Herringbone MaxT
Topics
6 min read
Understanding the maximum milking time (MaxT) is key to making your milking system as efficient as possible. MaxT is a strategy to milk cows at a predetermined time based on milk volume. This results in less time in the dairy for staff and cows without affecting milk production or udder health. The following guide will explain the basics of implementing MaxT in a herringbone dairy.
Step 1: Calculate
The easiest way to determine your MaxT time 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 below 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.
Step 2: Implement
Once you have your MaxT time the next step is to implement it in the dairy. Choose which system you will use to help you keep track of the MaxT time when milking. The most common options are:
- Use the first cow in the row to time the MaxT time for all the cows in row by:
- a timer visible from anywhere in the pit, or
- a phone with a timer, or
- Set a maximum milking time with your Automatic Cup Removers (ACRs).
Three key elements to a good routine when you are using the first cow to set the MaxT time for the row are:
- Start the timer as you attach the cluster to the first cow in the row, and work your way down the row attaching clusters in order. By keeping a consistent routine and order of cluster attachment for every row, the first cow acts as a timer for all cows in the row.
- After cupping the row and completing all other tasks, return to the front of the pit and wait for the MaxT time to be reached. Then change cups by working down the pit in order without waiting for any cows still milking, keeping that routine consistent.
- There are two options for teat spraying depending on your dairy. Spray as you go in your normal bunny-hopping routine, or because of the consistency of the MaxT routine, some milkers find it easier to teat spray after changing all cups in the row. With a MaxT milking routine you end up with all your waiting time at the front of the pit, rather than at individual slow cows, so you tend to have more time to teat spray and exit cows.
Note: if part of the herd is milked once a day, put these cows in one herd and allow them additional time.
Herringbone MaxT routine – milking smarter
This video shows MaxT in action during peak lactation and demonstrates how simple and relaxed the milking routine becomes.
When using MaxT, in order to keep the time consistent for all cows down the row, we recommend teat spraying after changing clusters.
This differs from the basic bunny hopping routine where tasks are completed in batches.
Example of a MaxT milking routine
Video 7:55 min
Step 3: Monitor
Once a week at an afternoon milking, monitor five groups of 10 cows. When monitoring, look at the cows while clusters are changed (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.
Alternative calculations
Using a MaxT specific for AM and PM milking can sometimes be impractical, for example when uneven milking intervals result in a target MaxT time as low as 5 minutes, or when ACRs settings have to be manually changed between milkings.
One solution is to use the morning MaxT time for both milkings, but this will result in reduced efficiency in the afternoons. Another is to make the milking intervals more even but that may mean milking at undesirable times of the day.
FixedT
An alternative option is FixedT – a MaxT based on the average yield per milking (see table below) applied at all milkings, ignoring differences in milking intervals. This shifts more milk from the longer milking to the shorter milking making both milkings more efficient while still allowing the milkings to occur at favourable times of the day.
A study at DairyNZ’s Lye farm tested FixedT for four milking intervals (TAD 8-16 h, TAD 10-14 h, 3-in-2 10-19-19 and OAD) at peak and mid-lactation, using a 70:30 pulsation ratio, and found no effect on udder health or milk production, when less than 33% of the herd had their milking shortened. For the 8-16 and 10-19-19 intervals, where one milking interval was 3-4 hours shorter than the others, the fat yield was reduced when more than 36% of cows were shortened.
Monitor the number of animals that have their milking shortened, as described in the MaxT pages, to ensure it is not more than 33%.
Find your FixedT time from the table below based on daily milk yield and milking frequency
| Daily milk yield | TAD Time | 3-in-2 Time | OAD Time |
| 12 | 04:40 | 05:40 | 07:20 |
| 14 | 05:00 | 06:00 | 08:00 |
| 16 | 05:40 | 06:40 | 09:00 |
| 18 | 06:00 | 07:20 | 09:40 |
| 20 | 06:20 | 08:00 | 10:20 |
| 22 | 07:00 | 08:20 | 11:00 |
| 24 | 07:20 | 09:00 | 11:40 |
| 26 | 07:40 | 09:20 | 12:20 |
| 28 | 08:00 | 10:00 | 13:00 |
| 30 | 08:40 | 10:20 | 13:40 |
| 32 | 09:00 | 11:00 | 14:20 |
| 34 | 09:20 | 11:20 | 15:00 |
| 36 | 09:40 | 11:40 | 15:40 |
FAQ's
Is MaxT too complicated?
Farmers who've adopted MaxT tell us that it simplifies the milking routine. The most complicated part is calculating the maximum milking time (MaxT), which is based on how long it will take 80% of your cows to finish milking. When implementing for the first time, MaxT is typically applied at the morning (highest volume) milking. Calculate your MaxT time with the DairyNZ Milking App (Apple App store and Google Play store).
Herringbone: the time begins once the first cow in the row is cupped. Then, cup the rest of the row. Once the MaxT time has passed, take the cups off the first cow and work your way down the row changing clusters, removing cups from all cows.
What if I can't do MaxT because I can't work any faster?
MaxT doesn’t mean you have to work faster. In most cases, you’ll be working at the same speed or more slowly.
Herringbone: milkers who use MaxT say it provides a logical milking routine and less walking back and forward to deal with slow-milking cows. This allows for a longer break at the front of the pit while waiting for the MaxT time to elapse.
How do I manage my in-shed feeding?
Meal feeding generally shouldn’t be a barrier to implementing MaxT. At peak milk, the full row/rotation time is likely to be between eight and 10 minutes, which should provide plenty of time for cows to finish their food ration. Farmers have found that, by implementing MaxT on rotary dairies with feeding meal, cow flow actually improves. The cows get used to exiting at the end of one rotation and there aren’t as many free-riders.
What if I have ACRs?
ACRs make implementing MaxT simple. For most devices, this is achieved by setting the ‘Maximum Time’ setting or ‘Point Takeoff’ setting (for rotaries) in the ACR to achieve the desired MaxT time (some models might need a modification from a service provider).
Another way is to lift the ACR low-flow threshold (similar to MaxT). For a rotary with one operator, set the platform speed to provide the required MaxT time between the cups-on and cups-off position, so more cows complete milking by the end of one rotation. Keep adjusting the low-flow threshold until you reach your desired balance.
What about pulsation ratios when doing MaxT?
Increasing pulsation ratio is a good strategy to reduce milking time in situations where the risk of overmilking is low – such as when using MaxT. Increasing the pulsation ratio will mean fewer cows are shortened than the estimated 20% for a given MaxT time. A key requirement when doing this is to achieve a d-phase of ≥ 20%.
- Set your pulsation ratio at 70:30 and pulsation rate at 55ppm if you have ACRs and are doing MaxT.
- Otherwise, set the ratio to 65:35 and rate to 60ppm if you are doing MaxT without ACRs.
Consult your milking machine technician to assist with changing your pulsation ratio.
Will MaxT cause mastitis?
No research or field study over the past 30 years has supported this theory. In fact, there’s a greater risk of mastitis when cows are overmilked at the end of milking. MaxT often results in a better let-down and removal of milk at the next milking for slower milking cows – and reduces overmilking for the rest of the herd.
Research shows that when a 500mL of strip milk is routinely left in the udder after milking, there’s no detectable increase in cell counts for both infected and uninfected quarters.
Will MaxT increase my bulk milk SCC?
Anecdotally, we know that herds milked using MaxT often see a decrease in somatic cell count (SCC). As mentioned earlier, there’s a greater risk of teat congestion, damage and mastitis when cows are overmilked at the end of milking.
Contrary to common myths, using MaxT and leaving milk behind in the udder has no negative effects on milk quality, milk production or somatic cell counts.
What if my cows produce too much milk to use MaxT?
Research in high-producing overseas systems does not support this theory. The most comparable study was in Denmark, where there was no significant difference in milk production or udder health when the ACR low-flow limit was doubled from 0.2 to 0.4kg/min, and cows were averaging 2.5kg MS/cow/d (32kg milk/cow/day).
Can you only use MaxT if you are milking TAD?
Although there's been no research yet to specifically test MaxT with milking three times in two days (3-in-2) or once a day (OAD), farmer feedback suggests it can work successfully. DairyNZ is expected to begin an experiment into this in October 2020.
Tags related to “Herringbone MaxT”