GOAT PARASITES Survey of endoparasites in goats in

GOAT PARASITES Survey of endoparasites in goats in Ireland DR THEO DE WAAL SCHOOL OF VETERINARY MEDICINE

INTRODUCTION • Parasites affecting goats – Protozoa – Arthropods – Helminths • Helminth parasite control • Survey of goat parasite Ireland • Anthelmintic resistance

PROTOZOA • Cryptosporidium spp – Intestinal epithelium – Intermittent diarrhoea, long duration – Important zoonosis • Coccidiosis (Eimeria spp) – Intestinal epithelium Cryptosporidiosis - dirty hind end and pot belly – Several species, some more pathogenic than others – Host-specific • coccidia from sheep will not infect goat – Profuse diarrhoea (with blood) • Hygiene – clean water/feed & management – isolation of sick animals – avoid overcrowding – don’t mix different age groups Coccidiosis - dirty hind end and pot belly

PROTOZOA • Toxoplasma gondii – Complex life cycle • Cat mammals & birds – Important cause of abortion in goats – Important zoonosis Abortion Lesions on cotyledons of a placenta Cats contaminate environment

ARTHROPODA • Mites – – • Burrowing (Sarcoptes scabiei) & Non-burrowing (Chorioptes & Psoroptes spp) Feed on lymph and skin debris Lice – – • Biting & sucking lice Feed on dermal scales or blood Ticks – • Blood feeding Skin irritation, itching & restlessness – Ticks also vectors of pathogens such as Anaplasma, Louping ill and tick pyaemia • Sub-clinical – production losses • Spread by direct animal-to-animal contact • Treatment – Synthetic pyrethroids, Macrocyclic Lactone – Repeat after 2 weeks Sarcoptic mange: A goat with generalized lesions (Wrinkled skin and loss of hair)

HELMINTHS • Large, multicellular organisms • Roundworms (nematodes) • Flatworms (flukes and tapeworms) Liver fluke Tapeworms Roundworms

FLATWORMS • Fasciola hepatica – liver fluke – Complex life cycle involving mammals (adult flukes), snails as well as free living stages (metacercariae) – Leaf like parasite affecting liver of many animals – Seasonal disease: acute chronic – Anemia, bottle jaw Liver fluke • Rumen fluke – Similar life cycle as liver fluke – Immature parasite in small intestine • Can cause diarrhoea – Adult parasite in rumen • Usually non-pathogenic Rumen fluke

TAPEWORMS • Adult tapeworms in small intestine • Moniezia spp – Complex life cycle: ruminants & free living mites – Little pathogenic significance • Larval stages in muscle of intermediate (goats & sheep) host • Taenia hydatigena – Life cycle: dogs & wild canids (adult), ruminants (larval stages) in abdominal cavity – Usually asymptomatic, but heavy infection can lead to liver lesions Taenia hydatigena • Taenia multiceps – “gid” – Life cycle: dogs & fox (adult), ruminants (larval stages) in brain – Nervous symptoms – circling, stumbling, visual defects • Control – dogs no access to carcasses; treatment Taenia multiceps

ROUNDWORMS • Large and diverse group • Parasitic gastroenteritis (PGE) – Abomasum, small intestine, large intestine • Lungworms Teladorsagia circumcincta lesions in abomasum Muellerius capillaris nodules in lungs

NEMATODE LIFE CYCLE L 4, adult • Short, direct life cycles – 3 -4 weeks – weather-dependent • Can overwinter on pasture. • Ability to go into hypobiotic (arrested) state (in host) when environmental conditions are not conducive to their development (hot, dry or cold, dry). L 3 • Vary in their egg laying ability. • Eggs look same under microscope. L 2 L 1

THE EPIDEMIOLOGY OF NEMATODE PARASITISM IN GOATS AT PASTURE 11

TYPICAL SIGNS OF PARASITISM GI NEMATODES • • Weight-loss Diarrhoea Rough hair coat Weakness (anaemia) Bootle jaw Decreased milk production Death LONG WORMS • Generally mild • Coughing • Fast breathing • Decreased milk production

CONTROL • Integrated parasite management • Treat only when necessary • Treat only those animals that need it

INTEGRATED PARASITE MANAGEMENT NON-CHEMICAL • Host immunity • Proper use of anthelmintics • Kidding and weaning management • Including Targeted Selected Treatment (TST) • Nutritional management • Pasture and grazing management • Genetic selection

HOST IMMUNITY: GOATS VARY IN THEIR SUSCEPTIBILITY TO PARASITES MOST SUSCEPTIBLE • Kids, kids – Weanlings LESS (BUT STILL) SUSCEPTIBLE • Mature bucks – Early weaned kids • Dry does – Spring born kids • Pet goats – Late-born kids – Artificially reared kids • Periparturient does – High producing does – Yearling does • Geriatric goats

PASTURE AND GRAZING MANAGEMENT • Grazing ‘clean’ or ‘safe’ pastures – not been grazed by goats/sheep ~6 m – pasture fields – hay/silage crop has been removed – pasture fields which have been rotated with field crops “Safe” pastures – pastures than recently established or renovated by tillage • Alternate/mixed grazing Mixed grazing 16

PASTURE AND GRAZING MANAGEMENT • Browsing • Alternative forages – Tanniferous and bioactive forages# • Legumes & herbs - high in condensed tannins • Delayed grazing • Night penning • Zero grazing (dry lot feeding) Bird's-foot-trefoil # Marley, Chicory et al, 2003. The effect of birdsfoot trefoil (Lotus corniculatus) and chicory (Cichorium intybus) on parasite intensities and performance of lambs naturally infected with helminth parasites. Vet. Parasitol. 112, 147 -155.

TARGETED SELECTIVE TREATMENT (TST) WHAT IS IT? • Only treating animals that require treatment or only treating animals that would benefit from treatment. WHAT DOES IT DO? • Slows drug resistance; – Reduces number of treatments – Increases refugia • Identifies resistant and susceptible animals for selection purposes.

TST: DECISION-MAKING TOOLS Faecal egg counts Dairy Goat Body Condition Scoring: https: //www. youtube. com/watch? v=FC 0 u 1 j 06 y 5 Y.

Check Point Observation Possibilities 1. EYE Anemia 1 -5 (FAMACHA© card) Barber pole worm (Haemonchus) Liver fluke Hook worms Other worms and causes 2. BACK Body condition score 1 -5 (BCS card) Brown stomach worm (Teladorsagia) Bankrupt worm (Trichostrongylus) Nodular worm Other worms and causes 3. TAIL Fecal soiling (1 -5) Dag score card 4. JAW Soft swelling “Bottle jaw” 1 -5 5. NOSE Discharge 1 -5 5. COAT Coat condition 1 -3 Brown stomach worm (Teladorsagia) Bankrupt worm (Trichostrongylus) Coccidia (Eimeria) Nodular worm (Oesophagostomum) Other worms and causes Barber pole worm (Haemonchus) Coccidia (Eimeria) Liver fluke Hook worms Other worms and causes Nasal botfly Lungworms Pneumonia Other causes Barber pole worm (Haemonchus) Brown stomach worm (Teladorsagia) Bankrupt worm (Trichostrongylus) Coccidia (Eimeria) External parasites Other causes

IRISH SURVEY • Faecal samples • 11 farms – 5 kids – 15 adult

FARMING ENTERPRISE • 11 responses

PERCENTAGE FARMS POSITIVE

PERCENTAGE POSITIVE BY AGE

FAECAL EGG COUNT

ZERO GRAZING AND PARASITE MANAGEMENT • 5 farms reported zero grazing

ANTHELMINTIC USE DOSAGE DRUG CLASSES USED • No wormers licensed for goats in Ireland • Goats metabolise drugs differently from sheep • Evidence to suggest higher dose rate required • 1 -BZ & 3 -ML – 2 x sheep dose • 2 -LV – 1. 5 x sheep dose (toxicity reported)

ANTHELMINTIC RESISTANCE Ability of worms in a population to survive drug treatments that generally are effective against the same species/stage at same dose rate

ANTHELMINTIC RESISTANCE QUANTIFIED (SHEEP)

DEVELOPMENT OF RESISTANCE • Heritable trait • Inevitable consequence of good nematode control • Why? – Drug eliminate the susceptible genotypes – Resistant parasite survive reproductive advantage and pass on their “resistant” alleles – Gradual build-up S S S S S S S R R S S S R R R S S S S S R S S R R R R S R R R R S S R S R R R S R R R R R

CONTRIBUTING FACTORS ASSOCIATED WITH AR • High treatment frequency • Under dosing • Incorrect calibration of equipment • Underestimate live weight • Treatment strategies that minimize in refugia population • Treat all animals • Treat when few larvae are on pasture – – • Early in grazing season Treatment at ecological critical times Treat & move to “clean” pasture • Lack of quarantine treatments • Animal movement disperses resistant worms • Worm/fluke combinations & ML for ectoparasites at inappropriate times Refugia = The helminth population not under selection pressure of drug treatments

HELMINTH CONTROL: BEST PRACTICE • Quarantine treatment on arrival – Treat with 2 effective drug classes – 48 hours – Turned onto contaminated pasture • Correct drench technique & right dose • Test for resistance • Examine control strategy – reduce treatments • Reduce dependence on anthelmintics – Grazing management, use resistant rams • Only treat when necessary – Pathophysiological markers, FEC, Performance indicators • Use most appropriate anthelmintic – Preserve new generation anthelmintics • Preserve susceptible worms – Leave some (10 -15%) sheep untreated – Treat few days before moving http: //www. nationalsheep. org. uk/