One of the unique strengths of Irish farming has been the ability to produce meat and milk cheaply from grazed grass. Our mild climate has allowed farmers to graze cattle for a large portion of the year, with a short wintering period.

Wet ground conditions are a new grazing challenge. The zero-grazing concept has come into focus in recent years as farmers aim to boost stocking rates and improve grass utilisation, especially during periods where grazing in poor ground conditions results in high levels of grass spoilage.

The zero-grazing system has been widely used on the Continent for many years. It has been attempted by Irish farmers with varying degrees of success since the 1960s.

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There are arguments for and against the modern zero-grazing system. Those supporting the system claim greater utilisation of the available grass and less grass wastage. The system has appeal for some fragmented farms, where it is easier to move the grass to the cattle, especially cows, on a daily basis, than moving the animals.

It also has appeal on farms planning expansion with limited land resources.

Those against the system cite costs and labour demands as the main factors that make zero grazing less attractive. As in all things, there is a balance, and very few Irish farmers will opt for full zero-grazing throughout the year.

More farmers will opt for zero-grazing at shoulder points in the grazing programme. This will involve zero-grazing in early spring, where there is a good cover of grass but poor ground conditions leading to grass spoilage due to poaching. Zero-grazing can be effective at the end of the grazing year for the same reasons.

This means that to be effective the machines must be relatively light and carry a modest load. It is important that the combined tractor and loaded zero-grazing machine does not lead to field surface damage and soil compaction.

For this group test, the Irish Farmers Journal invited all manufacturers and distributors of dedicated zero-grazing machines on the Irish market to a practical ‘workshop’ at Gurteen Agricultural College, Ballingarry, Roscrea, Co Tipperary.

With the help of Gurteen College principal Mike Pearson and Wray Platt, farm manager, several acres of grass were made available locally for the Irish Farmers Journal group test.

Some of the fresh grass was fed directly to livestock at Gurteen.

The remainder was added to existing silage pits for consumption later.

The growth in sales on the Irish market has encouraged a number of Irish manufacturers to build machines for our conditions. Some are well established, while others are new to the scene. We asked all zero grazing machine suppliers to participate in this group test.

Here, we take a closer look at two of the four different zero grazing machines that took part in our group test.

‘O’ Grass Grazer

The ‘O’ Grass Grazer is a robust-looking machine developed by Desmond Condell of Desmond Condell Engineering Ltd, Castlecomer, Co Kilkenny. Desmond has built up a reputation over the years as a manufacturer of simple and hardy silage feeders and he also refurbishes other feeder brands.

One of his feeder customers asked him to build a zero-grazing type machine. He has since built a second one.

The O-Grass-Grazer is a twin-axle machine with a capacity for around 4.5t of dry grass, says Desmond Condell. While it was not as well finished as some of the other machines in the test, allowances have to be made for the fact that this is only the second machine produced. Its robust appearance was followed through in the design of many of the machine’s features and functions.

The mowing element of the ‘O’ Grass Grazer is based on a PZ 220 drum mower. The PZ unit was chosen for a number of reasons, mainly its grass-cutting height adjustment.

The adjusters, one for each drum, are located at the top of the machine and allow the gap between the ground-following disc and blade to be easily adjusted. The adapted PZ mower remains a belt-driven machine through two wide-angle PTOs from tractor to drawbar and from drawbar to mower drive. The belt drive makes it easier for the tractor to start up, says Desmond.

The grass is transferred into the wagon by a hydraulically driven elevator with a high filling position, which Desmond claims is gentler on the grass. The elevator is driven by a roller chain which he says is easy to drive and very reliable.

The mower bed pressure and elevator flotation are adjustable on either side by springs. The mower and elevator are both raised into and out of work via a single vertical ram, acting on chains to the front of the elevator.

Once the grass is loaded into the wagon, it is moved backwards by two pairs of high-tension steel chains and bolted slats.

These chains run in tracks in the floor, which he claims reduces drag on the chain when the wagon is loading or unloading.

This is claimed to reduce the power required to operate the floor mechanism.

The ‘O’ Grass Grazer runs on four 500/50-17 BKT tyres and the axle width is wide.

Two conventional straight axles are used, running on springs with rockers between the front and rear axles to help follow undulating ground. Hydraulic braking is standard all-round.

Two double-acting hydraulic services are used to operate hydraulic functions.

Two diverter blocks increase hydraulic services available from the tractor and are operated by a simple and robust in-cab control box.

Operation

Co-piloting ‘O’ Grass Grazer was Liam Ryan, owner of one of the machines, who has considerable experience of the machine.

For the Irish Farmers Journal test, the ‘O’ Grass Grazer was operated by one of Gurteen College’s New Holland T6.140s. This is a compact four-cylinder tractor with 110hp and a maximum boosted power of 143hp. So, there were no problems in the power department.

In the field, the hydraulic ram on the drawbar was powered out which fully offset the machine ready to mow and collect fresh grass. To start up, the mowing unit was lowered to the ground and then the tractor’s PTO engaged to run the mower.

It take a bit of grunt to start but with belt drive, it was not harsh. After that, it was a case of activating the hydraulically driven loading elevator with tractor’s spool valve. As the freshly cut grass was loaded, the floor needed to be ‘nudged’ to fill it to capacity. You need a little practice to know when the machine is full, rather than electronic or mechanical indication.

In the field, Desmond advised cutting the headlands from the outside in. This means that the mower is always cutting the bigger arc into corners rather than trying to cut around the corners if you start from the outside round in. In practice, this worked well and was much tidier than cutting from the outside headland into the field.

Desmond advises making the initial cut in fresh grass at a height of 40mm and subsequent cuts approximately 16 days after at a cutting height of around 48mm to 50mm. This, he believes, gives the best re-growth.

In the field and on the road the loaded the ‘O’ Grass Grazer was steady behind the tractor, even at speed with a full load. Unloading was no problem. Some of the roads we travelled on were narrow but manoeuvrability was no problem when entering and leaving fields.

The wheels are positioned midway along the machine which can create a tail-swing that needs care.

The relatively low mower clearance of 160mm (6.5 inches) didn’t cause any problems either.

Riberi steady on the road

Barnaboy Enterprises Ltd from Kilcormac, Co Offaly, imports three different makes of zero-grazing machines from Italy – Enria, Riberi and Juscafresa – to suit different-sized farms. Justin Cleary from Barnaboy Enterprises brought two to the Irish Farmers Journal group test, one from Enria and one from Riberi.

We used the larger Riberi RS100 to take part in our group test and, interestingly, it was the only non-Irish machine. The Enria is among the smallest machines available from Barnaboy Enterprises.

Specification

Riberi builds zero-grazing machines with capacities from 11m3 to 28m3 and mower widths from 1.65m to 2.1m. The Riberi machines have been available in Ireland since 2007 but for only a year through Barnaboy Enterprises.

The Riberi RS100 zero grazer featured a rear discharge conveyor option, which allows the freshly-cut grass to be discharged either to the left or right of the machine for easier and more direct feeding. The tailgate, which incorporates the discharge elevator, can also be opened to unload directly behind the machine.

The Riberi RS100 is attached to the tractor by an hydraulically operated drawbar which incorporates a telescopic beam to provide A-drawbar like handling characteristics, says Justin. The design is claimed to be more stable than ‘single-leg’ drawbar designs when fully loaded. The telescopic section incorporates nylon wear pads, while check valves on the ram ensure that it remains locked in position when mowing.

Two wide-angled PTOs transfer the drive back to an Italian-built Galfre twin drum, 2.1m-wide mower. The machine has a triple hydraulic pump arrangement.

This makes the RS100 largely independent in hydraulic terms, using the tractor’s hydraulics, one double-acting service to operate the ram on the drawbar and the hydraulic jack.

After that, separate independent hydraulic systems driven from the PTO provide hydraulic services for loading elevator, floor elevator, feed-out elevator, plus oil for hydraulic rams for mower, tailgate and mower-drive engagement.

The elevator and mower ground pressure can be adjusted with springs on the side of the elevator housing. Some positional adjustment can be done at the rear of the mower through an A-frame type assembly, which is similar on most machines.

The typical capacity of the RB100 when fully loaded is between five and six tonnes of fresh grass, says Justin. To suit Irish conditions, the RB100 is equipped with 550/45-22.5 tyres and runs on a pair of bogie axles, with the left wheels paired on one bogie and the right on the other, without suspension. Hydraulic braking is standard on all four wheels.

Operation

In the field, the tractor’s hydraulics power the drawbar. The PTO is then engaged to bring the Riberi’s own hydraulics to life. The Galphre mower is lowered to the ground and hydraulically engaged at tick over.

While the Riberi was being operated by an 180hp Massey Ferguson 6490, Justin explains that an 115hp tractor will be more than adequate to operate the RB100. The bigger tractor for the test may have limited the Riberi’s manoeuvrability a little in terms of getting out of field on a narrow road.

Filling the Riberi was fairly standard. You fill up the front of the machine, then move the floor back and repeat until the wagon is completely full. Knowing when it is full requires a little intuition, as they all do, rather than a sensor system used on conventional silage wagons. With little experience, we still managed to get 4,740kg of fresh grass into the first load.

In the field, the hydraulic drawbar aids manoeuvring around corners, starts and finishes. Once the mower is running, it never leaves the ground until grass mowing is finished and it is shut off before the run back to the yard. All of the machine’s functions are set from the control box with the exception of the drawbar function.

The machine’s control box uses standard switches with descriptions of each function. This takes a bit of getting used to.

On the road, despite a lack of suspension, the Riberi travelled well, perhaps aided by its telescopic drawbar section. The bigger tractor, while more awkward to manoeuvre in and out of fields, was a bonus for the long road run back to the yard.

The conditions

Operating conditions for the group test were typical and almost ideal. It had rained heavily on the day before the test while it was dry on the test day. This allowed us to see how they all performed picking up wet grass early in the day compared with just wet grass later in the day.

Despite the previous day’s rain, ground conditions were good. All of the fields that we worked in were recently reseeded. This provided a good test of both the tractor and zero-grazing machines. We were able to see what effect this kind of traffic had on soft field conditions.

Each company provided a rundown on the machines on the day before the field test. On the day, all of the machines were weighed empty when loaded on the weighbridge of local farmer Patrick Cahalan, who kindly provided us with the weighing facility.

NEXT WEEK: We report on the other two machines and give an overall verdict.

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