12. Cattle helminths 1

Question 1

What are the common nematodes of the abomasum?

Answer 1

haemonchus placei
ostertagia ostertagi
trichostrongylus axei

Question 2

What are the common nematodes of the small intestine?

Answer 2

cooperia spp
nematodirus spp
trichostrogylus spp
bunostomum sppW

Question 3

What are the common nematodes in the large intestine?

Answer 3

oesophagostomum spp

Question 4

How are nematodes trasmitted in cattle?

Answer 4

almost exclusively pasture transmitted

Question 5

What is parasitic gastroenteritis?

Answer 5

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

Question 6

What is the economic burden of cattle GI nematodes

Answer 6

cost of parasitic nematodes to US cattle industry is >2billion/year, clinical dz, subclinical prod loss, incredibly important to the animal pharmaceutical industry

Question 7

What is the GE pathogenesis?

Answer 7

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

Question 8

What are trichostrongyles?

Answer 8

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

Question 9

What is the basic trichostrongyle life cycle?

Answer 9

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

Question 10

What is the pathogenesis of ostertagiasis?

Answer 10

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

Question 11

What is type 1 ostertagiasis?

Answer 11

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

Question 12

What is type 2 ostertagiasis?

Answer 12

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

Question 13

What is trichostrongyles - cooperia spp?

Answer 13

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

Question 14

What is the life cycle of nematodirus spp?

Answer 14

develops to L3 inside egg, eggs can overwinter on pasture, cattle >6mo of age resistant, can cause acute diarrhea in calves

Question 15

Which adults are parasitic of the strongyloides papillosus?

Answer 15

adult females

Question 16

What is the lifecycel of strongyloides papillosus?

Answer 16

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

Question 17

What is the PPP of trichuris spp?

Answer 17

4-6wks

Question 18

What is the parasitic nematodes of ruminants and basic epidemiology?

Answer 18

Infection thry ingestion of infective stages from pasture.

Question 19

What are possible sources of springtime pasture contamination?

Answer 19

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)

Question 20

What is peak pasture contamination and transmission?

Answer 20

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

Question 21

How do we diagnose GI nematodes in cattle?

Answer 21

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

Question 22

How do we manage GI nematodes?

Answer 22

treat and quarantine new stock - prevent introduction
good husbandry: good nutrition and prevent concurrent dz
pasture management (avoid overgrazing)

Question 23

How o anthelmintics manage GI nematodes?

Answer 23

increasing problems w/ resistance
long acting anthelmintics, rumen boluses, residual effects

Question 24

How can strategic treatments manage GI nematodes?

Answer 24

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