Unit Animal Science
Problem Area Growth and Development of Animals
Lesson Animal Health
Student Learning Objectives • 1. Find and time a pulse on a dog and understand what sound makes a “heartbeat”. • 2. Be able to successfully give a physical exam and listen to heart, lungs, and observe the overall condition of the dog and be able to recognize signs of an unhealthy or stressed animal (i.e., elevated or depressed temperature, erratic heart rate, irregular breathing, pale gums, etc.). • 3. Discuss common diseases found in pets and livestock animals.
Terms • Capillary Refill Time (CRT) • Contagious • Diseases • Non-contagious • Pulse • Respiration rate • Stethoscope • Vaccination
How do we find and time the pulse on a dog and what sound makes a “heartbeat”? • The pulseof an animal is the rhythmic expansion of an artery which may be felt with a finger. The pulse correlates with the heart rate (how quickly the heart is beating) of the animal. • A. To find the pulse rate of a dog, feel caudal and dorsal to the elbow of a standing dog. The pulse can also be felt on the inside of the dog’s thigh, about level with the knee. Count the number of beats in one minute (or the number of beats in 15 seconds and multiply by 4). This is the dog’s resting pulse, or heart rate.
B. The pulse happens at the same rate as the beating of the heart because the heart is pumping the blood. As more blood is pumped, the arteries expand and blood is cycled back to the heart. • C. The sound of a heartbeat is caused by the opening and closing of the valves of the heart. Because the heart is a muscle and is contracting to pump blood to the body, there is siderable force closing the valves of the heart. There are two valves that separate the chambers of the heart and give off the “lub-dub” sound that can be heard with a stethoscope, an instrument for listening to internal body sounds.
How do we give a physical exam and listen to the heart, lungs, and observe the overall condition of a dog? What are the signs of an unhealthy or stressed animal? • Giving a physical exam to a dog requires observation of the pulse, respiration rate, temperature, and capillary refill time (CRT). • A. The pulse can be taken from the inside of the thigh or elbow of the dog. Please refer to the procedures outlined in objective 1.
B. The respiration rate, or number of breaths per minute, can be calculated by simply counting the number of breaths the animal takes in one minute (or counting for 15 seconds and multiplying by 4). Respiration can also be found by holding a stethoscope to the dog’s chest to listen to lung sounds. • Respiration rate will decrease as the animal size increases. A normal respiration rate for a dog would be approximately 22 breaths per minute. A sign of an unhealthy animal would be rapid and shallow breathing or extremely slow respiration.
C. The temperature of the dog must be taken with a rectal thermometer. Dogs could become agitated and bite down on a thermometer inserted into the mouth. When using a rectal thermometer, insert the thermometer 1.5 to 2 inches into the rectum of the animal and leave it for one minute. The normal temperature range for a dog is 101 to 102.5°F. Unhealthy animals, like humans, will run a temperature if they are fighting an illness.
D. Capillary Refill Time (CRT), is an indication of how quickly blood will refill the capillaries of body tissues. To check CRT, raise the upper lip of the dog and press on the gum and release. In a healthy animal, the gum will turn white and then pink again. Unhealthy animals will have a CRT of longer than 3 seconds. Animals with CRT of more than 3 seconds could be exhibiting signs of shock.
E. An overall check of animal health is also important during a checkup. Things to observe in an overall check would be dog behavior (excited?, wagging tail?, lethargic?), coat condition (shiny or dull?), eye condition (bright eyes or dull?, responsive to activity?), and teeth condition (white, clean, strong teeth?, healthy gums?).
What are common diseases found in pets and livestock animals? • Diseasescan be defined as some disturbance of normal body functions or structures. Some diseases are specific to a certain type of animal or livestock. • Most diseases can be controlled with a vaccination, or injection of a disease fighting medicine. Some vaccinations are actually low doses of the disease itself, allowing the body to fight the disease and build up a resistance for the next exposure to the disease.
A. Diseases can either be contagious, able to be spread to other animals, or non-contagious, unable to be spread to others. Contagious diseases are caused by viruses, bacteria, fungi, protozoa, and parasites. Non-contagious diseases can be caused by nutrient deficiencies, body defects, animal injuries, and genetics.
B. Some selected common diseases of livestock are listed below. • 1. Anthrax—An infectious disease that will attack most warm-blooded animals. Can affect cattle during summer when they are on pasture. • 2. Brucellosis—An infectious disease of the reproductive tract of cattle, sheep, goats, hogs, and can be spread to humans. Also known as ‘Bang’s’, this disease causes developing fetuses to abort and can be fatal. • 3. Hog Cholera—A highly contagious viral disease of swine that can be fatal. There is no known treatment for cholera and all swine with cholera must be destroyed.
4. Coccidiosis—A parasitic disease affecting poultry that can be treated with a medication in the feed and water. Birds must be isolated for treatment. • 5. Sleeping Sickness—A virus in horses caused from insect bites. Symptoms include reckless walking, sleepy appearance, cannot swallow, and grinding of teeth. Most horses die within two to four days, but some can recover with treatment. • 6. Foot and Mouth—A disease that only affects animals with cloven or divided feet. Caused by a virus, it is highly contagious and has no known treatment at this time. Infected animals get watery blisters around the mouth and skin of the foot.
7. Mastitis—A bacterial disease that affects female cattle, sheep, goats, and swine. An inflammation of the udder that interferes with milk production. Although treatable, chronic mastitis can lead to death of the animal. Milk from a diseased animal cannot be sold for consumption or any use. • 8. Rabies—An infectious disease that can occur in nearly every warm-blooded animal. Caused by a virus, this disease can be spread to humans. Affected animals may become “crazed” or exhibit aggressive behavior, as well as other symptoms. Although treatment is available for humans, animals with rabies are destroyed and autopsied to diagnose the disease.
Review/Summary • How do we find and time the pulse on a dog and what sound makes a “heartbeat”? • How do we give a physical exam and listen to the heart, lungs, and observe the overall condition of a dog? What are the signs of an unhealthy or stressed animal? • What are common diseases found in pets and livestock animals?