Is flexible milking the future, or just a fad?

The popularity of once-a-day (OAD) milking in Ireland has increased dramatically over the last decade, with Teagasc now estimating that there are over 200 farmers practising it all year round.

Many hundreds more are practising it for parts of the year, either at the start or end of lactation or both.

A recent survey of New Zealand dairy farmers found that just 45% of farmers there practise twice-a-day (TAD) milking for the full season.

The proportion milking OAD for the full season is still relatively low at 8% so most of those who aren’t milking TAD all year are carrying out some version of OAD or flexible milking.

While the advantages of OAD are obvious, a major disadvantage is the initial hit in milk solids production, with around a 20% drop in production compared to TAD (see Moorepark results below).

Initially, farmers were using 16-hour intervals but this led to unsociable milking times every second day

Current research in New Zealand is looking at ways to reduce milking frequency while at the same time avoiding a big drop in animal performance.

This is termed flexible milking and the most common method is three-in-two (3-in-2) milking. So, rather than milking four times in two days (TAD) or two times in two days (OAD), cows are milked three times in two days.

Initially, farmers were using 16-hour intervals but this led to unsociable milking times every second day.

So the system has been tweaked to make it more attractive and the current research experiments at Dairy NZ are looking at 12-18-18 hour intervals and different variations of that.

A 12-18-18 hour milking interval is where cows are milked at 5am and 5pm one day, followed by 11am the next day when cows will be milked once and again twice the following day at 5am and 5pm.

Dairy NZ researcher Paul Edwards said that in a full-season 3-in-2 farmlet experiment using these milking times the reduction in yield was 5% compared to cows milked TAD for the full season. In this experiment, the TAD herd produced 460kg MS/cow and the 3-in-2 herd produced 437kgMS/cow.

Two shorter periods of 3-in-2 were also looked at, with cows starting their lactation on TAD and then moving to 3-in-2 at the equivalent of June and August for an Irish spring-calving herd. The findings suggest that for every day of 3-in-2, daily milk solids production drops by 0.09kg/cow.

He also said that the 3-in-2 milking times used in the experiment are not altogether attractive for farmers

In a recent Dairy NZ webinar, Paul emphasised that the study only ran for one year, so any follow-on effects in the next lactation of reduced milking frequency such as improved body condition score would not have been observed.

He also said that the 3-in-2 milking times used in the experiment are not altogether attractive for farmers as the day the cows are milked twice is a long working day – longer than typical TAD milking. He also pointed out that the 11am milking is too late for many people.

With this in mind, a shorter experiment looked at the effect of different milking intervals over a six weeks involving cows at peak production. Three 3-in-2 times were looked at: 12-18-18 (5am, 5pm, 11am); 10-19-19 (5am, 3pm, 10am); 8-20-20 (5am, 1pm, 9am) along with TAD and OAD. Average daily milk solids yield during the six-week trial period for the 12-18-18 herd was 1.93kgMS/day, it was 1.88kgMS/day for the 10-19-19 herd while it was 1.89kgMS/day for the 8-20-20 herd.

Paul said that while there were numerical differences between the treatments, there were no statistical differences. Nor was there a statistically significant difference between the TAD or OAD herds and the 3-in-2 herds but he said the fact that all herds were milked TAD prior to going on 3-in-2 may have had an impact.

One of the drawbacks is that 3-in-2 has a fortnightly cycle to it

Paul said one of the advantages of 3-in-2 milking is it can help to make milking cows more of an attractive role for people living in the community because every second day’s milking is carried out between the hours of 9am and 5pm.

“One of the drawbacks is that 3-in-2 has a fortnightly cycle to it, so when it comes to planning something, say in three weeks’ time, you don’t necessarily know based on the day of the week whether you have two milkings or one milking on that particular day without knowing what week it is. Which for some people is not an issue whereas for others its a big issue. This is why 10-in-7 has caught on because every week can be the same and there won’t be two milkings on every second Sunday,” Paul said.

A 10-in-7 milking interval is where there are 10 milkings in seven days. An example of this is where cows are milked TAD on Monday, Wednesday and Friday and OAD on Tuesday, Thursday, Saturday and Sunday. If 3-in-2 involves 25% fewer milkings and 10-in-7 involves 29% fewer milkings, a further reduction in milk solids output can be expected with 10-in-7 milking compared to 3-in-2.

A few things to watch for with flexible milking are the change in the value of milk solids as protein yield tends to drop more than fat yield so the value of each kilo of solid milk might change. The timing of AI and bulk tank size and collection schedule are also considerations along with managing SCC.

Moorepark research

Cows on the once-a-day milking trial at Teagasc Moorepark produced 3% more milk in 2020 than they did in 2019. Total production for the once-a-day (OAD) cows in 2020 was 409kgMS/cow, which is 19% lower than the twice-a-day herd which produced 505kgMS/cow.

The results were outlined by researcher Emer Kennedy at the recent Teagasc OAD conference.

Emer’s take-home message was that modest production performance can be achieved while milking cows OAD with low levels of concentrate

In terms of fertility performance, just 4% of the OAD cows were not in-calf at the end of the breeding season, while 9% of the twice-a-day cows were not in calf. The OAD herd at Moorepark was fed 330kg of meal/cow in 2020 and had an EBI of €169. Somatic cell count averaged 344,000 in the OAD herd while it was 204,000 in the TAD herd.

Emer’s take-home message was that modest production performance can be achieved while milking cows OAD with low levels of concentrate but that farmers need to be technically efficient and be very good at managing grass and cows.

Laois-based farmer MJ Delaney, who has been OAD milking since 2013, also spoke at the online event. His cows produced 398kgMS/cow in 2020 with an SCC of 215,000. MJ stressed the importance of grassland management as he only has one opportunity a day to give them the right amount of grass, compared to twice-a-day milking.

Teagasc adviser Brian Hilliard, who has spearheaded OAD milking in Ireland, has retired from Teagasc but said he will continue to work with farmers who are interested in OAD milking.

For me, flexible milking is the middle ground between the rigidity of TAD and the sharp drop in performance when cows go to OAD.

Research results from New Zealand on flexible milking look promising, with just a 5% reduction in milk solids yield from 25% fewer milkings. Milking 10 times in seven days is likely to lead to slightly higher production losses, but a much more attractive weekly work schedule.

It’s all about trade-offs between production, profit and making the farm a more attractive place to work. I know of farmers in Ireland practising flexible milking for periods of the year and getting on really well at it. I think we will see more of this in time.

On the subject of making farms more attractive places to work, it also needs to be said that there’s a job of work to be done to get a lot of TAD farmers to start the evening milking before 4pm.

What kind of a signal are they sending to young people if they’re working from early morning to late in the evening every day?

Going to an 8-16 milking interval doesn’t lose any milk and is what is practised at Moorepark, with cows milked at 7am and 3pm.