After a slow start to store lamb sales, demand has picked up in recent weeks. Demand in the west is being driven by positive grass supplies and while a sluggish factory trade is keeping a lid on price, numbers are moving more freely.

In the east and southeast, demand is being helped by buyers purchasing lambs for grazing on an increased area of forage crops.

Mart managers report many repeat buyers starting to buy longer-keep lambs with the best returns in recent years achieved from farmers trading lambs in spring.

For many, this system will not be a runner with the logistics of purchasing based on short-keep lambs grazing surplus grass and finished in a six- to eight-week period.

Whatever enterprise you are operating, the decision on purchasing store lambs should not be solely dictated by having a surplus of grass.

Economics need to be taken into account and the best way of doing this is to complete a finishing budget.

Variables will differ between farms but an aspect that should remain constant is using realistic costs and levels of animal performance.

Purchase weight and price

Weight, price and quality of lambs should all be taken into consideration.

The first factor to determine is what type of lamb suits your system best.

If grass supplies are limited, then you should be in the market for a short-keep store lamb weighing 38kg to 40kg upwards.

These 11 Charollais cross wether store lambs weighing 37.6kg sold for €79 at the latest sale in Mountbellew.

The mistake is often made of having a figure in your head of what you are willing to spend with weight and quality of lambs compromised to achieve a target purchase price.

Letting this happen can be the costliest mistake as purchasing a lighter lamb than suits your system, or what grass supplies can realistically cater for, can lead to high levels of supplementary feeding introduced to finish lambs with costs soaring quickly, especially given the spike in concentrate prices in recent months.

As a rough guide, a sward with grass height of 8cm to 9cm should provide grazing for 10 lambs per hectare (four per acre) for 10 weeks, while a lower sward height of 6cm to 7cm will provide grazing for seven lambs per hectare (about three lambs per acre) for 10 weeks.

This is based on a good-quality sward where there is not a butt of poor quality or high proportion of stem at the base of the sward and reasonable levels of grass utilisation (70% to 80%) are achieved.

While many don’t factor a grass cost into finishing budgets, a ball park figure of 5c to 10c per day for lambs can be used to calculate grass costs. This may also be available in the case of a short-term or temporary grazing agreement which many farmers opt for to take the risk out of a short-term finishing enterprise. Demand for grass is currently pretty strong in such a system.

Realistic performance

Performance will be greatly influenced by sward quality and potential of the lambs you purchase.

A good performance target for lambs on good-quality leafy grass in September with good weather and positive levels of utilisation is 170g to 200g per head per day.

Depending on previous management, lambs short of flesh may achieve compensatory growth for a period, while lambs that have been very poorly managed with their growth stunted will take a few weeks to start performing.

A small volume of concentrates may be beneficial in underpinning performance and keeping lambs on track.

When selecting lambs to purchase, avoid competing for lambs where there is a wide range in weight.

While the purchase price may look appealing, it will be the lighter lambs that will end up running into higher costs than expected. The exception to this is where there is scope to carry lambs for the longer term and it is seen as feasible to draft those coming fit for slaughter regularly.

Performance reduces as the season progresses in line with a drop in nutritional quality of grass and often diminishing levels of grass utilisation.

Daily liveweight gain is tested most in periods of poor weather

Performance targets on a grass-only diet should be eased back to between 150g/day and 170g/day as you progress into late September, with performance dropping to 100g/day into late October and November.

Daily liveweight gain is tested most in periods of poor weather. Thereafter, performance can be highly variable.

Unless you have a good run of dry ground or access to forage crops, it is realistic to factor some level of concentrate supplementation for lambs that will not be finished this side of Christmas. This is especially the case for lighter mountain or hill lambs.

These finishing systems are discussed in detail here.

Table 1 looks at the costs accumulating from varying concentrate supplementation levels based on purchasing a simple barley-based three- or four-way ration with minerals and costing €280/t loose or in half-tonne bags.

Costs will increase significantly where purchasing concentrates in 25kg bags. The table looks at supplementing for 10 and 12 weeks to show what costs can run into but if supplementation is required at higher levels for this length, letting lambs develop a frame at grass and indoor ad-lib finishing systems may be more economical.

Miscellaneous costs

While concentrate costs can increase quickly, so too can miscellaneous costs.

A reasonable figure to factor into account is €7 to €8 per head. This includes a cost for mortality, veterinary, transport and other costs such as purchase and sale costs which can range from €1.80 to €3 depending on the final destination of the sheep.

Shearing will add another 70c to €1.50 to costs when the value of wool and a contractor cost is factored into consideration. Where lambs will be retained in the longer term and could be finished on forage crops, crutching will help in keeping lambs clean and reducing the risk of falling foul of the clean livestock policy.

The important health costs that should be factored into the budget are clostridial disease vaccine, worm and possibly fluke treatment, dipping or treatment for external parasites and footbathing. As is the case when bringing any animals on to the farm, it is important to operate a quarantine procedure.

In short

  • Target purchasing lambs that suit grass supplies/target finishing date.
  • Take realistic levels of animal performance.
  • Meal bills can accumulate quickly at high feeding rates or long feeding periods.
  • Factor miscellaneous costs into the equation.
  • Where budgets are questionable, weigh up alternatives such as temporary grazing agreements.
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