Stockpiled Forage for Winter Grazing, Part 2: How to Supplement Forage and Develop Adapted Cattle 

In Part 1 of this series, we explored how stockpiled forage can help reduce winter feeding costs and keep cattle grazing when pastures go dormant. But making stockpiled forage work through winter takes more than simply leaving grass standing. Forage quality, cattle nutrition, and the ability of your herd to thrive on what the land provides all play a role. In Part 2, we’ll look at how to supplement strategically without replacing grazing, develop cattle better adapted to your environment, monitor nutritional needs, and make the most of your forage when winter conditions don’t go as planned.

Supplement Winter Forage Without Replacing Grazing

I've always been somewhat reluctant to supplement cattle. Part of that comes from cost, but part of it is because supplementation can become a crutch that hides other problems. We can compensate for poor grazing management, excessive stocking rates, or cattle that aren't adapted to the environment simply by buying more feed. At the same time, managing cattle in a brittle environment has taught me not to become too ideological about it. Sometimes it simply doesn't rain and I am left with one or two year old stockpiled forage I didn't get a chance to graze.

How Protein Supplementation Helps Cattle Digest Dormant Forage 

When I'm trying to carry cattle through a dry period on old stockpiled forage, strategic supplementation can be a very useful tool. In those situations, my objective isn't necessarily to feed the cow. I'm trying to feed the rumen microbes well enough that they can help the cow utilize the forage already standing in front of her. That distinction is important, and you will be amazed at how an adapted cow can thrive with so little. The right kind of cattle is extremely important. 

When dormant forage becomes low in protein, rumen microbial activity can become limited. Those microbes are responsible for breaking down much of the fibrous plant material the animal consumes. When microbial activity slows, fiber digestion and passage through the rumen can slow as well, eventually limiting how much low-quality forage the animal can process. A relatively small amount of supplemental protein can therefore help the animal utilize a much larger amount of standing forage.

Recognizing When Supplementation Becomes Feed Replacement 

This is why I try to maintain a distinction between supplementing vs substituting feeding. If a modest amount of protein or energy allows the cow to continue utilizing stockpile efficiently, supplementation is doing its job. If we have to continually increase the amount until a significant portion of her diet is coming out of a bag, bunk, or bale, then the situation has changed. At that point, we're no longer correcting a small nutritional deficiency. We're replacing what the pasture can no longer provide, and we need to reconsider the stocking rate, available forage, or overall winter grazing plan. With adaptive grazing, the early warning signs become more evident earlier in the year when pastures are no longer providing the expected grazing days. 

Choosing the Right Supplement

Non-protein nitrogen products, particularly urea-based supplements, can be useful and economical under the right conditions, but I don't like choosing a supplement simply because it appears inexpensive on a crude-protein-equivalent basis.

Rumen microbes can use ammonia produced from urea to synthesize microbial protein, but they also need sufficient fermentable energy for that process to work efficiently. If cattle are grazing extremely mature forage that is deficient in both protein and available energy, simply adding more nitrogen may not solve the entire problem.

This is one reason I tend to favor true-protein sources when they're economically available. Seed meals can work well, and good-quality alfalfa is one of my favorite options because it provides protein along with digestible energy, minerals, and additional roughage. In the right situation, a relatively small amount of alfalfa can improve how cattle utilize a much larger quantity of mature stockpile.

The cheapest product per ton isn't always the cheapest way to feed the cow. What matters is how much it costs to correct the actual deficiency.

How Maternal Nutrition Influences Calf Development 

There is another reason I think we need to look beyond simply meeting today's crude-protein and energy requirements, particularly when we're feeding pregnant cows and developing replacement females. The nutritional environment we create today can have effects that extend beyond the individual animal we're feeding.

Understanding Fetal Programming and Epigenetics 

We traditionally think about genetics as something relatively fixed: we select a bull and a cow, combine their genetics, and produce a calf. But genetics is only part of the story. The environment in which that calf develops can influence how some of those genes are expressed (epigenetics). This is the basis of what is commonly referred to as developmental or fetal programming, and epigenetic mechanisms appear to be one part of that process.

Research in cattle and other ruminants has shown that maternal nutrition during pregnancy can influence placental development, metabolism, growth, reproductive development, and later performance of the offspring. Researchers have also documented changes in gene expression and epigenetic markers associated with differences in maternal nutrition. In other words, what the cow experiences nutritionally during pregnancy can help shape how the developing calf responds to its environment later in life.

That doesn't mean we can look at a particular supplement and determine if it will create a good or bad epigenetic outcome. We aren't anywhere close to understanding the system well enough to make that claim. What it does tell me is that nutrition during pregnancy shouldn't be viewed only as meeting the cow's requirements for today. We are also creating the developmental environment of the next generation. And potential problems in the long term if we frequently rely on supplemental feeding.

Developing Cattle for Low-Input Grazing Systems 

This becomes particularly interesting to me when we're trying to develop cattle that are genuinely adapted to low-input grazing environments. If I want replacement females capable of maintaining themselves on diverse, mature forage with minimal supplementation, then I want their mothers functioning successfully in that same environment during pregnancy, while still meeting their nutritional requirements.

That is different from deliberately underfeeding a pregnant cow. Nutritional restriction and severe deficiencies can negatively affect both the cow and the developing calf. The objective isn't to create nutritional stress in the name of adaptation. Rather, I want to provide enough nutrition for the cow to function and reproduce while maintaining as much of that nutrition as practical from the grazing environment in which I expect her offspring to perform.

This is one reason I'm cautious about allowing supplementation to completely disconnect cattle from their environment. We can sometimes maintain animals that aren't particularly well adapted to a ranch simply by continually increasing the amount of nutrition we bring to them. The cattle may perform “ok”, but we are also masking the biological and economic feedback that tells us whether those animals actually fit the environment.

There is still a great deal we don't understand about developmental programming in cattle, and especially about how individual supplementation strategies translate into long-term epigenetic effects. I don't think we should pretend otherwise. But there is enough evidence around maternal nutrition and fetal programming that I don't think we should ignore it either.

How Cows Teach Calves to Graze and Become Adapted 

There is another process occurring that is much easier to observe in the pasture and shouldn't be confused with epigenetics: maternal learning.

How Calves Learn What to Graze 

A calf doesn't begin life knowing exactly what to graze. Young ruminants develop their dietary preferences through a combination of their own experience and social learning, and the mother is one of their first and most important teachers. Calves follow their mothers through the pasture, encounter the plants she chooses, learn where to graze, and gradually develop the physical skills necessary to harvest different kinds of forage.

I've watched this happen in diverse pastures. Cows that are comfortable grazing a broad range of grasses, forbs, and other plants tend to expose their calves to that same diversity. Those calves aren't simply inheriting a set of genes for "eating diverse forage." They are growing up in an environment where those foods are familiar and where their mother is demonstrating that those plants are acceptable foods. That early experience matters.

The Role of Maternal Learning in Cattle Adaptation 

Research on dietary learning in ruminants has shown that experiences early in life can produce preferences and aversions that persist later in life. Young animals also learn the physical skills required to harvest particular plants efficiently. An animal raised in a feedlot or simple pasture environment may therefore approach a complex rangeland very differently from an animal that spent its first months following its mother through that same plant community. 

This is something I think we sometimes overlook when talking about adapted genetics. Part of what we call an "adapted cow" certainly comes from genetic selection. Part may also come from developmental programming before birth. But another important part comes from what that animal learned after she hit the ground.

Those three processes—genetics, developmental programming, and learned behavior—are working together.

Building an Adapted Herd Across Generations 

That is why I place so much value on raising replacement females in the environment where I expect them to spend their productive lives, and keeping those replacement heifers as a single herd with their mothers. If I want a cow that can efficiently utilize dormant grasses, browse shrubs and other nutritious forbs, and travel across large pastures, I would rather have her learn those skills beside her mother than try to teach them to her as a mature cow.

Over several generations, that creates a powerful selection process. The cows that reproduce consistently under those conditions remain in the herd. Their calves experience that environment before birth, learn to graze it beside their mothers after birth, and, if retained, eventually raise another generation under the same conditions.

That doesn't mean every change we observe is genetic or epigenetic. Much of it may simply be learned behavior combined with normal selection. But from a management standpoint, all three processes point us in a similar direction: the environment in which we develop our cattle matters.

For me, that is the bigger objective. I'm not simply trying to get a cow through this winter. I'm trying to develop a herd that becomes progressively better suited to the environment I'm asking it to live in.

How to Monitor Cattle Nutrition

The cattle will usually tell you before the spreadsheet does. Forage tests and nutritional calculations are valuable, but I still spend a tremendous amount of time simply watching cattle; they simply know best what's good for them.

Use Rumen Fill and Manure to Assess Forage Utilization 

Rumen fill is one of the first things I look at. The left flank between the last rib and the hip gives us a quick indication of how well the animal has filled during the day. I generally want that area to appear reasonably full rather than deeply sunken. Visually assess this by the afternoon, if they are not full, open a new paddock as soon as possible.

I also pay close attention to manure. When manure becomes very loose, the diet may be highly digestible or out of balance toward rapidly available nutrients. On the other hand, when manure begins stacking higher and we can see coarse, poorly digested fiber, it often goes along with slower passage through the rumen.

I've found the combination of observing both manure consistency and gut fill particularly useful. If manure is beginning to stack and cattle also look hollow, I start asking whether protein or energy is limiting their ability to digest the forage in front of them.

Watch for Changes in Supplement Consumption 

Supplement consumption gives me another clue. I've seen cattle consume a relatively consistent amount of supplement for days and then suddenly increase consumption. When that happens, I don't automatically assume they simply like the supplement more that day. I start looking at the pasture and what cattle are selecting for more closely.

Often that spike is telling me that something has changed in the grazed diet. The cattle may have removed most of the higher-quality plant material, they may have reached a point where the remaining forage no longer meets their nutritional requirements, or the period of stay is long enough that despite available forage the fouling effect is having a negative impact. I've found this to be a useful early warning signal when deciding whether to increase supplementation or, more importantly, whether it is simply time to move.

None of these observations replaces a forage analysis or a properly balanced ration. But cattle are giving us information every day, and learning to read those signals can help us react before we see a major decline in body condition.