Starch Availability and Its Impact on Milk Yield
When dairy farmers evaluate their forage program, the conversation often starts with yield and moisture — but it should always come back to one core question: How much of the starch in this corn silage is actually available to the cow?
For all the science behind hybrid selection and harvest management, starch availability remains one of the most important — and most misunderstood — drivers of milk production. At Prairie Estates Genetics (PEG), our entire breeding and management philosophy centers around that connection: the starch structure inside the kernel, how easily it breaks down in the rumen, and how that translates to real milk yield.
The Role of Starch in Dairy Rations
In a typical dairy ration, starch is the single largest source of energy. It fuels microbial fermentation in the rumen and supports milk volume, milk fat, and body condition. But not all starch is created equal — or equally digestible.
Corn silage, unlike dry corn, contains starch that is physically and chemically bound within a matrix of protein (the zein protein). The tougher and denser that protein matrix, the harder it is for rumen microbes to access and break down the starch granules inside. That’s where starch availability — not just starch content — becomes the real performance driver.
Two hybrids may test similarly in total starch percentage, yet one may produce substantially higher milk per cow simply because its starch is more digestible.
Understanding Kernel Softness and Starch Structure
The physical structure of the kernel tells the story of how digestible that starch will be. Hard, vitreous endosperm kernels — common in grain-oriented hybrids — resist digestion because the starch granules are tightly packed and bound by dense zein proteins.
Softer, floury endosperm kernels — the kind PEG specifically selects for — have a looser structure with more open space between starch granules. This allows rumen microbes to penetrate and ferment starch more efficiently, releasing more energy for milk production.
Think of it as the difference between trying to chew through a rock-hard granola bar versus a soft cookie. The softer structure is easier to break down, and cows, like people, get more energy out of feed that’s easier to digest.
Why Kernel Processing Alone Isn’t Enough
Many producers rely on kernel processing during harvest to improve starch availability, and while processing is vital, it can’t compensate for poor kernel structure. If the starch is locked inside a dense matrix, even aggressive processing can only do so much.
In fact, over-processing can create its own problems — increased fines, reduced effective fiber, and packing challenges in the bunker.
That’s why PEG’s approach starts earlier: with hybrids that are bred for naturally higher starch digestibility. By selecting genetics that produce softer endosperm starch, PEG hybrids deliver better rumen availability without sacrificing agronomic strength or yield stability.
PEG’s Focus on High Digestibility
At PEG, we’ve spent more than 25 years developing hybrids specifically for the dairy cow — not the grain elevator. While most of the corn industry (roughly 95%) focuses on grain traits like hardness and test weight, PEG’s research and hybrid selection program has always centered on silage performance.
That means every PEG hybrid undergoes years of pre-market testing and data collection across 22+ trial locations. Our breeding criteria include:
Starch structure and softness (evaluated through kernel vitreousness testing)
Fiber digestibility (NDFD) and starch digestibility (7-hour and 30-hour lab analysis)
Whole-plant digestibility and fermentation stability
Agronomic consistency — standability, disease resistance, and dry-down rate
The result? Hybrids that combine soft, highly digestible starch with strong plant integrity — designed to maximize both energy and consistency.
Feeding for Faster Energy
One of the practical advantages of PEG hybrids is how quickly they become feed-ready after ensiling.
Most traditional corn silage requires at least six months of fermentation before the starch becomes fully available. During that time, microbial activity in the bunker gradually breaks down the zein proteins, softening the kernel and improving digestibility.
But PEG hybrids, with their naturally soft starch, can reach optimal digestibility much sooner — often in as little as 30 days. That allows producers to start feeding new-crop silage earlier without sacrificing performance.
In herds that rely on steady transitions from old crop to new crop, this early-feed capability is a game changer. It means smoother ration changes, fewer digestive disruptions, and more consistent milk production throughout the year.
Measuring Starch Availability: From Field to Tank
So how do you know if your silage starch is doing its job?
PEG Forage Managers work closely with nutritionists and farmers to track key metrics that reveal the true performance of starch digestibility:
Starch Percentage (%): The total starch in the silage, typically 30–38%.
Starch Digestibility (%): How much of that starch is actually available in the rumen.
IOFC (Income Over Feed Cost): The financial metric that connects feed efficiency to milk output.
PEG customers consistently see improvements in IOFC because the starch in PEG silage drives both higher milk yield and reduced reliance on purchased dry corn. As one long-time customer said, “The more digestible fiber and starch we can find, the more milk we make.”
That’s not theory — that’s what happens when genetics, forage management, and nutrition align.
Balancing Yield and Quality
A common misconception is that improving digestibility means giving up yield. PEG’s hybrids prove otherwise.
By combining soft starch with strong agronomics, PEG delivers hybrids that maintain yield performance comparable to traditional grain-focused hybrids — without compromising on feed quality.
This balance is what makes PEG hybrids uniquely dairy-ready: high starch digestibility, robust fiber profiles, and field performance that keeps silage inventories strong.
From Kernel to Cow: The PEG Advantage
At the end of the day, starch availability is more than a lab number — it’s a direct link between the genetics in your field and the milk in your tank.
PEG’s approach ensures that every hybrid contributes to that goal:
Softer kernels that break down more easily in the rumen.
Consistent starch and fiber digestibility for predictable performance.
Early-feed capability that supports smoother transitions and steady milk flow.
This is the kind of innovation that doesn’t just happen in research facilities — it’s built from decades of experience, thousands of field trials, and real-world collaboration with dairy farmers.
From seed selection to harvest strategy, PEG’s mission has never changed: help dairy farmers turn forage into fuel, and fuel into milk.