Parasites

Question 0

Two different meanings of the word “resistant”

Answer 0

Some animals are more resistant (resilient) to internal parasites.
Internal parasites can become resistant (not responsive) to some dewormers.

Question 1

Anthelmintic

Answer 1

General term for dewormers

Question 2

Animals that are more susceptible to parasitism

Answer 2

Weaned animals, yearlings, late born animals because there might be older ones around by the time they are born that are already shedding parasite eggs, high producing females, periparturient females, thin animals, geriatric animals, unadapted animals–new to your farm and not used to the parasites you have there, stressed animals.

Question 3

Animals that are more resistant to parasites

Answer 3

Mature animals, dry animals, pets, mature wethers, animals in good body condition

Question 4

What percentage of the herd expels 80% of the parasite eggs on the pasture?

Answer 4

20%

Question 5

Two types of internal parasites and their cellular type

Answer 5

Helminths (multi-cellular) and Protozoa (single-celled)

Question 6

Nematodes aka

Answer 6

roundworms

Question 7

Cestodes aka

Answer 7

tapeworms

Question 8

Trematodes aka

Answer 8

Flukes

Question 9

Examples of Protozoan parasites

Answer 9

Coccidia, Giardia, and Cryptosporidium

Question 10

Types of Roundworms

Answer 10

Haemonchus contortus, Bankrupt worm, Brown stomach worm, Meningeal worm, Hookworm, Small intestinal worm, Threadneck worm, Nodule worm, Common threadworm, Whipworm, Lungworms

Question 11

Parasite Life Cycle

Answer 11

1. Animals shed the parasite eggs in their feces 2. Eggs hatch into larvae on pasture and crawl up the blades of grass 3. Animals eat the grass with the larvae on it and they go inside animal and reproduce…

Question 12

Signs of Parasite Infection

Answer 12

Weight loss, bottlejaw, anemia, weakness, sudden death

Question 13

Pros of Using FAMACHA

Answer 13

Reduces number of anthelmintic treatments and therefore money spent on it, helps you identify resilient and susceptible animals (repeat offenders)

Question 14

Cons of Using FAMACHA

Answer 14

Only useful when H. contortus is primary parasite and takes a lot of time to check all the animals monthly

Question 15

Scour worms

Answer 15

Trichostrongylus and Teladorsagia
Usually seen in conjunction with H. contortus
Prevalent in fall, cooler seasons
Affect abomasum and SI
Cause decrease in performance and diarrhea

Question 16

Tapeworms

Answer 16

Affect SI–steal animal’s nutrients not blood, generally non-pathogenic (will not kill animal), can grow to be several feet long, life cycle has to go through a mite which is what the animals actually swallow, Benzimidazoles control them, worm segments are passed in feces

Question 17

Liver Flukes

Answer 17

Indirect life cycle with snail as intermediate host, mostly problem in Gulf states and Pacific NW, cannot be seen in fecal float, treat with Valbazen.

Question 18

Three Classes of Anthelmintics and which ones parasites are resistant to

Answer 18

1. Benzimidazoles 2. Macrocylic Lactones 3. Nicotinic antagonists. Parasites are resistant to all three.

Question 19

Benzimidazoles

Answer 19

Safeguard, Valbazen, Synantic, called white drenches, have wide margin of safety, Valbazen cannot be administered to pregnant animals in the first 30 days of gestation, these are broad spectrum dewormers.

Question 20

Nicotinics

Answer 20

Levamisole, Morantel, Pyrantel. Some of them work on adult worms only and some have only small margins of safety.

Question 21

Macrolides

Answer 21

Ivermectin, Doramectin, Moxidectin. Broad spectrum, wide margin of safety, effective against biting external parasites also.

Question 22

Why does resistance to dewormers occur?

Answer 22

Underdosing allows what’s not killed to proliferate, rotating dewormers every time, treating all the animals, not doing to fecal egg counts 10 to 14 days after using dewormers to see if they have been effective.

Question 23

Deworming Guidelines

Answer 23

1) Only deworm animals with FAMACHA scores of 3, 4, or 5. 2) Always get an accurate body weight to determine dose 3) Goats should receive 2x the dose as sheep or 1.5x for levamisole 4) Drench over back of tongue so animals do not spit it out 5) Fast animals 12 hours before dosing 6) Follow withdrawal times 7) Cull repeat offenders instead of spending money to keep treating.

Question 24

Coccidia

Answer 24

*Many species of coccidia with 10 known to affect small ruminants *Symptoms: dark foul smelling diarrhea, weight loss, dehydration, weakness *Usually affects young, just weaned, stressed animals *It damages the intestinal lining and causes poor feed utilization *Prevent by keeping feeders and waterers free from feces *Put coccidiostats in feed to slow down shedding *Extra-label treatment with Amprolium or Sulfadimethoxine

Question 25

Types of External Parasites

Answer 25

Keds, Lice, Ticks, Mange Mites

Question 26

What problems do external parasites cause?

Answer 26

Itchiness, irritation, transmit diseases, hair or wool loss, decreased weight gain, decreased milk production, respiratory distress.

Question 27

What are keds?

Answer 27

Wingless parasitic flies

Question 28

What are lice?

Answer 28

External parasite, common in winter, they are species specific, they can bite and chew.

Question 29

Where are ticks usually found?

Answer 29

Around the ears.

Question 30

Where are mange mites usually found?

Answer 30

On the skin or burrowed in the skin.

Question 31

How to Treat External Parasites

Answer 31

Shear and then treat entire flock. Mange mite and/or lice infestations should be treated twice two weeks apart. Wear gloves so products do not absorb through skin. Always follow withdrawal times. Products can be sprays, dips, or pour-ons.

Question 32

Nasal Bots

Answer 32

The fly Oestrus ovis (does not bite)– its larvae live in nasal passages and get sneezed out. Causes nasal discharge and head shaking. Can be treated with an Ivermectin drench.

Question 33

Fly Strike

Answer 33

Adult flies lay eggs in wool and tissues around wounds then the larvae burrow under the skin and feed on secretions. More prevalent in hot, humid weather. More of a problem than nasal bots. Usually seen in sheep with undocked tails. Best to prevent it but if already affected then scrub area with soap and treat affected area with spray or dip.

Question 34

Which breeds are more parasite resistant?

Answer 34

Hair sheep such as Kiko, Katahdin.

Question 35

Ways to Prevent Parasite Problems

Answer 35

1. Feed adequate energy and protein 2. Use resistant breeds 3. Rotational grazing, let pastures rest, let goats browse 4. Multi-species grazing (most parasites are species specific) 5. Use high tannin forages such as Birdsfoot trefoil and Sericea Lespedeza