Internal Parasites of Livestock

Internal Parasites of Livestock

  Internal Parasites: live within the internal organs of livestock ◦ They are not visible ◦ Effects on the host may be visible Divided into three groups ◦ Roundworms ◦ Tapeworms ◦ Flukes

Roundworms

   Most important from economic standpoint Many different types Affect almost every type of livestock

Stomach Worms

(Roundworm) 

Host: Every species of livestock

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Life Cycle:

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Adults live in stomach wall.

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Eggs pass from host and hatch into larvae

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Larvae are eaten by animal and travel to stomach where they mature.

Stomach Worms

(Roundworm)  Damage: ◦ Penetrate stomach lining ◦ Reduce digestion of nutrients ◦ Young undernourished animals are hit the hardest  ◦ ◦ ◦ Symptoms ◦ Anemia- paleness of gums and white of eyes Dull hair coat Scours Severe infestation can cause weight loss and death

Strongyles

(Roundworm)  Host: All species of livestock ◦ Cattle & horse can build up immunity by ages 4 or 5  ◦ ◦ Life Cycle: ◦ Adult is attached to lining of intestines Eggs pass from host Larvae attach to grass and are eaten by animal ◦ Pass through stomach and attach to intestinal wall

Strongyles

(Roundworm)  Damage: ◦ Most detrimental ◦ Anemia ◦ Scar tissue reduces digestion of nutrients ◦ Major cause of Colic in horses ◦ Poor feed conversion  ◦ ◦ ◦ ◦ Symptoms ◦ Anemia ◦ Weight Loss Scouring Loss of appetite Prostration Rough hair coat

Ascarids

(Roundworm)    Largest of round worms ◦ Can reach 8 to 15 inches in length Mainly affects younger animals Host: primarily cattle, sheep, hogs, and horses

Ascarids

(Roundworm)  ◦ ◦ ◦ Life Cycle: ◦ Eggs passed in feces contaminate pastures ◦ Animals ingest ◦ Larvae burrow into wall of intestine Migrate to liver, heart, and lungs Animal coughs up eggs and are swallowed Reach intestines a 2nd time and develop into adult stage

Ascarids

(Roundworms)  ◦ ◦ Damage: ◦ Develop pneumonia ◦ Weight loss Lung damage Colic in horses  Symptoms ◦ Weight loss ◦ Dull hair coat ◦ Colic

Pinworms

(Roundworms)  Small and found in colon or rectum of horses  Host: mainly horses, but can be found in other livestock species.

Pinworms

(Roundworms)  Life cycle: ◦ Adult females lay eggs around the anus of horse ◦ Eggs drop off and contaminate pastures, stables, watering and feeding area ◦ Eggs are ingested by animal ◦ Pass to colon and rectum and mature

Pinworms

(Roundworms)  Damage: ◦ Minor damage is caused ◦ Cause irritation around the tail  Symptoms: ◦ Tail rubbing ◦ White scales deposits are visible around anus

Habronema

(Roundworm)   Affects host in two stages Host: Horse is major host ◦ House fly is intermediate host

Habronema

(Roundworm)  ◦ ◦ ◦ Life Cycle: ◦ Adult stage is found in stomach Larvae is passed which is ingested by house fly House fly deposits eggs on lips of horse Horse swallows eggs and they mature in horses stomach

Habronema

(Roundworm)  Damage: ◦ Summer sores can form if larvae are deposited in open wounds ◦ Disfigure horses ◦ Hard to heal  Symptoms: ◦ Presence of summer sores ◦ Excessive tearing and running of eyes ◦ Open sores

Lungworms

(Roundworms)   Affect circulatory system & lungs Host: All species of livestock

Lungworms

(Roundworms)  ◦ ◦ ◦ ◦ Life Cycle: ◦ Eggs laid in lungs of animals ◦ Coughed up & swallowed Eggs hatch in stomach and larvae are passed Develop in moist earth or water Ingested by animal Burrow into lymph nodes and are carried to lungs where they mature

Lungworms

(Roundworms)  Damage: ◦ Mechanical blockage of lungs ◦ Collapse of infected area ◦ Blockage of windpipe and bronchea  ◦ ◦ Symptoms: ◦ Coughing ◦ Fast or forceful breathing Fever Animal reluctant to move ◦ Goes off of feed and water

Tapeworms

 Less important than roundworms  3 species of tapeworms ◦ Broad tapeworm ◦ Beef tapeworm ◦ Pork tapeworm

Broad Tapeworm

  Host: All classes of livestock and also in man Reach up to 10 feet in length  Life Cycle: ◦ Adult lives in small intestine ◦ Segments containing eggs break off and pass out of animal ◦ Eggs are eaten by oribated mite ◦ Mites are eaten by host and eggs hatch in small intestine

Broad Tapeworm

 Damage: ◦ No physical damage ◦ Tapeworm is in competition with animal for food.

 Symptoms ◦ Weight loss ◦ Diarrhea ◦ emaciation

Beef and Pork Tapeworm

   Both are similar and almost identical Host: ◦ Beef tapeworm- cattle and man ◦ Pork tapeworm- swine and man ◦ Man is necessary intermediate host Reach 5 feet in length

Beef and Pork Tapeworm

 ◦ ◦ ◦ Life Cycle: ◦ Adult lives only in man ◦ Eggs contaminate the feed of animal through human contact Animal ingests feed and eggs pass to intestinal wall Larvae lodge in some muscle causing a cyst Passed back to man when infected meat is eaten

Beef and Pork Tapeworm

 Damage: ◦ Little economic damage to cattle ◦ Causes mealy beef  Symptoms: ◦ No visible symptoms except when animal is slaughtered

Flukes

  Several species Liver Fluke is the most important

Liver Fluke

 Host: ◦ Parasite of cattle, sheep, goats, and man ◦ Damaging to young animals

Liver Fluke

 ◦ ◦ ◦ ◦ Life Cycle: ◦ Adult lives in bile ducts ◦ Eggs passed into intestines and passed out ◦ Eggs must be in water to hatch Larvae hatch and seek a snail Larvae develops on snail and then attaches to a plant Animals ingest infected plant Flukes pass to intestines and burrow through abdominal cavity to the lungs.

Liver Flukes

 Damage: ◦ Irritation and thickening of bile duct ◦ Fibrosis of the liver  Symptoms: ◦ Anemia ◦ Weight loss ◦ Death if not treated.

Tomorrow

 We will go over control methods of internal parasites.