Paper rations often get lost in the mix
The ration your nutritionist hands you and the ration your cows consume are rarely, if ever, the same thing.
The best way—perhaps the only way—to determine how far apart the two rations are is to ask your nutritionist to conduct a thorough audit of your feed mixing system.
Tom Oelberg, sales manager and field technical ser-vices specialist for Diamond V, says his company has conducted 150 such audits across the country in the past 30 months. Every one of the 80 audits Oelberg has personally done has resulted in at least some tweaking in how rations are being mixed.
After the fixes, milk responses of 1 lb. to 2 lb./cow/day are common. “Some herds see a 0.2 to 0.4 percentage point jump in butterfat,” Oelberg says.
To conduct an audit, Oelberg likes to get to the dairy early in the morning. He reads the bunks with the feeder and takes samples of the weigh-backs. “Most of the time, we see sorting,” he says.
He checks the mixer wagon to see if it shows wear on the kicker plates, knives and augers. He also visits the bunker silos to evaluate face management.
He then watches the filling and feed mixing process. He evaluates mixing order and how long the feed is mixed from the time the last ingredient is added until it is delivered to the bunk.
Once it is delivered, he’ll take 10 feed samples from that load. To get a consistent sample, he’ll actually count the number of posts in the barn, divide by 10 and draw his samples from those locations.
The samples are run through a Penn State shaker box to determine ration consistency. “Variation of 1% to 2% is excellent, and 3% to 5% is good,” he says.
But if the variation is 5% to 7%, the wagon is not mixing well. And above 7%, you’re asking for trouble.
The biggest problems come in a few key areas:
- Overfilling. Vertical wagons should be filled to 75% to 90% of the struck volume, but at least to the top of the screws. Horizontal reel wagons should be filled to 70% of maximum volume.
- Worn parts. “You really need to pay attention to worn parts if you are processing hay or straw,” Oelberg says. A $100 part that replaces a worn kicker plate can shorten mixing time from six minutes to two.
- Not mixing long enough.
- Improper loading of liquids. For vertical mixers, liquids should be loaded in the middle. For horizontal mixers, they need to be poured over the augers.
Oelberg is often asked which brand of mixer is best. “The more dollars you spend, the better job you usually get,” he says. “But we have gotten good results from all brands of mixers as long as you don’t overfill and mix long enough.”
- November 2010