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February 13, 2020

Spreadsheet Estimates Corn Hybrid IOFC

 |  By: Jim Dickrell

Seed cost and yield are important considerations when selecting hybrids for corn silage. But they are far from the most important, says Michael Miller, a dairy nutrition specialist at W.H. Miner Institute in Chazy, N.Y.

In fact, forage quality and fiber digestibility are the key drivers to how much of the corn silage cows can consume, how much milk they will produce from that forage and what the ultimate economic result will be.

Miller compared corn silage performance in 2014 and 2015 in the research herd at the Miner Institute. In 2014, a good growing year, corn silage quality was high and feed intake in the herd’s high group averaged 67 pounds of dry matter. The next year, forage quality suffered and intakes dropped to 62 pounds of dry matter. The result: Milk production dropped from 120 lb/cow/day to 105.

That 15-pound drop in milk production resulted in income over feed cost declining $1.52/day, or  $555/cow/year. For a 400-cow herd, that’s a loss of $220,000. “That’s huge,” Miller says. “Forage quality is really important.”

There are two steps to ensure forage quality: Hybrid/variety selection and harvest/feed management.

Hybrid selection.

Hybrid selection boils down to selecting hybrids with high levels of potentially digestible Neutral Detergent Fiber (pdNDF) and low levels of undigestible NDF 240 (uNDF240), which is the amount of undigestible fiber left after 240 hours of digestion. (uNDF240 levels are critical because higher levels impede rate of passage through the rumen, are never utilized by the cow and must be hauled back on fields through extra manure disposal.)

Brown Midrib (BMR) 3 and 1 varieties can be higher in digestibility, but typically have higher seed cost and lower yields per acre. Conventional corn hybrids are the reverse: Lower digestibility and cost, but higher yields.

Over three growing seasons, Miller has attempted to sort out these differences, and come up with estimates of income over feed cost.

His conclusions:

• BMR-3 hybrids had higher NDF digestibility and lower uNDF240 than BMR-1 and non-BMR hybrids.

• The yield of potentially digestible NDF was similar across all hybrids.

• Potential dry matter intake and potential milk production was higher for the BMR hybrids.

• Income over feed cost was 22 to 31₵/cow/day higher for BMR-3 hybrids compared to BMR-1 and conventional hybrids.

• Income over feed cost was 9₵/cow/day higher for BMR-1 hybrids compared to conventional hybrids.

Miller notes that his conclusions might be specific for his location and area of the country. Consequently, he has developed an Excel spreadsheet that anyone can use to develop estimates for their own farm. It can be used to compare hybrids using on-farm or local test plot data. The calculator can be found here: http://www.whminer.org/dairy/

Harvest/Feed Management.

The second step of feeding high quality forage is basic harvest and feed management, says Miller. First harvest corn silage at optimal maturity, 32 to 38% dry matter, and then process kernels to ensure optimal fermentation and digestibility.

Bunker management is also key. Without it, silage losses can reach 15 to 20% of the material harvested. So make sure you pack the pile correctly, place an oxygen barrier over the pile immediately after filling and then use a facer to remover feed from the bunker.

Proper harvesting and storage management allows you to feed high corn silage rations, up to and exceeding 50% of the ration’s dry matter. Doing so will allow you to minimize purchase feed costs and optimize income over feed costs, he says.

Click here to listen to a 45-minute podcast of Miller’s presentation, presented at World Dairy Expo last fall. https://www.youtube.com/watch?v=5Iq18iZ3g_4&feature=youtu.be&width=700&height=500