Unit 16: Parasitology

Unit 16: Parasitology

Lost production due to parasites = $10-$12 billion/yr in U.S.

Most economic losses in young animals Complete eradication impossible, must

control effectively Two types:

Ectoparasites Live on exterior of body

Endoparasites live on interior of body

Unit 16: Parasitology

Damage from parasites Ectoparasites

Damaging & irritating the skin Creating excitement, restlessness, nervousness Transmitting infectious organisms Sucking blood

Endoparasites Absorbing feed intended for the host Sucking blood & lymph from host Cause internal bleeding

Unit 16: Parasitology

Obstructing bile ducts, intestines, circulatory system Provide entry for infectious organisms

Parasites can mass migrate to major organs Liver, lungs, abdominal, chest, blood vessels

Symptoms Poor appetite, dehydration, unthriftyness, diarrhea, wt

loss, rough hair coat, slow gains, emaciation, weakness

Unit 16: Parasitology

Diagnosis of Parasitism Check fecal samples for parasite eggs Fecal examination

Smear fecal sample on a slide Check w/ microscope Can lead to false sense of parasite load

Flotation method Float parasite eggs to top of fecal sample using solution “catch” parasite eggs on a slide Examine w/ microscope

Unit 16: Parasitology

Most accurate method of diagnosis

Life cycles1. Parasite limited to outside of animal

2. Ectoparasites that penetrate into the body causing tissue damage

3. Endoparasites – eggs ingested into stomach, hatch & mature, adults remain in stomach entire life, eggs passed out in feces

4. Require assistance from intermediate host to complete life cycle - tapeworms

Unit 16: Parasitology

5. Ingested into host, migrate from digestive tract to another part of host – ascaris worms, lungworms

6. Require assistance from intermediate host, also migrate to other body parts to complete life cycle – liver flukes, lungworms

Control measures Proper nutrition

Maintain high nutritional status Keep pasture high quality

Unit 16: Parasitology

Prevent overstocking Increased stocking rates also increases parasite load Overstocking results in overgrazing

As grass is grazed closer to the ground, parasite risk increases

Most problematic during warm, wet conditions

Pasture rotation Keeps from overgrazing one single pasture

Prevent mixed grazing Don’t graze older and younger animals on same

pasture, if possible

Unit 16: Parasitology

Sanitation Keep lot, pasture dry Maintain good drainage Clean feed bunks

Controlling Parasites Endoparasites

Tapeworms, roundworms, flukes, flatworms Factors to consider before treatment

Pregnancy status Other illness & medications Method of drug administration

Unit 16: Parasitology

Rotate dewormers, keep on a schedule Keep in mind the life cycles

Ectoparasites Flies, lice, ticks, mites Cause: irritation, decreased production, tissue damage,

etc. Consider control measures carefully

Keep operation sanitary first Be careful of drug reactions & residues Be cautious of handling risks