Leaving Certificate Agricultural Science Grassland Part 4 Grassland

Leaving Certificate Agricultural Science Grassland – Part 4 Grassland Management

Grassland Management Good Grassland Management involves the following: 1. Finding out the amount of herbage required. 2. The application of ample fertiliser to achieve this. 3. Maximising the DMD of the sward by managing grazing and conservation. The amount of herbage output required is calculated by the amount / type of stock on the farm. Generally 1 livestock unit consumes 12 tonnes of herbage dry matter per year.

Fertiliser Requirements The amount of fertiliser applied to grassland greatly depends on the grazing level and the level of establishment. Fertiliser should be applied to newly established grassland where grazing is light, in the following proportions: N – 48 kg / ha P – 20 kg / ha K – 38 kg / ha Intensely grazed pastures should receive additional fertiliser as outlined by Teagasc.

Fertilizer Requirements Land set aside for silage or hay should also be fertilised in advance of each harvest. Hay is only cut once over the grazing season while silage can be cut repeatedly. The following is recommended by Teagasc:

Crop Silage 1 Cut 2 Cuts 3 Cut Hay Fertilizer Application (kg / ha) 1 st Cut 2 nd Cut 3 rd Cut N P K 100 35 150 - - 125 35 150 88 9 38 - - 150 44 188 100 18 75 81 - 75 26 112 - - -

Managing Grazing Good grazing management requires young leafy digestible grass to be available for grazing at all times. An efficient system of rotational grazing allows the farmers achieve this. There are various systems available including Paddock Grazing, Strip Grazing, Block Grazing, Set Stocking, Creep Feeding and Mixed Grazing.

Grazing Management - 2 Paddock Grazing Paddock grazing is the most efficient form of rotational grazing, whereby 20 – 25 paddocks are created using electric fencing. The paddocks are created to suit the herd, using the rule: 120 cows will graze 1 ha of young leafy grass in one day. The herd graze one paddock per day in a rotational manner. Nitrogen is applied to the paddocks as soon as they are removed.

Grazing Management - 3 By the time they return to the paddock, the grass should be at the height of its digestibility. This system can be quite expensive but is widely used on dairy farms. Silage fields are usually kept independent of the paddock system, as the small areas may be difficult to cut. Calves & replacement heifers graze any replacement grass. Paddock grazing systems are sometime called rotational grazing systems

Grazing Management - 4 Strip Grazing This system involves the use of a movable electric fence, to give the stock a fresh strip of leafy grass per day. Grass strips are fertilised in the same way as the paddock system. A back fence should be used however, as to allow the grass recover sufficiently. This system is cheap, but requires a lot of labour time and is therefore rarely used by itself.

Grazing Management - 5 Set Stocking This is simplest, cheapest but least effective form of grazing management. It simply involves allowing the stock free access to all areas throughout the grazing year. This allows set – stocked areas to become patchy, with areas of highly un -productive grasses evident.

Grazing Management - 6 Set stocking has a number of particular advantages. Fencing and water troughs can be kept to a minimum and the continuous general nature of the grazing encourages a close dense sward that is usually rich in clover. Set stocking is often practices in a modified way with beef, dairy and sheep systems utilising a few large blocks of pasture on a farm ( Block Grazing).

Grazing Management - 7 Block Grazing This system is the most common system used in Ireland, as it is cheap, effective and low on labour. It involves the division of the grazing area into blocks that provide grazing for 7 -8 days. Pasture management can be improved by using strip grazing in each block. Larger blocks can be set aside for silage once or twice a year. This system is cheap and is suitable for dairy, beef and sheep grazing.

Creep Feeding This system involves allowing young animals access to the best grass by means of a fence with a hole only large enough for a calf or lamb. The calf or lamb can “creep” through the small opening to the good grass but the adult cannot. This allows the young animals to get the best grass, avoid worm infection and still allows the animals to suckle their mother.

Leader - Follower This basically involves allow the younger animals onto a paddock, strip or block before the adults. This again allows the younger animals to get the best grass and avoid picking up intestinal diseases. It involves less “set up” than creep feeding. It is common practice on dairy farms, when replacement heifers lead the main herd.