Every year before forage harvest begins, the questions come regarding quality or quantity of forage. This discussion doesn't apply as much to corn silage but more so for small grain, alfalfa, and warm-season annuals like sorghum and millet. There are many factors that might influence the best answer to the quantity or quality question, but in my view, none of these are as important as drought.
A significant portion of the nation's dairy production is in the arid West where rain has been the topic of many prayer meetings since the pioneer days. With less and less irrigation potential, growing forage for dairy production is always a big concern.
There is a joke about a High Plains farmer discussing his 15-inch average annual rainfall with a farmer from the East. "So, 15 inches of rainfall doesn't seem like very much to grow a crop" comments the Eastern farmer. To which the Western farmer replied, "Well, it sure seemed like a lot the day we got it!".
Farming out West is not for the faint of heart.
Back to the cows
This reality is clearly in view in my ration formulation. In addition to nutritional expertise, we are expected to be of assistance in developing forage plans for our clients. This is a great reason why dairy science students should be encouraged to take some agronomy classes.
The holistic approach to building dairy rations out West is to always consider what we can grow and how we best complement that with purchased ingredients. This is the point where the status of the Ogallala aquifer intersects with hemispheric weather patterns and finally with rumen biochemistry and kinetics. How can we pick the best forage with the least weather risk, minimize irrigation risk, and then combine it with the right grains, protein, and by-products to make profitable milk?
My overriding principle for this topic is that the forage volume needed to operate a successful dairy is always the first requirement. The biology of the cow and, more specifically, the rumen tells us we need a certain amount of roughage to maintain her health. Having a secure supply of this roughage material is of the highest priority.
Learned to speak French
I remember in the drought of 2012 in the Texas Panhandle. We all had to work on our French a bit. We were having forage shipped out of Canada with French-speaking truck drivers from Quebec. This is not the norm out our way! Granted, this was an extreme situation, but I will never forget it. In almost all cases, ingredients like corn, protein meal, and various by-products are available at the end of a phone call. We may not like the price, but in almost all cases, you can get it. With forages, this is not the case.
So, back to the question, “Planning for quantity or quality from crops like triticale, sorghum, or millet out West?”
I almost always lean toward quantity. We don't want to take this to the extreme by making wheat straw or milo stalk silage. As well, carefully picking the right variety might help with some extra yield while still holding on to respectable digestibility.
An actual conversation might go like this: “Should we plan to harvest our triticale early for 9 tons of yield at 15% protein and 65% neutral detergent fiber digestibility at 30 hours (NDFd30 hour digestibility)? Or should we let it grow a little longer and increase the yield to 12 or even 15 tons but end up with 10% protein silage with a modest fiber digestibility of 55% NDFd30?
My answer will usually lean toward maximizing the yield. This will lower the overall cost per ton of the silage, reducing harvest and ensiling risk while providing more feeding days for the herd.
Can it make milk?
But you ask, how can we make the same milk with this higher fiber, lower digestibility, and lower protein silage. Well, the protein part is easy. Here again, we may not like the feed cost result, but we will get the cows fed. As for the fiber, this part is very interesting and lends itself to good ration formulation and modeling.
One of the primary differences between high fiber, more mature silage and what we might call "really good stuff" is the lower hemicellulose. As forages mature, the percent of highly digestible hemicellulose is reduced while lower digestible cellulose increases along with indigestible lignin. These chemical changes inside the cells of the plant are easily observed by what an experienced farmer can tell as he simply touches and feels the hay or silage.
As long as this hay or silage is nicely harvested, ensiled, or dried using best practices, we can formulate it into a ration and still make good milk. This may seem an affront to the mantra that good forage makes good milk, but science tells us we can add things to the ration using the more mature forage and make the same milk with more feeding days from the crop.
If hemicellulose is what we are missing with the higher-yielding, higher fiber silage, how do we add it back? Here is the good news.
Most of the by-products that we routinely feed in dairy rations are rich in hemicellulose. This fiber that is indigestible to humans is the perfect fit for the lower digestible forage. Using ingredients like soybean hulls, beet pulp, distillers and gluten are a perfect fit. You don't fix this problem by simply adding corn. It is not starch that you need.
I know everyone won't agree with this approach, but we are making it work very well in dairies even now. We are feeding very high-fiber, small-grain forage with less than impressive NDF digestibility, modest protein and are still making big milk. Increasing forage yield not only decreases the per ton cost of that forage but reduces the risk of hauling hay from long distances while hoping for the next rain to break the drought. Using strong nutrition modeling, we can "fix" the marginal quality forage and still produce high levels of milk.
