**Extended comments are highlighted in blue.
The rewards are feed-cost savings and higher milk production
John Mendonca is marking a milestone this month on his dairy farm near Tulare, Calif.
For the first time, Mendonca will be planting 100% of his corn silage acreage to brown midrib (BMR) varieties.
Inspired by the results that he has seen from limited BMR plantings on his farm for the past three years, Mendonca has high hopes for his dairy’s bottom line. He anticipates that there will be significant feed-cost savings and higher production out of his 600 milking cows—all benefits of feeding BMR corn silage.
"I don’t see any reason to plant anything but BMR because I want to plant what’s going to make us the most milk," Mendonca says.
BMR corn is not a genetically modified organism (GMO) but the result of a naturally occurring gene mutation. It features less lignin in the cornstalk, which results in higher fiber digestibility. That, in turn, leads to greater dry matter intake and more milk.
"When I started feeding BMR corn three years ago, I saw 3 lb. to 4 lb. or more in increased milk production per cow per day," Mendonca says "When I ran out of BMR corn, I definitely noticed the reduction in production."
Last year, Mendonca increased his BMR planting to 75% of his corn silage acreage. With the greater feed supply of the corn hybrid, he saw his herd’s milk production rise even higher. "I was seeing increases of 5 lb. to 6 lb. per cow, and that was after cutting back 4 lb. on grain in my rations," Mendonca says.
That reduction saved his operation almost $15,000 per month in grain costs. "The BMR corn was much more affordable than the rolled corn we replaced in the ration," he says.
Neutral Detergent Fiber (NDF) digestibility rates for BMR corn silage with the bm3 gene are generally 10% to 14% higher than conventional corn silage, says Chris Dschaak, forage nutrition specialist with Mycogen Seeds. The greater corn silage intake from BMR varieties means producers can reduce grain in their ration formulation. Most dairy producers can feed 2 lb. to 4 lb. less grain per cow per day when feeding BMR corn silage.
Those BMR feed-cost savings can reach $100,000 to nearly $600,000, depending on the size of the dairy, Dschaak says. For example, a dairy feeding 500 cows, based on a 3-lb. ration reduction of rolled corn at the current price of $350 per ton, would save $96,725 a year or 53¢ per cow per day by feeding BMR corn silage instead of conventional corn silage. The savings for a 2,000-cow dairy could potentially reach $386,900.
"And that’s just the feed-cost savings," Dschaak says. "If a 2,000-cow dairy added the increased milk benefit of 4 lb. more milk per cow, that would be another $525,600, at $18 per cwt. In all, the BMR corn benefit would be close to $1 million a year."
Mendonca has seen milk production climb by as much as 6 lb. per cow per day by feeding his herd BMR corn silage.
When he first considered growing BMR corn, Mendonca worried about reports of lodging, meaning the corn stalks would fall over in the field. He also was concerned about yield drag, or reduced tonnage.
"We were typically getting a yield of 28 tons to 32 tons per acre with conventional corn silage," Mendonca says. "With early BMR varieties, we were seeing only 24 tons to 25 tons per acre."
Last year, Mendonca heard about new BMR varieties that offered improved yields and standability compared to first-generation BMR hybrids. So, he increased his BMR plantings to 75% of his corn acreage. Not only did he see better production in the field but higher output in the milk barn.
This month, Mendonca is planting BMR corn on 230 of his 450 acres—alfalfa, wheat and oats make up the rest. BMR corn silage will account for 50% to 55% of his herd’s ration. Dschaak recommends feeding a minimum of 40 lb. of BMR corn silage per cow per day (on an as-fed basis).
Through the summer, Mendonca will grow his BMR crop exactly like regular corn silage varieties. "Same soil prep, same nitrogen and same irrigation," he says.
Vernal Gomes, the Mycogen sales representative who works with Mendonca, recommends planting BMR corn on your best ground. "It’s a crop that needs to be well-managed," Gomes says. "The root system isn’t always as robust as conventional corn. In California, you don’t want to stress the crop without enough water."
When Mendonca harvests his BMR crop in August, he’ll likely go for a longer chop length of 5⁄8" to 3⁄4" length. Dschaak recommends an even longer chop length of 1" and a moisture level of 68%.
The results of that harvest bode well for Mendonca. "If you’re a grower who’s going to sell corn silage to a dairyman, BMR won’t work because you’ll pay too much for the seed," he says. "You won’t get the benefits that dairymen will. BMR corn is a no-brainer for dairies. We’ll get the reward in our milk checks."
BMR Yield Drag AN Issue
Despite the fact that brown midrib (BMR) corn hybrids are now in their fourth generation, grain yield is still an issue, says Joe Lauer, a corn agronomist with the University of Wisconsin.
"In terms of quality, BMR corn silage is off the charts in digestibility of the stover," he says. "Forage quality, as measured using milk per ton, is always at the high end for BMR hybrids."
But in Wisconsin yield trials dating back to 1997, BMR does not have the same
forage yield as conventional corn hybrids, he says.
Over that time, BMR hybrids consistently lag conventional hybrids by about
1.4 tons of dry matter, he says. Most of that is the result of lower grain yield. And the BMR is not gaining ground.
There are also some standability and lodging concerns with BMR corn. "But for corn silage, we’re usually not worried about BMR standability because the plant is still green when we harvest it," he says. "Even if it does go down, you can usually get a chopper under it."—Jim Dickrell
Five Tips for Better BMR Ration Results
Mycogen Seeds offers these BMR ration formulation tips:
1. Plan ahead. Before growing BMR corn, meet with your nutritionist to discuss feeding strategies.
2. Evaluate storage needs. Although BMR can be mixed with conventional silage in a ration, it’s best to store the different types of silage in separate structures.
3. Work with your nutritionist on ration formulation. Ask your herd nutritionist to create a sample diet with BMR corn silage and other ingredients on the farm to predict the impact it will have in dry matter intake, rumen efficiency, grain savings and milk production. As with any ration change, incorporate BMR gradually to ensure a smooth transition.
4. Test silage after harvest. Select a lab that has experience analyzing BMR corn silage using both near infrared spectroscopy (NIR) and wet chemistry/in-vitro methods.
5. Adjust for higher silage digestibility. When formulating rations with BMR, use dynamic ration formulation software to help optimize health, productivity and profitability. Higher levels of digestible fiber will enhance rumen microbial efficiency and replace a portion of the energy from starch sources. This leads to higher dry matter intake.