fits Irish bill
Self-service winter grazing
fits Irish bill
Extended grazing is cutting
production costs and raising
profits on one Irish sheep
unit. Sean Flanagan,
researcher at the unit,
run by advisory service
Teagasc, explains why the
efforts of assessing grass
supplies and moving fences
daily can be justified
GRAZED grass as a substitute for silage and housing is being used as the sole diet during December and January for a 200 March-lambing ewe flock at Knockbeg, Carlow.
The mainly Belclare x Cheviots, stocked at 14.6/ha (6/acre), achieve 400kg/ha carcass output and gross margins of almost £64 a ewe and £893/ha (£361/acre).
The basis of the system is to close a suitable area of pasture in autumn, reserve it for winter grazing and ration it out. On the Teagasc unit 4.3ha (10.6 acres) of pasture was closed and grass allowed to accumulate. An allowance of 1.3kg DM a ewe a day is allocated by block grazing using portable electric fencing. Ewes are then housed five to six weeks before lambing and fed silage plus concentrate supplements.
For spring lambing ewes, December and January coincide with mid-pregnancy, when feeding can be restricted to a level sufficient to maintain ewe bodyweight only.
It is not until late pregnancy that foetal growth becomes significant. For a 70kg ewe in good body condition, a daily intake of 0.8kg DM of good quality grass will maintain bodyweight in mid-pregnancy. Because the rate of grass utilisation is only 65%, a daily allowance of 1.3kg DM is allocated.
To manage grass in this way, the supply must be estimated. Pasture supply in early December 1997 on the autumn saved area amounted to 2300kg DM/ha, as estimated by taking clips to ground level. To provide a daily allowance of 1.3kg DM a ewe, the 4.3ha area was block grazed at a rate of 1 ewe/6sq m a day. That means that on a whole flock basis at Knockbeg, the 200 ewes were allocated a pasture area of 100m x 12m (328ft x 39ft) each day.
The trial is not complete, but work in 1994 and 1995 showed that a pasture supply similar to the above and rationed as described maintained 40 ewes a hectare for 44 days from Dec 8 to Jan 21. Liveweight changes over this time were negligible.
A back fence is used to prevent access to previously grazed ground, thereby protecting grass recovery. In this way poaching is minimised and immediate grass regrowth facilitated because it is grazed for one day only.
So, is extended grazing justifiable? Results to date can be interpreted to suit individual farms.
Housing 200 ewes for 90 days from December to March at Knockbeg requires 120t of silage at a production cost of £1500; 1000 small bales of straw costing £750; and 1.5 man hours a day for feeding, bedding and attention. The standard wage for hired labour is £5.53/hour plus overtime at weekends, giving a wage bill of £750 for 135 man hours. These input costs amount to £3000.
Last six weeks
Use of extended grazing to reduce this housing period to the last six weeks or so pre-lambing cuts the costs by about a half, saving £1500. Costs of fencing and labour for managing extended grazing must be charged against this saving. For a 100m (328ft) wide paddock, 100m of portable electric fencing at both front and rear are required – 200m at a cost of £240.
Time required for moving fences and for inspecting the flock is 0.3 man hours a day for 45 days. The bill for hired labour in this case is £94. Thus, the net saving is £1500 less £240, less £94 – £1166 for 200 ewes or £5.83 a ewe.
On some farms the opportunity cost of the farmers own labour may be much lower than shown here, so the value for man hours should be adjusted accordingly.
So extended grazing offers the chance for significant savings in the costs of flock management during winter, nearly £6 a ewe on this unit. The workload is reduced because the ewes feed themselves. Labour tied up with bedding down ewes in straw bedded sheds is released.
Tractor transport and equipment for trough feeding silage daily are also released. Accumulation of manure in the shed is reduced by a half and, as a result, so is mucking out.
Estimating the amount of grass available is down to skill in "eye-balling" pastures. The starting point is to get a minds-eye picture of what 1000, 2000, 3000kg DM a hectare look like as benchmarks. Between these, intermediate yields can be estimated.
Grass height gives a good indication of the amount of grass and is measured with a sward stick or plate metre. Alternatively, cutting, weighing and drying samples in a microwave oven will further develop estimation skills. Farm visits where grass supply benchmarks are demonstrated should not be missed.
Extended grazing
• Ewes feed themselves.
• Costs cut by nearly £6 a ewe.
• Workload for 200 ewes reduced from 1.5 to 0.3 man hours a day.
• Reduced housing means less manure and mucking out.
• Free draining soil required.
• Willingness to assess grass supply and to ration it.
Sean Flanagan…extended grazing for sheep offers significant cost savings.
EXTENDED GRAZING
• Ewes feed themselves.
• Costs cut by nearly £6 a ewe.
• Workload for 200 ewes reduced from 1.5 to 0.3 man hours a day.
• Reduced housing means less manure and mucking out.
• Free draining soil required.
• Willingness to assess grass supply and to ration it needed.
A daily allowance of 1.3kg grass DMa ewe is allocated by block grazing on a daily basis using portable electric fencing. Bank fencing limits poaching.