Slide 1: Caudal Fold Tuberculin Test (CFT test)

First screening step in the TB-testing process

Slide 2: Handling Equipment

Veterinarian will use the on-farm equipment or set up additional equipment

Animals are moved into handling equipment for testing

Slide 3: Caudal Fold Tuberculin Test

The Purified Protein Derivative (PPD) tuberculin is injected intradermally (between the layers of skin) of the caudal tail fold, under the animal's tail

Slide 4:

Some veterinarians will make a mark on the animal's hide to indicate which side of the caudal tail fold was injected

The animal is also given a unique, permanent identification number, usually an ear tag. Registration tattoos may be used as official identification

Slide 5:

The injection site is examined 72 hours later, plus or minus 6 hours

The same veterinarian who injected the caudal fold tuberculin must examine the injection site

The veterinarian will feel and observe the injection site

Slide 6:

Five to seven percent of the cattle, goat,and bison population will respond to the CFT test

This may happen because the animal was exposed to another disease that causes the response, for example

Mycobacterium avium (Bird TB)

Mycobacterium Paratuberculosis (Johne's Disease)

Slide 7:

If there is any response at the injection site

swelling

redness

hardness

etc.

The animal is considered suspect and further testing is required

Slide 8:

The herd is quarantined if even one animal is suspect

This means no animals can come into the herd and no animals can move out of the herd without approval from MDA

Slide 9: Comparative Cervical Tuberculin (CCT) Test

Slide 10:

This test is only done on animals that respond to the caudal fold test (CFT)

The CCT test must be done within 10 days of the injection date of the CFT

CCT must be administered by a state or federal veterinarian

Slide 11: Handling Equipment

Veterinarian will use the on-farm equipment or set up additional equipment

Animals are moved into handling equipment for testing

Once the animal is secured a section of the neck is shaved in two places before administering the CCT test between (intradermally) the skin layers on the animal's neck

Slide 12:

Skin thickness is measured using a special caliper and then the veterinarian will inject avian (bird) tuberculin and bovine (cattle) tuberculin into two shaved sites on the neck

Slide 13:

The animal is released from the handling equipment

Injection sites are examined three days later

Slide 14:

The same veterinarian who administered the CCT test must examine the injection sites approximately 72 hours (plus or minus six hours) later

Slide 15:

When observing the injection sites, the veterinarian looks for differences in the two sites, and measures the skin thickness with a special caliper

Slide 16:

Swelling is often the reaction to the avian TB injection.

Producers should not be alarmed

The veterinarian or an assistant records the tag number and test results

Test results are plotted on a scattergram. Based on where the results fit on the graph, the animals will be classified

Slide 17: Classifications

Negative

Suspect

Reactor

Slide 18: Negative

These animals are considered TB negative

If the entire herd tests negative then the quarantine is released

Slide 19: Suspect

An animal whose response to the CCT test is plotted midway on the graph is classified as a suspect

Herd owners must decide whether to:

have the suspect animal removed for euthanasia and testing at MSU

have the animal re-tested on the farm after 60 days

Slide 20: Euthanasia

If the owner chooses euthanasia then:

the animal is removed for necropsy and further testing, the herd owner will receive payment for the animal based on the animals value as written in PA 446

Shipping costs will also be paid for by MDA

The herd remains under quarantine until initial laboratory results are available

Slide 21: Re-Test

If the owner chooses to wait and re-test the animal:

The herd remains under quarantine until the second CCT test results are available

Animals that respond to two CCT tests are reclassified as reactors and arrangements are made for removal from the farm

Classification as a suspect does not mean the animal has bovine TB

Slide 22: Reactor

An animal is classified as a reactor if

its response to the CCT test falls into the reactor range on the scattergram

it plots as a suspect on the graph on two separate CCT tests

Classification as a reactor does not mean the animal has bovine TB

Slide 23: Reactor cont.

The animal is removed from the farm for necropsy and further laboratory tests.

The herd remains quarantined until test results are available.

If laboratory results show definitive signs of bovine TB, the animal is classified as a reactor

Slide 24: Reactor cont.

Milk from reactor animals cannot be put into the milk bulk tank or consumed by humans or animals

Livestock producers are advised to keep reactor animals confined and separated from the rest of the herd until they can be removed from the farm

Slide 25: Necropsy and Laboratory Testing

Animals removed from the farm go to the Animal Health Diagnostic Lab (AHDL) at Michigan State University for necropsy and histopathology

Scientist look for:

internal lesions

swollen lymph nodes

other signs of disease

Slide 26: Necropsy and Laboratory Testing

Tissue samples are collected and sent to the lab for culturing and further diagnostic testing

The herd remains under quarantine until laboratory test results are available

Slide 27-32: Lesion Pictures

Slide 33: Test Results

If lab results indicate infection with bovine TB, the herd is considered affected

Animals classified as bovine TB suspects by the first CCT are re-tested

Animals classified as suspect on a second CCT test are reclassified as reactors, and subject to the rules and regulations governing this classification

Slide 34: Herd Owner's Choices

If a farm owner is notified that the CCT reactor had bovine TB, the owner may choose one of two options:

Complete herd depopulation

Test and remove program with a specified herd plan

Farmers are encouraged to consider whole herd depopulation

Test and removal can be costly and may have long term implications for the farm operation

Slide 35: Test and Remove

The farm remains under quarantine until all testing reveals a bovine TB-negative herd

Each time an animal responds to a CFT rest it will immediately be removed and testing will commence again

This process of a minimum of 6 whole herd tests may take as long as 24 months providing no additional infected animals are found

Slide 36: Test and Remove (cont.)

Once the quarantine is released, yearly tests may be required for five years

Dairy herds in the test and remove plan may continue to sell milk as long as the herd plan is followed

Slide 37: Depopulation

Depopulation= destruction of all livestock exposed to bovine TB in the herd before any restocking of the premises with cattle, privately owned cervids, bison, or goats

Slide 38: Depopulation (cont.)

Livestock are removed from the premises

The farm is disinfected

May be repopulated when determined clean, or one year after removal of all animals

Slide 39: Accreditation

When herds have passed at least two consecutive annual whole herd tests

There is no evidence of bovine TB

Standards of the Uniform Methods and Rules (UMR) for bovine TB eradication have been met

Herds are eligible to be recognized as bovine TB-free by USDA

Slide 40: Herd Additions

Cattle

All animals 24 months of age and older

Any animals other than natural additions under 24 months of age

MUST BE TESTED

Goats

All animals 12 months of age or older must be tested

Slide 41: A Commitment to Safety

The MDA, the Michigan Department of Natural Resources, and their partner agencies maintain a strong commitment to eradicating bovine TB from Michigan livestock and deer. In keeping with its long-standing tradition of making food safety a top priority, MDA pledges and equally rigorous effort to continue ensuring the safety of venison, beef and milk, through comprehensive testing, monitoring and educational efforts from the farm or processing plant to the retail store.