Chapter 15-16 Disease Prevention and Classification — Key Concepts

What is essential for immunity to develop after vaccination?

The animal must be able to respond to the vaccine; maternal antibodies and other factors (stress, illness, poor nutrition, medications) can prevent the response.

Why can very young animals fail to respond to vaccines?

Maternal antibodies may bind the antigen, preventing the immune system from responding.

Name the two major types of vaccines used in veterinary practice.

Killed vaccines and modified live vaccines (MLVs).

How does a killed vaccine stimulate immunity and what is the typical booster timing?

The organism is inactivated; a primary vaccination initiates the response, and a booster 3–4 weeks later stimulates the memory response.

What is the typical duration of immunity from killed vaccines and how are boosters spaced?

Immunity is relatively short; boosters are needed every several months to a year to maintain protection.

How do modified live virus vaccines (MLVs) work?

The virus is weakened so it can replicate without causing disease; replication increases antigen, stimulating a strong immune response.

Do modified live vaccines (MLVs) usually require boosters in the same schedule as killed vaccines?

Many MLVs do not require a booster in the initial 3–4 week period; boosters may be needed every 1–3 years, but immunity is not guaranteed to be indefinite.

What are key handling/storage considerations for modified live vaccines?

They are reconstituted from a dehydrated powder and must be used immediately; they are sensitive to extreme temperatures, direct sunlight, and many disinfectants; require proper refrigerated storage.

What happens if the organism in a vaccine does not replicate?

Not enough antigen is produced to stimulate an adequate immune response, leading to potential vaccine failure.

Why is booster timing after a killed vaccine important?

If given too early (

What is metaphylaxis in farm management?

Prophylactic use of antibiotics at times of high risk (e.g., arrival of calves) to reduce cases, lessen severity, and improve weight gain.

What is quarantine and how long should it last?

Isolating new animals from the herd for 2–4 weeks with separate utensils to ensure they are not incubating disease.

What is an all-in all-out system?

All animals leave the farm, the facility is cleaned and sanitized, and the next group arrives, ideally from one source.

What is kennel cough and why is vaccination often required for boarding?

A highly contagious respiratory infection in dogs with a severe dry cough; spreads by air or direct contact; vaccination is often required to reduce risk in close-quarters housing.

What is equine infectious anemia (EIA) and why screen horses before events or purchases?

A viral disease causing fever, anemia, depression, and weight loss; carriers can shed virus under stress; screening helps prevent introduction of disease.

What does biosecurity aim to prevent on a farm?

The introduction of pathogens by vectors such as visitors, trucks, rodents, birds, water, and new stock; includes sanitation and screening.

What is bio-containment?

Practices used to minimize the spread of disease if it is introduced onto the farm.

List common vaccine side effects.

Soreness and swelling at the injection site; mild fever, lethargy, poor appetite; sometimes abortion risk in pregnant animals; rare anaphylaxis.

Can vaccination increase abortion risk?

Yes, some vaccines may increase the risk of abortion in pregnant animals.

How do vaccines differ in the level and duration of immunity they provide?

Modified live vaccines generally provide higher and longer-lasting immunity than killed vaccines.

Is there a vaccine for canine distemper?

Yes, vaccines exist and are routinely used as part of canine vaccination schedules.

What does the MAD TIN mnemonic stand for in Chapter 16?

Major classifications of diseases: Metabolic, Anomalies, Degenerative, Traumatic, Toxins, Infectious, Immune, Iatrogenic, Idiopathic, Neoplasm, Nutrition.

What is pregnancy toxemia and a key diagnostic/therapeutic feature?

A metabolic disease in late-pregnancy ewes/does with multiple fetuses; ketone buildup (acetone) causes a sweet breath; treated with energy replenishment and, if needed, removal of fetuses (induction or cesarean).