This new research finding is in contrast with the traditional belief that diets high in protein or nitrogen and energy could lead to embryo mortality.
Results from a recent MLA-funded project show flushing naturally cycling Merino ewes by grazing lucerne pasture seven days before joining and for the first seven days of joining lifted the number of lambs marked by 19%.
Researcher Dr Susan Robertson, of the Graham Centre for Agricultural Innovation, Wagga Wagga, NSW, said the study was prompted by industry concern regarding the potential fertility impact of grazing of ewes on lucerne prior to joining.
“We have been advocating for flushing with lucerne as it is cheaper than feeding lupins and it appears to have a better, more consistent response but we wanted to confirm these results and whether grazing lucerne throughout joining would have an impact on embryo mortality, “ Susan said.
In the grazing trial, lamb marking percentages increased from 96% to 115% when the ewes grazed lucerne for seven days before joining and to day seven of joining, compared with grazing dead annual pasture.
The results also showed ewes could graze lucerne throughout joining without any reduction in fertility or lambs marked (114%).
Management recommendations from the research include:
“The optimal nutritional management can be expected to vary in artificial situations, but we recommend producers with AI ewes only graze lucerne at maintenance levels,” Susan said.
Further research is required to evaluate different feeding strategies for both AI ewes and naturally cycling ewes.
Source: Meat & Livestock Australia