The MaxT strategy is where cows are milked to a pre-determined time based on their milk volume, resulting in less time in the dairy for staff and cows, without affecting milk production or udder health.
There are three steps to implementing MaxT - calculate, implement and monitor.
The first step is to determine your MaxT time. The easiest way to do this is to download DairyNZ’s Milksmart app. By entering the number of litres from the tanker docket, the number of cows going in the vat and your milking start times, the app will calculate the average milk volume per cow for each milking, and the appropriate MaxT time for this volume.
Alternatively, use these tables to calculate your MaxT time manually.
Note: Farmers implementing MaxT for the first time have found it easier to start with using the morning MaxT time and monitoring at cups off as per Step 3.
Alternative calculation to simplify implementation is possible for some herds
The method described above will calculate a MaxT time specifically for each milking session (e.g. AM/PM). This can complicate practical implementation or lead to inefficiency. For example, due to uneven milking intervals the target afternoon milk time could be as low as 5 min, which could be difficult to achieve, or for those implementing via ACRs it requires a manual change of settings between milkings.
One work around suggested above is to use the AM MaxT time at both milkings, however, this will leave unrealised efficiency in the afternoon. An alternative approach called FixedT can be used to determine the MaxT time based on the average yield per milking (see Table below) and use that time at all milkings, ignoring differences in milking intervals – shifting milk from the longer milking to the shorter milking.
Research has concluded that this approach will not compromise milk production as long as no more than 33% of cows have their milking shortened. This means that if your milking interval does not diverge too much from the average interval of 12-12 h (TAD) or 16-16-16 h (3-in-2) then this 33% threshold is unlikely to be exceeded and the FixedT approach can be used.
In the experiment, which also used a 70:30 pulsation ratio to increase milking speed, fat production was affected when the TAD milking interval was 8-16 h. In this herd 40%+ of cows had their milking shortened at the morning milking due to it being 4 h divergent from the average 12-12 h interval. Conversely, there was no affect for a TAD 10-14 hr interval, which is only 2 h divergent from 12-12.
For 3-in-2, a 10-19-19 hr interval was tested, where the longer milkings were 3 h divergent from 16-16-16. There was no affect on production in mid-lactation, but there was a tendency for a reduced fat yield at the mid-morning milking in peak lactation where 36% of cows had their milking shortened.
For those looking to maximise their milking efficiency by using the FixedT approach to simplify milking and improve efficiency, monitor the number of animals that have their milking shortened (see Step 3) to ensure it is not more than 33%. In some cases this may require an adjustment to your milking interval.
Daily milk yield
Once you have your MaxT time the next step is to implement it in the dairy.
Before milking, make a list of the number minutes it takes for a bail to get from cups on to cups off at a range of speed settings on the platform control console. The fastest way of doing this is to time the number of seconds it takes for each bail to pass, multiply this by the number of bails from cups on to cups off (or the bail before the teat sprayer), then divide this number by 60 to convert it to minutes.
If you have ACRs
Just about every ACR has this functionality except the Waikato Ultimate, but there is an upgrade for this. Some models of Delaval and GEA may require a service technician to change the maximum time setting. If this is the case, choose a time from the start of lactation to handle peak milk and plan to change the MaxT time 2-3 times during the season. Make sure you contact your service technician if you have further questions.
Some ACRs can take the cups off at a set point (point take-off) i.e. just before the teatsprayers and/or exit on bridge. If you have this capability, then setting the correct platform speed and maintaining it is extremely important.
- Use the list on your console to set the desired MaxT time from cups on to cups off.
- Do not slow or stop the platform to fill empty bails and always stand next to the bridge as you need to ensure cows have the longest milking time possible between cups on and cups off.
- At cups off - depending on your rotary, your options to remove cups are:
- Person at cups-off removes all clusters on every cow and exits every cow after one rotation, or
- Use the maximum milking time or use the ‘point take-off’ function of your ACRs to remove clusters one bail before the teat sprayer as explained above.
Both methods still require the correct platform speed to be set and maintained. Milkings should also be monitored and/or checks put in place to ensure platform is not operated at faster speeds than the those required to ensure the correct platform MaxT times.
Note: if part of the herd is milked once a day, put these cows in one herd and allow them additional time.
The final step is regular monitoring. Once a week at an afternoon milking monitor five groups of 10 cows.When monitoring, look at the cows at the cups-off position (i.e. once the cluster has been on for the MaxT time.
- If most groups have fewer than two cows that are being shortened, you can reduce the MaxT time.
- If most groups have more than two cows that are being shortened, increase the MaxT time.
- If most groups have two cows in every 10 that are being shortened, you do not need to make any changes.