4 ways to optimise milking robots’ efficiency

Optimising the efficiency of each robot box is vital to deliver a good return on investment. This is achieved by maximising outputs while minimising input costs.

In practice, inputs for automatic milking systems (AMS) are difficult to change, so the primary way of improving efficiency is to increase the output of each box: saleable milk.

The main performance metric is milk sold/box each day, with a target of more than 2,000 litres.

See more: Benefits of robotic milking in a pasture-based system

About the author

Tom Greenham
Tom Greenham is a director of Advance Milking, a consultancy service for all aspects of udder health and milking machine performance. Advance Milking works with dairy farms across the UK and Ireland to optimise udder health, milk quality and milking efficiency. Mr Greenham also provides research, training and independent support to the dairy industry internationally.
Read more articles by Tom Greenham

Performance targets

To achieve the magic number of 2,000 litres/box each day, we must hit certain targets:

  • Less than 2% of milk discarded
  • Target milking time more than 20 hours (84% of the day)
  • Target wash/maintenance less than one-and-a-half hours (6% of the day)
  • Allowable idle time two-and-a-half hours (10% of the day).

This target can be hit by focusing on the following areas:

1. Minimise unsold milk

If high levels of milk are being produced that are not fit for sale (or sold below the maximum payment band) then box efficiency is reduced.

This could be caused by high levels of clinical mastitis, high incidence of medical treatment for other diseases, or withholding milk to manage bulk tank cell count or Bactoscan.

  • If more than 1% of milk is being withheld from sale, review the reasons why.
  • Evaluate udder health management and milk hygiene in AMS.
  • Variable milking intervals increase somatic cell count rejections. Select cows that visit the box regularly.
  • Milk withdrawal for other disease incidence should be discussed with your vet.

2. Maximise yield

Although AMS can be (and are) used with more extensive dairy herds, it is much more challenging to achieve profitable levels of efficiency at lower yields.

These result in shorter visit durations, potentially increasing visits/hour. However, overall yield/hour for each box will still be lower, as milking duration is not directly proportional to milk yield.

  • Optimise attachment to reduce yield losses from failed milkings. A missed milking reduces subsequent quarter yield by 20-30% and it can take seven to eight milkings to recover.
  • Use a nutritionist who understands the unique demands of AMS feeding. They may advise driving visits by feeding a partial mixed ration with lower metabolisable energy, rather than by limiting feed space/access, or driving yield with protein while moderating highly fermentable energy sources.
  • Optimise transition and fresh cow health. If cows do not peak adequately, the robot does not have a high yield to maintain.
  • Monitor heifer performance. If heifer yields are less than 85% of average cow yield, then investigate this further.

3. Maximise visits/hour

Occupancy is one of the biggest contributors to box efficiency, and there is usually a lot of scope for improvement.

  • Improve cow flow by optimising building layout. Separate robot entry and exit areas and a protected entry race will reduce bullying/displacement, while pre-selection pens make fetching cows more efficient.
  • Increase milk flow rates to reduce unit-attachment times. Paradoxically, the best way of reducing box times is to lengthen the pre-milking teat preparation: longer teat cleaning is outweighed by faster milking.
  • Box times can be further reduced by using dynamic testing to optimise vacuum settings, liner choice and unit detachment thresholds.
  • Reduce the number of refused visits to less than 25% of total box entries to prevent disruptions to eligible cow entry. This can be achieved by optimising feeding regimes, eliminating fat cows and altering permission settings to allow heifers more entries.
  • Use low-traffic times (usually 10pm to 6am) efficiently. Alter permissions overnight to minimise refusals; consider extra feed or push-ups to stimulate traffic; consider filling a fetch pen at the start of quiet periods; and perform washing and maintenance during quiet times.

4. Manage cow behaviour traits

Managing health and behaviour traits that influence how efficient cows are, individually and as a group, can improve yield and box occupancy rates.

  • Fresh cow visit frequency drives later performance, and heifers in particular will require fetching in early lactation.
  • Lame cows and sick cows do not perform well in AMS – they have fewer visits, leading to a negative cycle of lower yields and still fewer visits. Foot health and transition management should be areas of key focus for all AMS herds.
  • Some cows are simply unsuited to an AMS. Select cows based on efficiency measures: yield; milk flow rate; milking failure rate; and visit regularity.

Key action points (in approximate order of priority)

  1. Eliminate lameness – aim for less than 5%
  2. Maximise heifer performance – yield should be at least 85% that of cows
  3. Maximise fresh cow visits – more than three a day, at regular intervals
  4. Minimise failed milkings – aim for fewer than 5% of visits
  5. Maximise udder health – target less than 2% milk separated
  6. Select efficient cows with high yield, low box time, low failures, low fetches
  7. Feed for yield, not just visits
  8. Increase milk flow – aim for more than 4.2 kg/minute by optimising pre-milking settings
  9. Reduce unit-on time by optimising vacuum settings, ACR thresholds and liner choice.
  10. Increase traffic at quiet times
  11. Increase number of cows using each box – if all other points are addressed, this is the final way of improving box yields