Catching up on spring grazing
April 29, 2021
Recent research suggests that an extra 1 tonne of utilised grass (dry matter per hectare) will deliver an increase in net margin of £160 on beef and sheep farms. Nigel Gould, Beef and Sheep Adviser Enniskillen with the College of Agriculture, Food and Rural Enterprise (CAFRE) highlights the benefits of spring grass.
“Ideally, swards will have received an early application of a suitable fertiliser such as standard or protected urea this spring.” On farms where heavier soils or weather conditions haven’t allowed fertiliser application, spread as soon as conditions allow. Urea is often the nitrogen source of choice for grassland at the start of the year as it is cheaper than CAN per unit nitrogen, and generally more effective on wetter soils compared to CAN products as it is less prone to loss via leaching. The opposite is the case later in spring and summer where nitrogen loss is generally greater in urea products especially in dry conditions. For this reason, it is preferable to apply urea on an overcast day. Protected urea products have gained popularity in recent years. They consist of standard urea with a urease inhibitor added which prevents nitrogen loss to the atmosphere. Protected urea can be spread at any time of year and is intermediate in price (per unit nitrogen) between standard urea and CAN products.
The CAFRE crop nutrient calculator can be used to develop a fertiliser plan for each field on your farm. This can be accessed online via your government gateway account. Soil index, field size and proposed cropping details (e.g. first cut silage) can be entered along with estimated slurry volume to be applied where applicable. The program will then provide you with recommended amounts of N, P and K to apply. An appropriate fertiliser product can then be matched with the requirement. The recommended values are maximum values. Lower figures may be appropriate depending on individual circumstances.
If not already turned out, turn cattle out as soon as weather and ground conditions allow. Target priority stuck such as spring calved cows and calves. Weaned autumn calving cows will more likely be last on the list. On heavier farms, prioritise lighter stock, especially if grass covers are likely to get too strong. Ideally turn cattle out in the morning to allow time to acclimatise to colder night time temperatures. This is especially the case for young calves and sheltered areas are preferable.
Rotational grazing systems will generally maximise total annual grass dry matter on farm however, good grassland management is essential for it to be successful. Some farmers have found the rising plate meter, accompanied by good online grass management software a useful tool in grass measurement and maximising grass production and utilisation on farm. Weekly grass measurements are taken across the farm and recorded. You can then make informed decisions on whether paddocks need to be taken out of the rotation for cutting for example. Target opening grass covers of 2800 kg DM/ha (8-10 cm) and graze down to 1600 kg DM/ha (4-5 cm). Generally, when grass growth has picked up, the ideal scenario is to graze at the three leaf stage, for three days and return to graze in three weeks. Rotation length will be longer and shorter than this for early spring and the peak growing season, respectively. Grazing at the three leaf stage will help maximise total grass production. By the time the fourth leaf appears, the first leaf will die. This is the reason why a build-up of dead material can occur in summer when pre-grazing grass covers are too heavy and impacts nutritional content which in turn limits animal performance. On the other hand, grazing before the three leaf stage, when the root reserves have not had enough time to replenish will impact grass recovery post grazing. Striking a balance is key.