Articles

Making High Quality Alfalfa Forages
Mark G. Cameron, Ph.D. Dairy Nutritionist, Cargill Animal Nutrition

For most dairy producers in Western Canada, winter arrived early with lots snow and spring has arrived later than usual, so thinking about new crop forages has not been the focal point of most dairies.

However, a new season of forage feeding will begin within the next 3 to 5 weeks and with it comes

the challenges of maximizing the utilization of the nutrients from these forages into milk. Alfalfa hay and haylage/silage are commonly used forages in lactating dairy diets and it is important to identify strategies that allow you to harvest high quality alfalfa feedstuffs.

Enhance Alfalfa Quality and Reduce Nutrient Losses:

• The Stage of Maturity of the alfalfa at time of cutting will determine its nutrient profile.
• Alfalfa cut at an earlier stage of maturity will be higher in protein and energy, and lower in Acid Detergent Fiber (ADF) and Neutral Detergent Fiber (NDF). Under normal growing conditions, as you harvest alfalfa with lower ADF and NDF values; the plant contains less lignin which means that the alfalfa is potentially more digestible in the rumen.
• High quality alfalfa can reduce the cost of purchased feeds, increase feed intake, increase digestibility of the total ration and increase milk production.
• Management practices that allow rapid forage dry down and involve harvesting at the proper moisture content will minimize forage quality losses.
• To minimize exposure to the environment and respiration losses in the field, the fastest possible drying (hitting a targeted dry matter level) is desirable regardless of the type of storage (bale, silo, bunker or bag).

Alfalfa Hay Management Guidelines*:

Time of mowing (mowing early in the day allows a full day’s drying in humid conditions; mowing after maximum solar radiation in cool/dry conditions may increase sugars and palatability.
Use of weather forecasts to plan harvesting.
Spread or windrowed swath (spread swaths dry faster when ground moisture is low).
Raking or tedding (exposes wet underlayer and speeds drying).
Swatch structure (loose swaths dry faster).
Windrow inversion (exposes wet underlayer and speeds drying).

*Guidelines from Northeast Regional Agricultural Engineering Service

Alfalfa Haylage/Silage Management Guidelines:

Match the size of silos, bunker or bags with the needs of the dairy herd and the size of the harvesting equipment. To minimize exposure to the environment and respiration losses in the field, the fastest possible drying is desirable.
Harvest at proper moisture content – 60 to 65% in bunkers and 55 to 60% in conventional upright silo or bags. Do not harvest above 70% moisture to prevent seepage of soluble nutrients and Clostridia growth.
Chop at proper length of cut (3/4” TLC) to ensure proper compaction and less oxygen entrapment. The goal is to chop as long as possible for more effective fiber while and still being able to achieve density.
Evaluate the length of chop using the Penn State Particle Size Separator. By weight you should have: 40 to 50% in the upper sieve, 30 to 40% in the middle sieve and 15 to 20% on the bottom pan.
Ensure forage harvester knives are sharp to reduce seepage and plant tissue destruction. This will also reduce fuel consumption.
Rapid filling of bunker, silo or bag reduces oxygen exposure.
Proper packing equals high density and usually a faster fermentation process. Density goal is 14 to 18 lbs/DM/ft3 or 40 to 50 lbs as-fed.
Fill the bunker using a progressive wedge from back to front; multiply tractors on “drive-over” piles to ensure good density. Remember SAFETY is #1!
Cover and seal the bunk or pile ASAP with tires. Split tires should be touching each other.

With Alfalfa Haylage/Silage Look at Using Aerobic Stabilizers and Fermentation Enhancers:

Enhances fermentation and reduces heating in storage.
Retains a high level of nutrients.
Decreases yeasts and molds and controls growth of spoilage organisms.
Retains more digestible dry matter and improves palatability which may enhance dry matter intake.

Why We Do It:

The growth, harvest and storage of high quality alfalfa is critical to the productivity and profitability of your dairy operation. Being able to bale high quality hay is important whether you plan to sell the hay or feed it to your dairy cows. Being able to harvest, store and feed high quality haylage/silage is important since it can help maximize your forage utilization in the diet. High quality alfalfa is important in dairy rations since cows need a digestible and effective fiber source for good rumen health; plus it is rich in protein which often helps you to reduce daily feed costs.


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Summer 2017

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