Forage Quality vs. Concentrate Level: Finding the Economic Balance for High-Producing Holsteins

There is an old tug-of-war in every dairy ration. More concentrate pushes energy density and milk, but it costs more per ton and it raises risk to the rumen. More forage is cheaper and keeps cows chewing, but it fills the rumen and can limit how much a high-producing cow can eat. The economic answer is rarely at either end. It depends on forage quality, feed prices and the milk check, and the best way to see that is through trial data.

This article uses published trial results summarized by USDA Agricultural Research Service scientist Dr. Kalscheur and colleagues to show what happens to intake, milk and income over feed cost across forage levels, then turns it into questions you can apply to your own herd. The prices in the trials are old, so use the pattern, not the dollar figures.

Why forage quality changes the whole equation

A ton of forage is not one thing. A high-quality, highly digestible forage lets cows eat more and extract more energy, so a ration can carry more of it without losing milk. A poor forage fills the rumen and slows digestion and passage, which reduces intake. The ARS summary puts it plainly: poor digestibility slows rumen digestion and passage and cuts intake through rumen fill, which is why it recommends frequent analysis of forage particle size and digestibility and adjusting rations accordingly.

In other words, the right forage-to-concentrate ratio is not a fixed number. It moves with your forage tests. Our guide to forage quality and testing explains how to get the data you need.

Trial one: forage from 42% to 66%

The ARS summary describes a trial by Schuler and colleagues (2013) in which canola meal diets varied forage from 42% to 66% of dry matter. Results across the four treatments:

Result	Lowest forage (42%)	Highest forage (66%)
Dry matter intake	28.0 kg/day	24.8 kg/day
Feed efficiency (ECM/DMI)	1.36	1.57
Milk fat	3.17%	3.52%
Feed cost per cow per day	$6.23	$5.49

Milk yield across the four diets was 40.1, 40.4, 40.8 and 39.1 kg/day. The differences were not significant, and the highest-forage diet was lowest. The important result is income over feed cost, which was $6.73, $7.21, $7.72 and $7.52 per cow per day, peaking at 58% forage. More forage saved feed cost, but at the top end the milk income dipped enough to give some of it back.

Trial two: 50% versus 60% forage

The same summary reports Martinez and colleagues (2009) with two experiments. In the first, built on alfalfa haylage and corn silage, moving from 50% to 60% forage cut intake from 29.7 to 27.3 kg/day, left milk statistically unchanged (47.0 versus 45.8 kg/day), improved feed efficiency and nudged income over feed cost from $8.51 to $8.88. In the second, using more corn silage, intake fell from 29.7 to 28.2 kg/day, milk was essentially the same (40.8 versus 41.1) and income over feed cost moved from $6.65 to $7.07.

Notice what repeats in both trials. Moving to higher forage lowered intake, held milk about steady, improved feed efficiency and raised income over feed cost, until the highest forage level, where intake limits finally began to cost milk.

What this does and does not mean

These are controlled trials with specific forages, a specific commodity price set and one lactation stage. Several cautions apply:

• Prices matter. The summary used average prices from 2003 to 2013. If concentrate is expensive relative to forage the peak moves toward higher forage; if forage is dear, it moves the other way.
• Forage digestibility matters most. The more digestible your forage, the further the optimum slides toward forage.
• Lactation stage matters. Early-lactation cows have different limits than mid-lactation cows.
• Single trials are single trials. The patterns line up, but your cows, your forages and your milk contract may not.

The grazing version of the same question

On pasture the same trade-off appears as supplement strategy. Penn State work summarized on Farms.com shows milk response per pound of concentrate shrinking as the amount increases, from roughly 1.2 to 1.4 lb of milk for the first 4 lb down to 0.4 to 0.6 lb at 16 to 20 lb. It also notes that with adequate forage, up to 18 to 20 lb of grain per day is unlikely to cause acidosis in the studies cited. Diminishing returns are the common thread: the last pound of concentrate always earns less than the first.

How to find your own balance

1. Know your forage. Test every forage lot for fiber, fiber digestibility and particle size, and update when you open a new bunker or bag.
2. Calculate income over feed cost per cow per day, not just feed cost. A cheaper ration that cuts milk may lose money. Our guide to the dairy enterprise budget shows how to anchor those calculations.
3. Look at intake first. If forage digestibility is high and cows are cleaning up feed, there may be room to push forage. If intake is limited, check fill and quality before adding grain.
4. Watch rumen signals. Milk fat, cud chewing and manure consistency show whether a change is working. Excess concentrate can trigger rumen problems; see our article on SARA and claw health.
5. Change in steps and keep records. Move a pen, not the whole herd, and compare results over several weeks.
6. Revisit when prices move. The optimum slides with feed prices, so the answer from last year may not hold this year.

Working with your nutritionist

Bring your forage test history, intake records and milk components to the table, and ask the nutritionist to run alternative rations at current prices. Ask what the model predicts for intake and milk at each forage level, then check that prediction against measured results. For how a ration conversation should work, read TMR and ration basics.

Bottom line

In the trials summarized by USDA-ARS, milk stayed about the same across a wide range of forage levels while feed efficiency improved with more forage and income over feed cost peaked in the middle, around 58% forage in one trial. The pattern is a reminder to chase income over feed cost, not milk alone, and to let forage quality and current prices set the ratio. For more resources see the agriculture directory, and for the farm community visit farm.fm's dairy pages.