Friday, 10 July 2020
Grazing dry cows and youngstock on pasture closed and set aside for winter grazing can significantly reduce feeding costs.
Deferred grazing involves the removal of livestock from grassland in late August/early September to allow a grass wedge to build up for feeding in mid-November. As autumn grass growth rates can vary considerably, you need to be flexible in your approach when it comes to when and how much land to set aside. In some cases, there may be an impact on next season’s early grazing – don’t compromise this. Take this into account when deciding which areas to use – any fields that are underperforming now could be used, as an April reseed will correct compaction issues and enable stock to be kept out later.
The quality of the grass is important – a good percentage of leaf and live material is needed. Reasonably dense swards are preferable to protect from weather damage and to minimise soil damage, so longer-term leys or permanent pasture are ideally suited. Some producers who utilise deferred grazing divide the stock into small groups to minimise soil compaction. Because of this, it probably has similar labour requirements to housed cows. Only select animals in good body condition for this system – do not select old or thin cattle. Also, consider how exposed the site is to harsh weather, as maintenance energy requirements will be higher in wet and windy conditions.
Plan to turn animals onto covers of around 3,250–3500 kg DM/ha and graze down to 1,500 kg DM/ha. It is important to understand what deferred grazing can provide nutritionally – from November onwards, DM can range from 18–19% in dry conditions, to 14–15% in wet; ME will be around 11 MJ/kg DM. Therefore, a seven-month-old, 200 kg heifer, which requires an average of 50 MJ/day of energy for maintenance, needs 4.54 kg DM/day to achieve the target liveweight gain.
An example of working out the area needed in deferred grazing:
Example: 50 heifers eating 5 kg DM/day = demand per day of 250 kg DM.
Deferred grazing top cover of 3,500 kg DM/ha and stock grazing to 1,500 kg DM/Ha = 2,000 kg DM/ha available.
2,000/250 = 7 days to graze a hectare.
With 10 hectares available, there are 70 grazing days available.
More information is available here on deferred grazing.