MANAGING milk quality is of critical importance to the Australian dairy industry — it increases farm profi tability,

improves animal welfare and protects dairy export markets.

The Australian Milk Quality Steering Group (AMQSG) was established three years ago to improve milk quality across the industry. Its members have broad-rang-ing expertise in the fi eld and have worked hard to set targets that are worthwhile, measurable and achievable.

Milk quality is based on three key cri-teria:• white blood cell count, which is the cow’s response to pathogens such as mastitis;• bacterial contamination, measured as plate count, from sources such as milking machines and milk vats; and• presence of residues such as antibiotics.

High white cell and bacterial counts have implications for milk’s keeping abilities, its taste and the ability to process it into high-value products such as yoghurt and cheese.

Stuart Griffi n, the steering group’s chair-man, and a Westbury, Victoria, farmer rep-resentative on AMQSG, said: “We don’t drive RD&E (research, development and extension) in the industry because we don’t have a budget for that but we do prioritise it. We identify gaps in the industry’s knowl-edge relating to milk quality and point to the projects required to fi ll them. The ma-jority of our focus is pre-farmgate, deliver-ing benefi ts for farmers, on farm.”

The group is a community of interest within the Dairy Moving Forward Frame-work and for the past three years was sup-ported by funding from the Gardiner Foun-dation and Dairy Australia, with Harris Park Group acting as convenor.

The group has met nine times and is aiming to keep Australia at the forefront of milk quality standards. To achieve this, farmers need access to the most up-to-date national and international information with

results of new R&D made available as soon as possible.

Targets have been set across all themes in the milk quality portfolio, which provide a framework for determining investment priorities.

One aim is that by 2020, 80% of farms should not exceed the Countdown trigger points for clinical cases of mastitis. Those triggers are fi ve cases per 100 cows in the fi rst month after lactation and two cases in the subsequent months.

Milk with a cell count of above 400,000 per millilitre is considered unfi t for human consumption by the European Union.

The current average annual bulk milk cell count (BMCC) in the Australian dairy herd is 232,500/ml (The Australian Dairy Herd Improvement Report 2012). By 2015, the steering group’s target is that 96% of farms will have an average annual BMCC of less than 400,000/ml and 65% of farms will have less than 250,000 cells/ml. In 2020 these targets become more stringent.

To help achieve this tar-get, the group recommended a research project examining the value of new m o l e c u l a r techniques for i d e n t i f y i n g mastitis patho-gens in milk (see boxed ar-ticle).

On the training front, to ensure that farm-ers and advisers in mastitis management are up to speed, the group has set a goal to increase the number of people who at-tend the National Centre for Dairy Educa-tion Australia’s Cups On Cups Off courses across fi ve years and to make Countdown Adviser training available annually.

Since the fi rst meeting the issue of the availability and training of milking ma-chine technicians has been a major con-cern, particularly in regions where dairy farm numbers are small or declining.

The AMQSG’s goal is that “all Aus-tralian dairy farms have access to suitably qualifi ed and competent milking machine technicians by 2020”. D

32 The Australian Dairyfarmer September-October 2014

UPDATE FROM THE GARDINER FOUNDATION

Targeted approach to improving milk quality

By ALEXANDRA DE BLAS

Patrice Marshall, apprentice at Paynter Farms, Ellinbank, Vic, checks the temper-ature of the milk vat to ensure milk qual-ity is maintained.

INSET: Premium quality milk awaiting collection on farm.

The Australian Dairyfarmer September-October 2014 33

UPDATE FROM THE GARDINER FOUNDATION

Maximising benefi ts of molecular mastitis testingAS any dairyfarmer knows, mastitis in the herd can be a costly business, causing distress for cows and farm workers alike.

A number of different bacteria cause mastitis in dairy cows and it is impor-tant to identify the correct pathogen to ensure the most appropriate treatment and control methods can be applied. Any new tool to reduce the incidence of this disease is worth careful consid-eration.

Australian dairyfarmers have had access to a milk PCR (molecular test), via Dairy Technical Services Ltd, since 2011. PCR stands for polymerase chain reaction and it is a type of test used in agriculture, science and medi-cine to assess a biological sample for the presence of specifi c types of DNA.

Compared with the more traditional methods, which require growing a mi-crobe in the lab, the PCR test is more rapid and specifi c. However, its greater sophistication means the fi ndings can be more diffi cult for farmers and vets to interpret.

To ensure the benefi ts of the new tests could be realised under Austral-ian conditions, a team of scientists with a long association with Dairy Aus-tralia’s (DA) Countdown 2020 program undertook a large research project, which was completed in 2013. Primari-

ly funded by the Gardiner Foundation, it was a collaboration between Harris Park, DA, Dairy Technical Services and the University of Sydney.

The research team used its fi ndings to develop clear, evidence-based rec-ommendations for the industry on how to best utilise the new technology.

This information should soon be publicly available through Countdown 2020.

One version of the milk PCR test has the ability to identify 11 different mastitis-causing bacteria. However, the researchers have concentrated on the value of the milk PCR test for preventing and controlling Streptococ-cus agalactiae (Strep ag) and Myco-plasma bovis (M. bovis) in Australian herds.

Only these two pathogens — Strep ag and M. bovis — can be claimed to have originated inside the udder since the other nine bacteria may have come from other sources. This means that when Strep ag or M. bovis is de-tected it has almost certainly origi-nated inside the udder of one or more of the cows in the herd and they are almost certainly causing udder health problems.

Although the other nine target or-ganisms might have originated from an infected udder too, it is also pos-

sible they have entered the milk supply via contamination of teat skin, as the environment is the primary source of those organisms.

Therefore, a second version of the milk PCR test, which covers only four pathogens (Strep ag, M. bovis, Staph aureus and Strep uberis) seems more suitable for Australian dairyfarmers.

The researchers developed deci-sion process tools to effectively use and interpret results in a range of sce-narios. They include:• taking biosecurity measures to re-duce the risk of buying in new cows with Strep ag or M. bovis;• investigating elevated Bulk Milk Cell Counts (BMCC) and/or high incidence of mastitis;• segregating or treating cows infect-ed with Strep ag;• segregating or culling cows infected with M. bovis; and• carrying out herd surveillance in nu-merous circumstances.

While conventional bacteriology takes about 24-28 hours, the milk PCR test takes fewer than four hours to run. The rapid test costs about $45 per sample.

Contact: website <www.gardiner-foundation.com.au> or phone (03) 8621 2900.

—ALEXANDRA DE BLAS

Dr Lauren Clyne, from the Maffra Vet Clinic, collects a milk sample from a cow with mastitis.INSET: Close up of milk sample collection.