Vet Resources

Information and resources to help vets understand LIC products and services.

This season LIC is offering a Staphylococcus aureus (S. aureus) mastitis test on herd test milk samples.

The S.aureus test uses standard DNA detection methodology (PCR), optimised by LIC for detection of S. aureus in herd test milk samples.

Using herd test milk samples, the S.aureus test can be a convenient way of identifying whether subclinical S. aureus is a problem in a herd. It can enable more informed decisions for dry cow treatment vs culling as part of an overall mastitis management plan.

The turnaround time for results is 7 working days from when the herd test lab strip is received in the lab, and when a nominated list of animals to test has been provided.

A test report will be emailed to the vet with 3 possible outcome categories:

  • ‘S. aureus Detected’
  • ‘Suspect’
  • ‘S. aureus Not Detected’

It is recommended that any animals in the ‘Suspect’ category should have the presence of S. aureus confirmed either by a follow up S. aureus test on a subsequent herd test or bacteriology.

Test lists

A nominated list of animals can be either:

  • A list selected by the vet and farmer

This will allow a selection of animals based on a combination of high SCC history, clinical history, past treatments, potential new infections or any other selection criteria relevant to the herd.

OR

  • A list selected by LIC based on agreed SCC criteria

The SCC threshold will be decided in consultation with the vet and farmer and a maximum number of samples for testing can be specified.

LIC Validation Trials

Herd test milk samples and aseptic quarter foremilk samples were tested for S. aureus using PCR and results compared to bacteriology as the gold standard.

The sensitivity and specificity of S. aureus test was found to be 99.1% and 99% respectively for the aseptic quarter samples; however herd test milk was found to be less sensitive, with only 70% of true positive cases identified, with specificity remaining at 99%.

Limitations of the test

S. aureus is not consistently shed in the milk so at the time of the herd test it is possible that an infected cow is not shedding sufficient bacteria to allow detection. Herd test milk is a composite sample of all quarters, so the expected sensitivity will be less than individual udder quarter samples.

How to book

Bookings for this test must be booked through a vet clinic with LIC Animal Health.

Further information

For further information on Staphylococcus aureus testing, please contact the Animal Health Advisor’s team at LIC on 0800 436 362 or email testyourcows@lic.co.nz

Download a PDF about Staphylococcus aureus testing.

Johne’s disease (JD), also known as paratuberculosis, is a chronic infection caused by a bacterium called Mycobacterium avium paratuberculosis (MAP). The bacterium infects the gut of cattle and other ruminant animals, causing the intestinal wall to gradually thicken and become inflamed. This results in leakage from the gut wall and prevents uptake of vital nutrient by the animal.

Johne’s disease is widespread amongst NZ dairy herds. Most infected herds harbour low levels of JD with occasional clinical disease. In some herds Johne’s disease becomes problematic with annual losses of 1% and more in the milking herd.

Vets by vat - Innovation farm

What are the symptoms?

Calves and young stock are particularly susceptible to infection, however the disease has a long ‘incubation period’ so clinical signs of Johne’s disease typically do not appear until several years later in the adult cow.

Falling milk production (lower lactation worth) may precede overt clinical disease. Clinical Johne’s disease is characterised by ill-thrift and weight loss with profuse diarrhoea – the animal basically starves in spite of a good appetite. “Bottle jaw” (swelling under the jaw) is the result of severe protein loss. There is no cure for this disease and the condition is fatal.

How is it spread?

MAP bacteria are primarily spread through faeces and ingested with contaminated pasture, colostrum/milk, feed, and water.

Infected cows start shedding bacteria some time before clinical signs of disease appear. As the infection progresses, increasing amounts of bacteria are excreted in faeces of heavy shedder cows. Calves may pick up the infection in the calving paddock and remain at risk if they are exposed to faeces or effluent from the adult herd.

Cows with advanced infection (both clinical JD cows and subclinical) will also transmit the bacteria to the unborn calf in utero and via colostrum or milk.

JD Toolbox.jpg

Download MAP bacteria lifecycle diagram

How can Johne’s disease be managed / controlled?

During the early stages of Johne’s disease infection diagnostic tests are unreliable, so JD control can be a challenge. It is possible to minimise the impact of JD by reducing the exposure of disease to replacement heifers.

The severity of Johne’s disease in an individual (ie time until clinical signs develop and the amount of faecal shedding) depends on several factors including the age when infection occurred, the amount of bacteria ingested and the number of times the animal has been exposed to JD. Therefore any management measures that reduce exposure (eg avoiding effluent paddocks and paddocks grazed by the adult herd) will help limit the spread of Johne’s disease.

The risks and control measures vary from farm to farm and good veterinary advice is critical to control JD. Key to a successful risk management plan are:

  • Eliminating the source of bacteria by early removal of clinical JD cows and other high-risk shedders.
  • Removing susceptible calves and young stock from possible sources of infection as soon as practicable.

Convenient testing

LIC Animal Health offer whole herd Johne’s testing for dairy cows on herd-test milk samples to identify high-risk cows with advanced Johne’s disease.

These cows shed high numbers of bacteria and are a major cause of the spread of the disease to other animal’s especially young stock and calves. Our testing may detect “super –shedders” that are not showing signs of the disease at the time of testing, but they are likely to develop clinical JD in the near future.

Test Limitations and timing

The Antibody ELISA test detects the immune response of the animal to the MAP infection. While it generally does not identify cows during early stages of subclinical infection (ie low-risk non-shedders or intermittent / low shedding), the test performs very well in advanced stages of JD and will identify most heavy shedders.

The test will identify 8 to 9 out of 10 cows with clinical disease or that are excreting large amounts of bacteria (heavy and super shedders).

The screening test should be carried out later in the season (Feb/March herd test for NI herds and April/May herd test in the SI) to maximise the benefits and identify as many high-risk cows as possible to be culled before calving.

Risks

Low milk volume can cause false positive results, so avoid testing too close to dry off or when part of the herd has dried off.

How to book

All animals at the herd test will be tested.

This test must be booked by the herds veterinarian to ensure follow up interpretations of the results and implementation of a disease management plan.

Further information

For further information, please contact the Animal Health Advisor’s team at LIC on 0800 436 362 or email testyourcows@lic.co.nz

Download a PDF about Johnes testing.

Vet - Innovation Farm

Take advantage of the growing international demand for A2 milk by using our A2 gene test to identify A2 cows. About 30% of New Zealand dairy cows produce A2 milk. It contains a protein called A2 β- casein. A1 milk contains A1 β- casein, or a mix of both A1 and A2 β- casein. Some consumers are willing to pay more for A2 milk because they believe it prevents the digestive problems they say they experience after drinking A1 milk. We do not endorse any of the claims made about A2 milk. If you want to set up an A2 herd, every animal in the herd must have the A2 gene. You must also breed with bulls that have the A2 gene.

Tests to obtain an A2/A2 result

Animals already G3 profiled can obtain a retrospective result - 5-7 working days

Combine the A2/A2 test with DNA parentage testing - 4-5 weeks

Combine the A2/A2 test with your regular herd test - 10 working days

Standalone A2/A2 test on a tissue sample - 4 weeks

For information about taking samples and submitting samples, view our A2/A2 test page.

Download a PDF about A2/A2 testing.

Staphylococcus aureus (SA) mastitis testing

  • The Staphylococcus aureus (SA) test may be a beneficial option where subclinical infection due to SA is suspected or identified as a mastitis problem in a herd.
  • This test will provide information important for dry cow treatment vs culling as part of an overall mastitis management plan.
  • This test can only be booked via a vet clinic.
  • This test can be used for nominated animals present at herd test.
  • The results report will go to the vet.

Milk Pregnancy Testing (MPT)

  • MPT detects pregnancy associated glycoproteins produced by the placenta from 28 days after mating.
  • The results report has 3 possible outcome categories:
  • Pregnant, no pregnancy detected or re-check (should have pregnancy diagnosis confirmed by other means).
  • Screening is of the entire herd (all cows present at the herd test) or a nominated list ($49.95 admin fee applies to nominated lists)

Johne’s disease testing (JD)

  • Johne’s disease is a chronic infection caused by a bacterium called Mycobacterium avium paratuberculosis (MAP).
  • The disease is spread through faeces, milk and can be transferred in utero or during birth.
  • Identification and culling, helps reduce infection spread to young calves and loss of milking cows due to clinical Johne’s disease in the following season
  • Testing should be done in mid-to-late lactation to help decision-making prior to end-of-season culling - usually between December and March.
  • Screening is of the entire herd (all cows present at the herd test).•Repeat testing (and any intervention) is required for a number of years.
  • This test must be booked by the herd’s vet clinic.
  • Result reports and charging will be sent to the vet clinic directly.
  • Vet to complete on farm consultation using results.

BVD PI Hunt

  • BVD (Bovine Viral Diarrhoea) is a highly prevalent and infectious viral disease found in NZ, and in many other countries around the world.
  • It spreads through body fluids and excretions and has damaging effects on the health, reproductive performance, growth, productivity of a dairy herd and sometimes causes death.
  • The BVD PI Hunt detects an individual BVD positive animal present at herd test and can be completed after a virus positive bulk milk BVD test.
  • Lifetime BVD status of individual animals tested are uploaded to MINDA®

Turnaround time for all the above tests is 7 working days from when the samples are received in the Animal Health lab, and are subject to available capacity.

Download a PDF about Diagnostics Animal Health testing on Herd Test milk samples.

We have been BVD testing since 2009 and were the first to generate a BVD bulk milk monitoring package for farmers which has significantly contributed to the improvement of controlling BVD on farm.

Individual BVD bulk milk tests are also available allowing farmers to tailor their BVD testing to their on farm needs. We also offer a number of easy and convenient BVD tests on herd test milk, tissue and blood for individual animals to help identify BVD on farm.

Bulk Milk Monitor Pack

Our Bulk Tank Milk option is the most comprehensive BVD testing package on the market, detecting both BVD virus and antibody levels within the vat sample at the most optimum times of the year.

Using the Bulk Milk Monitor pack will ensure farmers receive the best information regarding their herd BVD status allowing for efficient and cost effective decisions to be made should BVD ever become an issue on farm.

Benefits include:

  • Two bulk milk samples tested two weeks apart, in the early season once most cows have calved. This ensures a high percentage of animals are included in bulk milk testing (animals not milking into vat at the time of testing should be tested individually)
  • Sample collection dates are flexible
  • Detection of BVD virus early in the season allows for timely individual animal testing to identify the source of infection on farm
  • Historical test information can aid in on farm management decisions
  • Easy and convenient rollover booking ensuring that on farm BVD testing is completed each year
  • LIC Animal Health advisor team available for result analysis and customer support

Bulk Milk BVD Antibody ELISA

One off Antibody ELISA test is able to detect the herds immune response to BVD virus by identifying BVD antibody levels within the bulk tank milk.

This test may be used for herds that have continued low antibody levels. A rise in bulk milk BVD antibody levels, between seasons, indicates the herds exposure to BVD virus and this should be discussed with the vet.

This test can be combined with BVD PCR on the same bulk tank milk sample if required.

Bulk Milk BVD PCR test

One off PCR test is able to detect BVD virus within the bulk tank milk. Although this test is primarily used to detect persistent BVD infection within the herd, with historical data, and expert result analysis offered by the Animal Health advisors, this test may also be able to identify a transient BVD infection.

This test may be used for herds that have continually high antibody levels and therefore continued exposure to the BVD virus.

It can also be combined with Antibody ELISA on the same bulk tank milk sample if required.

Note: Although one off tests may be suitable for some herds, veterinary interpretation of the results is highly recommended. Some animals may not be included in one off bulk milk testing if they are not milking into the vat on the day of testing. These animals should be tested individually.

Timing of testing may also impact the efficiency of BVD control and increase the associated on farm costs should a BVD infection arise.

Individual BVD Testing

Calves and dry stock can be individually tested for BVD using tissue or blood samples.Herd test milk samples can be used to individually test lactating animals.

Further Information

For further information, please contact the Animal Health Advisor’s team at LIC on 0800 436 362 or email testyourcows@lic.co.nz

Download a PDF copy of BVD Bulk Milk Testing options.

Herd Test in Shed

Milk Pregnancy Testing (MPT) for dairy cows is a hassle-free option for non aged pregnancy diagnosis.

MPT utilises a Herd test milk sample to detect pregnancy associated glycoproteins produced by the placenta.

MPT has great benefits:

  • Detects pregnancy from 28 days after mating
  • Easy and Convenient
  • Non invasive
  • Pregnancy results uploaded to MINDA Live and reported via email.
  • Test your whole herd or a select group of animals at the herd test(partial herd* - minimum 25 samples).

The Milk Pregnancy Test has been validated for herd test milk samples against veterinary pregnancy diagnosis.

Results

Turnaround time for results is approximately 7 working days (from when the herd test lab strip is released).

The results report will be directly emailed to the farmer.

The report will have 3 possible outcome categories:

  • Pregnant
  • Re-Check
  • No Pregnancy Detected

Animals in the Re-check category should have Pregnancy diagnosis confirmed by other means.

Results will be uploaded to MINDA Live with the following categories:

  • Pregnant MPT
  • Re-Check
  • Empty *

* If an animal has been tested within the 28 days of their last mating, an empty result may be given.

Test Limitations

  • The Milk Pregnancy Test does not age pregnancy
  • The Milk Pregnancy Test accurately detects pregnancy 28 days after mating
  • All customers are subject to eligibility criteria and lab capacity
  • On average, the percentage of animals falling into the Re-check categorywas 1.86% during trials – however, this can vary from 0% to 10% for individual herds

Risks

False positives may occur if an animal has recently aborted (it can take at least two weeks for pregnancy protein levels to drop following a slip). If the herd test date falls within this period this animal may still give a ‘Pregnant’ result.

Further Information

For further information, please contact the Animal Health Advisor’s team at LIC on 0800 436 362 or email testyourcows@lic.co.nz

Download a PDF about Milk Pregnancy testing.