Purchasing Hay Equipment: Forage Mowers

The first step in the hay-making process is mowing the forage crop at the appropriate stage of maturity to best optimize hay yield and forage quality. Mowing and conditioning methods can influence drying time, quality, yield, and regrowth of the forage.

Types of Forage Mowers

Mowers can generally be broken down into two basic components:

1. how the crop is cut
2. the conditioning method (if present)

This fact sheet will review the two categories of mowers—those with conditioners and those without. When deciding which hay mower to purchase, consider what will best complement your forage production needs and work with the available horsepower on your farm.

Sickle Bar Mower

One of the earliest designs used to mow forages, and still commonly used among small acreage and Amish farms, is the sickle bar mower.

The sickle mower operates with a reciprocating action where a series of knives (called sickle sections) move back and forth as the mower is pulled forward.

Advantages

• lightweight
• requires least amount of horsepower
• relatively inexpensive

Disadvantages

• slowest mowing option
• potential to clog in heavy forage stands
• may or may not require a hydraulic remote

Disc Mower

Similar to a sickle bar mower, a disc mower has a cutter bar rather than a series of reciprocating blades. It uses a series of discs with blades that spin opposite of one another, similar to a lawn mower. The rotating blades and cutter bar design allow forages to be cut closer to the ground.

Advantages

• increased speed
• lower risk for clogging
• less blade maintenance than sickle mowers

Disadvantages

• requires hydraulics
• potential to cut grass too short
• increased weight of machine
• increased cost over sickle bar mower

Table 1. Tractor requirements for mower types and mower conditioners.

Tractor Requirements	Mower Type: Sickle Bar	Mower Type: Disc Mower	Mower Type: Drum Mower	Mower Conditioner: Sickle Mower Conditioner	Mower Conditioner: Disc Mower Conditioner
3-Point Hitch	some models	most models	most models	some models	some models
Hydraulic Remotes	0–1	1	0–1	1–2	2
Horsepower	low	medium	medium	high	high
Front End Weight	low	medium	high	low	low

 

Drum Mower

 

Drum mowers are a European design that is becoming more popular in the United States with small acreage hay producers. Drum mowers work in a similar manner to disc mowers with rotating blades, but the blades are attached to drums. Rather than using gears, which drive the cutter bar in disc mowers, the drums are often driven by belts. This design windrows forage between the oppositely rotating drums.

Advantages

• may or may not require hydraulics
• machine durability
• high ground speed
• low horsepower requirements

Disadvantages

• difficult to maneuver the heavy machine on slopes, especially for tractors that are light in the front end
• windrowing the forage requires tedding or inverting to allow for proper drying
• shorter mowing widths

Mower Conditioners

Some of the most common forage mowing machines in Ohio are mower conditioners. These machines cut and condition the crop in one pass to promote faster drying. Sickle-mower and disc-mower conditioners can be purchased for two general conditioning methods—roller/crusher type or the impeller/tine type. Roller conditioners come in either steel or rubber designs. Roller conditioners tend to have a greater demand for tractor horsepower than mowers with impeller conditioners of the same cutter bar width.

Sickle-mower conditioners can be run with smaller tractors and are generally less expensive than disc-mower conditioners. Sickle-mower conditioners are good for smaller acreage farms due to their slower speed and lower horsepower requirements.

Disc-mower conditioners require larger tractors to run efficiently, but some models are advertised with a minimum power-take-off (PTO) horsepower of 65. These machines operate at a higher speed and will most likely require one to two auxiliary hydraulic remotes.

When mowing a forage for haylage production, set the conditioner to make a swath as wide as possible to reduce the drying time of the forage.

Conditioning Systems

 A properly adjusted conditioner can significantly reduce the drying time of the hay crop (Figure 3). Two different conditioner designs are available depending on the primary forage crop being harvested. When harvesting or mowing legumes (alfalfa or clover), a roll-type conditioner is most desirable. The rolls crimp the stems of the legumes, while minimizing leaf loss.

When mowing predominately grass hay, an impeller or flail-type conditioner will aid in reducing drying time. This design uses free-swinging impellers against a conditioning hood. As the forage goes through the conditioner, the impellers strip the protective waxy coating off the grass. Impeller or flail-type conditioners have 1%–4% higher leaf losses in alfalfa compared to roller-type conditioners. Mowers with flail conditioners also require less horsepower compared to roller-conditioning systems.

Numerous studies have shown that a properly adjusted conditioning system has a greater effect on drying time than the type of conditioning system used.                             

Conditioner Adjustments

Having a properly adjusted conditioner is key to managing the drying time of forage once it is cut. When adjusting a roller conditioner, the rolls should be close enough to crimp the stems of the forage. For most mower conditioners, the range of roll clearance should be between ¹/₁₆ and ³/₃₂ of an inch. Be sure to check your owner’s manual to make proper adjustments. Rolls that are too close will cause additional leaf loss and excessive wear to the rolls. Clearance greater than what is defined in the owner’s manual for the machine will result in poorly crimped forage and longer drying times in the field.

The following instructions explain one method of determining if a roller conditioner needs adjusting.

Before performing any maintenance or adjustments on a mower conditioner:

1. Shut off the tractor engine.
2. Disconnect the mower conditioner from the tractor PTO.
3. Lower the cutter bar.
   (Shinners, 2002)

PROCEDURE

1. Cut three (3) pieces of typical household aluminum foil 18 inches in length. The foil strips should be at least 12 inches wide.
2. Take each strip of foil and wrap around a rod that is ³/₈ of an inch in diameter. Slide the roll off the rod, being careful not to crush the foil tube.
3. Place one foil tube in the approximate center of the conditioning rolls and the remaining two foil tubes about one foot from each end of the conditioning rolls. The foil tubes should be placed perpendicular to the roll’s longitudinal axis.
4. Make sure the cutting platform is fully lowered to ensure safety when measuring. Additionally—on some mower conditioners—raising the platform increases the clearance of the rolls which prevents an accurate measurement of the minimum roll clearance.
5. Turn the rolls over by hand until the foil tubes come completely through the rolls.
6. The rolls will crush the foil tubes. Measure the thickness of the foil tube with a digital or dial caliper to determine the minimum roll clearance. Take several measurements of the thickness along the length of each foil tube to determine an overall average. The measurement should be taken where the “crimp” or smallest clearance occurs.

Swath Width

Mower conditioners typically have adjustments that can be made to narrow or widen the width of the hay swath as the forage exits the conditioner. The wider the swath is, the faster the forage will dry. When possible, the swath should cover close to 70% of the total mowed area to promote faster forage drying times (Undersander & Saxe, 2013).

Used Equipment Considerations

When purchasing used forage mowing equipment, evaluate not only the condition of the equipment, but also its maintenance and lubrication history as well. Examine wear on cutter bars and blades, gear box lubrication, and the condition of the rolls or impellers on the conditioner. Parts displaying excessive wear will need to be replaced, adding to the cost of the machine.

Additional Resources

For more information on purchasing hay equipment: forage mowers, check out the Forages, Ohio State University Extension website (forages.osu.edu/home).

References

Shinners, K. J. (2002). Getting the most from a mower-conditioner. University of Wisconsin Extension.
fyi.extension.wisc.edu/forage/getting-the-most-from-the-mower-conditioner

Undersander, D. (2007). Conditioners for hay and haylage. University of Wisconsin.
slideplayer.com/slide/6666633

Undersander, D & Saxe, C. (2013). Field drying forage for hay and haylage. Focus on Forage – Vol 12: No. 5. 2013. University of Wisconsin Extension.
fyi.extension.wisc.edu/forage/files/2014/01/SwathDrying-FOF.pdf