This year’s lambing is progressing pretty well for most. There have been a few turbulent patches over the last three weeks, but a few fine days either side of heavy rainfall has allowed most farmers to overcome challenges in getting ewes and lambs outdoors and freeing up space in lambing pens.

The year to date has also been largely positive in terms of grass growth and grass supplies. Farmers who closed up paddocks last October and November capitalised on favourable autumn and winter grass growth and some have found themselves with a surplus of grass this spring. This has been helped in other cases by farmers pushing back the lambing date to be in a better position to cope with rapidly rising demand.

It is a good position to be in, particularly when you think back to the last three years and in particular to 2016, when growth rates were very poor in March and April, resulting in widespread grass shortages and poor lamb performance.

Of course, it is worth highlighting that all farms are not in a situation of abundant grass, with those on marginal lands who had difficulty getting fertiliser applied or located in more exposed areas with later growth matching grass supplies with rising demand.

Still, these farmers are in a better place than 12 months ago and, given some luck with weather over the next week, should be in prime position to set the farm up and achieve favourable performance.

Good grass supplies

As mentioned above, a high percentage of farmers reporting very strong grass supplies are those on drier lands and located in areas where growth kicks in quicker.

They are also the farms that followed a programme of rotationally closing paddocks last autumn.

Teagasc sheep specialist Ciaran Lynch says many advisers have reported grass growth rates of 25kg DM/ha to 50kg DM/ha in the last week, which is putting these farms in a very strong position.

It is also creating some challenges in managing grass, with some farmers concerned grass may get too strong to achieve high levels of lamb performance, while others have pointed to swards not being grazed before closing for silage.

When discussing management options, it is important to remember that it is still early days and a lot can change, as we have seen in previous years, in April. Therefore, the mistake must not be made of taking the foot off the pedal and reducing or cutting out fertiliser application.

Swards should continue to receive fertiliser as they are grazed or slurry applied, depending on how soon it is required to be regrazed. The rate of nitrogen applied will be dependent on the stocking rate, ranging from 10 to 15 units for lowly stocked farmers (six to eight ewes per hectare) to 20 to 25 units for farms with a higher stocking rate (10 to 12 ewes per hectare). Applying a compound fertiliser or a nitrogen/phosphorus compound will also help in low P index soils.

Managing grass

The way grass is managed will also have a big bearing on its quality. At this stage, ewes with lambs aged about three weeks or older should be batched in larger numbers.

Leaving these animals spread out over a large grazing area will make it considerably harder to manage grass. Grouping these animals will allow a rotational grazing system to be implemented.

Some farmers are also splitting or temporarily dividing larger paddocks at an earlier stage. This is being carried out particularly where ewes and lambs are grazing swards with a strong cover of grass to achieve better utilisation and grazing to a lower height (3.5cm to 4cm).

The latter is critical to promote high-quality regrowth and allow paddocks to be grazed tight in subsequent grazings. Splitting paddocks into smaller areas will also allow ewes to be forced to graze down paddocks for a short period (eight to 10 hours), before moving to fresh grass without hitting milk yield and performance.

When splitting paddocks temporarily, have the fence set up correctly at the start so that animals quickly get accustomed. This will reap the rewards of easier management thereafter, with ewes and lambs less inclined to try to breach the fence.

Some farmers use four strands of electric wire at the start, reducing to three once animals have become accustomed, while others get animals accustomed with electric sheep netting before moving on to a few strands of wire. Having good strength in the fence is also critical in this regard.

Where working on a battery fence with lower output, starting with a smaller area and shorter length of fencing may help. It is also important to check on young lambs regularly at the outset where netting is being used to ensure lambs do not get caught in the wire.

Another option is taking heavy covers of 2,000kg DM/ha and above out for silage and targeting an early cut in five to six weeks’ time.

Recommended grazing height

Table 1 details recommended post-grazing sward heights to achieve optimum lamb performance.

As can be seen, set-stocking will result in a higher accumulation of poorer-quality grass at the base of the sward and reduce utilisation.

Therefore, where at all possible, it is beneficial to introduce even a few paddocks or grazing divisions.

For farmers operating at a higher stocking rate, Table 2 details the grazing targets in the research demonstration flocks led by Philip Creighton in Teagasc Athenry.

The farm has five permanent paddocks per group and utilises a network of temporary electric fencing to subdivide each paddock into two, depending on grass supply and demand. The average length of time spent in a paddock in April, May and June is five days, with grass measuring and budgeting a key management tool.

Building grass supplies

For those who are tight on grass, the same advice should be followed in terms of applying fertiliser as detailed earlier.

A balance should be sought between offering ewes and lambs grass and providing a chance for grass supplies to build. This may include introducing meal supplementation at grass to conserve supplies and give a chance to paddocks being rested to build grass supplies and carry animals for longer.

Entering paddocks too early may provide a short reprieve, but, in the longer term, will make it difficult to get ahead of rising grass demand.

Grass measuring

Knowing the volume of grass present in a paddock and the weekly growth rate are invaluable tools for managing grass.

For example, in early lactation, a ewe’s intake is about 2.4kg DM/ha to 2.5kg DM/ha per day. This increases for a twin-suckling ewe to 3.2kg in week five and 3.4kg in week seven of lactation and eases off thereafter following peak milk yield, as demonstrated in Figure 1. However, it remains fairly static through the pre-weaning grazing period as intake from lambs rises.

Knowing the volume of grass in a field and the growth rate will allow farmers to budget grass supplies to demand. For example, if we take 10 ewes grazing with a grass demand of 2.5kg DM/ha, daily demand is 25kg DM. Take a paddock with 7cm grass height on average across a sward or 1,050kg DM/ha, there is enough grazing in theory for 42 days, or, for 50 ewes, there is just over eight days’ grazing without taking current growth into account.

Teagasc recently relaunched PastureBase Ireland, its online grassland management facility, and is encouraging more farmers to participate. Those who are interested should contact their local Teagasc adviser.

The organisation will also be holding a number of grass walks and focused grass groups under the initiative Grass10. This aims to help farmers improve grass utilisation and achieve an average of 10 grazings per paddock and growth of 10t DM/ha. It is a four-year initiative running from 2017 to 2020.

Where farmers are not in a position to participate, there are still steps that can be taken. Sheep specialist Frank Hynes and researcher Philip Creighton have developed a sward stick which is targeted at helping you to become accustomed to the height of grass in a sward. It is a simple but effective tool that is colour-coded with key information. A video explanation of the sward stick and further information can be found at www.teagasc.ie/animals/sheep/grassland.