Johne’s Disease

Question 1

Why is MAP hard to control

Answer 1

Resistant to disinfectants and antibiotics
Survives >1yr on pasture; survives well in slurry and water
Can infect (and affect) other species
Sheep
Deer
Rabbits

Question 2

What is Johne’s disease most common transmission route

Answer 2

Faeco-oral

Question 3

When do majority (80%) of infection occur

Answer 3

First month of life

Question 4

Cows infected Usually remain bright and appetent until terminal stages (T/F)

Answer 4

True

Question 5

C/S for Johne’s in Dairy

Answer 5

Reduced milk yield
Reduced fertility
Poor body condition
Usually culled for poor performance

Question 6

C/S for Johne’s in Beef

Answer 6

Poor fertility
Small calf born,calf does not do well
Poor condition
Diarrhoea
Peripheral oedema (Bottle jar)

Question 7

Why is testing for Johnes tricky in regards to blood antibody levels

Answer 7

Takes 2-3 years to meet detection threshold
Antibody level ebbs and flows

Question 8

Is antibodies effective

Answer 8

No. Only useful in testing

Question 9

What samples detect MAP organism

Answer 9

Faecal PCR
Faecal Culture/Smear

Question 10

What samples detect antibodies

Answer 10

Serum and milk ELISA

Question 11

If cow is infected with MAP, what will a positive faecal smear Ziehl Nielhson

Answer 11

Clumps of acid fat

Question 12

Faecal culture or faecal smear is gold standard

Answer 12

Faecal culture but takes a long time to grow

Question 13

Johne’s disease treatment

Answer 13

NO TREATMENT BLEH. Get rid of animal.

Question 14

What to do in a farm visit when controlling Johnes

Answer 14

Identify risk areas
Identify risk assessment
Discuss control

Question 15

Step 1 in detecting MAP in dairy herd

Answer 15

Bulk tank antibody ELISA

Question 16

Step 1 (beef) and step 2 (dairy) in detecting MAP

Answer 16

Sample proportion of herd to determine prevalence

Question 17

Step 3

Answer 17

Individual screening

Question 18

What is the age of cow to be blood tested for MAP

Answer 18

> 2 years

Question 19

Johne’s accredited free must pass how many annual screening

Answer 19

3

Question 20

Outline CHeCS disease status accreditation

Answer 20

Level 1-5. Completely voluntary
1- pass 3 annual test
2- not cleared 1
3- there is reactors but <3%
4- more than 3%
5- no testing

Question 21

Why is beef cows harder to control transmission

Answer 21

less ability to manage transmission between infected dam/adults and young calves than dairy
Possibly increased chance of calves being exposed to other host (sheep/deer) as more likely to be outside during critical period (first month)
Environmental management probably most feasible (fencing off standing water etc.)

Question 22

5 key concepts in controlling Johnes in beef/dairy

Answer 22

1. Identify status of breeding cattle
2. Seperate into neg and pos cow groups
3. Biosecurity: establish status of new comers
   4 .Keep replacements from negative-test cows and from calves that have had less infection-pressure (i.e. calved at grass)
4. Slurry and / or manure management: not on pasture grazed by youngstock; esp slurry from known positives

Question 23

Johne’s control in dairy herds

Answer 23

As for beef, plus:
Don’t pool colostrum in herds with known Johne’s disease from cows with unknown / positive test status
“Herdwise” testing scheme

Question 24

What is herdwise testing scheme

Answer 24

quarterly individual milk antibody testing used as a tool to control the disease within a herd.

traffic light system is used to categorise cows, and inform management decisions about which milk to collect for replacement feeding and animals testing positive are put into separate calving facilities.

all cattle are re-tested every 3 months when in milk, so decisions are less based on a single antibody result.

Repeat positives are culled as they are likely to have reduced milk yield and will be contributing to environmental contamination.

Question 25

Is Johne’s vaccination effective

Answer 25

Not regular in UK. Not used much