Healthy Populations Block 2 Problem Investigations

problem investigation definition

a targeted assessment of health and welfare of a group of animals (herd, flock, or other population) to investigate and address a specific problem

problem investigation vs health assessment

problem investigation:

1. targeted

2. specific

3. presenting complaint

4. make diagnosis for existing problem

health assessment:

1. holistic

2. non-specific

3. annual physical exam

4. determine if there are existing problems

When to do a problem investigation?

1. perceived/real increase in disease frequency

2. production issues

3. husbandry or population management issues

Why do a problem investigation?

1. identify likely cause

2. prescribe correct population treatment

3. choose recommendation most practical, affordable, and impactful

Steps in Problem Investigation

1. gather information

2. verify problem exists

3. establish case definition

4. plan investigation

5. formulate hypotheses

6. test hypothesis

7. design intervention

Gather Information

1. Who

   1. establish population

2. What

   1. signs and symptoms

   2. consistency across groups

   3. prior diagnostics

3. When

   1. what ages

   2. when in calendar year are cases occurring

4. Where

   1. sites/barns/pens/within-pen location

5. How many

   1. prevalence

   2. incidence

   3. use records

Verify problem exists

look at how many, consider denominator and accepted standards

Establish case definition

ask for animals representative of problem and do physical exam

Plan investigation

resistance vs challenge; want to improve resistance and decrease challenge; also plan diagnostics

resistance vs challenge

• high resistance and low challenge = prevention

• high challenge and low resistance = disease

formulate and test hypothesis

Is it…

1. plausible

2. deficient relative to standard

3. published evidence

4. on-farm association

design intervention

generate recommendations that are…

1. practical

2. feasible

3. consider labor inputs

4. consider opportunity costs