What’s new with 4x/6x milking?

Other articles on this topic:
6X cows near the parlor
6X works on small farms, too
21 days to more milk
Are you ready for 4X or 6X?
Optimal start time for 4X or 6X
Management factors impact 4X or 6X response
Frequent milking does not alter response to BST
BST response following 6X milking
4X may help improve body condition, too
6X milking lowers SCC
Keep the dry period, even if you use 4X
Avoid these 4X/6X barriers

Frequent milking during early lactation continues to make the headlines. However, some of the latest research has found no benefit to 6X milking during the first 21 days of lactation. The following question-and-answer format describes the results of this research. Add it to your collection of frequent-milking information so you can make an informed decision about applying this practice on your dairy.

Q. Do any research studies show no response to frequent milking?

If you've tried milking fresh cows more frequently and have not seen an increase in milk yield, you're not alone.

An on-farm study from the University of Arizona, published in the November Journal of Dairy Science, shows that 6X cows actually produced less milk than 3X cows on a large commercial dairy in Arizona.

This is the first published study to show no response to frequent milking. It contradicts two other published studies that show an immediate and long-term increase in milk production from 6X milking. The first of those studies, published in the December 1995 Journal of Dairy Science, showed a favorable milk-production gain in cows milked 6X for the first 42 days of lactation. The other study, published in the April 2004 Journal of Dairy Science, showed that cows milked 6X for the first 21 days of lactation yielded more milk than 3X cows. That study involved an analysis of monthly DHIA records.

Research on 4X milking also has yielded conflicting results. A study published in the June 2003 Journal of Dairy Science showed that 4X milking for 21 days yielded a positive milk-production response. In contrast, a study presented at the 2004 American Dairy Science Association annual meeting by researchers from CornellUniversity found that milk-component yields of 4X cows were no different than that of 2X cows. However, that study revealed a trend for higher milk production among 4X cows during the first nine months of lactation.

Q. Why did the Arizona study show no response to frequent milking?

It's not completely clear why the cows in the University of Arizona study did not see a response to 6X milking.

However, the study's authors say that it may have something to do with factors specific to the farm where the study was done, including:

  • Walking distance to the parlor.
  • Time away from feed and water.
  • Pen changes (social effects).
  • Slope of milk production.

During the study, the 6X cows walked 4,872 feet per day —  almost a mile — on their way to and from the parlor. The 3X cows walked 1,008 feet per day, for a difference of 3,864 feet per day. By comparison, cows were housed in tie-stalls in the other two published studies on 6X milking.

The 6X cows in this study also spent twice as much time — 6.5 hours per day, on average — outside of their pen as their 3X herdmates.

Although walking distance and time away from feed and water "could have indeed" affected the outcome, the researchers still harbor some reservations, acknowledges Matt VanBaale, extension dairy specialist at the University of Arizona. First, it did not hurt dry matter intake. The 6X cows ate the same amount of feed as the 3X cows.

Second, when compared to other large dairies, walking distance was nominal, even for the 6X cows, VanBaale says. In this study, the 6X cows walked 406 feet one way. It's not uncommon for some cows on commercial dairies to walk a lot further -— as much as 1,000 feet one way, he contends.

So, why do they think slope of milk production may have influenced the outcome?

During the first 21 days in milk, average milk production was 79 pounds per cow per day across all three treatments and the 3X control group. Because milk production climbed so steeply at the beginning of lactation, it's possible that the cows gained no additional benefit from more-frequent milking, VanBaale says.

Although the researchers can't say for sure why 6X milking yielded less milk than 3X milking, they don't think it had anything to do with heat stress. It was winter and the average daily temperature was 57 F, with low humidity.

It probably didn't have anything to do with nutrition, either. As previously mentioned, these cows were high producers. If the ration was limiting their potential, the cows would not have performed so well.

The take-home message: Results can vary tremendously between farms and can hinge on variables specific to your farm, like facility logistics or level of milk production.

Q. Is there an additive effect when I use BST?

Two studies show that a frequent-milking routine, followed by BST administration later in lactation, does not yield an additive response.

During the Arizona study, 6X cows given BST starting at 63 days in milk produced 10.1 pounds more milk per cow per day (between week 10 and 44 of lactation) than 6X cows that were not given BST. This gain in milk production is considered a typical response to BST.

Previous research from the University of Illinois also showed a normal BST response in cows that were milked 6X for 21 days after calving. In that study, cows gave 14 pounds more milk per cow per day between 63 and 90 days in milk than non-BST cows. And, they gave 9 pounds more milk per cow per day after 90 days in milk.

Both studies indicate that frequent milking does not change the way a cow responds to BST.

Q. Is 14 days long enough to get a response?

Many producers who implement a frequent-milking program in early lactation do so for the first 21 days in milk. However, not all producers have seen an equal response. But, for those who have had good results, the next question is: Can I shorten the time frame that I implement frequent milking and still get the same response?

It's too soon to say. Researchers have not adequately explored the duration of milking frequency.

The Arizona researchers had hoped to shed more light on the length of time required to milk cows more often. As part of their quest, they milked cows 6X for seven, 14 or 21 days after calving. However, they saw no milk production response.

These cows did not respond to 6X milking

A study reported in the november journal of dairy science shows that 6X milking does not enhance milk production. This bar graph shows that, during the first nine weeks after calving, cows milked 6X for seven, 14 or 21 days after calving produced about the same amount of milk — or less — than cows milked 3X. Milk production did not differ between the 3X and 6X cows between week 10 and 44 of lactation (data not shown).