When considering strategies to finish lambs during autumn, grazed grass is the low-cost option. In order to maximise average daily gain (ADG), adequate supplies of high-quality grass must be offered.
Therefore, it is important that good grassland management is practiced, otherwise ADG could be disappointingly low.
According to previous Teagasc research, the expected ADG from good-quality late-autumn grass alone ranges from 70g/day to 115g/day.
At this stage of the year, the demand for grass from the breeding-ewe flock must be prioritised.
Therefore, it may be an option now to start feeding concentrates to lambs as a supplement to grass or even consider finishing lambs indoors on a high-concentrate diet.
Supplementation at grass
Concentrate supplementation of autumn grass has been shown to increase the ADG of lambs.
Teagasc research indicates that, supplementing late-autumn grass with 250g/head/day of concentrates is expected to increase ADG to an estimated 186g/day compared to grass only.
Furthermore, increasing concentrate supplementation of autumn grass to 500g/head/day has been shown to achieve an estimated ADG of 227g/day.
The ADG response to offering supplementary concentrates with late-autumn grass will depend on grass quality and supply.
Finishing indoors
An alternative option is to finish lambs indoors. The diet offered during indoor finishing generally consists of ad-lib concentrates in combination with high-quality forages.
Finishing lambs indoors on a high concentrate diet can generate relatively high animal performance.
According to Teagasc research, the expected ADG generally ranges from 250g/day to 300g/day for lambs offered ad-lib concentrates.
When considering a suitable concentrate for finishing lambs indoors, it is important to focus on the ingredients. The concentrate should contain relatively high-energy ingredients such as barley, wheat, maize and beet pulp.
Soyabean meal is an excellent protein source, but is relatively expensive. Therefore, it should be limited in its inclusion rate in the concentrate of choice; as this will only increase the cost of the diet offered.
As a precaution, particularly when finishing ram lambs on an ad-lib concentrate diet, ensure that ammonium chloride is included in the concentrate to help prevent against urinary calculi.
Cost of production
Feeding concentrates is expensive and requires high levels of animal performance in order to be justifiable.
For example, assuming a concentrate price of €280/t and an estimated average concentrate intake of 1,400g/head/day, lambs, on average, would require an ADG of 220g/day, a kill-out of 40% and a base price of €4.50/kg to break even.