If you are a dairyman or a dairy nutritionist, you’ve been there. You open up a new silage pile, bunker or silo, or begin to feed a new crop of hay and you pull the first samples, take them by the lab and that afternoon get the email … and the nutrient values or the digestibilities are not what you expected – not even close.

This silage or lot of hay is supposed to last a month, or more, sometimes until the next crop season. That’s when you look at your nutritionist (or have the dairyman look at you) and ask, “So what are you going to do about this?” This is one reason the nutritionist needs at least some input on what forage sources are grown or purchased.

This is the base they will have to work with for an extended period of time. Building a ration or a program in general without a solid foundation almost always guarantees sub-adequate performance.

It’s happened to us all, and in my opinion, is one of the most challenging parts of feeding the dairy cow (and the whole dairy). Sometimes the forages we produce just aren’t what we expect or need. Subsequently, it’s common to produce large volumes of silage or hay per cutting with each cutting expected to provide substantial levels of nutrients for an extended period of time.

Thus, this becomes the basis of what the farm has to build on as its nutritional foundation. If the quality of this forage leaves something to be desired, then compensating for the shortcomings become critical. But decisions have to be made concerning:

1. How to properly balance for the required nutrients at the cow’s current stage of production based on the forage base available to work with

2. How to prioritize the inclusion of nutrients from available and cost-effective sources

3. Evaluating current production levels and condition to properly support current and future volume, components, reproduction and health (Anticipation of future requirements becomes challenging as the previously mentioned forage quality is considered, especially when we also know how much forages can also vary.)

Obviously as we consider how to overcome and compensate for forage base shortcomings and prioritize nutrient delivery, we have to determine what is most important for a given farm. We know that feeding programs directly affect:

• Milk volume
• Components
• Reproduction
• Cow health
• Cow longevity

Some of this has a direct effect on monthly revenues, some more long term (revenues generated in coming months or years). In many cases, especially when milk prices are low, we tend to focus on what is required immediately to cash flow or at least minimize losses.

If forage quality is inadequate, it becomes necessary to first look at the nutrients, constituents or characteristics that are most or first limiting. Fortunately, we have access to a variety of computer-modeling systems that can help us evaluate, not only the nutrient levels, but the value of these nutrients as well.

We can model fermentation profiles and generate production estimates based on the nutrient and constituent values we enter into the system.

Initially, these might include something as basic as protein (soluble, rumen-degradable and rumen-undegradable). As we improve our understanding of protein nutrition and chemistry, we recognize the limiting nutrients may in fact be metabolizable protein (MP) in general but also MP essential amino acids such as lysine and methionine.

Fortunately, these nutrients are easily supplemented. Note that I did not say “inexpensively supplemented” since there is cost involved to provide added protein components, and at times this can be significant, particularly when contrasted against low milk prices.

However, when all the data is considered regarding the effects of proper protein and amino acid balance on a wide range of production parameters, the need for keeping protein components balanced is fairly clear cut.

A second (or simultaneous) consideration is digestible fiber levels. Research and practice have shown repeatedly how important the various fiber components of varying digestibilities (rate and extent) are to rumen fermentation. Since the availability of fiber sources of proper digestibility (as balanced against other nutrients that directly affect the fermentation process) is so critical, having a forage base that provides these core components is likewise very critical.

If the forage base lacks proper digestibility or rates of fermentation, it may become necessary to procure another fiber source that can supplement or complement the base fiber. This then becomes a matter of evaluating the base and determining what fiber component is necessary and what ingredients can best provide that component.

For instance, if the dairy’s forage base consists of corn silage and alfalfa haylage and this combination proves inadequate, it may be necessary to source a grass or legume hay to obtain a proper balance. Other options include beet or citrus pulp, whole cottonseed, soy hulls, etc.

These will not contribute to physically effective fibers, but will contribute to the overall fiber balance and digestibility and have direct effects on fermentation and rumen pH.

On this same note, it becomes necessary to evaluate more soluble carbohydrate levels such as sugar, starch, non-structural carbohydrates, etc. Again, these components have a direct effect on fermentation rates, acid production and energy levels in the cow. For the most part these levels can be supplemented fairly easily using common ingredients. Ingredients such as corn, grain sorghum, wheat, barley, etc., are readily available.

A question that comes into play is that of form. How the basic grain is processed can directly affect how it is digested and also affect the ration cost. The form of the grain source also plays a role. For instance, fermentation differences exist between conventional ground and high-moisture corn.

Another consideration may include what additives or rumen modifiers might be used to overcome or offset a poor forage base, at least to some degree. It’s been said countless times: Feed additives are not a silver-bullet nor are they a Band-aid to be used when base forages are inadequate.

However, products such as yeasts, enzyme sources, direct-fed microbials, plant extracts, buffers and so on, may be used in some combination to assist with modification of the rumen function in an effort to improve nutrient yield that might otherwise be limited by a poor forage base.

These products must be evaluated carefully since they come with a cost, one that is sometimes very significant. And when stacking these one on top of another, the cost adds up.

Conclusions

So how do we prioritize nutrient recommendations, particularly when something in the diet or forage is lacking? That depends on what is most lacking or will have the greatest effect on production, efficiencies and profits if left unaddressed. When all is said and done, nothing replaces quality forage in the dairy feeding program.

Something that must be recognized is we can find a variety of replacements and means to fill the gaps created when forages are lacking quality. But each of these comes at a cost in the ration.

We have the ability to access numerous ingredients and to balance rations to the “Nth” degree, but we never truly know how a given diet will work until we get it into the cow. We can create supplements to fill all the gaps but, again, nothing replaces quality forages.  PD

• Steve Blezinger

• Management and Nutritional Consultant
• Reveille Livestock Concepts
• Email Steve Blezinger