Food Animal Parasitology

Question 1

Major parasites in cattle:

Answer 1

GI Strongylid nematodes (GIN, Trichostrongyles)
Coccidia
Flies
Lice

Question 2

Major parasites in small ruminants:

Answer 2

GIN- Haemonchus contortus
Coccidia
Less important: lice, meningeal worm, tapeworms

Question 3

T/F: If Haemonchus is controlled in small ruminants, typically all other species are controlled too.

Answer 3

TRUE

Question 4

What is the impact of trichostrongyles on young cattle?

Answer 4

Clinical disease
Subclinical impact on growth and development (primary impact)

Question 5

What is the impact of trichostrongyles on mature cattle?

Answer 5

Clinical- unusual
Subclinical- controversial
Beef- no consistent evidence, except first calf heifers
Dairy- unlikely to have effect unless cows pastured

Question 6

What is the veterinarian’s job in parasite control for cattle?

Answer 6

-Fix animals in trouble
-Help producers understand importance of integrated parasite control and what goes into it (not relying on drugs alone)
-Make sure owners are using effective drugs

Question 7

“Big 3” groups of cattle dewormers?

Answer 7

Macrocyclic lactones
Benzimidazoles
Nicotinics

Question 8

What are the major differences in dewormers for cattle?

Answer 8

-Macrocyclic lactones available as pour on
-Long acting eprinomectin (lasts about 5 months)

Question 9

What is the best deworming protocol for spring born beef calves?

Answer 9

May treat at start of grazing season
Calves <4 months don’t have much worm population
Midsummer tx of calves has shown benefit
Tx at weaning (replacements, not calves being sold)

Question 10

What is the best deworming protocol for fall born calves?

Answer 10

BEST: Deworm at pasture turnout (Start of grazing season) to limit maturation of larvae remaining from previous season

Question 11

What other times should we routinely deworm cattle?

Answer 11

Animals entering feedlots
Backgrounding depending on hx
Bringing in cattle from multiple sources