Unit 16: Parasitology

1. Unit 16: Parasitology

2. 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

3. 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

4. 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

5. 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

6. Unit 16: Parasitology • Most accurate method of diagnosis • Life cycles • Parasite limited to outside of animal • Ectoparasites that penetrate into the body causing tissue damage • Endoparasites – eggs ingested into stomach, hatch & mature, adults remain in stomach entire life, eggs passed out in feces • Require assistance from intermediate host to complete life cycle - tapeworms

7. Unit 16: Parasitology • Ingested into host, migrate from digestive tract to another part of host – ascaris worms, lungworms • 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

8. 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

9. 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

10. 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