One of the best ways to quickly orient someone to a lactation dairy ration is to compare it to the diets of a mama cow grazing native pasture and a feedlot steer. These are the two extremes in the range of forage’s role in providing nutrients for growth, production, and the well-being for different classes of cattle.

The mama cow makes her way on as close to a 100% forage diet as possible, depending on seasonal changes and rainfall. The owner of the feedlot animal is on the other extreme, feeding the bare minimum of roughage necessary to keep that animal healthy until harvest. We hope one of these animals lives as long as is productively viable, and the other has a date with destiny somewhere around 2 years old. The forage level in their respective diets plays a part in this life expectancy strategy.

The dairy cow finds herself situated in the middle of these two extremes. Unlike the feedlot steer, we need to keep her rumen appropriately filled with roughage to keep her on track for at least three or four lactations before she experiences a career change from being a milk producer to a beef producer. We would love to be able to feed her a diet more like the mama cow, and from the dairy cow’s perspective, that would be fine. But for the dairy owner, a profitable level of milk production will require a diet that supplies around 50% grain and grain by-products.

The 50% or so that remains as forage is still important as it relates to several factors including protein and fiber levels, as well as more general quality considerations. The protein level is mostly determined by forage species and stage of maturity at harvest. Fiber levels are influenced by the same factors, though there are differences in the types of fiber in legumes and grasses.

When considering these nutrient differences by forage type in a dairy diet, we are lucky that cows have nutrient requirements as opposed to having ingredient requirements. In other words, cows have requirements for fiber, roughage, energy, and protein, but there are options for these nutrients coming from legumes, cool-season annuals, warm-season annuals, or various perennial forages.

This is good news for cows that find themselves in different geographies. After having built these dairy rations for more than 30 years, this flexibility of ingredient supply not only keeps the process interesting but also economically viable. When going to a new area to formulate dairy rations, the first question I ask is, “What forages grow well here?”

Finding good forage

My experience feeding dairy cows has mostly been in the Southern U.S. Early in my career, this was Central Texas where cowboys and beef cows were aplenty, but true forage farming to the level needed for good dairy production was hard to find. The answer there was to ship in high-quality alfalfa hay from the high country of Colorado all the way to Stephenville, Texas. That seems like a long way to ship hay!

Several years later, after some dairy manure was added to those caliche hills, some sorghum for silage and improved bermudagrass hybrids were established. But the long-haul deliveries of alfalfa hay didn’t slow down until relationships with corn farmers in the Brazos River Valley were formed to grow corn for silage for these rapidly expanding dairies.

It wouldn’t seem possible that hauling wet corn silage from 70 miles away would be feasible, except that the other option was shipping the alfalfa hay all the way from Colorado. I always think this story is a good example of cows just needing forage no matter if it was primarily alfalfa from Colorado or corn silage from Texas. It was my job to be sure that the diet was balanced with either forage as the base.

Feed quality criteria

That all happened in the 1990s. If we fast-forward 30 years, the dairy industry and the predominant ration choices have changed a bit. Just like what happened in Central Texas, alfalfa feed rates have gone down and corn silage has gone up. In spots around the U.S., there are still pockets where alfalfa hay is the primary dairy forage. In most areas though, corn silage has emerged as the larger component.

The reasons for this are many and relate mostly to the advantage of a large dairy having a giant pile of corn silage that is pretty much the same as they move through the pile. Alfalfa hay, on the other hand, has numerous characteristics that can vary from load to load, field to field, and cutting to cutting. So, where can alfalfa and other dry forages find a place in the modern dairy ration?

When I was in school, there was the thought that a dairy cow would not do well on a ration that only included chopped and fermented forages. These notions have turned out to be mostly untrue and many dairy cows do just fine on a diet with no dry hay. One of the ways dairy rations differ from the feedlot rations mentioned above is that not only does the nutrient supply of the forage matter for the cow, but the physical form is important as well. In addition to carefully managing the nutrients in the forages I include in a ration, I also have to be sure the roughage portion is not too long or too short to be consumed correctly and not sorted out by the discriminating palate of the average dairy cow.

While this forage length decision can mostly be made at the point of silage harvest by the setting on a chopper, it is much more consistent in the feedbunk than dry hay arriving at the farm one truckload at a time. These loads can have as many different chop lengths and forage rigidity as the trucks that delivered it. No matter if a dry forage is long and stringy or dry and shattery, it is critical that when it is blended in the mixed ration and fed out, it needs to contribute to specific particle size goals for the cow.

We measure forage length variations by using the Penn State Particle Separator, commonly referred to as a shaker box. Using this tool with its multiple sieves and a particular process of shaking, we can measure how much of each length of material is in the diet. This way, we can be sure the cow gets the correct nutrient supply and the correct roughage particle length to keep her healthy, help her maintain good rumen motility, and support good butterfat production.

Dry forage ideals

In an ideal situation, every dairy ration would have a few pounds of the perfectly chopped dry forage in the ration. Many of the diets I design have 5 to 10 pounds of dry forage comprised of mostly alfalfa hay and small grain hay. There are opportunities for bermudagrass hay, sorghum hay, and even wheat straw to contribute to this valuable roughage ingredient.

The dry hay can be of various maturities, protein level, and fiber content, but it must be free from mold and excessive weeds, and low in ash. Another reason that dry hay is fed at lower rates and is sometimes a problem for dairy producers is due to the art of putting up good hay. The patience and timing to accomplish this results in much of these forages ending up in haylage when the dairy is managing the forage program. This haylage production has its own challenges, but it seems to be a better fit for most dairies that put up some of their own alfalfa or small grain forage crops.

A good hay farmer with experience, attention to detail, and a good eye for the weather can be a real value to a dairy by delivering consistent hay for specific uses in dairy rations. Yes, dairy cows can do just fine on a 100% silage forage program, but adding a few pounds of dry hay to specific rations on the farm can improve the results for milk production as well as cow health and well-being.

This article appeared in the July 2025 issue of Hay & Forage Grower on page 38-39.

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