If your herd’s production isn’t as high as you think it should be, or if milk or milk components fluctuate too much, your cows may not be consuming the same ration at every feeding.

A TMR Audit can help ensure that the ration formulated on paper is always the one fed, says Tom Oelberg, dairy technical services specialist at Diamond V, Cedar Rapids, IA.

He and other Diamond V dairy field representatives conduct the audits to evaluate clients’ feed storage and preparation, feed mixing and TMR delivery. Their goal is to identify possible causes of ration inconsistencies.

“Basically, what we do is follow the feeder in his steps to making a TMR,” says Oelberg.

Nearly 500 audits have been done since 2008, and most have uncovered obstacles to ration consistency.

“There have only been a handful of dairies where we didn’t have a lot of suggestions for change,” says Oelberg.

The most common problems are in these areas:

Silage face management. “It can contribute to a lot of variability in the TMR,” says Oelberg.

Moisture and nutrient levels vary from top to bottom and side to side in bunkers and piles. So shave corn silage or haylage from the entire face before every feeding, blend it by pushing it into a pile, and load the mixer from the pile, he says. Shave only enough silage for that feeding so no loose silage is left behind.

Loading and mixing. Make sure the mixer wagon is level, watch the loading order and don’t overfill, Oelberg emphasizes.

Load hay into vertical mixers first, then follow with dry ingredients, haylage, corn silage and any liquid feeds.

With horizontal mixers, hay usually is run through a tub grinder ahead of time and added after concentrates. Some dairies with vertical mixers also preprocess hay, and that’s a good thing because long hay varies in toughness and feeders sometimes don’t pay attention to detail, Oelberg says.

“Generally speaking, when we process hay in a vertical wagon during the loading of a TMR, we see more variability in the TMR.”

To adequately mix liquid supplements, usually added last, load them between the augers of twin-screw vertical mixers, over the augers of reel-auger horizontal wagons and in between the two pairs of augers on four-auger units. Then be sure to run the mixer long enough for thorough mixing.

“One thing we see a lot is undermixing of the last ingredient,” says Oelberg. “Usually after the last ingredient is added, you need about three to five minutes, depending on the mixer and on the wear of the mixer. The problem is, everybody is in a hurry.”

Overfilling of mixer wagons is one of the most common problems uncovered in TMR Audits, and it doesn’t take much to cause ration inconsistencies.

Oelberg says to fill vertical wagons no higher than a foot below the top of the metal. For TMRs that don’t have a lot of wet distillers grains or other very wet byproduct feeds, horizontal wagons can be filled level with the top, “just so feed’s not running out. However, you can easily overfill reel-auger wagons with TMRs containing a lot of wet distillers.

“There’s another issue with vertical wagons, and that’s minimum load size,” Oelberg adds. “One of the advantages horizontals have over verticals is that they can mix very small loads and get them mixconsistently.”

Sometimes producers mix very small batches for close-up dry cows or fresh cows. If the TMR doesn’t cover the top of the augers of a vertical mixer, some concentrate feeds may get hung up on the auger flighting and not get added to the ration. The TMR size needs to be sufficient so the haylage and corn silage knock those feeds off the flighting.

“That volume is going to vary by wagon,” says Oelberg. “We’re trying to get the manufacturers to tell us what percent of the total volume that is.”

Worn augers, blades and kicker plates in wagons are a major contributing factor in TMR inconsistencies. He says to check critical components periodically and replace them as needed.

Feed delivery. Feeding cows at the same time every day, especially the first feeding, helps keep dry matter intake consistent. Feed tracking software monitors the performance of feeders and can ensure that rations are mixed correctly and delivered on time, he suggests.

Each TMR Audit includes an evaluation of the overall efficiency of the feed center, and one thing the Diamond V representative looks for is whether or not the producer is preblending commodities. Preblending reduces loading time and shrink and improves TMR consistency.

“When they’re loading the TMR, they’ll have the preblend and a couple of forages, and we’ll see loading times of 12 to 15 minutes per load,” Oelberg says.

“The other thing we like to see is the liquid supplements added to the preblend, which reduces shrink and loading time and we think helps ration consistency. The downside of that is you’d have to make up a preblend fresh every day to prevent heating and spoilage. But we’re seeing good results with that.”