Lambs thrive on stubble turnips
By Jonathan Long
GRAZING STUBBLE turnips this summer could help producers maximise lamb performance and save on feed costs, but to take advantage crops need sowing soon.
Independent sheep consultant Lesley Stubbings says summer stubble turnips are an undervalued opportunity, with some varieties able to yield as much as 10t/ha of dry matter.
“With seed costs of just 13-15/ha and minimal fertiliser requirements of about 88 units/ha of nitrogen, establishment and growing costs are low. Using farmyard manure as a source of nutrients could cut costs further.”
Although fertiliser demands will depend on previous cropping and residual soil nutrients, turnips sown into grassland destined for arable crops this autumn should benefit from reasonable residual nutrient levels.
Crops should be sown in mid to late April and will be ready to graze about 10-12 weeks later, says Ms Stubbings. “And once crops are established stubble turnips are relatively easy to grow, as they are reasonably drought resistant.
“Turnips ready for grazing in July will be just in time for many flocks to wean lambs on to. Lambs grazing turnips will probably gain about 150g a day and in most cases you”ll get at least 3000 lamb days a hectare.
“Lambs weaned in mid-July weighing between 32kg and 35kg should gain about 1kg a week, so most should be finished by mid-September. Even relatively lightweight lambs should finish off turnips over summer,” she reckons.
On the financial side, Ms Stubbings says up-to-date costings are few and far between, but she believes the value of the liveweight gain is more than 400/ha, while variable costs are less than 100/ha.
“Another benefit is the reduced demand on grazing over summer months meaning there should be more grass to flush ewes on in autumn. Additionally, it avoids worm problems.
“Lambs should be drenched before being turned on to turnips to clear out any problems, but after that it will be unnecessary to treat them, as there won”t be any worms present on turnips,” she says.
SUMMER TURNIPS
* Avoid worm problems
* 1kg/week gain
* Ideal for weaned lambs
* Sow mid-April
