We’re off to a fine start, so don’t spoil it with bad quality pasture
knowing the desired pre-grazing yield that is required by the cows for each week.
The pre-grazing cover can be calculated as shown below and is often referred to as the “trigger level” as any pasture with a cover greater than this amount is presenting a surplus above the herds feed demand.
Target pre-grazing cover = (stocking rate x intake of pas- ture x rotation length) + residual cover
For example, four cows/ha x 17kg DM grass/cow (-1kg ration/cow) x 20days + 50kgDM/ha = 1,410kg DM/ha
This target, alongside the residual cover target, should be used with the feed wedge to help you identify both immediate and upcoming surpluses and deficits throughout the main grazing season (April– August).The graph (left) identifies the surpluses and deficits for the pre-grazing target calculated above.
In this example, there is an immediate surplus with the paddock covers in excess of the pre-grazing target and also a potential surplus in about two weeks' time. To manage such a surplus there are three management options to consider;
Accumulate a surplus on a small area to be conserved as pit silage/bales (long-term silage)
Surplus on a small area to be conserved immediately, often as bales (short-term silage)
Remove a small area of pasture and reseed or sow a crop that can be eaten after the period of surplus
All three options aim to prevent the immediate surplus manifesting into a surplus all over the farm and an overall loss of quality. After such a good start to the year, it would be a shame to compromise the cow at such a critical stage of her lactation. So walk the farm, create your feed wedge and act on the information accordingly.