What’s the ‘right’ alfalfa-to-corn-silage ratio?

By Jarrod Blackburn, Vita Plus dairy specialist

Alfalfa and corn silage make up a substantial portion of ration dry matter (DM) in dairy diets, especially in the Upper Midwest. Producers often ask, “How can I make best use of my acreage for the greatest return?” That question challenges consultants to rethink traditional forage strategies.

Why combine alfalfa and corn silage?

These forages complement each other nutritionally. Alfalfa provides higher protein and faster fiber digestion, promoting rumen turnover, while corn silage offers energy and fermentable starch. Corn silage has lower undigestible fiber (uNDF) than alfalfa, making it a better source of digestible fiber, though its fiber digests more slowly. Combining both helps maintain rumen pH and passage rate. Ratios vary widely — from 20% alfalfa and 80% corn silage to the reverse.

Is there a ‘right’ ratio?

Cows require nutrients, not specific forages. The goal is balancing economics and nutrition across available feedstuffs. Recently, many farms have reduced alfalfa due to rising land prices and competition for acres. Yield, management demands and bottom-line impact drive decisions.

Alfalfa: Pros and challenges

Alfalfa improves soil health and boosts yields of subsequent crops, reducing nitrogen needs. It typically yields 4-5 tons of DM per acre annually. However, multiple harvests (three to five per season) require time, labor and equipment, increasing costs and soil compaction risk. Weather adds complexity — harvest timing depends on dry conditions, and harsh winters or drought can slash yields and fiber quality.

Corn silage: Pros and challenges

Corn silage appeals for its high yield — often 8 tons of DM per acre — and single harvest. Longer growing seasons allow double-cropping, yet corn demands heavy nitrogen inputs, raising costs. Fall weather can complicate harvest, causing equipment wear and field ruts that require repair.

Managing for productivity

Once stored, both forages present management considerations. Inventory planning ensures nutrient allocation across heifers, dry cows and lactating cows. Consistency matters: alfalfa’s nutrient profile varies by cutting, while corn silage is more uniform. Setting ratios early and making minor adjustments helps maintain stable diets.

Advances in corn hybrids make high-corn-silage diets (70%+ DM) attractive. Corn silage can reach 40% starch, reducing the need for ground corn and allowing inclusion of low-cost byproducts like soyhulls and corn gluten feed for digestible fiber and rumen stability.

Grasses are also gaining popularity in the Upper Midwest. They offer more potentially digestible fiber (pdNDF) than alfalfa, better winter survival and compatibility with manure applications between cuttings.

Bottom line

There’s no universal ratio. Producers must consider herd nutrient needs, land resources and financial goals. Work with your nutritionist, agronomist and financial adviser to develop a forage strategy that maximizes productivity and profitability.

An expanded version of this article originally appeared in Progressive Dairy.