EWES flushed with lucerne have up to 22per cent higher ovulation rates than those grazing on dormant grass pasture.
That is the findings of a study conducted in-part by Jim Meckiff of NSW Department Industry and Investment (DII) and his co-authors, who examined the ovulation rates of 400 ewes in southern NSW between 2006 and 2009.
Ewes flushed with lucerne were also found to produce 40 per cent extra lambs due to the increased number of twins, according to the study founded by Future Farm Industries sheep CRC.
DII advisory officer Jim Meckiff said the research echoed his belief that nutritional management of ewes was the key to achieving higher conception rates.
“The access to green feed stimulates follicle development so more ova are released at ovulation increasing the chance of conceiving twins,” Mr Meckiff said.
“This allows most of the flock to complete one oestrus cycle whilst grazing the high quality pasture and increase the chances of multiple ovulations.”
The study identified the highest ovulation rates occurred when ewes had access to Lucerne pastures one week before joining and then joined for another week on the lucerne prior to be moved off the best quality pasture.
Levels of little as 900 kilograms a hectare of dry matter were found to stimulate ovulation rates.
A similar demonstration at Bookham in 2009 backed the EverGraze results, achieving a conception rate of 164pc in mixed age Merino ewes that grazed Lucerne during joining compared standard practice of joining on dormant annual pasture where ewes conceived.
While Mr Meckiff stands by lucerne flushing, he said producers needed to be aware that it was not without problems.
“It is important to restrict access of joined ewes to lush lucerne pasture after the flushing period,” Mr Meckiff said.
“Anecdotal evidence suggests a risk that joined ewes remaining on a lush lucerne pasture can loose the pregnancy."
He said the problem occurred because progesterone – a hormone which maintains pregnancy- falls below critical levels.
To combat this problem, he said, once joining has started the lucerne paddocks should be below 10 centimetres and ewes should not run on lucerne for more than the oestrus cycle (15-20 days).
As an example of how to decrease the digestibility of lucerne, producers should graze lucerne after it flowered.
Mr Meckiff said he still found it hard to believe that at this time of year there was still “lush stands” of lucerne being under utilised.
“The economics still needs to be done on flushing ewes versus finishing off lambs because if you’re getting 4.50 kilogram it might be worth prioritising grazing access.”