- We refer here to 3-in-2 milking as a 12-18-18 schedule
- Milkings are at 5am, 5pm and 11am over a 2-day cycle
- The milking times you pick may differ to above, so any suggestions outlined below need to be adapted to fit your chosen intervals.
How do I choose which interval to use?
Choosing how to space the three milkings over the two days will have implications for the attractiveness of the system to the people on farm. What is attractive varies from person to person so depending on individual and farm goals, or the time of the season, use the following information to work with your team to identify the best milking times to maximise benefits.
In 2020/21 DairyNZ ran two six-week experiments to determine if there was any impact on the timing of milkings on production levels during peak and mid-lactation. The first experiment ran from September 11 to October 22, 2020, and the second from January 15 to February 25, 2021. Cows were an average of 34 and 146 days in milk at the start of each experiment. There were three different 3-in-2 milking intervals: 12-18-18, 10-19-19, and 8-20-20. All herds contained 40 cows and were grazed side by side in the same paddock, separated by an electric fence.
Changing these intervals brings the afternoon and mid-morning milkings earlier. Both changes are likely attractive: firstly, to get home earlier on day 1; secondly, to still get milking completed relatively early on day 2, leaving the day open for other farm tasks (Fig 1).
Statistically, there were no differences in the kilograms of milksolids produced between each of the 3-in-2 herds, 1.93, 1.88 and 1.89 kg MS/cow/d in spring and 1.67, 1.67, 1.64 kg MS/cow/d in summer for the 12-18-18, 10-19-19 and 8-20-20 herds (Fig 2).
More detailed analysis of results
Within the two six-week trials, we also utilised two control herds (OAD and TAD) to explore whether there were differences in milk production that were too small to detect in the previous analysis. Each AM, PM and mid-morning milking for all milking frequencies were plotted separately (see figure). The overall trends, linear for fat and curvilinear for protein, are supported by previous research and match those observed in our 2019/20 farmlet study.
These trends can be used to estimate the scale of underlying differences between 3-in-2 intervals. These predictions are presented in Table 1, including one for an even 16-16-16 interval, as well as further refinements to the 3-in-2 system, such as milking 10 times over 7 days (10-in-7). 10-in-7 changes the fortnightly cycle of 3-in-2 into a weekly pattern by milking OAD on Saturday and Sunday, fitting a seven-day-a-week business into a weekend-centric society. This is estimated to cost 0.01 to 0.02 kg MS/cow/day over the week, relative to 3-in-2.
Table 1. Difference in kg MS/cow/d between 3-in-2 milking intervals. E.g. there is a predicted difference of 0.01 kg MS/cow/d between 16-16-16 and 12-18-18.
0.010 0.025 0.050
This research shows us that, although there may be small biological differences to using longer milking intervals, these differences were too small to detect at the herd level. Therefore, a change in milksolids under more attractive 3-in-2 milking times, particularly 10-19-19 relative to 16-16-16 or 12-18-18, are unlikely to be noticeable on commercial farms, particularly if the improved interval results in a more engaged farm team with less fatigue and improved farm management.
This should give farmers confidence to select the milking times that are most suitable to their farm and team, particularly if flexibility is a key reason for adopting flexible milking. For examples of milking intervals in practice, check out the info on our 2020/21 pilot farmers.
How can I adapt flexible milking times to suit my farm?
As the popularity of 3-in-2 milking increases, it is clear there is no one-size fits all approach, hence the term 'flexible milking'.
This allows you flexibility in choosing when you want to milk, based on your values and situation. As the season progresses you may find that your milking intervals do too. It's all about finding what works best for your farm. See examples of how our flexible milking pilot farms have managed their milking and mating times.
You can also see the pilot farms flexible milking times in an easy-to-view table.
The following table outlines several examples that we have seen on farms throughout New Zealand and is by no means an exhaustive list. Note some of these intervals may affect milk production.
Under flexible milking systems, milking times on the day with one milking are generally timed to be halfway between the previous milking and the next milking. E.g. for 13-in-7, Sunday 10am is 19 hours after Saturday 3pm and 19 hours before 5am Monday.
Monday 5am:3pm 5am:5pm 5am:3pm 5am:3pm 5am:4pm 6am Tuesday 5am:3pm 11am 5am:3pm 5am:3pm 10am 6am Wednesday 5am:3pm 5am:5pm 5am:3pm 10am 5am:4pm 6am Thursday 5am:3pm 11am 5am:3pm 5am:3pm 10am 6am Friday 5am:3pm 5am:5pm 5am:3pm 5am:3pm 5am:4pm 6am Saturday 5am:3pm 11am 5am:3pm 5am:3pm 11am 6am Sunday 5am:3pm 5am:5pm 10am 10am 8am 6am Milkings in a fortnight 28 21 26 24 20 14 Reduction from TAD 25% 7% 14% 29% 50%
Should I put the whole herd or part of the herd on 3-in-2?
This question is often asked in mid-lactation. The answer will depend on what you are trying to achieve by changing milking frequency.
If the goal is to reduce milking hours for staff, and reduce walking for the herd, then it is likely 3-in-2 for the whole herd is the better option, as part of the herd on OAD does not reduce the number of milking events, and only reduces walking for part of the herd.
If the goal is around improving the body condition of lighter cows, then putting part of the herd (lighter cows) on OAD may be a better strategy. Milking 3-in-2 may help these lighter animals but will likely still result in a range of BCS across the herd, whereas putting these lighter cows on OAD will help improve their BCS and reduce the variation in BCS across the herd.
How do I manage grazing with 3-in-2 milking?
A strong theme from the farmers we spoke to was that 3-in-2 is not a strategy to reduce feed intake.
To limit milk production loss, and maintain BCS, cows should be fed to the same level as they would have been on TAD. The energy savings from dropping one in every four milkings may lead to an improved energy status and BCS profile of the herd.
Tips from farmers include:
- Manage feed as 48-hour blocks
- Split that feed into three, rather than four breaks
- Split equally, or according to the hours between milkings
- Work in with your paddock sizes, number of paddocks and target rotation lengths to find the most suitable system
Another theme identified from farmer experience was not to overcomplicate your grazing plan. Cows can eat their allocated pasture in a relatively short period of time, therefore splitting the feeds may not to lead to reduced intakes during the shorter intervals. It may be more straightforward if all break sizes are the same to avoid confusion between staff members and allocation errors, particularly in larger teams where multiple people are involved.
Will 3-in-2 reduce costs on farm?
Changes to farm costs as a result of milking 3-in-2 will be highly farm-specific, so it is advisable to prepare a budget. The most frequently discussed costs are dairy shed expenses and labour (discussed below). For more information on potential cost savings as a result of farm system changes see the flexible milking farmlet results.
There are some obvious cost savings in the dairy with 25 percent fewer milkings. For example detergent, electricity and rubberware are all likely to decrease. However, combined shed expenses are unlikely to reduce by 25% for the time you are using 3-in-2 because there is more milk to harvest at the remaining milkings which will offset some of the potential savings.
Whether 3-in-2 results in a decrease in labour costs will be highly farm specific. With the exception of large farms it is unlikely to change the number of full-time staff required. Costs may be reduced if you pay hourly or are able to reduce the need for relief milkers due to different milking intervals.
With milkings occurring at different times, a further opportunity may be to secure relief milking or part time staff from alternative sources – such as those that can work outside of 9-5, or around school hours etc. In some situations this could result in fewer full-time staff, replaced by more part-time staff.
The use of flexible milking intervals such as 3-in-2 provides an excellent opportunity to reduce hours of work and increase flexibility for people on farm. Ask your team and come up with a plan that is desirable for everyone, whether that be a sleep-in, earlier finishes, or a bit of both. Working with the farm team on the best way to structure the day is important to ensure that they can benefit from the change without affecting other non-milking jobs that are important for the farm. Reducing day length will likely benefit farm efficiency through a more motivated team (work-life balance) and improved rest time, resulting in fewer mistakes.
How do I manage the colostrum mob with 3-in-2?
Many farms milk colostrum cows OAD to help with workload during a busy calving period, the aim is to select times that will make the intervals as close to 24 hours as possible.
Here’s how one of our pilot farmers plans to manage this while milking 3-in-2:
- Day 1 – milk colostrums at ~4pm before the main herd at 5pm.
- Day 2 – milk colostrums after the main herd at 11am milking (~2pm)
The aim is to select times that will make the intervals as close to 24 hours as possible, the above example is 22 and 26 hours.
To ensure that colostrum doesn’t get into the supply milk when milking before the main herd, NZCP1 states that milking equipment must be hot washed after milking to ensure that any remaining residue is effectively removed.
Alternatively, other farmers continue to milk their colostrums at every milking when on 3in2. Typically, TAD farmers use a 4-colour tape system to identify when cows have reached their 8 milkings. Under a 3-in-2 system, this would need to be tweaked. See the below table for an example 5-colour option that will help to meet the 8-milking standard - modify to suit your needs. This scenario assumes that calved cows are only brought into the colostrum mob once a day.
Cow calves on a day with 2 milkings AM - paddock MID - milking 2 AM - milking 3 MID - milking 5 AM - milking 6 MID - milking 8 AM - in the vat PM - milking 1 PM - milking 4 PM - milking 7 PM - in the vat Cow calves on a day with 1 milking MID - milking 1 AM - milking 2 MID - milking 4 AM - milking 5 MID - milking 7 AM - milking 8 PM - milking 3 PM - milking 6 PM - in the vat Colour Green Blue Yellow Red White Green Blue Draft Greens at MID milking and attach green to newly-calved cows Draft Blues at AM milking and attach blue to newly-calved cows
How do I manage somatic cell count and tanker scheduling?
Many farmers that were interviewed had expected the longest milking interval to result in the highest Somatic Cell Count (SCC), due to pressure in the udder, and the previous knowledge around SCC increasing when going on OAD.
However, it is the shortest milking interval that tends to have the highest SCC.
This is due to there being a lower volume of milk in which to dilute a similar number of somatic cells, generating a higher milk SCC. A bulk tank containing only milk collected after a short interval will have a higher bulk milk SCC.
If you are on daily tanker pickups, work with your milk supply company to select the most suitable time for your pickups (see Figure 2).
If you are on skip-a-day pickups, then SCC of individual milkings will not come into play, as every pickup will have all three milkings.
Over spring, some farmers implementing flexible milking strategies have experienced issues with vat capacity. If you know you have issues with your vat size, make sure you chat with your milk supply company prior to making the change to discuss options to minimise the risk of flooding the vat.
Be sure to let you milk supply company know your updated milking times to avoid tanker collections during milking.
How can I adapt my plant wash programme for 3-in-2?
How should I treat mastitis under a 3-in-2 milking regime?
It is likely that any mastitis treatments administered under 3-in-2 milking regimes would be considered as going 'off-label' due to treatment intervals. Off-label use of any product has a default milk withholding of 35 days.
Not getting vet approval or following the 35 day withholding would likely breach the conditions of supply with your milk processing company or the overarching regulations in NZCPI (MPI regulations for milk supply for human consumption in NZ). Therefore, it is important to discuss your options and withholding periods with your vet and get the required sign-off to be using the treatments under your new regime.
Things you should discuss with your vet to select the most appropriate treatment and get sign off include:
- Your planned milking intervals
- Preferred treatment options
- Suitable treatment plan, e.g. treating OAD vs at every milking
- Suitable withholding periods for your chosen plan
How do I manage the mating period using 3-in-2?
One of the common barriers for farmers to use 3in2 during early lactation is the management of the mating period. We spoke with several farmers who have been using full season 3-in-2 for multiple years, and they have provided us with their mating plans.
Please note that these are working examples from the farmers that we spoke to. When creating your own plans, be sure to consider the following:
- Interval between matings.
- Interval between standing heat and mating:
- Check out LIC’s 'Best time to Mate' graphic to help with your decision making.
- Technician vs DIY:
- Work with your technician or provider to come up with a plan that works for everyone, including the cows.
Draft and mate at all 3 milkings
Mate at the same time each day
Mate once daily, at different times
5AM milking Draft and mate Draft and mate Draft and hold separately to mate before 5PM milking Draft and mate 5PM milking Draft and mate* Draft and hold seperately to mate before 11AM milking 11AM milking Draft and mate Draft and mate Draft and mate Suitable for DIY herds Suitable for technicians Suitable for DIY and flexible technicians**
* Can hold overnight and mate the following morning if more suitable to schedule
** Check with your technician or provider if this might work for you
Under all three scenarios above, the farmers found their results to be similar, if not better than when they used a standard milking and mating system. Depending on what system you choose for your farm, and your previous experience and results, you may find that your results differ. See examples of how our flexible milking pilot farms have managed their milking and mating times.
You can also see the pilot farms flexible milking times in an easy-to-view table.
Research in NZ has shown that non-return rates of animals detected in heat at the previous PM milking or the AM milking directly before AI under OAD mating systems were not significantly different, suggesting that there may be some flexibility in the time of AI in relation to standing heat.
For flexible milking intervals, it is possible that an improvement from energy status and BCS of the cows may offset some timing issues if cows are being mated with long intervals between standing heat and ovulation (e.g. >28 hours), resulting in similar reproductive outcomes. Talk to your technician or herd improvement representative to help select the best plan for your farm situation.
What do I do if my milk cooling system isn't working effectively?
The large difference in the volume of milk between milkings can create issues with milk cooling, however the specific reasons, and therefore best solutions, may differ between farms.
Bacteria in raw milk grow rapidly above 6˚C so NZCP1 states that raw milk must be:
- cooled to 6˚C or below within the sooner of:
- six hours from the commencement of milking, or
- two hours from the completion of milking; and
- be held at or below 6˚C without freezing until collection or the next milking; and
- must not exceed 10˚C during subsequent milkings.
Two examples are listed below, that have been experienced by pilot farmers during the 2020/21 season:
Example 1: Failing to remain within blended milk temperature requirements (point 3)
The farm (using a 10-19-19 hr interval) was on daily milk collection, on a daytime collection. This meant that there was a 10hr (PM) milking going into an empty vat in the afternoon and being cooled overnight, and then a 19hr (MID) milking, with a much larger volume, was being added into the smaller volume, which was resulting in the blended milking temperature going above the requirement not to exceed 10˚C during subsequent milkings.
In the short term, an option to manage this was adjusting the refrigeration so the milk was at 1-2˚C, so it was at a lower starting point before the mid-morning milking (there is a device that can be purchased to automate this). Longer term they have discussed the issue with their milk processor and have opted to increase vat size and move to skip-a-day collection. An alternative option, which was not possible for this farm due to location, was to change the pick-up time to evening (after the PM milking) which would result in the larger milking being in the vat first.
Example 2: Struggling to cool milk in the required timeframe (point 1)
The farm had historically struggled with milk cooling over the summer months, so in winter 2020 upgraded his milk cooling unit, as per refrigeration company specifications, to help address this issue.
However, prior to summer there have already been issues with meeting requirements, even with the new, and larger unit. In the short term, the calf milk vat has been used to pre-cool water to run through the plate cooler. Longer term, despite having already sought guidance, the refrigeration unit may need to be upgraded again.
Overall, it’s worth getting to the bottom of the issue specific to your farm with your milk processor and refrigeration supplier and identifying all the options available. Often there are multiple options available, which differ considerably in cost and effort to implement. Monitor your milk telemetry results and look for the most cost-effective option. In some cases, there will be opportunity to improve the effectiveness of the primary cooling at little cost.
- cooled to 6˚C or below within the sooner of:
How do I manage staff time and rosters on 3-in-2 milking?
One of the top 3 reasons that farmers make the move to flexible milking is for their people – mainly to help reduce staff hours, increase flexibility and work/life balance for them and their staff, and improve staff retention.
Each farm is different in terms of staff numbers, responsibilities, milking times etc. so there is no one-size-fits-all approach for how to best manage your roster. However, we have included some examples of how farms already implementing 3-in-2 around the country have organised their roster and/or day to day management of time to create flexibility or reduce overall hours worked. This may help to spark ideas for how to best implement it on your farm to maximise the benefits of using a flexible milking approach.
If you are thinking about changing your roster structure, or want to find out if your current roster is the best fit for your farm, you can find more information on selecting rosters here.
Angela Reid (Southland, 1250 Cows, 6 Staff)
I have 6 staff members and we run 2 teams of 3 people on each team. The teams do one milking each a day and a rostered rotation of 11 on, 3 off (Table 1).
The aim of our roster is to have consistent 8-hour working days, and we have structured our roster and workloads to accommodate this (Table 2).
We do have additional staff (e.g. calf rearers) around calving and mating while the workload is higher, and they slot in as needed.
Each team has 3 people, who rotate around the jobs within milking – e.g. cows in, cups on, cups off, vat wash etc.
We found that we had to stagger the days off when we moved to 3in2, with one team taking Fri-Sun, and the other team taking Sat-Mon the following weekend, to ensure that it was fair with 2 TAD and 1 OAD on each set of days off (Table 1).
Table 1: Structure of roster
Ben Wilson (Kirwee, 710 cows, 4 staff)
We run a 7-2, 7-2, 7-3 roster year-round, which has stayed the same between TAD milking and 3-in-2 milking. The main change that we have made moving to 3-in-2 is to how the team structure tasks within their day.
Structure of day
As a team, we decided to use alternating long and short days when we are milking 3-in-2 (see below).
This approach allows the team to get more jobs done on the day with 2 milkings to allow for a shorter day on the day with one milking, where the aim is to only do the basics unless something urgent comes up.
“It is still important to provide the team a long lunch break on the longer days, to keep hours manageable and give the team a break before they come back for afternoon/evening milking.”
Flexible Milking approaches allow farmers to think outside the square.
There are a vast number of ways to take advantage of the flexibility that 3-in-2 milking offers. Below we share ideas to illustrate how some creative thinking can maximise the benefits for people on-farm.
When considering how to make the most of flexible milking, take the time to think about what hours and days of the week work well for your farm and staff. Here are a few examples:
- 10-in-7 can be great for staff that are involved in sports teams or community groups, as it is on a weekly cycle and can be staggered to allow for trainings and game times.
- For smaller owner-operator herds with no staff, flexible milking allows the owners and their families to maximise time away from the farm at a lower cost to the business by maximising the structure of their milking. For example, they could get away for an overnight trip (~36 hours) while only needing 1 milking to be covered by a relief milker.
- 3-in-2 example: Milk early Saturday morning, relief milker on Saturday afternoon and be back for Sunday midday milking
- 10-in-7 example: Milk Saturday mid-late morning, relief milker on Sunday morning and back for Monday morning milking.
- For multi-farm operations, there is the possibility to stagger the milking roster so that the farms are on opposite cycles – this could help with any staff shortages or covering days off.
This page was created by the Flexible Milking Project. This project is co-funded by NZ dairy farmers through DairyNZ and MPI through the Sustainable Farming Fund.
Could reducing the number of milkings in a week help the dairy sector attract new staff and improve work-life balance? One farmer who’s gone to a flexible milking schedule is John Totty in Canterbury, currently starting his second full season milking 10 times in 7 days. What were his reasons for changing his milking schedule, and what kind of outcomes is he seeing?