With the June bank holiday weekend looking like it will deliver promising weather, it is crucial that you do not delay your first cut silage any further.
The focus for first cut silage should be ensuring it is of high quality. The earlier your cutting date, the more quality silage you will have.
When we talk about high quality silage, we always talk about the dry matter digestibility (DMD), as high DMD (>70%) will result in improved animal performance due to higher feeding values and increased intakes.
With seven month winters now becoming a reality in recent years, a lot of farmers fear that they won’t have enough silage for next winter.
However, if you have completed a fodder budget, you will know approximately how much silage is needed to get you through.
The aim should be to produce approximately eight tonne of silage per cow which equates to about 10 bales/cow, according to the head of dairy knowledge transfer, Dr. Joe Patton.
Dr. Patton warned that if you are concerned about meeting this demand, do not focus on bulking up your first cut silage, but try and solve your feed deficit problems by focusing on the second cut.
The impact of delaying your first cut silage
The cutting date has a huge impact on DMD and as your crop heads, DMD will be no higher than 70% and will continue dropping 1% every every two to three days until cut.
The following table is a guideline on grass silage DMD for different classes of dairy stock:
Dry cows Spring cows in milk Growing heifers Winter cows in milk DMD % 68-70 72 72 75 Typical first cut date Early June Late May Late May Mid May First cut yield (t DM/ha) 5.5-6 5-5.5 5-5.5 5
There is a clear indication that the DMD percentage decreases the later the harvest date, with the tonnage/DM/ha increasing as the harvest date is delayed.
With a lot of silage ground getting fertiliser later than usual and lower than normal growth rates in April and May, many may be tempted to delay cutting their silage even further to bulk up silage crops.
Having extra silage in the yard is better than running out, however, having low quality silage that the cows won’t eat, that has decreased the cow’s intakes could be part of the reason why there is silage left over, according to Dr. Joe Patton.
Concerns about nitrogen content
A real concern around silage cutting time is the nitrogen (N) content of the grass – grass uses approximately two units of N/day.
In practice, if you apply 100 units of N for first cut silage, the grass should use up the N in 50 days- depending on conditions, the N can be used up quicker.
However, Dr. Joe Patton has emphasised to not be waiting for N to go out of the grass, as he believes the two units rule is a fallacy that restricts farmers.
The head of dairy knowledge transfer said that the two unit rule should be “used as a guideline to put out the fertiliser, but it shouldn’t preclude you from cutting”.
Higher N will also lead to higher protein, so, if conditions allow, the grass should be cut straight away, left to wilt, and then picked up, according to Dr. Patton.