Parasites of Domestic Production - Cattle (11)

Question 1

What are trichostrongylid nematode parasites of cattle, sheep, goats and camelids?

Answer 1

small, gut-dwelling nematodes
no extensive tissue migration

Question 2

What is the life cycle of trichostrongylids of cattle, sheep, goats and camelids?

Answer 2

simple, direct life cycle

Question 3

What is arrested development, aka hypobiosis?

Answer 3

an important adaptation to survival and maintenance of parasite populations

Question 4

What is the most economically significant parasite for cattle?

Answer 4

ostertagia spp. (type I and II)

Question 5

What is the most economically significant parasite for sheep, goats, and camelids?

Answer 5

haemonchus contortus - fatal anemia

Question 6

What is arrested development?

Answer 6

recently ingested pasture larvae enter the gut tissue, stop developing, and remain in juvenile state for several months
resume development when environmental conditions are favorable for parasite reproduction
adaptive strategy for survival of parasite populations

Question 7

What is the life cycle biology of trichostrongylid parasites?

Answer 7

adult worms live in the gut and reproduce
eggs passed in feces
free, living larvae develop to infective stage on pasture

Question 8

For trichostrongylids, animals become infected while _____

Answer 8

grazing

Question 9

The pre-patent period for trichostrongylids is ____ days

Answer 9

about 21 days

Question 10

How do you diagnose trichostrongylids nematodes?

Answer 10

periodic assessment of herd health (as a production unit)

Question 11

Eggs of trichostrongylids for all species are morphologically [indistinguishable/distinguishable]

Answer 11

indistinguishable

Question 12

What are the diagnostic methods for trichostrongylids?

Answer 12

fecal flotation
McMasters Quantitative (Fecal Egg Count Test)

Question 13

What is the appearance of trichostrongylids like on a fecal examination?

Answer 13

thin-shelled, modulated eggs

Question 14

What is the brown stomach worm?

Answer 14

ostertagia spp.

Question 15

For ostertagia spp., adult worms are parasitic in the ______

Answer 15

abomasum

Question 16

What are characteristics of ostertagia spp.? (Sex differentiation, size)

Answer 16

size: small
females larger
males with copulatory bursa - morphology of spicules are diagnostic

Question 17

Ostertagia spp. has a [direct/indirect] life cycle with _____ in the gastric pits

Answer 17

direct
arrested development

Question 18

Type [1/2] ostertagia spp. has tissue damage to abomasum

Answer 18

2

Question 19

What is Type I ostertagia spp. disease?

Answer 19

many worms acquired over short period of time
favorable environmental conditions
usually young animas (1st season on pasture)

Question 20

What is Type II ostertagia spp. disease?

Answer 20

occurs months after initial infection
older animals (2nd season on pasture)

Question 21

In Type 1 disease ostertagia spp., young cattle acquire substantial worm burdens grazing pasture between _____ and ______

Answer 21

October
March

Question 22

For Type I ostertagia spp., ingested infective larvae begin to arrest in tissues ______-______

Answer 22

April - September

Question 23

For type 1 ostertagia spp., larvae mature in the _____ of the stomach. Damage occurs when larvae leave here to become adult worms and reproduce. The process is continuous and _______

Answer 23

gastric glands
cumulative

Question 24

Type I ostertagiosis is characterized by what?

Answer 24

profuse watery diarrhea (often bright green)
bottle jaw from tissue leaking and impaired digestive function
loss of appetite, failure to Gian weight, loss of body condition
young animals most severely infected

Question 25

Type II ostertagia spp. infected larvae are acquired during ______

Answer 25

late spring months

Question 26

In Type 2 ostertagia spp., larvae enter the ______ and are [active/dormant]

Answer 26

gastric glands
remain dormant

Question 27

How does damage occur in Type 2 ostertagia spp.?

Answer 27

when larvae leave the glands “en masse” during late summer-fall months

Question 28

What is Type 2 ostertagia spp. clinical disease?

Answer 28

accumulation of large numbers of parasites over longer period of time when environment is hostile to pasture larvae survival
clinical signs similar to type 1 disease - this most severe
fecal exams likely negative

Question 29

What is Type 2 ostertagiosis characterized by?

Answer 29

brown, watery diarrhea
loss of appetite and loss of body conditoin
rumen pH approaches neutral
negative fecal exams
older animals

Question 30

Type 2 ostertagiosis has a [good/poor] response to treatment.

Answer 30

poor

Question 31

T/F: Type 2 ostertagiosis diagnosis is based on clinical signs and seasonal onset of disease from emergence of larvae

Answer 31

TRUE

Question 32

What are the other trichostrongylid parasites of cattle?

Answer 32

trichostrongylus sp.
cooperia - calves
nematodirus spp. - calves in late spring

Question 33

What is strategic de-worming?

Answer 33

removal of parasites from the host by exploiting their seasonal biology
- targeting inhibited larval stages - differential selectivity against inhibited larvae

Question 34

What is selective de-worming?

Answer 34

removal of parasites from “selected hosts” within a managed population
allowing a portion of the total parasite population to survive and reproduce in the absence of drug selection
host selection based on risk-mapping

Question 35

T/F: Strategic and selective de-worming is mutually exclusive

Answer 35

FALSE - is not mutually exclusive

Question 36

What is the prevention and control of ostertagiosis?

Answer 36

goal is to reduce pasture contamination and hazardous re-infection
map disease risk in herd