Grass Silage Quality – Think Ahead!

As milking cows are now indoors and rations are being fine-tuned, our minds turn to grass silage quality which is normally the greatest variable in a winter ration.  It also has the greatest effect on potential forage intakes, protein costs and ultimately milk yields.

Ironically, some of the best silage analysis we see comes from spring-calving dairy herds.  Why is this?

  • Grass silage is treated as a surplus from the milking platform and as such is generally cut younger than crops grown specifically for silage.
  • Most silage paddocks will have been grazed at least once before cutting.  This means the crop is 100% spring growth, with no dead or decayed material from the winter.
  • Fields that have been grazed for at least part of the season will generally have better soil health, meaning the plant gets more of what it needs to build protein and sugars.
  • Good white clover content.  White clover generally prefers a grazing situation with shorter intervals than a 3 or 4 cut system.

Obviously, this can’t be replicated in all situations, but what can we learn from this and apply to silage-only grass leys?

  • Clean out the old growth.  This is particularly relevant with the current warm, wet conditions which may leave high covers.  Grazing with youngstock or sheep (yes, the white lice) is a useful tool BUT aim to graze late in winter or early in spring after winter dormancy, so that the grazing stimulates growth.  This way no silage yield will be lost, and letting light to the base of the sward will increase density.  Grazing early in winter will lead to cold soil and slow spring growth.
  • Sward diversity – monocultures will have a shorter optimum harvest window.  Clovers in particular help maintain quality for a longer window and of course improve the quality of later cuts. 
  • Get some grazing animals on at some point in the season.  Not always possible, but investment in fencing and water to enable silage and grazing fields to be alternated will reap long -term rewards.

A  drop of 0.5ME in grass silage energy alone fed to a 250 Cow AYR milking herd for 180 days at 60% of the diet will cause a drop in silage intake and energy intake resulting in lost milk income of at least £21k, at 35ppl milk price

Are you happy with your five year average silage quality?  Is there room to improve?  

Contact Tom at or Tel:07496
760242, to review your silage production from soil to mouth.