JOHNE’S DISEASE - PREVENTION AND CONTROL

IN DAIRY HERDS

 

A Manual for Veterinarians

 

Designed and edited by:

C. A. Rossiter Cornell University, D. Hansen Oregon State University, L. J. Hutchinson

The Pennsylvania State University, R. H. Whitlock University of Pennsylvania

 

Revised Edition

 

This Manual is designed for use by veterinarians with their dairy clients to develop a farm plan

A-2

Performance goals____________________________________________________

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Herd health concerns you are or plan to address____________________________

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Management concerns you are or plan to address___________________________

_______________________________________________________________________

Area(s) you want to improve profitability in__________________________________

_______________________________________________________________________

 

Herd History for Johne’s Disease (JD):

First diagnosed case of Johne’s in your herd:

Year_______ Animal source (owned or purchased)_______________________

 

Clinical cases in the past.

List ID, date, age, source (raised or purchased) and offspring still in herd for animals that were confirmed or suspected of having Johne's disease in the last 10 years. If there are no records, then memory will suffice.

 

Interpretation. Considering which animals you now suspect had JD can help you understand how much the infection has spread. Clinical cases shed, often explosively, billions of the M. avium subspecies paratuberculosis bacteria in their manure.

 

Interpretation for raised or purchased status of suspects or cases: Where animals were born and reared is important, as it can indicate whether animals were infected on your farm, or possibly brought the infection with them. If cases have occurred in purchased and not in raised animals, infection is not likely well established in the herd.

Youngest clinical case (age, date, source)_________________________________

 

Interpretation for age of clinical JD suspects, or test positive animals: Cases in home-raised, first-calf heifers are an alert that infection may be widespread in the herd. Generally,  the younger the clinical case, the greater and/or longer the exposure that animal had to the JD microbe.

 

Recent Herd History

B-3

PREVALENCE AND RISK

Prevalence is percentage of infected animals in the herd at any one point in time. Prevalence can be estimated by testing all adult animals with a serologic or fecal culture diagnostic test.  Another way to get a rough estimate of the prevalence is to apply the interpretative information that follows.  Neither of these methods will be exact but they can used to measure, a beginning point, status of a prevention plan or progress made in a control program.

 

Scoring Johne's Herd Prevalence from the Herd History

 

Low,  Score 1 or 2  

Ø     no culture confirmed clinical cases (i.e., > 4 yr old animals (raised or purchased)

Ø     clinical cases 1 % or less of herd /year/ on average for several years

Ø          management history includes low risks for spread,  i.e., good  hygiene in calving areas, minimal contact between calves and adult animals or their manure.

 

Moderate to Moderate High,  Score 3 or 4 

Ø     occasional clinical cases in raised animals, generally older (i.e., > 4 years)

Ø     clinical cases are 2 to 5% of herd/year/average over past several years

Ø     number of cases increasing, and/or cases are younger in age (i.e., < 3 years)

Ø     occasional clinical cases in acquired animals

Ø          management history includes some risks for spread in the past: i.e., overcrowding, poor colostrum management, some contact between calves and adult animals, manure contamination of feed or water

 

High to Very High,  Score 5 or 6

Ø     frequent clinical cases or groups of cases in raised animals

Ø     clinical cases are > 6% of herd/year average over several

Ø          progressive pattern - prevalence has increased rapidly: increasing number of cases/year over several years; decreasing age of cases; several cases in 2 year old or younger

Ø     significant cost associated with animals culled for Johne's, and or increased cull rate

Ø     cases may be occurring in acquired animals as well

Ø          several risks for spread existed in the past: i.e. poor hygiene in calving area, calves nursed cows, regular contact of young stock with mature animals, manure contamination of feed or water.

 

 

 

1

2

3

4

5

6

                    low                                  moderate                            high

Place an X at estimated herd prevalence

 

 

 

 

 

B-4

 

Johne’s Disease Control—Risk Assessment Checklist for Dairy Herds

 

Estimate the degree of risk for each listed item under Risk Factor. The highest risk = the maximum risk score, the lowest risk = 0 for each item in that Risk Factor category. Enter your risk estimate of item the Herd Risk column.

For example, under the Risk Factor Calving area, calves are left with their dams for 6 hours, you estimate the risk to be 5 on a scale of 0 to10. Place a 5 in the Herd Risk column.

Use comment section to note differences from current to past situations. For example: Last year calved in common group, this year isolated close up cows until they calved.

Total the Herd Risk values for each Factor and multiply by the estimated herd prevalence value from page B-3, or by 1 if there is no Johne’s disease in the herd.

 

Risk	Max risk	Herd risk	Current Comment	Past Comment
Calving area: multiple animal use manure build-up calves born in free stalls, tie stalls, other cow areas calving area used for sick cows JD clinicals/suspects in area newborn calves stay with cows after birth calves nurse cows manure-soiling of calving cows, especially udders	10 10   10 10 10   10 10   10	____ ____   ____ ____ ____   ____ ____   ____
Risk Total: Calving area	80		1          2          3          4          5          6 x herd prevalence score = total current risk ______

 

 

Risk	Max risk	Herd risk	Current Comments	Past Comments
Pre-weaned calves ·     fed pooled colostrum ·     fed pooled sick-cow milk ·     calves have direct cow contact ·     calves have indirect cow contact, housed near cows ·     potential for contamination of milk, feed, water, stall with cow manure	10 10 10   10     10	____ ____ ____   ____     ____
Risk Total: Pre-weaned calves	50		1          2          3          4          5          6 x herd prevalence score = total current risk ______

 

 

 

 

 

 

B-5

 

Johne’s Disease Control—Risk Assessment Checklist (continued)

 

Risk	Max risk	Herd risk	Current Comment	Past Comment
Post-weaned calves/heifers: ·     direct contact with cows/cow manure ·     potential for contamination of feed, water, housing area with cow manure ·     shared feed, water, facilities with cows ·     shared pasture with cows ·     manure spread on pasture and grazed same season ·     manure contamination of feeding equipment	5     5   5 5   5   5	____     ____ ____ ____   ____   ____
Risk Total: Post-weaned calves/heifers	30		1          2          3          4          5          6 x herd prevalence score = total current risk ______

 

 

 

Risk	Max risk	Herd risk	Current Comment	Past Comment
Bred heifers: ·     direct contact with cows/cow manure ·     potential for contamination of feed, water, housing area with cow manure ·     shared feed, water, facilities with cows ·     shared pasture with cows ·     manure spread on pasture and grazed same season ·     manure contamination of feeding equipment	4     4   4 4   4   4	____     ____   ____ ____   ____   ____
Risk Total: Bred heifers	24		1          2          3          4          5          6 x herd prevalence score = total current risk______

 

 

 

 

 

 

 

 

B-6

 

Johne’s Disease Control—Risk Assessment Checklist (continued)

 

Risk	Max risk	Herd risk	Current Comment	Past Comment
Cows ·     manure contamination of feeders, waterers ·     manure contamination of feed storage, feed equipment ·     manure spread on pasture and grazed same season ·     direct access to manure storage areas	4   4   4   4	_____   _____   _____   _____
Risk Total: Cows	16		x herd prevalence score = total current risk______

 

 

 

Copy totals from each category onto the Herd Risk Assessment Summary table.  Summary scores may be used to help set priorities for areas that need most attention.  Usually immediate action should be taken in areas with the highest score.  Action in lower score areas can be delayed, if needed, in order to spread out additional expenditures of labor, management and/or facilities.

 

Johne’s Disease Herd Risk Assessment Summary

 

Herd Risk Areas	Risk X Prevalence Score
Calving area
Pre-weaned calves
Weaned calves/heifers
Bred heifers
Cows
Total

 

 

 

C-7

 

Choosing a Testing Strategy - Issues to consider

 

1.  How aggressive are the objectives for controlling Johne's in the herd?

 

a.   Minimally aggressive: primarily preventive management; maintain a low prevalence herd; prevent from getting worse; unknown status herd/Johne’s-free herd; minimize risk if JD infection is present

b.      Moderately aggressive: preventive management plus testing and culling; reduce spread; prevalence; clinical disease; premise contamination.

c.   Very aggressive: thorough preventive management; repeated herd test with cull and management of positives; reduce prevalence; rate of spread; clinical disease to zero; eliminate in minimal time

 

1.     How do you plan to use test results?

Making these decisions will aid in selecting appropriate test(s) and in defining your overall strategy for a prevention/control plan. Examples may include:  Screen to estimate prevalence; Identify most infectious individuals to cull; Identify asymptomatic infected individuals to manage; Determine/achieve low risk herd; etc.

 

3. What animals do you want to test?

Herd - all at once or groups, high risk groups, target groups i.e., replacement dams, acquired animals, clinical suspects or a statistical sample - estimate herd prevalence

 

4. How will testing complement your management efforts in meeting herd goals?

a. Are you able to implement management that is adequate to control spread of JD?

b. Can positives be segregated, culled, managed in the operation?          

c. Consider how to optimize the effects of risk management and test and cull strategies by        putting them in place together.

 

What would it cost to test your herd?

 

Test choice	Herd	Part of herd, groups, statistical sampling	Selected individuals
Serology
Fecal culture
Serology plus fecal confirmation positives
Serology and fecal culture

 

D-8

 

Johne’s Disease Control—Management Procedures and Plan

 

This section is designed to assist in the development of a farm-specific plan to manage or prevent Johne’s disease, outlining suggested management objectives and recommendations for achieving success in each management sector of the farm. Owners, managers and their veterinarian are encouraged to discuss each topic in this section and answer the planning and responsibility questions in detail. Completion of this section will provide the basis for a comprehensive farm plan that addresses all areas of risk for disease.           

 

1. Calving area:

a. Management objective: keep it clean and dry.

b. Suggestions for achieving objectives:

1. For inside area: use area for calving only; use single-animal pens; assure adequate size area; remove manure and bedding after each use; always have adequate bedding.

2. For outside calving areas: use adequate area and monitor use to minimize mud and manure accumulation;

3. Clip and clean udders before calving and remove calf immediately after birth.

c. List specific procedures to be done right away and those that will be added later.

 

2. Pre-weaned calves:

a.   Management objectives are:  avoid feeding infective colostrum/milk and to prevent contact with other infectious materials.

b.    Suggested procedures to achieve objectives are: use colostrum from known JD-free cows; feed 4 qts. colostrum within 2 hours; feed milk replacer rather than milk in JD herds; prevent manure contamination of feed and water; house calves in separate facility/location from cows, manure and traffic; minimize manure transfer from cows to calves (feed calves first, separate equipment, clean boots, etc.).

c.     List specific procedures to be done right away and those that will be added later.

 

3.  Post-weaned calves

a.    Management objectives for this area are to prevent exposure to infective animals and manure and to prevent contamination of feed and water.

b.    Suggested procedures to achieve those objectives are: house young stock in total separate facility; do not co-mingle young stock with mature animals; do not allow contact with cows or their manure; prevent water drainage from cow areas to young stock areas; do not use common feedbunks or waterers for cows and young stock; use separate equipment for feed and for manure; design and maintain feed and water areas to prevent manure contamination.

c.     List specific procedures to be done right away and those that will be added later.

 

 

 

 

 

 

D-9

 

4. Bred heifers

a.         Management objectives are:  prevent exposure to infective animals and manure and to prevent contamination of feed and water and pastures.

b.    Suggested procedures to achieve objectives are: house young stock in totally separate facility; do not co-mingle young stock with mature animals; do not allow contact with cows or their manure; prevent water drainage from cow areas to young stock areas; do not use common feedbunks or waterers for cows and young stock; use separate equipment for feed and for manure; design and maintain feed and water areas to prevent manure contamination; do not give refused cow feed to young stock; avoid vehicle and people traffic from cow areas to young stock areas; do not put young stock on pastures used by cows; do not spread manure on pastures to be grazed by young stock in that grazing season.

c.     List specific procedures to be done right away and those that will be added later.

 

5. Manure and Animal Risks

a.    Management objectives are: minimize contamination of premises.

b.    Suggested procedures to achieve objectives are: keep facilities and premises free of  manure build-up; haul and store manure away from feed, water and young animals; restrict access; use tuberculocidal (phenolic or cresylic base) disinfectants after manure is removed.

c.     List specific procedures to be done right away and those that will be added later.

 

6. Cows

a.    Management objectives are: eliminate high-risk animals; manage test-positive animals

b.    Suggested procedures to achieve objectives are: segregate, test, cull all animals with clinical signs of JD as soon as possible; manage asymptomatic JD test-positive animals to reduce premise contamination; cull when economically feasible

c.     List specific procedures to be done right away and those that will be added later.

 

7. Acquired animals

a.    Management objective: not to purchase or bring back Johne’s infected animals

b.    Suggested procedures to achieve objective: know identity, health history and hygiene of herd(s) of origin; know JD history and JD testing record of herd(s) of origin;  avoid buying animals from herd with JD risk higher than your herd; test acquired animals’ serology or fecal culture; do not buy or retain any positives; segregate and/or prevent oral/fecal contact with young stock until test status is known.

c.     List specific procedures to be done right away and those that will be added later.

 

 

 

 

 

 

 

D-10

 

8. Herd testing

a.         Management objectives are: determine presence and/or prevalence of disease; identify infected animals; monitor progress of herd management plan.

b.    Suggested procedures to achieve objectives are: Do baseline herd test to assess  prevalence and target control; Test herd regularly to complement and enhance preventive  management efforts; Use results appropriately as part of management plan; Test suspects to know status and track clinical cull rate.

c.     List specific procedures to be done right away and those that will be added later.

 

9. Records

a.    Management objectives are: know baseline or beginning disease status; identify infected animals; to determine costs of disease and/or plan; help monitor progress and compliance with farm plan.

b.    Suggested procedures to achieve those objectives are: ID test-positive animals; Record body condition score, salvage value of Johne’s culls to track cost of Johne's in herd; Develop management plan Checklist to review monthly; Periodically review and update checklist with herd veterinarian and other herd decision-makers.

c.     List specific procedures to be done right away and those that will be added later.

 

 

List other health/ management objectives that will be integrated with and benefit from Johne's preventive efforts

 

Calving management

 

 

Calving area hygiene

 

 

Calf raising management

 

 

Developing heifers

 

 

Nutrition/feed management

 

 

Records

 

 

Culling strategy

 

 

 

 

 

 

 

D-11

 

Review plan feasibility  &  define follow through/accountability

 

2.        Establish a team and achieve a consensus among the members as to the design and       implementation of the plan. Plan should be comprehensive to be effective, and practical and feasible to implement to successfully meet the Johne's control objectives for the farm.

 

Plans continue to evolve

a. Plan strategy should be effective enough to meet control goals.

b. Plan is practical or feasible to implement.

c. Plan designed to fit with other management objectives and resources.

d. Plan designed to fit with farm's business objectives.

 

Define a routine for monitoring implementation, evaluating and modifying the Johne's plan on a regular basis, i.e., review plan checklist routinely with veterinarian.

 

a. Plan to monitor and assess implementation and effectiveness on a regular basis, i.e. seasonal checklist.

 

b. Plan to evaluate the feedback,  i.e. identify and discuss areas "not working" each  season/month; define priority and plan for areas needing attention.

 

c. Assure plan is modified as needed, i.e. seasonal/monthly monitoring information      provides basis for determining need and ideas for modification.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

D-12

 

Example Farm Management Plans for different levels of aggressiveness