♫ Bad Bugs, Bad Bugs, Whatcha Gonna Do? ♪ : Parasites in Sheep Dr Chris Clark WCVM University of Saskatchewan

Sheep Parasites  The price of doing business!  PGE  Coccidiosis  Tapeworms  Fluke  Skin parasites

There’s a problem  When we think of parasites we think of drugs  Minimal drugs licensed for parasites for sheep in Canada

What does this mean for a sheep producer?  Drugs used in food animals are federally regulated  Only a veterinarian can prescribe extra-label drug use

Its more complicated  Drugs  Identified by DIN number on packaging  Extra-label use permitted with veterinary prescription and withdrawal period  Pesticides  Identified by PCP number on package  No extra-label drug use permited

Antibiotic labels tell you all you need to know SC = under the skin IM = in the muscle IV = in the vein

 Treatment options for sheep are limited  You need a veterinarian to prescribe parasite treatments  Use gFARAD for withdrawal information Implications

The Canadian Prairies  Good for sheep  Bad for most parasites  “its’s a dry cold”  It is not bad luck it is bad management

Coccidiosis  Mainly a problem of intensively raised lambs  Especially indoors  Outdoors needs specific conditions

 Onset early as 8d  Typically 4-6 weeks  Severe diarrhea +/- blood  Tenesmus  Morbidity high, mortality low

Coccidiosis  Etiology  E. cradallis, E. ovinoidalis  Diagnosis  Epidemiology, fecal, PM  Not all that easy!

Management  Avoid the epidemiology  Use of coccidiostats  Deccox  Baycox  Monensin  Amprolium  problems  Treatment  TMS

 Means different things in different regions  Teladosagia (ostertagia)  Haemonchus  Nematodirus  Trichostrongylus Parasitic gastro-enteritis (PGE)

 Eggs passed in feces  Hatch and develop to L3 on pasture  L3 ingested  Develop to L5 – adult in host causing disease  Pass eggs in feces  Hypobiosis  Small ruminants – Periparturient egg rise is significant  Adults develop some immunity Trichostrongyloidea

Canadian Prairies  Egg –L3 development  Requires heat and humidity

Haemonchosis  Barbers pole worm  Found in abomasum  Blood sucker  Prolific  Results  Ill thrift  Anemia, bottle jaw  Sudden death

 Eggs passed in feces must develop to L3 on pasture  5 day minimum  Requirements  Heat 18-26C (< 5 dormant, <10 nothing)  Humidity 100%  Canadian prairies –lucky to get one cycle Epidemiology

Significance  Most years disease is rare  If the weather is right you have a problem

Haemonchus diagnosis  Reality  PM  Clinical signs  High egg count

Haemonchus control  Traditionally  Deworm  Repeat as required

 Nematode of the abomasum  Larval forms disrupt acid production  Type 1 disease  Diarrhea and weight loss  Type 2 disease  Early spring – bottle jaw Teladosagia

Natural cycle in ideal conditions

 Deworm ewes at lambing  Deworm lambs repeatedly throughout late summer and fall Traditional control

Nematodirus  Intestinal worm  Egg development in 2-3 months  N. battus – different epidemiology  Diagnosis difficult as disease is prepatent  Egg looks like liver fluke

 Intestinal worm with epidemiology and effects similar to Teladosagia  Eggs are indistinguishable Trichostrongylus

 Understanding the epidemiology  All research is done in a different climate  Periparturient egg rise  Egg – L3 development on pasture  Cycling in lambs  Some winter die off Controlling PGE

 Periparturient egg rise  Can last 8 weeks  Deworming ewes in association with parturition  Can be used to minimize pasture contamination in late spring Using epidemiology to control PGE

 Deworm lambs at weaning and move to new pasture/feedlot

 BZ- Benzimidazoles  LM – Levamisol, Pyrantel, Morantel  AV- Avermectins Anthelmintics

 Do you have a problem?  Fecal egg count reduction test 1.FEC 2.Weigh and dose 3.Wait 10d then redo FEC 4.Should be >85% reduction in egg count Anthelmintic resistance

 Biosecurity  Dose all new arrivals on arrival  Weigh and dose  Dose on an empty stomach  Wait 2-3 days before turn out Anthelmintic resistance

 Weigh and dose  Avoid rotation of dewormer classes  Dose when needed (egg counts, FAMACHA, BCS)  Refugia  Dose and move Anthelmintic resistance

 Intestinal  Cystic Disease Tapeworms

 Monezia  Not important Intestinal tapeworms

Intermediate hosts

Taenia ovis Dog - sheep

The costs of disease  2009 – 270 lambs in the 1 st 6 months ”In heavy infestations the carcass is condemned. It is commonly considered that an animal is heavily infested if lesions are discovered in two of the usual inspection sites including the masseter muscle, tongue, oesophagus, heart, diaphragm or exposed musculature and in two sites during incision into the shoulder and the rounds. Carcasses with C. ovis infestations may not be acceptable for export.”

Traditional control  Typified by Australia and New Zealand  Routine deworming  Mandated with appropriate products  Feed control  Freezing  Cooking

Liver fluke  Complex life cycle  Absolute requirement for snail  Lymnaea truncatula

Liver fluke - disease  Acute  Sudden death at pasture  Sub acute  Poor doing fall/winter  Chronic  Anemia, hypoproteinemia poor BCS

Fascioloides Magna Sheep is an aberrant host  Continual fluke migration  Presentation  Death  Control  Avoidance f snail areas  Triclabendazole

Liver Fluke Control  Albendazole  Adult fluke only  Triclabendazole  V effective  Not in Canada

Skin parasites  Lice  Keds/ticks  Mites  Flies

Lice  Bovicola ovis – chewing  Linognathus spp. -sucking

Keds  Melophagus ovinus

Ticks Ticks latch on and feed Have 8 legs Do not live on the goat

Mites  Sheep scab  Psoroptes ovis  Treat with an avermectin twice (7d apart)

Fly strike in sheep  Management problem  Severe welfare issue