Chop wet, process well, says dairy nutritionist
Custom operators harvesting snaplage for clients should “err on the wet side rather than on the dry,” says Bill Mahanna, nutritional sciences manager at Pioneer.
“We want to start harvesting right when the kernels are physiologically mature, when they hit black layer. With most hybrids that will mean kernel moistures at about 34-36%,” he says. Optimal harvest moisture for the entire ear should be 36-42%.
More harvesters and their clients are showing interest in snaplage, which consists of kernels, cob and parts of the husk and shank harvested with a forage chopper equipped with a snapper head and kernel processor. But Mahanna says it needs to overcome the bad reputation it gained in the 1970s, when it was combined and called high-moisture ear corn or earlage.
“I’ve taken quite a bit of heat for talking about snaplage, because most nutritionists hate the stuff. It fell out of favor because, in a lot of situations, it was harvested too dry. We didn’t get good fermentation on it; it was separating when we blew it into tower silos and kernels weren’t processed as fine as dry ground corn.”
Today’s large choppers harvest the crop faster, at the correct moisture, and do a much better job of processing kernels than was possible a decade ago, he insists.
“Snaplage in the modern era is distinctly different. I don’t think you’ll find a better or more economical form of fermented corn grain to feed to dairy cows.”
Custom harvesters like that snaplage can be harvested quickly and between corn silage and dry grain harvests. Snaplage’s yield per acre is higher than grain harvest yields and, when chopped, costs 25-30% less to harvest compared to combining and running through a tub grinder or roller mill, Mahanna says.
“It also has increased starch digestibility compared to feeding dry corn. That may be an advantage and it may not be, depending on what the rest of your ration looks like.”
Snaplage’s feeding value, according to a recent Pioneer study, is about 85-90% that of dry shelled corn if “suitable” hybrids are grown and if they’re harvested at the proper maturity, he says. The study also showed that cob digestibility drops rapidly as the ear matures, another reason for harvesting on the wet side.
Further study findings show that husks and shanks are more digestible than expected and may be a good roughage source.
Nutritionally, when harvested at around 40% ear moisture, snap-lage tests around 25% NDF and 60% starch, Mahanna says. Yet he’s also seen samples come in at 24% moisture that may look similar on paper, but don’t feed as well because of poor fermentation, slow starch digestibility and a tendency to spoil if feed-out is slow in warmer months.
To make snaplage work for a client, custom operators must be at the top of their game.
“It needs to be processed extremely well, and we can get that done with an aggressive roller mill, higher differential on the rolls and the correct roller mill gap,” he says.
Generally, finer-tooth rolls with five to seven teeth per inch are recommended and may need adjusting to a much higher differential compared to how the chopper was set up for corn silage harvest. Also, set chop length as short as possible, Mahanna says. Proper processing breaks kernels and increases surface area, making starch more ruminally available to the cow.
The development of inoculants specific for high-moisture corn, which contain L. buchneri strains to reduce heating and mold, are another reason why snaplage is more acceptable today, he says.
It costs about $50/acre, including trucks and pack tractors, to put snaplage in Upper Midwestern bunks, according to 2009 prices. Compare that to combining costs of $25-30/acre, plus hauling, tub grinding or rolling and packing costs, and “it’s a no-brainer that with snaplage, the economics are quite favorable,” Mahanna says. Crop put into snaplage also reduces dry grain storage costs, drying costs and spreads out harvest risk.
But there are disadvantages to harvesting corn as snaplage vs. dry grain, including higher storage shrink loss and inventory carrying costs.
“It’s not as consistent as dry grain because you have a lot of trash in the product, and less flexibility in marketing it,” Mahanna adds.
The Pioneer nutrition specialist has another hesitation about snap-lage, and that’s when dairy producers switch from feeding well-processed, high-moisture shelled corn to snaplage, which often has a more coarse kernel particle size.
The trash that comes with snap-lage also can skew the estimation of grain particle size. Mahanna recommends a method Pioneer developed to quantify snaplage kernel particle size. Snaplage is first run through sieves used to determine a corn silage processing score. Then the top four sieves of material, primarily cob and husk, are removed. The material in the remaining sieves, mostly grain, is put through the normal K-State grain sieves. Dairyland Laboratories offers the Pioneer method.
For a spreadsheet to help determine snaplage and high-moisture ear corn prices, email Mahanna at firstname.lastname@example.org.