AS264 Exam 2 (Answered) 161
Questions and Correct. Latest
2025/2026. 100% Verified.
What are the 3 components of the epidemiologic triad?
agent, host, and environment
What are some predisposing factors that make neonatal calves susceptible to scours?
1. Failure of passive transfer
2. Overwhelming pathogen exposure
3. External stressors
How can neonatal scours be prevented? Which part of the epidemiologic triad does each strategy
address?
Increase resistance in host (host), nutritional support for sick calves (host), dry environment
protected from wind (environment), and preventing overwhelming exposure (agent)
How does the pathogen spreading of cows differ from calves?
cows carry and shed pathogens at low levels
What is the Sandhills Calving System and how does it work?
Multiple calving pastures are used, herd begins calving on one pasture, 7-10 days later, pregnant
cows move to a new pasture, process is repeated every 7-10 days, and when youngest calf is >4
weeks old, groups can be mixed
What is biocontainment?
Minimizing exposure to germs already on the farm
What are some examples of biocontainment that are used in production agriculture?
Sandhills Calving System, isolation of sick animals, removal at birth, early weaning, and all-in-all-out
production
What is biosecurity?
Denying entry of new infectious agents
What are some biosecurity risks that could be encountered on a livestock operation?
People transporting pathogens, vehicle traffic, rodents, insects, wildlife, supplies, equipment, and
long-distance aerosol spread
What are the primary differences between killed and modified live vaccines?
- Killed vaccines are unable to replicate in the host, fairly stable, and require boosters
- Modified vaccines must be live and able to replicate, rare possibility of regaining virulence, and
must be kept viable
, What factors can reduce the viability of a modified live vaccine?
1. Time after reconstitution
2. Heat
3. Sunlight
4. Freezing
5. Disinfectant in syringes
What factors in the animal might prevent a vaccine from working properly?
1. Stress
2. Maternal antibodies
3. Poor vaccine timing (animal is already infected)
4. Malnutrition
5. Immune system suppression (BVD)
What factors associated with the vaccine might prevent it from working properly?
1. Improper storage and handling
2. Incorrect strain in the vaccine
3. Improper dose used
What are the different types of adverse reactions that livestock can have to a vaccine?
1. Injection site reactions
2. Anaphylaxis (allergic reaction)
3. Endotoxin stacking
4. MLV IBR vaccines given to pregnant cows
Where should injections be administered to beef cattle?
in the neck
How do internal parasites spread?
Eggs shed from adult in feces, juveniles hatch in manure and eat bacteria, and juveniles leave
manure and crawl up blade of grass to be eaten by cows
What are the most important species of parasites in cattle?
Strongyles, such as ostertagia
What is the best, middle, and worst way to administer dewormer?
Oral, injectable, and pour on
What are some external parasites?
flies and lice
What length needle should be used for intermuscular injections? How does this differ for sub-
cutaneous injections?
- IM = >1 inch - SC = <1 inch
What are 4 alternatives for marketing feeder calves?
Questions and Correct. Latest
2025/2026. 100% Verified.
What are the 3 components of the epidemiologic triad?
agent, host, and environment
What are some predisposing factors that make neonatal calves susceptible to scours?
1. Failure of passive transfer
2. Overwhelming pathogen exposure
3. External stressors
How can neonatal scours be prevented? Which part of the epidemiologic triad does each strategy
address?
Increase resistance in host (host), nutritional support for sick calves (host), dry environment
protected from wind (environment), and preventing overwhelming exposure (agent)
How does the pathogen spreading of cows differ from calves?
cows carry and shed pathogens at low levels
What is the Sandhills Calving System and how does it work?
Multiple calving pastures are used, herd begins calving on one pasture, 7-10 days later, pregnant
cows move to a new pasture, process is repeated every 7-10 days, and when youngest calf is >4
weeks old, groups can be mixed
What is biocontainment?
Minimizing exposure to germs already on the farm
What are some examples of biocontainment that are used in production agriculture?
Sandhills Calving System, isolation of sick animals, removal at birth, early weaning, and all-in-all-out
production
What is biosecurity?
Denying entry of new infectious agents
What are some biosecurity risks that could be encountered on a livestock operation?
People transporting pathogens, vehicle traffic, rodents, insects, wildlife, supplies, equipment, and
long-distance aerosol spread
What are the primary differences between killed and modified live vaccines?
- Killed vaccines are unable to replicate in the host, fairly stable, and require boosters
- Modified vaccines must be live and able to replicate, rare possibility of regaining virulence, and
must be kept viable
, What factors can reduce the viability of a modified live vaccine?
1. Time after reconstitution
2. Heat
3. Sunlight
4. Freezing
5. Disinfectant in syringes
What factors in the animal might prevent a vaccine from working properly?
1. Stress
2. Maternal antibodies
3. Poor vaccine timing (animal is already infected)
4. Malnutrition
5. Immune system suppression (BVD)
What factors associated with the vaccine might prevent it from working properly?
1. Improper storage and handling
2. Incorrect strain in the vaccine
3. Improper dose used
What are the different types of adverse reactions that livestock can have to a vaccine?
1. Injection site reactions
2. Anaphylaxis (allergic reaction)
3. Endotoxin stacking
4. MLV IBR vaccines given to pregnant cows
Where should injections be administered to beef cattle?
in the neck
How do internal parasites spread?
Eggs shed from adult in feces, juveniles hatch in manure and eat bacteria, and juveniles leave
manure and crawl up blade of grass to be eaten by cows
What are the most important species of parasites in cattle?
Strongyles, such as ostertagia
What is the best, middle, and worst way to administer dewormer?
Oral, injectable, and pour on
What are some external parasites?
flies and lice
What length needle should be used for intermuscular injections? How does this differ for sub-
cutaneous injections?
- IM = >1 inch - SC = <1 inch
What are 4 alternatives for marketing feeder calves?
