Despite the interest in brown mid-rib corn hybrids to increase neutral detergent fiber (NDF) digestibility of corn silage and increase potential milk production, haylage quality and digestibility hold a bigger key to having a positive impact in the overall ration and production scheme.
There is an emerging understanding of the rates and amount of digestible NDF in haylage. It may be the amount of NDF that is digested in 30 hours of incubation in rumen fluid expressed as NDFd30, or the amount that is undigested during the same time as NDFu30.
The idea is to measure not only the extent of digestion, but the rate. The more digestion, the better the dry matter intake and the greater the milk production it will support. The resulting diets can take advantage of alfalfa haylage of exceptional quality.
These haylages are typically clear alfalfa, cut early or at a short harvest interval, chopped quickly and stored in conditions to retain quality. They will generally test well in excess of 20% protein, with less than 34% NDF. When tested for 30 hours in rumen fluid, haylages will have a NDF undigested 30 score of less than 15%.
The exact numbers, or even the determination of the numbers is still far from an accepted and exact science, but it is becoming well regarded that alfalfa that is grown under really good conditions, harvested at an early maturity stage, chopped quickly and stored properly has an increased ability to support exceptional milk production.
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It is one thing to talk about feeding "super" haylage; it is another challenge to produce it on a sufficient and consistent scale to take advantage of the concept.
It raises the bar of agronomic management of the farming side of the dairy business. Depending on your location, the production of hay crop forages has a tremendous regional influence.
Simply what is possible and common in the Northeast and upper Midwest will be different in the South and Southwest. Size of the farming operation, management systems and scale of the harvesting operations will greatly influence the production of an alfalfa crop. But there are some common threads that I will try to focus on.
- Pick varieties that have a proven record producing a high-feed value. Often such information is lacking in the seed catalogue. Such traits as leafiness, and growing characteristics are important.
- Dense stands tend to produce plants with less stem and more leaf area. The idea is the smaller stem produces a more digestible plant.
- Schedule a shorter cutting interval and start early. The concept is to start harvest before the plant begins to produce an increasing amount of the slower and more undigestible fractions of fiber. Then keep cutting to maintain that schedule. The last few days of growth in the production cycle is the biggest swing to the more structured fibers that are more resistance to digestion. The shift from a 35-day to a 30-day schedule has great implications for quality, but also for a chance of lesser total yields and increased sustainability issues for the crop.
- Maintain young stands. The first year of alfalfa in the rotation is the most productive in terms of quality yield. Third year and older stands will seldom yield the super quality forages that we are looking for.
- Pay attention to the agronomy and fertility issues. High yielding alfalfa removes huge quantities of potassium and other elements. Maintaining high levels of fertility is essential to supporting the alfalfa plant in producing healthy and lush growth.
- Depending on your location, growing season temperatures and late season photo period, making 3, 4 or 5 cuttings will be an important decision affecting several factors of your farming and alfalfa production system.
- Harvest and storage practices are critical. Rapid harvest, i.e., chopping within 24 hours or even the same day, preserves critical nutrients. Properly placing in storage, proper packing, using silage treatments to enhance fermentation and good feed out practices are part of the system.
- You likely will not make all of your haylage as "super" haylage. You will need to be able to separate it so take advantage of it as a feed for the high end of your herd. A separate and accessible area of your bunk system needs to be setup.
The concept is exciting. Our nutrition professionals have begun to identify what "super" haylage is and how to take advantage of it as a feed ingredient. The farming side is learning what it takes to grow and harvest the exceptional quality feed. Our dairy management systems are beginning to develop the systems to put it all together. The bottom line is more milk production.
JIM PECK is an independent nutrition consultant based in Newark, N.Y. You can contact him at firstname.lastname@example.org.
- June/July 2014