A recent review of 11 scientific and popular press articles shows nearly a 5% digestibility advantage for "high chopping” corn silage—at 18” to 20” versus 6” to 8”.
But that doesn't tell the whole story, notes Bill Mahanna, global nutritional sciences coordinator for Pioneer. There will be growing season effects and hybrid effects. In some cases, there may be no difference in NDF-d (neutral detergent fiber-digestibility). If there is none and you high chop, you give up one ton/acre of wet corn silage for every 4” of high chopping above a 6” to 7” chop height.
But if there is a difference in digestibility, you might be far better off giving up that yield because dry matter intakes and passage rates with the higher digestible forage could be significantly better. And that usually will translate into higher milk production.
Mahanna recommends hand chopping a representative sample of corn stalks seven to 10 days prior to silage harvest. Have those stalks analyzed for digestibility to determine if high chopping is worth it.