Animal Diseases & Health

1. Animal Diseases & Health

2. Disease: not be at ease, uncomfortable due to a variety of causes such as – nutritional defects, virus, bacteria, protozoa, etc. Infectious Disease: caused by microorganisms that invade the animal’s body. Usually contagious (infected animal can pass the disease on to a healthy animal) Bacteria: harmful bacteria invade the cells of an animal’s body. Parasitic bacteria may harm the animal by feeding off the body cells or by secreting a material known as a toxin. Toxin: substance that causes harm to an organism (poison)

3. Types of Bacteria Cocci: round, spherical-shaped bacteria. Ex: pneumonia, strep infection Bacillus: rod-shaped organisms that may be single, in pairs, or arranged in chains. Ex: anthrax, tetanus, blackleg, intestinal coliform, salmonella, tuberculosis Spirilla: shaped like spirals or corkscrews. Very motile (move very easily). Also require a moist atmosphere to survive. Live well in reproductive tracts of animals. Ex: leptospirosis, spirochetosis, vibriosis Most bacteria can be controlled by the use of antibiotics. (Ex: penicillin)

4. Viruses Very tiny particle of matter composed of a core of nucleic acid and a covering of protein that protects the virus. Made up of some of the material found in cells, but they are not a cell because they don’t have a nucleus or other cell parts. Viruses don’t grow and can’t reproduce outside a living cell. Viruses reproduce using the energy and materials in the invaded cell. They harm cells by causing them to burst during mitosis of the virus and by using material in the cell that the cell needs to function properly.

5. Viral diseases cause the animal to be sick by preventing certain cells in the animal’s body to function properly. Viral diseases are more difficult to treat than diseases caused by bacteria. Many are incurable. The best means to deal with them is prevention Exs: foot-and-mouth disease, influenza, hog cholera, and pseudorabies Protozoa Single-celled organisms that often are parasitic. Cause harm to animals by feeding on cells or by producing toxins. Most protozoa can be controlled by drugs. Exs: African sleeping sickness, anaplasmosis, coccidiosis

6. Noninfectious Diseases – not contagious Genetic Diseases: caused by defects in the genes that were transferred from the animal’s parents Nutritional Diseases: all animals need certain amounts of a variety of nutrients. If these nutrients are not in the animal’s diet, the animal can become very ill. (ex: milk fever) Poisoning – agricultural animals can be made sick by ingesting toxic materials. (ex: milkweed) PARASITES Parasitism: relationship that’s beneficial to one animal and harmful to another. The animal that lives off the other animal is called a parasite; the animal that is the parasite lives on or in is called the host.

7. Most parasites live off the blood of the host animal. The continual loss of blood causes anemia. An animal becomes anemic when the blood supply is greatly diminished from the parasites living off the blood. The host becomes ill because the body cells aren’t getting enough oxygen and food nutrients. Parasites often carry disease organisms from one animal to another. Parasites can be divided into two categories: internal parasites and external parasites.

8. Internal Parasites: live within the animal’s body and may feed on the animal’s blood or on feed that passes through the animal. There are three (3) major groups: Roundworms: cause more damage to agricultural animals than any other group of internal parasites. They infect almost all types of livestock and exist by living in the digestive tracts of their hosts. - Stomach worms: infect all classes of livestock and cause damage by the adults’ burrowing into the lining of the host’s stomach and sucking the animal’s blood. The worms lay eggs in the stomach of the host and pass out of the animal in the feces. - Strongyle: similar to stomach worms in their life cycle, except that they live in the intestines of the host animal. Strongyles cause damage by causing scar tissue in the small intestine and sucking blood from the host animal.

9. - Ascarids: often attack young animals. Ingested by animals grazing on blades of grass to which larvae have attached themselves. The larvae burrow into the walls of the intestines and from there work their way through the host’s heart, liver, and lungs. Tapeworms: class of works that are segmented. Body of the worm is made up of distinct segments. Each segment contains both the male and female reproductive organs. These segments are broken off the body of the worm and reproduce. The adult of the tapeworm lives in the small intestine of the host. They grow to be quite large, with some reaching lengths of 25 ft! These worms live off feed that is passed into the host animal’s intestine. It causes the animal harm by devouring the food the animal has eaten.

10. Intermediate Host: an animal that a parasite uses to support part of its life cycle. An intermediate host is not harmed by the parasite. Since the mite lives on grasses, they are swallowed by the grazing animals. The eggs are then passed through the animal to the small intestine, where they hatch and live until maturity. Flukes: small, seed-shaped flatworms that live in various parts of the host animal. The most damaging of the flukes are those that live in the liver. EXTERNAL PARASITES: Generally don’t cause as much damage to animals as internal parasites. They can cause losses in terms of animal comfort and through the loss of hide quality and blood loss. External parasites include ticks, lice, and flies.

11. Ticks: generally attach themselves to most of the warm-blooded agricultural animals. They cause damage by penetrating the skin and sucking blood from the host animal. Tick eggs are laid in the grass to hatch in the spring. When an animal passes by, the tick attaches itself to the animal and gorges on the animal’s blood. When the tick feeds, it inserts its mouth into the host animal’s skin and injects saliva into the wound. The saliva contains an anticoagulant and allows the blood to flow freely into the tick. Lice: tiny, wingless insects that spend its whole life on the host animal. Two types: - blood-sucking lice that feed by drawing blood through the animal’s skin - biting lice that feed on the hair or skin particles Heel flies: (cattle grub) larvae burrow through the soft tissue of the lower leg of cattle and travel to the back, where they eat a hole in the skin of the back for a breathing hole. They feed on the animal’s flesh until they mature.

12. Physical exams are performed to assess a patient’s condition. After a patient’s assessment, the information is written into a medical record. The animal’s signalment should always be included. This is a description of the animal, including species, breed, age, and sexual status (intact or neutered). Vital signs are parameters taken from the animal to assess its health. These include: temperature, pulse, respiration rate, and blood pressure.

14. RESEARCH: In your notebooks, you will research 5 different diseases to include a chart like this: You will also choose 2 parasites (1 internal & 1 external) to research their symptoms, treatment, and prevention taken for each in animals.