18 Oct 2018
Best use of grass for finishing lambs
Grass can be used for all batches of lambs but needs careful management to ensure quality and quantity is maintained.
This is the advice from Eblex’s Liz Genever, who says sheep producers should also be aware weaned lambs can readily eat into the reserves kept for flushing and over-wintering ewes, which may affect ewe performance and bought-in feed requirements.
She says: “Some monitoring of the grass is required to optimise the performance of the stock and the grass. Sward heights are the simplest way.” (See table).
“Grazing pasture at the right height ensures the lambs are eating high-quality grass. The leaf is the most nutritious part of a plant, so maximising the leaf and minimising the amount of stem in each bite increases the nutritional quality of the diet and lamb performance.”
Dr Genever adds white clover in pastures can increase the rate of lamb liveweight gain from weaning to slaughter by 25 per cent and counter the summer dip in grass growth and quality. “Good grazing management in spring is key to achieving good clover levels from midsummer onwards.
“Using a group of weaned lambs is a good way to start rotational grazing systems, as it is simpler to manage a group of animals of similar weight and feed requirements. Give them the priority in terms of feed quality, moving them through each paddock first, so they are able to select the best bits.”
Optimal sward heights
| Weaned finishing lambs | ||
|---|---|---|
| Rotational grazing | Pre-graze (cm) | 10-12 |
| Post-graze (cm) | 5-7 | |
| Set stocking (cm) | - | 6-8 |
Using kg dry matter per hectare to allocate groups of lambs to paddocks
- Remember finishing lambs should be allocated 4 per cent of their bodyweight (1.2kg DM per day for one 30kg lamb)
- So 200 lambs (average weight of 30kg) would have a daily demand of 240kg DM per day
- The target residual for grazing lambs would be 1,600-1,700kg DM/ha, as they want to select the best bits as they move through the rotation
- This is why it is important to have a second class or ‘followers’, such as replacement ewes or cows and calves, being used to tidy up behind them
- It is worth considering the rotation length at this time of year as growth is dropping– if the pastures need to gain 400kg DM/ha before the animals return and if grass growth is 20kg DM/day then there needs to be 20 days before the animals return (400/20 = 20)
Farmers Guardian and FarmersGuardian.com are trademarks of Farmers Guardian Ltd, a subsidiary of AgriBriefing Ltd.
All material published on FGInsight.com and FarmersGuardian.com is copyrighted © 2018 by AgriBriefing Limited. All rights reserved.
