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Pre-graze mowing is a technique sometimes used to manage surplus pasture. However, research shows it doesn't increase cow intake or performance, and actually reduces pasture performance. It decreases the amount of pasture available for silage and increases the need for imported feed. A recent experiment showed that there was no advantage to pre-graze mowing in terms of milk production or cow condition. It resulted in less dense pastures, reduced silage conservation, and increased silage feeding to maintain cow intakes. While pre-graze mowing can be used as a tactical tool, research suggests post-graze topping may be a better option.
Mowing before grazing (pre-graze mowing) is a management strategy sometimes used to achieve target pasture residuals when there is a surplus of pasture.
Collectively, research results indicate that compared with good pasture management, pre-graze mowing during spring:
Key results from a recent research experiment conducted at Lincoln University Research Dairy Farm (LURDF) are outlined below.
An experiment with four treatments (two farmlets per treatment) was carried out at Lincoln Farm for four months (October 2016 – February 2017). Stocking rate was 3.5 cows/ha.
If target residuals are not met during spring, then mowing before grazing or topping after cows have left the paddock can be used as a tactical tool to meet target residuals. This will increase pasture quality in the following round, particularly in regions exposed to summer dry.
However, research indicates that post-graze topping is preferable to pre-graze mowing from a cow and pasture perspective. Cows can select higher quality feed, as smaller leaves (e.g. clover, new tillers) do not fall below the grazing horizon. It is also easier to identify a surplus if cows graze pastures first. Pasture wastage occurs with both post-graze topping and pre-graze mowing.