Feeding group-fed cows long-particle TMRs in a tight situation? Some of those cows — especially the more submissive ones — probably aren't getting the nutrients they need for good milk production.

Producers may need to add bunk space and mix TMRs that make sorting difficult. They should also either feed cows more often or push feed toward cows several times a day.

That's according to a review of several papers researching dry matter intake. The purpose of the study, by University of Minnesota dairy specialists Jim Linn and Marcia Endres, was to see if formulas for predicting dry matter intake for individually fed cows would work for group-fed.

In their review, Linn and Endres found that group-fed cows need a different impetus to eat than do cows in tie-stalls.

“The group-fed cow has to consciously make a decision to say ‘I'm hungry’ and to eat as long as the stimulus (after milking or when fresh feed is delivered) is there. Or until another cow kicks her out,” Linn says.

The individually fed cow can eat anytime, lying down or standing up. But submissive group-fed cows wait while their more-dominant herd mates consume more than their share of the TMR, he adds.

More aggressive cows also might sort out long particles in a TMR, leaving a coarser diet that takes longer to consume and offers less energy for the submissive ones.

“I like to see as much bunk space as possible,” suggests Endres. ”I've seen some folks who put extra feed bunks at the end of barns to increase the feeding area.”

Some farmers say that, since cows only eat five hours a day, they don't need extra room, she adds. “As long as you don't have a lot of sorting, that's okay — all cows will be eating a similar ration. But if you have a lot of sorting, some cows will be eating a ration much lower in fiber, which can create acidosis. And some cows might be eating a ration that's much higher in fiber, so they maybe won't produce as much milk.”

Avoid sorting by providing TMRs that aren't too dry and have shorter particle lengths, Endres explains. Follow Penn State's four-drawer shaker box particle size recommendations for TMRs: 2-8% in the upper sieve, 30-50% in each of the two middle sieves and less than 20% in the bottom pan.

Pushing feed five to six times a day also improves intake, she says.

“Ideally, if it is practically possible, I would prefer to feed them twice a day rather than just push up the feed,” Endres adds. “But if you can't do that, it's important to make sure that the cows can reach the feed.”

For more information on particle size, Penn State's forage particle separator guidelines can be accessed at: www.das.psu.edu/dcn/catforg/PARTICLE/pdf/DAS0242.pdf.