The value of having sufficient supplies of spring grass to meet the nutritional requirements of ewes in early lactation was highlighted at Friday’s Grass10 early spring grass event on the farm of Tom McGuinness, Bellewstown, Trim, Co Meath.

The walk, organised by local Teagasc adviser Edward Egan and his colleagues, took place on an ideal farm to showcase the benefits of closing up paddocks in autumn.

The standout message highlighted by Philip Creighton of Teagasc was the huge cost savings that can be achieved by having a sufficient quantity of spring grass available for ewes and lambs in early lactation.

Philip Creighton told farmers that nitrogen should be applied once ground conditions allow.

Philip said that in a normal year with typical grass dry matter levels, good-quality spring grass is capable of meeting the high energy and protein requirements of lactating ewes. A ewe suckling two lambs will require in the region 2.4kg to 2.5kg grass dry matter daily.

1kg of early spring nitrogen has the ability to generate 10kg grass DM growth.

Applying nitrogen as soon as possible in spring will help underpin supplies, with 1kg of nitrogen capable of delivering 10kg grass dry matter. This 10kg grass DM will sustain the nutritional requirements of a ewe and her two lambs for four days. At a urea cost of 81c/kg N or a CAN cost of €1.04/kg N, this equates to a daily feed cost of 20c/day to 26c/kg.

Philip said that this is still a significant cost but it is well below the cost of having insufficient grass available and having to bridge the nutritional gap with concentrates.

The savings on a 100-ewe flock work out to be as high as greater than €60 per day.

He showed that in the worst case scenario, where no grass is available, meeting the nutritional demands with concentrates at a cost of €300/t will cost upwards of 85c/day. For a 100-ewe flock, this quadruples costs, with a saving of €60/day achievable from early spring grass. Philip said that even where the nutritional demands of lactating ewes is made up of a mixture of grass and concentrates, there are still considerable savings to be made.

The cost of failing to have sufficient grass in spring.

Early application

While most farms generally have a supply of grass available in spring, a problem that regularly occurs is ewes eating into the grass reserves before growth is capable of sustaining demand. A big contributor to this is not enough nitrogen being applied or spreading too late in spring. Philip’s advice to farmers is that they should be following three simple guidelines:

1. The first was having nitrogen available and sitting in the yard so that once ground conditions allow there will be no delay in spreading.

2. The second piece of advice was for farmers to walk closed paddocks and see what supplies of grass are available. This will allow reactive measures to be put in place well in advance.

3. The third piece of advice was to watch the weather forecast so that plans can be put in place.

The first paddocks closed in mid-October had a cover of 2,400kg DM/ha (12cm of grass).

The advice for farmers was to blanket-spread 23 units of urea as soon as possible, with another 23 units targeted for application in late March/early April. Replying to questions relating to the merits of applying compound fertilisers in place of urea, Philip advised against this and highlighted possible complications in doing so with grass tetany. His advice was to apply compound fertiliser and lime to rectify a soil fertility deficit as the season progresses, with autumn applications also having the benefit of working over the winter months.

Perfect example

The McGuinness farm provided the perfect example to showcase the advantages of closing up paddocks early in autumn. The first paddocks closed in mid-October had a cover of 2,400kg DM/ha (12cm of grass). Paddocks closed in the first 10 days of November had covers of 1,600kg DM/ha to 1,800kg DM/ha, while paddocks closed from the middle to end of November had a cover of just 150kg DM/ha to 500kg DM/ha.

Sheep specialist Ciaran Lynch echoed Philip Creighton’s advice and told farmers that it was vital that nitrogen was applied in order for those paddocks with a lower cover of grass to be in a position to sustain demand towards the end of March and early April.

Read more about Tom McGuiness’s system where 600 ewes are lambed outdoors in next week’s special lambing Focus.

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