A change in the weather means ground conditions have taken a big hit in many parts of the country. Around this time of year zero grazing machines are being used by some farmers as both a grass management tool and a way of avoiding land damage in ground that has become soft and susceptible to poaching.
These machines tend to suit farmers in the shoulders of the grass growing season when growth rates are still reasonable but the ground isn't dry enough to support cows being out 24/7.
Most tend to use them at certain times of the year, but there are some farmers that zero graze year-round with fragmented farms to avoid having to walk cows long distances or over heavier land.
Some important things to remember about zero grazing are the added building, diesel and machinery costs that will be incurred, as well as the extra slurry storage requirements required.
The farmer needs to ensure he has the infrastructure to support this approach. Extra volumes of slurry will need to be spread, as well as the added daily job of actually going out to cut and collect the grass.
The cost of these machines varies depending on size.
For those looking for a small machine, there was an interesting development at last month's National Ploughing Championships from Irish company Hand Engineering.
Based in Oldcastle in County Meath, the company manufacture zero grazing systems under the ZeroGrazer brand and have just launched a small unit called the Minigrazer which is priced at €24,000 including VAT
Two sizes of the Minigrazer are available; a five cubic metre capacity machine with a 2.1m cutting width drum mower and a 4.5 cubic metres machine with a 1.85m cutting width drum mower.
The five cubic metre Minigrazer can hold one tonne of grass, and has a sloping floor a door design which allows easy unloading and without any moving parts.
The Minigrazer is suitable for all types of grassland management and can be adjusted to be used as a trailed mower for mowing meadows and other crops. It is fitted with 500mm flotation tyres to use during wet conditions.
Hand Engineering says the new machine is suitable not just for zero grazing on a smaller scale, but also for the likes of equine grass management and parkland maintenance. The Minigrazer can be used by low to medium horsepower tractors.
For those looking for something bigger that would cater for a 100 cow dairy herd a machine like the AB 70 Zero Grazer is a bit of a classic and would be a hit with dairy farmers who want a no-frills unit.
It cuts down to about 6cm using two drum mowers and takes a six-foot wide swath. It has a 28 cubic metre capacity. The drum mowers are similar to what you would see on a hay mower.
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.
In terms of tractor size needed, the guidelines for a machine of this size state that around 90hp is enough; during cutting the tractor doesn't need to be overly stretched and can operating at around 1400rpm max.
In hilly ground and for road haulage another 20hp is always a comfort but for a centralised farm you could manage with less.
Some models can now be shod on up to eight wheels in order to make the machine footprint as light as possible.
Prolonging your machine's working life
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 that 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.
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 six feet 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 will wear wide angle shafts. When turning right it is good practice to tuck the drawbar gradually back in behind the tractor, allowing the machine to follow tractor. This will keep the tractor's wheels away from the drawbar and PTO shaft.
When the load is full the correct 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 of 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.