Mid-lactation once-a-day (OAD) milking


4 min read

Late-season OAD experiment Case study

Once-a-day (OAD) milking is a practice adopted by dairy farmers to manage their herds during late lactation, particularly from Christmas onwards. The page explores the reasons farmers implement OAD milking, such as improving work-life balance, reducing the risk of heat stress, and increasing the body condition of cows for calving. It also shares results from an experiment comparing OAD with twice-a-day (TAD) milking, showing a decrease in milksolids production but an increase in body condition score. The page includes a case study of a sharemilker who has benefited from OAD milking, providing insights into its impact on production and cow health.

Christmas often marks a waypoint in the dairying calendar for deciding how best to approach the remaining four to five months of the season.

Statistics from over 7000 Fonterra suppliers showed 40% of farmers were using once-a-day milking at some point in the 21/22 season. 32% are using it in conjunction with twice-a-day and/or flexible milking. A large portion of these part-season once-a-day farms are post-Christmas OAD.

Farmers implement once-a-day in later lactation, such as Christmas onwards, for several reasons including:

  • Work-life balance: using the summertime to spend with family, have a break or enjoy some time for hobbies.
  • Reduce long walks to the shed and milking in the afternoon heat – both are unenjoyable for people and animals and increase the risk of heat stress.
  • Reduce energy demand so cows can begin to increase body condition for calving.

Late-season OAD experiment

Once-a-day (OAD) milking compared with twice-a-day (TAD) for three months in late lactation.

Key results

  • 13% decrease in milksolids production while cows were on OAD

  • Approximately a 5% decrease in milksolids at the season level

  • ¼ body condition score (BCS) unit increase at dry off

  • Approximately 2% decrease in dry matter intake

Experiment details and results


Duration: January - end of lactation 2013

Cows: 52 Holstein-Friesian cows in two herds: Herd 1 milked twice a day (TAD), Herd 2 milked once a day (OAD)


  • Cows feed intake
  • Milk production
  • Somatic cell count (SCC)
  • Body condition score (BCS) gain



  • Production per cow dropped 13% while cows were being milked OAD.
  • The 13% loss in milksolids production in this trial occurred when production was past its peak.
  • Cows had already delivered about two-thirds of their season’s total yield.
  • The overall impact on the season’s production was approximately 5%.

Feed intake:

  • A small decline in feed intake.
  • The decline in feed intake by the OAD herd was not as great as expected.
  • Cows milked OAD ate about 2% less than cows milked TAD.

This small decrease in intake needs to be considered if milking OAD during a dry summer. Once-a-day milking will not solve a feed shortage problem. Although intake levels were similar, the OAD herd had a better energy balance because less energy was being put into milk production and walking. This resulted in OAD cows being on average a ¼ of a BCS unit more at dry-off than the TAD cows and therefore had less BCS to gain during the dry period to achieve calving BCS targets. BCS improvements take time; it wasn’t until after six weeks of OAD milking that there were detectable differences in BCS.

Somatic Cell Count and future lactations:

Although SCC was not greatly affected in this trial, it did increase in OAD cows as lactation progressed and milk volume decreased. The impact on SCC of switching cows to OAD milking in mid/late lactation needs to be considered, especially in the first few days.

To avoid grading when making the change to OAD the SCC needs to be able to double. Cows with high SCC or mastitis are not good candidates for OAD systems. Consider drying them off early. An option to prevent the large spike in SCC when switching, is to stagger it over a few days so they are not all spiking at the same time.

Cows that had been milked OAD were then followed into the next season where there was no reduction in milksolids yield when they commenced TAD milking again after calving. This disproves the 'mammary memory' myth that implies putting a cow on OAD will negatively impact future lactations.

These cows will likely have a higher BCS at dry-off, are more likely to reach the BCS targets at calving, and reap the production and reproduction benefits.

In this trial OAD milking did not extend the cows’ days in milk, cows were dried off individually based on their milk production and BCS. BCS was the deciding factor for drying off all the TAD milked cows (≤4.0), compared with the OAD herd which had 2 of 4 cows dried off due to production (<5 L/day for 5 days).

If contemplating milking OAD post-Christmas, these performance factors need to be considered alongside other farm-specific variables such as lifestyle and milking-associated costs.

You can access the full research article here.


Case study: Once-a-day milking as part of summer routine

Structure: Sharemilker
Location: Waikato
Cows: 460 larger Friesian-cross cows
Change to OAD: January
OAD trigger: Normally change when producing ~1.7kg MS/cow/day
OAD impact: ~0.2 kg MS/cow/day reduction. Therefore ~1.5kg MS/cow/day production January-March. March drop to 1.3kg MS/cow/day. April drop to 1.2kg MS/cow/day
Milking regime: TAD from calving to January, OAD January to dry-off

Waikato sharemilker Mark van Hellemond.

The big drought of 2007-08 prompted Waikato sharemilker Mark van Hellemond to try putting his herd on once-a-day (OAD) milking for the first time.

“It was almost unheard of at the time to consider going OAD after Christmas, but that is how dry it was that year,” says Mark. “We felt it was the best option to try and continue milking in a season where the dry had come very early.”

Since then he has not looked back, and now the herd goes once-a-day (OAD) in early January every season.

Mark’s 460 head herd of larger Friesian cross cows are typically producing 1.7kg MS a cow a day when he switches to OAD.

“We only get a small drop in production, usually by about 0.2kg MS (to 1.5kg MS/cow/day). They will sit on that until March when they drop to 1.3kg MS, then down to 1.2kg MS in April.”

“I go to once-a-day before feed tightens up and before I have to start feeding supplement, putting them on 24 hour grazing.”

Mark maintains the 11 percent drop gets channelled into body condition instead.

That in turn reduces the need to increase condition score over winter, has the cows peaking higher the following spring and achieving better cycling and in-calf rates. He regularly achieves the national goal of 78 percent in calf within six weeks.

He knows his bulk somatic cell count will double the first day he starts OAD milking, but settles back to the TAD average after three days.

"If you leave going once-a-day too long and milk volumes have already dropped down to 1.2kg MS or below, then you will run into problems.”

The lower milk price in 2015/16 had prompted him to consider once-a-day before Christmas. “But that’s pretty hard to do when your cows are still producing 2kg MS/cow/day.

“Going OAD is hard that first year, you do forgo a bit of production, but you can make it up the following season with better cow condition into spring.”

Last updated: Sep 2023
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