is now the primary strategy for slowing dewormer resistance. Leave a portion (10-20%) of the flock/herd untreated. Dilute resistant worms on a pasture by putting untreated animals on pasture previously grazed by treated animals or by returning treated animals to same pasture for a week or so before moving them to a clean pasture.
  7. 7. PASTURE MANAGEMENT BASICS Pasture is the reservoir and vector of transmission.
  8. 8. ROTATIONAL GRAZING A well-designed rotational grazing program can help to reduce worm burdens.
  9. 9. SHORT DURATION GRAZING GOAL IS TO PREVENT “AUTO-INFECTION.” Though weather dependent, worm eggs can develop into infective 3rd stage larvae (L3) as quickly as 3-4 days. It takes longer when weather is cooler and/or drier. If animals are moved every 3-4 days (or less), they will not ingest infective larvae unless they are returned to the same paddock too soon.
  10. 10. LONG PASTURE REST PERIODS GOAL IS TO CREATE LOW-RISK PADDOCKS. Once the larvae lose their metabolic reserves, they die. In hot weather, reserves are quickly used up. Cool, moist conditions support survival of larvae. Rest pastures long enough for most larvae to die. Parasite larvae will die more quickly if the pasture is mowed or after a hay crop is removed. Tillage buries any worm eggs and cleans the pasture up. Max Temp Time for 90% to die Cold < 59°F 4 months Warm About 72°F 3 months Hot About 95°F 1.5 months Very hot Over 104°F 1-2 weeks
  11. 11. MINIMUM GRAZING HEIGHTS TO MINIMIZE INGESTION OF L3 Parasite larvae can migrate laterally and vertically in films of moisture. Most larvae migrate no more than 4 to 6 inches up the canopy. Most larvae (~80%) are found in the first 2 inches of vegetation. Do not overstock or overgraze. Graze above 4 to 6 inches to minimize ingestion of infective worm larvae. Let animals browse, esp. goats. Plant taller growing forages.
  12. 12. ALTERNATIVE FORAGES Forages containing condensed tannins have been shown to have inhibitory effects on barber pole worm infections: sericea lespedeza, birdsfoot trefoil, and chicory. Annual crops provide clean, nutritious forage for grazing. Legumes and forbs improve the nutrition of pastures. Pasture composition can affect movement of infective larvae. Browse provides clean, nutritious forage for grazing.
  13. 13. MULTI-SPECIES GRAZING TO REDUCE PASTURE CONTAMINATION Parasites are mostly host- specific. Sheep/goats are generally not infected by the same parasites as cattle and horses. The exception is young calves and H. contortus. Can co-graze, alternate pastures, or use a leader- follower system. There are numerous other benefits to multi-species grazing.
  14. 14. INTERNAL PARASITISM WHEN IT’S DRY Internal parasites are generally not a problem in dry climates (<25 in. annual rainfall) or during a drought, as environmental conditions aren’t conducive to egg hatching and larval development. During dry weather, larvae are retained in the fecal pellets. The larvae don’t need rain to survive. When it rains, the larvae are released from the pellets. Lower risk Higher risk
  15. 15. INTERNAL PARASITISM WHEN IT’S DRY Livestock can still get infected in a drought because they graze closer to the ground to get the last vegetation (where the larvae are) and in green areas (hot spots). When/once it rains, there can be a huge increase in infectivity (disease several weeks later), as the larvae are release from the egg. During a drought, there are more refugia in the animal than on pasture.
  16. 16. ZERO GRAZING STRATEGIC USE OF CONFINEMENT (BARN OR DRY LOT) Worm parasites do not spread in barns or dry lot. Coccidia can be more of a problem. Remove severely parasitized animals from pasture for recovery (e.g. FAMACHA© 5). When other control measures are not working, put animals in dry lot. Raise more susceptible animals in dry lot, e.g. weanlings.
  17. 17. BIOWORMA® BioWorma® is a worm- killing fungus. (Duddingtonia flagrans) It kills roundworm larvae in the manure of animals It prevents reinfection of pastures with infective worm larvae (L3). It is feed-through product with no effect in animal (wormy animals still need treated). Natural-Biological control Environmentally-friendly Not organic (yet)
  18. 18. FEEDING BIOWORMA® Feed daily to livestock during periods of peak worm transmission, >40°F. Feed to the most susceptible animals, usually peri-parturient females and young, weaned lambs/kids
  19. 19. TWO BIOWORMA® PRODUCTS BIOWORMA® Feed additive that contains 34% fungus. Dosage is 0.1 oz per 100 lbs. Needs to be mixed into a batch of feed Can only be purchased by veterinarians and EPA-certified feed manufacturers and mixers.  Premier 1 Supplies is now able to sell because they have veterinarians on staff. LIVAMOL® + BIOWORMA® Nutritional supplement (20% CP) that contains 2.2% fungus. Dosage is 1.6 oz per 100 lbs. Read-to-use product Mix or top dress in feed Anyone can purchase www.bioworma.c
  20. 20. COST OF BIOWORMA® + LABOR TO FEED IT Reducing the cost and labor Feed BioWorma® instead of Livamol® Research questions Could BioWorma® be fed for two weeks out of the month and give similar results? Could BioWorma® be fed every other day and give similar results.? Would feeding BioWorma® to periparturient females control parasites sufficiently in weaned lambs/kids? Could BioWorma® be put in a mineral product and give similar results. Would you need to feed less BioWorma® over time, as your pastures became cleaner?
  21. 21. SUSAN SCHOENIAN SHEEP & GOAT SPECIALIST UNIVERSITY OF MARYLAND EXTENSION SSCHOEN@UMD.EDU | WORMX.INFO | SHEEPANDGOAT.COM Thank you. Questions? Comments?

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