The post first cut forage gap

Published 26 March 15

If you graze some of the first cut aftermath it’s common to experience a forage gap, says DairyCo technical extension officer Piers Badnell. This happens when you have cut all your first cut, and it will be few weeks before regrowth allows grazing of this area. Cows are out, and the grazing demand is higher than the supply, and for a short window you have a grass shortfall.

One solution to this limited period of short supply is to cut about 15% of your first cult silage 10 days earlier than you take the rest of the cut. The extra time for regrowth means you have an area ready for grazing before the main bulk of first cut ground. A pre-cutting grass analysis at this stage will help you decide if nitrogen levels are too high, or whether enough nitrogen has been used up.  

It is important to avoid the temptation to send the cows in to the aftermath “to clear up behind the forager”. If you do this the cows graze the new regrowth, slowing regrowth by up to two weeks. The plant has created a store of water soluble carbohydrates (WSC) in the base of the plant while it has been growing. This is there to power the emergence of the plant’s first leaf, which then starts photosynthesising and the regrowth of the second and third leaf.

If cows eat that first leaf, the WSC has been used up to grow it, and the plant has to depend on photosynthesis of the green on the stem to kick start growth. The stem has a much smaller area than the first leaf, meaning regrowth is considerably slowed down, reducing the plants potential yield for the year. Never graze the grass plant before two leaves have emerged. After this stage the plant and its root have been able to recover from previous grazing and cutting, and will be in a position to be able to regrow well from a subsequent cutting or grazing.