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 cycles 1. 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