Farm Table says:
Management in short-term flushed ewes
What is the problem?
Flushing on lucerne pasture has been recommended as a means of increasing the number of lambs born, but there has been a concern in the sheep industry that grazing lucerne during joining causes embryo mortality.
What did the research involve?
MLA funded two studies which aimed to determine whether the quantity of lucerne consumed altered fetal numbers and whether removal of ewes from lucerne during early pregnancy would increase or decrease fetal numbers.
What were the key findings?
- Artificially inseminated ewes are best fed at maintenance levels after insemination to maximise foetal numbers
- Grazing naturally cycling ewes on leafy lucerne pasture for 7 days before joining and the first 7 days of an autumn joining can produce large increases in twinning rates and the number of lambs born. The level of response will vary with the quality and quantity of Lucerne
- Naturally cycling ewes can remain on lucerne throughout joining without risking a reduction in foetal numbers, but there may be no increase in foetal numbers if most ewes mate and fall pregnant in the first 14 days of joining. This means that if there is a limited quantity of lucerne, ewes can be removed from Lucerne at day 7 of joining while still gaining an increase in the number of foetuses
- Avoid grazing lucerne heavily infected with fungus or aphids – this is known to reduce ovulation rates in ewes
- Higher twinning rates result from flushing – producers need to appropriately manage the higher nutritional needs of twin-bearing ewes and twin-born lambs, and lamb survival, to gain the most benefit from flushing ewes
By giving more attention to nutritional management on ewes either artificially or naturally cycling will determine a farmer’s success rate in productivity. By following this study, embryo mortality rate is ensured for success.