Rotational grazing is normally something just practised on cattle farms, but it also has a role to play on sheep farms. Those implementing the principles find that moving lambs to fresh grass either once or twice per week improves lamb performance, grass utilisation and increases grass growth.

Last week, Castlederg sheep farmer Isaac Crilly hosted a farm walk as part of the AgriSearch GrassCheck programme.

The event was used to demonstrate how Isaac has implemented a rotational paddock system on a section of his 26.4ha grassland farm.

It was Isaac’s first move into a dedicated paddock system. While sheep would have rotated around fields in the past, the process was not structured.

To set up his paddock system, Isaac identified two land blocks that would suit moving sheep on a weekly basis to fresh grass.

A large crowd attended the AgriSearch event held on the Crilly farm outside Castlederg.

Set-up

Both land blocks measured 4.8ha in size. One block was divided into eight paddocks, with each one measuring 0.6ha in size. The second 4.8ha block was split into four paddocks, each measuring 1.2ha. Fields were divided using temporary electric wire.

As the paddocks were grazed by ewes and lambs, fencing consisted of four strands of electric wire to keep animals secure in each grazing area.

Rather than run four separate fencing reels, Isaac opted to use the Gallagher smart fencer system, which combines four reels of wire in one mobile unit. Each unit covers up to 100m in length.

Plastic fencing stakes are placed every 10m. Fencing costs came to £1.70/m for wire, plastic posts and reels.

Fencing is powered by battery-operated units, which cost £70 to purchase. Additional water troughs were required and located in fields so that they could serve multiple paddocks.

“Setting up the fencing takes time, but once you are finished the paddocks are in place for the rest of the year. When you get into the routine of moving sheep every few days, you become more confident in judging how long a paddock will last and when sheep need to be moved again.

“It has been a great year with the weather, which has helped, but the paddocks have worked really well and I will put more paddocks in place for next year,” said Isaac.

Battery-operated electric units power the fencing.

Stocking levels

Isaac runs 400 breeding ewes on just over 65 acres of grassland, which is a stocking rate of six ewes/acre, excluding lambs. Therefore, at such a high stocking rate every acre of ground must be productive.

Each 4.8ha (11.85 acres) grazing block carried 70 ewes and approximately 100 lambs from turnout on 9 April until weaning on 10 July.

After weaning, paddocks were primarily reserved for grazing lambs. However, ewes were added to the grazing block for brief periods to control grass quality and to clean out swards.

Rotation management

“There were periods of the summer when there would be three groups of lambs grazing on the eight-paddock block, such was the availability of grass,” said Isaac.

“The paddocks definitely allow more stock to be carried on the same size of grazing area. Resting grass is key to increasing growth, with paddocks rested for at least a fortnight in the summer between each grazing.

“We were always trying to move lambs onto the best-quality grass to maintain high levels of performance,” Isaac told visitors.

In practice, lambs in the four-paddock system were moved every five days, and on the eight-paddock block they were moved every three days. However, Isaac acknowledges that at certain times lambs were moved before fully cleaning out the grass available.

“Next year, I will look at possibly sub-dividing paddocks during the summer so that the grazing area is reduced and matches grazing demand. I think this will help to increase grass utilisation,” he said.

Fertiliser

Fertiliser use on the farm this year started with a bag of urea/acre in early spring, followed by a bag of Superstart.

From May onwards, paddocks have received a monthly application of one bag per acre of 25-5-5 or 25-0-13.

No reseeding has been carried out and no silage is made on the farm, as ewes are wintered on a straw and concentrate diet.

Slurry was applied at a rate of 1,600 gallons/acre in July, along with a tanker-load of water per acre to try and increase soil moisture levels. As part of the GrassCheck programme, Isaac measured grass weekly using a platemeter. The farm has grown 9.8t of dry matter per hectare (DM/ha) by September, with approximately 90% of this grass utilised through grazing. Most set-stocked sheep farms struggle to grow more than 4t DM/ha.

Along with grazing 400 ewes plus lambs on the 65-acre grazing block, there was a significant surplus grown on the paddocks in July once ewes were weaned.

This equated to around 48 round bales of silage, but as Isaac does not have the machinery or winter housing facilities to handle silage feeding, he chose to graze this extra grass on the paddocks with dry ewes.

Key to finishing lambs

Grass on the Crilly farm was analysed every fortnight for feed value. In July, quality dipped as grass had become harder to manage.

As a result, energy content of the swards fell to 10.5 MJ ME/kg DM. According to AFBI researcher Dr Elizabeth Earle, this will typically support growth rates of just over 100g/day in lambs.

However, grass quality improved throughout August and by September the DM energy content in grass increased to 11.2 MJ ME/kg DM, which can support daily liveweight gains of 200-300g/day in lambs.

Earle stressed the importance of grass quality in late season.

“As lambs get heavier, they require more energy to finish as their food conversion efficiency will be lower. Therefore, unless you have top-quality grazing swards, lambs will require concentrate feeding to get them finished properly in autumn,” said Earle.

Isaac’s system is based around finishing as many lambs as possible off grass, with no concentrate feeding. Ewes weaned 1.7 lambs/ewe this year, with lambs averaging a daily liveweight gain of 290g/day from birth to weaning. The first draft of fat lambs was in June, with lambs producing carcase weights of just over 17kg at fat class three. Carcase weights have since increased to around 19.5-20kg.

“The first lambs were sold in June at 17kg and were worth £120/head. Lambs sold now at 20kg are worth £80/head. There is no point in keeping lambs to try and get heavier carcase weights if they are at the right fat cover. Lambs are sold as soon as they are covered on this farm. This eases demand for grazing,” said Isaac.

Farm facts

  • Farm size – 26.4ha grassland (65 acres).
  • Stock details – 400 breeding ewes, including replacements.
  • Lambs slaughtered at 19.5kg to 20kg carcase weight.
  • Average scanning rate – 1.9 lambs/ewe.
  • Average weaning rate – 1.78 lambs/ewe.
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