With feed prices increasing, making the most from spring grazing will be crucial to maintain margins, according to Mark Oliver from Gallagher.
Mr Oliver says that temporary electric fencing can play several important roles, improving quality and quantity while reducing waste.
He says ensuring the correct grazing infrastructure allows for a flexible approach to management to be maintained, keeping grass at the optimum three-leaf stage for grazing and encouraging rapid regrowth by making sure cows have access to sufficient but not excessive grazing while allowing grazed swards to recover.
“Spring grass growth increases significantly in just a few weeks. Average growth rate data shows grass is growing at about 30kg dry matter (DM) per hectare per day in mid-April, but this increases to more than 70kg DM/ha/day in mid-May.”
He advises setting a target pre-grazing cover of 3,000kg DM/ha (1,214kg DM/acre) and taking cows out when covers are 1,700-1,800kg DM/ha (688-728kg DM/acre). This will help maintain a high-quality sward at the 3 leaf stage.
Mr Oliver says: “Use growth rate data to allocate sufficient grazing and decide how and where paddocks need to be split as required. For example, if covers pre- and post-grazing were 3,200kg DM/ha and 1,700kg DM/ha respectively, then the available grazing is 1,500kg DM/ha/day.
“At a target intake of 14kg DM/day, the target stocking rate is 107 cows/ha/day, meaning a group of 150 cows would need a 1.4ha paddock.
However grazing access needs to be carefully controlled. While cows will require sufficient dry matter in front of them, Mr Oliver says letting them have too much will result in wastage which, in turn will reduce the rate of early spring growth. It is also important to prevent back grazing to encourage rapid regrowth.
“Temporary fencing allows paddocks to be split to control access to grazing while keeping animals on smaller paddocks can maximise efficiency of utilisation and reduce waste. The use of back fences can increase rates of sward recovery.
“They can also be used to control access, fencing off tracks and allowing additional gateways to be created as required.”
Mr Oliver says temporary fencing systems can either be run off existing permanent fencing infrastructures or set up as standalone options depending on individual farm circumstances.
Whichever approach is used, he says there are a number of factors influencing fence effectiveness.
“Any electric fence must carry sufficient voltage across the entire length to be an effective deterrent.
“For cattle you need a minimum of 3,000 volts. If adding temporary fences to existing infrastructure, make sure the energiser is powerful enough by checking the voltage at several places along the fence.
“If the voltage drops you should consider upgrading the existing energiser. Alternatively, buy an additional energiser and run the temporary fence as a separate operation.
“Solar energisers are a flexible and easy option to use in these cases. If you upgrade an existing energiser, ensure you have sufficient earth, working on having one metre of earth pole per stored joule of power in the energiser.
Mr Oliver points out the importance of ensuring the conductor is at sufficient tension. While electric fences are a psychological barrier, as opposed to a physical one, it is important to keep the wire tight.
He recommends placing poles no more than 10m apart and ensuring the ends of the conductor are attached to suitable posts.
He advises using springs for high tensile wire to help maintain fences at the correct tension as they accommodate the natural cycle of expansion and contraction, fitting one to every run of temporary fencing.
“Geared reels are ideal for temporary systems as they ensure the correct tension while making it easy to move fences as required.
“If you are joining a temporary wire to an existing fence, always use a proper connector to ensure no loss of power.
“A simple temporary electric fence system can make a big difference to how well you can manage early season grazing to improve forage utilisation and set the grazing block up for the whole season.”