Artificially rearing: Costs can quickly escalate in lambs reared artificially if volumes of milk replacer fed are not kept in check and weaning dates are delayed. The optimum rearing process was discussed in a recent Teagasc OviCast sheep podcast. Michael Gottstein stressed the importance of taking steps to reduce the volume of milk replacer lambs are consuming and wean lambs in a timely fashion.
This includes reducing the temperature of milk offered to lambs from 28°C to 30°C back to 18°C to 20°C after 10 days and to reduce this to the environmental temperature (cold water from a tap) after 21 days.
Where there are a couple of batches of lambs drinking from a feeder, the first reduction in temperature can be secured by running the pipe supplying the older batch of lambs through a bucket of water.
Concentrates and hay / straw or silage should be introduced during this stage, with small volumes offered to encourage higher intakes via fresh feed.
The benefit of moving lambs to cold milk is that it will encourage a higher intake of concentrates and limit milk intake to somewhere in the region of 400g daily over the last two week period. Any lambs that are maintained on warm milk will consume 600g or more of milk powder.
This will result in the budgeted allocation of 13kg of milk powder, which will end up costing approximately €40 – potentially jumping up to a cost of €60-€70 on milk replacer. It is especially important to keep these costs in check this season given higher milk replacer prices and the escalation in concentrate costs.
It will also prevent lambs gorging on milk and should limit bloat issues. Weaning should take place at about five weeks of age, and at this stage lambs should be consuming at least 250g of concentrates on three consecutive days and weigh at least 9kg liveweight.
It is critical that lambs have access to water even if intakes are initially low. A tip from Michael is to offer lambs water from a trough where ewes are drinking from if convenient, as the saliva from ewes will contain beneficial bacteria which will aid rumen development in lambs.
Grass management: While recent rainfall may help to lift growth rates, the forecast is such that there is no significant jump in grass growth expected. Grass reserves are running tight on many farms and steps may need to be taken to slow down the rotation and ration existing supplies until growth lifts sufficiently to meet demand.
Concentrates are expensive but offering 0.5kg per head to ewes in early lactation will help reduce grass demand slightly, and will ensure that ewes are not compromised in reaching peak milk yield. To reduce grass demand by 40% to 50% requires feeding in the region of 0.8kg to 1.2kg of concentrates, so the ultimate aim must be to do what you can to boost grass growth rates.
Fertiliser applied to boost grass growth represents a significantly lower cost per kilo of dry matter intake than concentrates, while other steps can also be taken to promote growth. These include batching ewes and lambs into larger grazing groups to aid recovery times, and applying lime in soils with a pH, phosphorus or potassium deficit.