Tight Grazing of Swards will Influence Pasture Quality Later
Type Media Article
By Anthony O'Connor, Teagasc Adviser, Galway/Clare Region
Grazing grass tightly in late April/early May will have a huge influence on sward quality for the remainder of the grazing season. However, adopt a flexible approach to grazing; be prepared to house stock, if necessary, if very wet weather occurs.
Grazing pastures bare at this time of the year keeps the sward leafy and maintains its high feeding value into the summer. Low post-grazing heights (down to 4cm-5cm) also produces a denser sward which captures a high proportion of light for photosynthesis and produces high yields at relatively low sward heights. These dense swards also need to be grazed before they get too tall, i.e., a pre-grazing height of 10cm-12cm in order to maximize the yield of digestible grass dry matter. As the yield of grass accumulates in a sward the content of decayed leaves also accumulates. In a dense sward, as light is shut out from the base of the plant, the rate of decay can approach the rate of growth when the sward goes above 12cm. In addition, as grass height increases in early summer the sward starts to produce a flowering stem, making it less digestible and more difficult to graze back to 4cm-5cm. Therefore, to keep pasture leafy and to maximize the production of digestible dry matter, aim to keep grazing pastures between a pre-grazing height of 10cm-12cm and a post-grazing height of 4cm-5cm. Grass is also an aggressive plant and maintaining dense swards helps to keep out weeds as well as maintaining ryegrass content.
High quality leafy grass has a feeding value of about 85%-90% that of a concentrate ration and therefore has the potential to produce live weight gains of about 1.2kg per day at a fraction of the cost of concentrate feeds under good grazing conditions. Grass quality and grass dry matter intake are the two factors that will determine the rate of gain. In order to keep the pasture leafy the stocking rate needs to match grass supply.
Keep a close watch on the rate of consumption of grass by each group of cattle to see how many days it takes to graze out each paddock or field and from this make an estimate of the numbers of grazing days you have already. If it is more than 14 days you are getting into a surplus. Walk around the whole grazing area once per week (or more often in times of rapid growth) to see if the grass in reserve is increasing or decreasing. If you think that you will have a surplus of grass, consider closing an extra paddock/field for baled silage.
If wet weather occurs, avoid excessive poaching. Be prepared to house some stock and feed them on silage left over from winter.
Stock proof electric fencing is crucial to control stock, while protecting farm boundaries such as stone walls, hedges, and watercourses. Well-designed electric fencing is an essential element of grassland management, for controlled grazing and utilisation of grass. The type of livestock you want to control is the most important consideration when erecting a fence. For example, two strands of wire will be needed to control a suckler herd. To implement a controlled grazing policy such as dividing up large fields into smaller paddocks and carrying out rotational grazing of these paddocks using temporary electric fences, then having a well-designed electric fence system is a must. Also, as mentioned above, if you want to cut extra bales of silage where there are heavy covers of grass, then an electric fence system will be needed.