Managing External Parasites in Beef Cattle - Effective Control Strategies

1. Combating External Parasites in Beef Cattle A.J. Tarpoff Beef Extension Veterinarian Kansas State University

2. Pests • Horn Flies • Stable Flies • Face Flies • Ticks • Lice

3. The culprits • Horn Flies • Accounts for up to a $1 Billion worth of losses to the cattle industry • Blood feeders • Decrease in ADG, Milk production, feeding patterns, treatment/control costs • 1.5 lb of weight gain per week spring born calves

4. Horn Flies • Lay eggs in fresh manure • Life cycle 10-20 days • Spend majority of life cycle on cattle! • Rarely move from animal to animal • Population rise in late may and persist into fall** • Depending on weather conditions

5. Horn Flies • When do we treat? • Economic threshold= 200-300 flies/animal • Each fly feeds 20 to 30 times/day • Highest numbers on dark hided animals/bulls

6. Stable Flies • Found on legs of cattle • Very painful bite • Only feed during day • Economic threshold: • 5 flies/leg • Adults spend time off of cattle.

7. Stable Flies • Any moist organic matter is prime location for eggs and larvae • Straw bedding, spilled feed, manure piles, round bale feeding sites, calf hutches, alleys, feed areas, etc. • Historically a confinement or barnyard issue • Why an issue in pastures??

8. Stable Flies • Winter feeding sites!!

9. Stable Flies • Round bale feeding sites is a main breeding ground in pastures • Residue from a bale ring can result in 1 million more stable flies the following year

10. What do we do? • Continual movement of feeding sites • Rolling hay out • Feed in areas with low moisture and well drained • Disturb hay residue • Pile and compost the residue (before the next season) • Burn the residue (before the next season)

11. Bale rings • 2 to 60% of the bales fed in rings is wasted due to feeding habits • Residue from a single bale ring can spread 50 feed beyond the ring

12. Feedlot Premise Control • Pen slope to reduce standing water • Manure management! • Remove any feed residue from around bunks • Weed control on perimeter • If using a premise spray, spray early in morning, or late in evening • Walls, ceilings, posts, wind breaks, and other fly resting sites • Fly Traps

14. Face Flies • Feed on secretions from eye and nose • Vector in spreading Pinkeye • Lay eggs in fresh manure • Able to travel long distances between hosts

15. Face flies • Difficult to control since they spend so much time off the animal • Forced exposure to insecticide on a daily basis • Ear tag • Dust bag/oiler/spray

16. Insecticides • Insect Growth Regulators (IGR) • Pyrethroids • Organophosphates • Avermectins

17. Treatment options • Feed through products • Insecticide impregnated ear tags • Pour-ons • Sprays • Oilers/dusters • Injectable • Vet Gun

18. Feed through • Altosid (S-Methoprene),Clarifly(Diflubenzuron), Rabon (Organophosphate), • Feed though products delivered in mineral/blocks/feed • Inhibit larval development or kill larva in the fresh manure • House, face, and horn flies

19. Feed Through • Must begin application before the vector season • April 1st Kansas • March 15th far SE Kansas • ***Remember, Adult flies can still move in from a distance • Combination therapy is often warranted

20. What is Resistance • The intended target no longer responds as it once did • Occurs more commonly when exposed to a low dose of insecticide for long periods of time • Up to 32 generations of flies w/in 1 grazing season • Or when exposed to the same insecticide for multiple years in a row • When can this occur??

21. Ear tags • Must be removed at the end of the season!!! • Effective duration of 12-20 weeks • Class of insecticide must be rotated on a yearly basis! • Pyrethroid: no more than once every 3 years • Organophosphate: no more than two years in a row • Abamectin: Products newer to market. Have not developed resistance yet.

22. Tags Bayer Animal Health

23. Other tips • Hold off application of tags until economic threshold has been reached • Do not apply a tag more than once during a fly season • If additional control is needed later in the season: Use of sprays, pour-ons, dusts or back rubbers should be used • Alternate insecticide class

24. Just because it worked this year, does not mean it is sustainable or will continue to work!!!

25. Pour-ons/sprays • Generally do not carry as much risk to develop resistance • Do not have the residual activity • Provide control for 2-4 weeks • Pyrethroids/Organophosphates • Macrocyclic Lactones: (Ivermectin/Moxidectin/Doramectin) • Primarily used to control internal parasites • Reliance on this class for fly control can lead to resistant internal parasites

26. Self Treatment Dusters/Oilers • Follow label instructions when charging/re-charging • Many animals will not use these voluntarily! • Work very well when forced use near mineral/feed/water areas *FSA7031- Conrolling Horn Flies on Cattle

27. Vet Gun • “Paintball” filled with insecticide CO2 gun • Pyrethroid • Abamectin • 15-30 ft range

28. Talley 2017 AVC Proceedings

29. Parasitic Wasps • Commercial parasitic wasp release • Labor intensive • Continued release (APR-SEPT) • House/stable flies • Several Species available • Don’t use premise sprays in conjunction with wasp release

30. My Personal Favorite

31. Ticks

32. Ticks • Hard ticks • Rhipicephalusspp(Brown Dog Tick, Brown Ear Tick, Cattle Fever Tick) • Amblyommaspp(Gulf Coast Tick/Lone Star Tick) • Dermacentorspp(American Dog Tick, Rocky mountain wood tick, Pacific Coast Tick, Winter Tick) • Ixodesspp(Deer Tick) • Soft ticks • Otobiusmegnini(Ear tick)

33. Tick Damage

34. Tick Infestation (Gotch Ear) Dryden and Broce, K-State

35. Tick Infestation Dryden and Broce, K-State

36. Ticks • 4 stages of development • Egg • Larvae • Nymph • Adult • Two, or 3 host ticks • Small mammals, birds, large mammals

37. Ticks • Eggs are laid off the host • Thrive in high humidity areas • Brush • Trees (cedars) • Tall grass • Depending on species, can be active from Feb-Oct

38. Control • Microenvironments or microclimates • Burning • Reduces overall burden • Low lying areas may still hold large numbers • Cedar trees

39. Tick Control • Difficult with pasture animals – must handle the animals • Sprays and Pour-On are labeled for ticks and do a good job for about 3 weeks • Spraying ears • Ears tags are labeled for Spinose Ear Ticks and Gulf Coast Tick and will help with others • Tags do not get insecticide to groin and tailhead (Dog Tick)

40. Winter Lice Control Heather Smith Thomas

41. Economic Impact • Variable • $126 Million loss of production/year • Decreased ADG (0.25 lbs/day), anemia, weight loss, hide value • Does not include damage to equipment/fences

42. Lice • Biting lice (1 species), Sucking lice (4 species) • cattle specific • Egg-Nymph-Adult • Lifecycle ~28 days (spend entire life on cattle) • Can live 10 days off host • Infestations peak during winter months • Dec-Feb (march) • Economic threshold? • 10 lice/ square inch

44. Control • Systemic Treatments • Pour-on and injectable Avermectindewormers • Not ideal time to deworm (dormant stages of worms) • Treatment late fall (weaning) may not eliminate infestation of herd • Topical Treatments • Many insecticide products available. • Pour-ons, sprays • Usually Pyrethroids/Organophosphates • Work by contact

45. Treatment Tips • Face to poll to tailhead • Complete coverage • Treat ALL animals • Missing one animal can serve as a source for reinfection • New animals!! • Most products labeled for retreatment at 14 days • Work on adults but not the eggs or larvae • Is a product available labeled for only one treatment

46. Thank You tarpoff@ksu.edu