Other forage silages

There are many reasons why you might decide to incorporate conserved forages other than grass and maize silage into your feeding system, says Chris Coxon, DairyCo extension officer.

"In the current season we're experiencing the farm growing a small range of crops, i.e. grass/ grass silage/maize silage/wholecrop/crimp or a combination of these may be more able to cope with the challenges," Chris says."The risk of crop failures and poor yields or quality can be better managed.

"The option of providing your farm with a sound rotation to base a good late summer reseed on is useful for many, while 'buying acres' from arable neighbours is often worthwhile where the cost per tonne is easily calculated.  Plus the fact that not the entire country is suited to growing large tonnages of quality grass every season means such decisions are often well founded."

As the table below highlights, the use of multiple forages in a ration is well demonstrated to stimulate higher intakes which, given the correct structure, can provide increased production.

"Varietal changes, harvesting technology, inoculants and in most recent years a fairer climate also have made an even wider range of cropping options available, crimped grain being a good example of this.

"The options are varied. For example any cereal crop with 35-70% dry matter can be made into fermented wholecrop, with the decision on when to cut being based on desired end use," he says.  

"It is a good compliment to high protein grass and low fibre maize, and yields well in most areas.  Clearly the later you cut the more mature and fermentable the grains are and so some milling by the forager will be required to ensure feed value is obtained by the animal.  Also, the 'concentrate' feed value increases so there is a need to limit the amount in the ration to ensure a stable rumen.

"On from this, the decision to combine the crop and crimp the grain at 65-70% dry mater is increasingly popular.  The feedstuff is digested slower in the rumen than dry rolled grain and therefore reduces acidotic potential in the cow's rumen.

"The challenge with this operation is getting the whole acreage cut at the correct stage, in warm weather the window will be narrow and so it involves careful planning and organisation to allow contractors and/or farm staff to concentrate on the job and get it finished and clamped quickly.

"Alkalage is the final option before dry combining and is best carried out at 85% dry matter.  The crop is cut with a forage harvester with grains processed by the machine and the crop is treated with a urea source to bring the pH to alkaline conditions for preservation. 

"The urea is either spread in layers across the clamp or thoroughly mixed to each load prior to clamping," Chris explains. "Urea can preserve the crop because it combines with moisture to produce ammonia, which raises the pH, inhibiting organisms such as yeasts and moulds.  This process also makes the straw more digestible and produces the rumen buffer ammonium biocarbonate."

The summary table below highlights the options available and feed values that can be expected from such feeds based on a wheat crop.

                                                                       

 

 


 

 

Dry Matter %


 

 

Average Yield t/ha DM


 

 

Metabolisable Energy MJ/kg DM


 

 

Crude Protein


 

g/kg DM


 

 

Utilised DM Cost £/t


 

 

Fermented Wholecrop


 

 

40


 

 

13


 

 

10.5


 

 

100


 

 

116


 

 

Wholecrop (milled)


 

 

50-60


 

 

13


 

 

10.8


 

 

100


 

 

116


 

 

Crimp (grain only)


 

 

65-70


 

 

7.5


 

 

13.6


 

 

100


 

 

136


 

 

Alkalage


 

 


 

 

85


 

 

13


 

 

10.8


 

 

150


 

 

121


 

 

Dry Combined


 

 

85+


 

 

8


 

 

13.6


 

 

100


 

 

130


 

 

"The costs for these options are clearly important but difficult to predict with accuracy as yield is the determinant factor and therefore a suitable farm crop budget should take place prior to any decisions being made.  

"For those with enough land, management skills and often machinery and labour to utilise throughout the season alternative conserved forage can prove a cost effective option which benefits cow health, production and margins," Chris concludes.