Ground Zero - Farmers up and down the country have bought zero grazers in numbers


The AB 70 Zero Grazer is a basic machine popular with dairy farmers and designed to feed 60-100 cows
The AB 70 Zero Grazer is a basic machine popular with dairy farmers and designed to feed 60-100 cows
Derek Casey

Derek Casey

Farmers lucky enough to be in parts of the country where grass is starting to grow now face a different challenge - soft ground is the latest barrier in letting livestock access grass.

In situations like this, zero grazing machines are often used by farmers who are eager to avoid poaching and potentially jeopardising future grass growth. Some models can now be shod on up to eight wheels in order to make the machine footprint as light as possible.

These machines were scoffed at by traditionalists when they hit the ground proper around 10 years ago. However, in the interim, farmers up and down the country have bought zero grazers in numbers.

They tend to suit farmers with fragmented farms or those farming on heavier land - particularly at times such as now in unusually wet years, or in the shoulders of the grass-growing season when growth rates are not yet sufficient to meet demand. Most tend to use them at certain times of the year, but there are some farmers that zero graze year round.

Opponents of zero grazing claim it goes against the natural system of letting cattle graze outdoors and can make cattle unfit. Some definite disadvantages of zero grazing are the added diesel, labour and machinery costs, as well as the extra slurry storage requirements required. The farmer needs to ensure they have the infrastructure to support this approach. Extra slurry will need to be spread, as well as the added daily job of actually going out to cut and collect grass.

One of the most popular machines among dairy farmers is the AB 70 Zero Grazer. This machine is a bit of a classic and would be a hit with dairy farmers who want a no-frills unit capable of delivering grass to the 100-odd dairy herd. This machine is an older model but newer equivalents are available from supplier Zero Grazer Ltd, based in Cavan. It cuts down to about 6cm using two drum mowers and takes a 6ft wide swath. It has a 28 cubic metre capacity. The drum mowers are similar to what you would see on a hay mower, as pictured. The cutting height can be adjusted with a hydraulic ram controlled by one of the tractor's spool valves. Once the grass is cut it is then picked by tines on a reel that lifts the grass into the trailer body of the zero grazer. A 90hp tractor is enough for this size machine.

Replace worn cutting knives to ensure a clean cut and faster regrowth
Replace worn cutting knives to ensure a clean cut and faster regrowth

Dos and don'ts of cutting

To get the best out of your machine and prolong its working life, Zero Grazer advise on a number of operating tips. Before starting, you need to check that the mower drums are level with the ground on both sides - this is done by adjusting the top link on either side. A spool valve drops the cutting drums to ground. It is recommended you always put the mower down first before engaging the PTO. Turn on the PTO slowly if possible as this helps to gently ease the mower on, making it easier on the tractor and slip clutch on the drive shaft. Once on, you can increase the tractor's revs.

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The next step is to move forward and move the drawbar out into cutting position via another spool valve. In practice, the zero grazer doesn't follow the tractor directly but is offset by about 6ft to the right via a spool valve for the drawbar. This ensures the zero grazer isn't trying to cut grass that has just been flattened by the tractor's wheels.

During cutting it is best practice to allow grass to build up in the front of the trailer body and then move the floor rearwards as the load builds. The floor is controlled with a third spool valve, and will usually need to be moved about 10 times in order to fill the trailer properly. A common mistake here is that farmers try to overload the trailer and squeeze in a huge load. This puts pressure on the floor chains and slats as well as the elevator that takes the cut grass up into the trailer body.

Excessive left or right turns wears wide-angle shafts. When turning right, tuck the drawbar gradually back in behind the tractor, allowing machine to follow tractor. This keeps the tractor's wheels away from the drawbar and PTO shaft.


When the load is full, the next step is to move the drawbar back in, leaving approximately three inches on the ram. To reduce pressure and wear on the drums and machine, be sure not to lift the mower when the zero grazer is in the offset position. With the drawbar back in, it is safe to lift the mower drums and slowly reduce tractor revs before turning off the PTO.

During unloading it is recommended to put a small rev on the tractor. Open the door and move the floor rearward via the spool valve. The zero grazer floor has chains and angle iron slats that move rearward when activated with a hydraulic pump. These slats push the grass load out the back of the trailer. If on a feedlot you can slowly drive forward, allowing the grass to fall in front of the cows. With the load empty, it is important to clean off any grass that is stuck on the latches of the trailer door and close the door properly to prevent waste from the next load.

Zero grazer top 5 tips

• A weekly oiling of the chains on the conveyor.

• To grease all greasing points.

• Clean out old rotting grass from the conveyor and door latches.

• Check the tension on the elevator chains and floor chains.

• Replace worn cutting knives.

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