Disease & other Testing

The “basics” – required for interstate transport and most sales:

• Bovine Tuberculosis (TB) test
  
• Brucellosis (“Bangs”) vaccination
  

Major dairy diseases of consideration:

• Johnes
• Bovine Leukosis (BLV)

(There are many, many, many diseases and tests available – speak with your vet or local farmers to see which other tests may be relevant to your area. Some others potentially relevant to dairy are: Neospora, Anaplasmosis, Mycoplasma, Q-Fever, BVD.)

Other (non-disease) testing:

• Milk testing (for lactating animals)
  
• Preg Testing (If animal is being sold as “pregnant”)

A word about disease testing:

Animals may be exposed to a number of various diseases. It’s up to you how extensively you want to test. Keep in mind, this testing can become very expensive. Also, be aware of false-positives. If you are unsure about a test result, consider re-testing with a different type test (ie: PCR vs. Elisa, milk vs. blood vs. stool) or a different lab and compare results.

Buy from credible sources that are aware of disease and prevention. Paying a little more for a healthy cow will save $$ in the long run. We like to see a maternal line that has longevity, which is a great indicator of health!

ABOUT THE DISEASES, TESTING TYPES, WHERE TO GET TESTING, & PREVENTION:

Bovine TUBERCULOSIS:

• Most states are TB free. Bovine tuberculosis CAN be transmitted to humans and make them sick. So therefore, though it is not very prevalent, it is important to be aware of TB. (TB testing is required in our state for raw milk producers.) Clinical signs of the bacterial infection are not easy to identify as TB.
• A TB test is done by a vet. They will stick a small amount of fluid (tuberculin) under the skin of the cow and come back in 72 hours to read the results (a raised bump = positive). If positive, ask your vet about re-testing to eliminate error. [Keep in mind, this test requires a vet to make TWO visits.]
  
• Prevention: If in California, people have become sick from TB from cattle, so definitely extra caution in that state. Avoid housing animals in enclosed areas with poor ventilation. Avoid feeding/watering where wild animals can co-mingle with your herd. If you attend a fair, avoid “community watering” areas for the animals!

Sample definition of results

BRUCELLOSIS:

• You may have heard an older person speak of “undulant fever” – they are referring to Brucellosis. In the cow world, it is known as “Bangs” or “contagious abortion.” Brucellosis is eradicated within the United States, thanks to a federal eradication program, EXCEPT for populations near Wyoming, where officials refuse to vaccinate wild bison populations. Many states do not allow transportation of animals unless they are Brucellosis vaccinated, so check before moving or selling cattle!
• Most animals are vaccinated. To tell if your animal is vaccinated, check the animal’s RIGHT ear. In the ear should be a tattoo, a “shield” (looks like a flower, kind of) that has a letter on one side and a number on the other side. These reference the year of vaccination. In addition, most cattle have a ear tag, which is a long skinny metal tag of silver or orange color that is clipped to the top edge part of the ear close to the head (The first two letters on the metal tag identify the state in which the cow was vaccinated.). [Click here for photos]
  
• If not vaccinated, Brucellosis can be checked for in milk or blood samples.
• To vaccinate an animal:
  • A vet is required to vaccinate/tattoo/tag/record your animal.
  • The animal should be vaccinated between 4-12 months old.
  • If not vaccinated as a calf, an adult cow can often be vaccinated after a blood test confirms she is negative for the disease.
• If you have a breed-specific registered & tattoo identified animal, you can ask for the vet to NOT put in the metal tag. Instead of the tag number, they will use the animal’s registration number.
• Prevention: Vaccinate calves. Adults can be vaccinated after being tested and proven negative.
  

 

Sample definition of results

Johnes:

• M. paratuberculosis: Pronounced “Yo-nees”, is an infectious bacterial infection of the digestive tract.  Johnes is in the same group as leprosy & tuberculosis. The most distinct sign of Johnes is long-lasting, foamy/bubbly diarrhea and chronic weight loss. Cattle infected at a young age that are shedding the bacterial spores and show symptoms tend to be cows around three years of age, often getting ready to have their second calves. Johnes is tricky in that it may not show symptoms in a cow until late in life (perhaps even to 10 years of age or older, carriers that do not show symptoms until late in life!). Johnes DOES spread from manure and any identified sick cow should be removed immediately, as the bacteria can spread to other cows and survive in the soil. Any land where a Johnes infected cow has been should not have cows on that land for at least a year as a precaution. This disease affects the white blood cells. More info: http://www.aphis.usda.gov/publications/animal_health/content/printable_version/faq_johnes_cattle3-06.pdf
• Why is Johnes so important to test for? Because Johnes is very likely linked to Chron’s disease in humans: http://www.wnd.com/2004/10/26829/ 
• Blood (Elisa/AGID, antibodies) and manure (PCR, organism) tests. We always tested the herd with blood and manure samples at the same time. PCR is best for detecting already sick cows, but AGID is better for cows not showing symptoms, so both tests are valuable. For more in-depth discussion on testing types: Johnes: What Tests?
• Your vet should be able to help you send in a sample for Johnes testing. Note: testing can take up to 6-8 weeks to get results back!
• Prevention: If you test your animal, before purchase, this is probably THE most important test to do! Because testing is the only way to monitor Johnes in your herd! There is NO cure. In the dairy industry, Johnes is a very touchy subject and not every state is as intense about eradicating Johnes as others. Most herds have dealt with Johnes, whether they know it or not.
• There is a Johnes vaccine, but the use should be carefully discussed with your veterinarian before deciding whether to give or not.
• Do not feed raw milk to calves from their own mother if the mother has signs of Johnes. (Powdered colostrum and powdered/pasteurized milk are safer alternative feeds in this situation.) If the calf is a heifer that you plan to raise as a replacement, the calf should be removed immediately from the pen, ideally without the calf touching anything in the birthing environment. The heifer should also be carefully monitored through testing throughout her life.
  
• Resource: http://johnesdisease.org/

Sample definition of results

BLV – Bovine Leukosis:

• September 2015 study: http://medicalxpress.com/news/2015-09-virus-cattle-linked-human-breast.html
  
• Bovine Leukosis Virus is most noticed when a cow loses weight and cannot gain weight no matter how hard you try. This disease is often uniquely and visibly noticeable for tumors and swollen lymph nodes (this is a key indicator suggesting leukosis over Johnes as a diagnosis). She will usually dramatically drop in production if milking, perhaps even dry up completely. Stress, such as calving, can be fatal to a cow showing clinical signs of this disease.  More info: Cause for Concern: Bovine Leukemia Virus (WSU)
• Types of testing for BLV are Elisa, AGID and PCR. Elisa is an inexpensive “screening” test that can have false readings. AGID is similar to Elisa and can also have false readings. PCR is more accurate by testing for DNA of the actual virus, and therefore is the testing of choice. Here’s more about the testing types: Available Tests for BLV
• Where to get testing done: Available Labs
  • An example of a lab that offers PCR: Texas BLV PCR Test
• Prevention: Spreads via blood contamination. Never share needles between animals. Test new animals before adding them to herd. Ask vet to use a new obstetrical glove when checking each individual animal. Disinfect any equipment that comes in contact with blood. For example, always disinfect between animals at dehorning, tagging, vaccinating, AI, etc. MERCK
  

Sample definition of results

MILK TESTING

• Probably the most useful test to anyone purchasing a dairy cow is milk testing!
• Prevention is all about cow health from udder health to general cleanliness.
• “Somatic cell” testing is a cheap, useful indicator of general health and udder health.
• Bacterial cultures or DNA testing from individual quarter(s) can help identify specific pathogens.
• Click here for more information on how to do milk testing: MILK TESTING

PREGNANCY TESTING

• Seeing accurate signs of pregnancy are often difficult or impossible.
• To verify pregnancy, we highly recommend preg checking cows, otherwise you assume the risk of a non-pregnant cow going 9 months unbred at your cost.
• For details on pregnancy tests, click here: PREGNANCY TESTING

REPORT SAMPLES for DISEASE TESTING:

When a sample is returned, it should contain the animal’s name/identifying number, indication of which test was performed, test results, and sometimes a number:

Some also contain a number (for example: SP ratio) in addition to the result of negative/suspicious/positive/inconclusive:

Another style of sampling, disease testing through milk: