Watch: Farmer know how – rotational sheep grazing

One of the most important aspects to consider when setting up a paddock grazing system is power for the electric fence. An electric fencer works by converting electricity into a high-voltage pulse. This pulse is connected to an insulated wire. If an animal touches the wire, the pulse will run through the animal and into the ground. All electric current wants to get back to source. Therefore, power on the fence wire needs to get back to the fencer via the earth field. A fencer works best when it is well earthed to damp ground via the ground rods.

To divide a field the main options for sheep farmers are electric sheep netting; temporary electric fence using plastic or pigtail posts and three strands of polywire with timber posts at either end; or with units such as the Gallagher smart fence.

Ger Lynch sells the Gallagher smart fence to sheep farmers interested in strip grazing larger fields to utilise grass efficiently and reduce waste. He says the fence consists of three-strand polywire and one turbo-wire on a 10-insulated post system. The top wire is 90cm or 35in high and comes complete on a 100m reel system to allow quick erection/removal.

Water supply can be one of the biggest barriers to paddock or strip grazing. Ideally every paddock should have a permanent water supply. Keeping water troughs in the centre of the paddock allows for further splitting up with temporary fencing. Alternatively, many farmers transport water troughs to the different grazing areas by leaving connections available to tap into an over-ground water pipe. The fence can be tied at either side of the trough (see picture) depending on the side the flock are grazing without having to make any major changes to the setup.

Ger says the Gallagher fencing system he uses makes strip grazing sheep easier because all the components are combined in one unit. Once the first post is fixed at one boundary he starts reversing and puts down a post every 11m or so. If the ground is hilly, the posts can be adjusted to suit the terrain and reduce the chances of sheep getting under the wire. When he reaches the 100m limit, the last post is placed in the ground and stay wires can be erected to increase the stability of the fence. The reel can then be tightened.

As mentioned earlier, farmers also have the option of using electric netting, which comes in 50m lengths and has 14 insulated posts. Some farmers divide paddocks by using pigtail posts with timber posts at both ends and strands of poly wire, approximately 10 posts per 100m can be used in this scenario.

Once the fence and water supply are up and running, it is down to the farmer to manage the grass. In midsummer, the pre-grazing yield (the amount of grass in a paddock before stock are allowed to graze) should be 1,300kg DM/ha to 1,600kg DM/ha (8-10cm). The paddocks should be grazed out to 4cm if quality allows because this will encourage excellent quality regrowth in the next rotation. If the cover of grass is too strong in a paddock this should be cut and baled for silage quickly. The key focus should be to offer high-quality leafy material to the flock as often as possible without offering excessive amounts of grass.

It is a well-known fact now that grass is the cheapest available feed for livestock on Irish farms. Unfortunately, it is not being utilised properly to get maximum benefit on a lot of farms. The best way to utilise grass is to set up a rotational grazing system. Many farmers who set stock (where animals graze one area for a long period) say in periods of high growth, grass becomes too strong and is impossible to control unless stocking rates are increased. By dividing up bigger fields into smaller paddocks or blocks you have far more control of grass growth. When grass growth is very strong some paddocks can be skipped and baled for silage.

Positives of rotational grazing

Negatives when rotational system is not in place