Sheep technical workshop – Planning winter feed options and setting up grazing rotations for the spring

IMG_1994AHDB Beef & Lamb recently hosted Phil Creighton from Teagasc, Ireland’s agricultural and food research, advisory and training body, to run a series of five on-farm events with AHDB’s Liz Genever.

The objective of the meeting was to ensure this season did not have wider impacts on the next season. The risk this year is due to lower grass growth rates and winter forage supplies, sheep farmers will be grazing fields harder this autumn. One of the key message from the events was to shut up proportions of the farm to ensure grass is available in the spring where feed requirements for lactating ewes are higher.

 Phil’s argument is that autumn closing date, closing cover, spring nitrogen application and spring grazing management is all in the control of the farmer. The farmer has some control of winter grass growth rates by managing the closing cover (i.e. not scalping the grass so there is leaf there to fix sunlight) and optimising soil fertility (pH, phosphate and potash).

 

The following closing plan has been developed by Teagasc for sheep systems, similar to the autumn grazing plans that have been used in the dairy industry for a while. It is based on the fact that grass needs around 120 days of rest to ensure it builds up around 600 kg DM/ha of cover (at an average of 5 kg DM/ha growth per day over the winter). This means if the field is shut up at around 1,200 kg DM/ha (around 3 cm) it will be around 1,800 kg DM/ha (around 6 cm) in the spring ready for lactating ewes.  Table 1 shows what should have happened so far and will help you assess if you are on track.

Table 1: Teagasc’s closing plan for March lambing systems starts in late October until mid-December

Event Report 1

 

If the grass is shorter, more time is needed, and vice versa. If lambing is later, then closing dates can be moved later. The remaining 20% is where the sheep are grazed until housing, moved on to forage crops or feed-out on a sacrifice area.

Another key message from the events was supplementing ewes in mid pregnancy to ensure enough grass for lambing will save costs in the long run as their requirements are lower. During mid pregnancy, ewes’ energy and protein requirements are around maintenance, while supplementing at lambing when ewes’ energy and protein requirements are two to three times higher will increase the cost as both quality and quantity will need to be higher.

The importance of spring fertiliser applications of around 30 kg nitrogen (N) per ha was also highlighted, with the target of early to mid-February for March lambing systems, depending on ground conditions. This will help to drive growth in fields during February and March, with response rate increasing as soil temperatures warm, for example 5-10 kg DM per kg N applied. Buying nitrogen to drive grass growth in the spring will be cheaper than feeding out silage or hay and buying in supplements, by around a factor of three.