- 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.
When in the season should I use 3-in-2 and will it affect milk production?
Interviews with farmers indicate that they have started using 3-in-2 earlier each year, as they begin to see the advantages for both their people and cows.
In 2019/20 an estimated 14% of herds were milked using 3-in-2, with around half using it from Christmas onwards, and half using it in late lactation.
When (during the season) to use 3-in-2 will be determined by what you are trying to achieve. Preliminary results from a farmlet experiment run as part of the DairyNZ-led Flexible Milking Project give an indication of the likely effect on milk production. There were four herds, one being milked TAD for the full season, with the remaining three milking 3-in-2, either full season from Dec 1, or from March 1. Milking intervals were 10-14 for TAD and 12-18-18 for 3-in-2.
The preliminary analysis from this trial indicates that for a herd producing 460kgMS/cow on TAD, there is likely to be a 0.09kg MS/cow/day decrease for each day of 3-in-2 milking during the season. This equated to a 5% decrease in MS for the full season 3-in-2 herd. Fat production was less affected than protein, decreasing by 3% compared with 8% for protein. These results suggest that milking 3-in-2 may be a viable strategy for many farms to help reduce the pressure on both the cows and staff over the busiest time of the season – early lactation.
For more information on this trial see the Flexible Milking Research page.
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.
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 5am:3pm 10am 8am 6am Milkings in a fortnight 28 21 26 24 20 6am 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?
There are some obvious cost savings in the dairy, whereas labour costs will be highly farm-specific.
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
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.