Management of ewes and lambs post turnout - grouping up to kick-start rotational grazing

Damian Costello and Philip Creighton, Teagasc Animal & Grassland Research & Innovation Programme, Mellows Centre, Athenry, offer practical advice on managing spring grass on sheep farms.

The lambing of mid-season flocks is now well underway and is nearing completion on many farms. The strategic closing up of paddocks last autumn largely determined the grass supply available to ewes and lambs at turnout.

The ultimate goal is turning out ewes and lambs to grass covers that will meet their feed requirements with little or no concentrate supplementation. This makes a lot a sense not just from an economic and management point of view but also saves on the labour of feeding meal to the various groups at grass. There are of course cases where some supplementary meal feeding will be appropriate - where grass supply is inadequate or where growth is poor and you need to slow down the rate at which ewes are getting through the grass available.

Group up ewes and lambs to appropriate size grazing groups

On farms operating a rotational grazing system the aim should be to group up most ewes and lambs into larger grazing groups as quickly as is practical, usually about two weeks post turnout. It’s a good idea to keep an “ICU” type paddock, ideally close to the farmyard, for the group of ewes and lambs that have had issues and require close observation and/or further treatment. A number of factors determine the optimum grazing group size at farm level, these include:

• Number of grazing divisions available, need minimum of 5 per grazing group
• Average size of paddocks and is there an option to sub-divide with temporary fencing
• Maximum group size of ewes with their lambs the sheep handling unit accommodates
• Overall flock size
• Farm all in one block vs fragmented holding

How it works – a practical example

Take a simple example of a 10ha grazing block divided into 5 permanent divisions of about 2ha each. The farm successfully carries 10 ewes/ha, so 100 ewes and their lambs is the planned grazing group size for this block up to weaning. Lambing date is early March with lambs turned out to grass 2 to 3 days later, weather permitting of course.

Paddock 1 was closed first in mid-October and will be grazed first, paddock 2 closed late October and so on. When weather conditions allow, turnout of ewes and lambs to paddock 1 begins and continues until reaching 50 ewes and their lambs. The next 50 ewes and lambs are gradually turned out to paddock 2.

For a farm stocked at 10 ewes/ha, the target average farm cover in early March would be 650kg DM/ha. On the Teagasc Research Demonstration farm in Athenry paddocks closed in mid-October had covers in the region of 1,100-1,200kg DM/ha (7-7.5cm) when measured in early March. Assuming the 2ha plot in our example had a cover of 1,100kg DM/ha and the daily requirement per ewe in early lactation is 2.5k grass DM per day, then our 50 ewes will get 16 to 17 days grazing here. This group can be then either be moved to paddock 3 or joined with the group in paddock 2 to finish grazing it out. Both groups join in paddock 3 forming their permanent grazing group.

In summary the key targets for an early March lambing flock are:

• Aim to stretch end of first rotation to mid-April (40 days) when hopefully growth will be matching demand;
• 20% (paddock 1 in our example) to be grazed, fertilised and re-growing by mid-March;
• 40% (paddocks 1 & 2 in example) to be grazed, fertilised and re-growing by end of March;
• From end of March, full grazing group (100 ewes and lambs) grazing paddock 3 and moving on to paddocks 4 and 5 subsequently;
• Mid-April first rotation complete and sheep return to paddock 1 (having had a month to regrow) to commence second rotation, ideally divided in two with temporary electric fence.

Troubleshooting spring grass supply issues on a sheep farm

The following are among the points to consider in reviewing the spring grass supply on your sheep farm:

• Low grass covers at turnout point to issues like the lack of an autumn closing plan, delay in winter housing of ewes, sub-optimal soil fertility and/or no early N applied;
• Adequate covers at turnout but running short of grass a month later can be the result of turning out smaller number of ewes and lambs to all paddocks with the entire grazing area being grazed together with little opportunity for grass regrowth. In this situation it is also worth considering if your lambing date should be pushed back to better tie in with when growth normally starts on the farm;
• Among the many benefits of using PastureBase to record regular grass measurements for your farm is that the information can be used to determine the appropriate stocking rate and lambing date for the farm. It also provides an accurate picture of the farm grass covers throughout the year allowing for more informed decision making.

Also read: Preventing grass tetany post turnout