12. Cattle helminths 1 Flashcards
What are the common nematodes of the abomasum?
haemonchus placei
ostertagia ostertagi
trichostrongylus axei
What are the common nematodes of the small intestine?
cooperia spp
nematodirus spp
trichostrogylus spp
bunostomum sppW
What are the common nematodes in the large intestine?
oesophagostomum spp
How are nematodes trasmitted in cattle?
almost exclusively pasture transmitted
What is parasitic gastroenteritis?
PGE, generic term for dz caused by nematodes in the GI
predominant in yg anims
subclinical dz cause major production loss
control depended on regular use of broad spectrum anthelmintics
anthelmintic resistance growing problem
What is the economic burden of cattle GI nematodes
cost of parasitic nematodes to US cattle industry is >2billion/year, clinical dz, subclinical prod loss, incredibly important to the animal pharmaceutical industry
What is the GE pathogenesis?
reduced feed intake and utilization, growth and prod
inc loss of protein into gut
blood loss anemi (haemonchosis in sheep)
IF clinical effects: dirrhea and failure to thrive
effects greater in yg animals, poorly fed anims, anims w/ concurrent dz
What are trichostrongyles?
all small worms (5-10mm long)
L3 is infective (hatches from egg)
PPP ~3wks, translation is 1 week in ideal conditions
all eggs look the same except nematodirus
What is the basic trichostrongyle life cycle?
eggs pass in feces, free living stages of 1+2 larvae in manure pat, infective L3 develops in ~1wk and remains infective for wks/mo in mature pats or on vegetation where larvae migrate > cattle ingest infective L3 while grazing > immature worms migrate into gut mucosa > worms mature in digestive tract where adult worms lay eggs
What is the pathogenesis of ostertagiasis?
nematode growth in gastric gland, causes distension of gastric gland lumen 1. rupture of intercellular junctions > leakage of plasma proteins into gut lumen > hypoproteinaemia
2. destruction of HCL prod cells to ^^ OR dec HCL secretion - inc abomasal pH > 1. failure to activate pepsinogen to pepsin > leakage of pepsinogen into blood + maldigestion, anorexia > elevated plasma pepsinogen or 2. Bacterial overgrowth
What is type 1 ostertagiasis?
summer ostertagiasis
grazing calves, high burdens of larvae in glands, bright green water diarrhea, weight loss
onset may be gradual, morbidity is high, mortality is low, FEC may be high
What is type 2 ostertagiasis?
winter ostertagiasis, yearlings, inhibited larvae emerge at once, depression, weight loss, anorexia
Hypoalbuminemia and submandibular oedema, sudden onset, morbidity is low, mortality is high
FEC may be zero or low
What is trichostrongyles - cooperia spp?
common in temperate regions, contributes to PGE as part of mixed infections, sometimes the predominant species, may see inappetence and reduced weight gains
generally the dose limiting parasite
most resistant GIN in cattle in north america
What is the life cycle of nematodirus spp?
develops to L3 inside egg, eggs can overwinter on pasture, cattle >6mo of age resistant, can cause acute diarrhea in calves
Which adults are parasitic of the strongyloides papillosus?
adult females
What is the lifecycel of strongyloides papillosus?
feces in larvated eggs > L1-3> ingested, L3 in colostrum
PPP 10 days
Heterogonic cycle has freeliving adults have have filariformthat is then ingested by the host
What is the PPP of trichuris spp?
4-6wks
What is the parasitic nematodes of ruminants and basic epidemiology?
Infection thry ingestion of infective stages from pasture.
What are possible sources of springtime pasture contamination?
overwintered eggs or larvae (esp. nematodirus) on pasture
Infected cows returning to pasture (even if treated in fall - reactivation of hypobiotic larvae from infected adult cows)
What is peak pasture contamination and transmission?
peak pasture contam and transmission: second half of grazing season (as more animals become infected the pasture becomes more contaminated and then more animals become infected
outcome of infection largely depends on immune status
How do we diagnose GI nematodes in cattle?
Hx - age, season, mgmt (pasture systems beef vs dairy)
clinical signs - anorexia, diarrhea, weight loss, or nothing obvious
Fecal examination - fecal egg counts on a herd basis (not individual animals) can be qualitative or quantitative, or by centrifugal best
fecal culture or new molecular appoaches
How do we manage GI nematodes?
treat and quarantine new stock - prevent introduction
good husbandry: good nutrition and prevent concurrent dz
pasture management (avoid overgrazing)
How o anthelmintics manage GI nematodes?
increasing problems w/ resistance
long acting anthelmintics, rumen boluses, residual effects
How can strategic treatments manage GI nematodes?
give spring (turnout) tx to head off pasture contamination
treat younger animals in first grazing season 6-8wks later, give fall tx to get arrested larvae
