Keeping Grass Quality Good in June

The results from over 1,400 grass silage samples sent to the Dairygold laboratory for analysis are in, and there is very little difference in the average DMD (feeding value) of silage made in 2014 versus 2013 (69.4 versus 69.1) or in the crude protein level (11.7 versus 11.8). Averages from the last five years are shown in the graphics below.   
Dairygold Silage Analysis Average DMD by Year (2010-2014)
 
Dairygold Silage Analysis Average Crude Protein by Year (2010-2014)
 
Averages can hide a multitude however; and there are large variances between and within farms as can be seen in the pie charts below.
Range of Silage DMD levels in 2014
 
Range of Silage Crude Protein % in 2014
 
It’s a powerful reminder that nobody should rely on guess-work for determining silage Quality. Recommended concentrate supplementation rates for milking cow will vary by up to 3Kg per head per day for <60 DMD silages versus >70 DMD silages. 
Key point: We recommend testing all silage, each pit / cut of bales to accurately determine supplementation rates

Key point this Month: AVOID STEMMY GRASS!!

Every 4% reduction in Grass Digestibility will reduce milk yield by 1kg/cow/day and milk solids yield by 5%

 

May has been a difficult month for grazing management.  Many paddocks got too “strong” and were not able to be removed as silage due to poor weather.  It was also difficult to graze paddocks out well or graze them out clean.

 

Grass quality will be poorer in June due to increased stem content. This will decrease the digestibility of the grass to be grazed.  Therefore the energy intake of the cow will decrease and then cow performance will decrease.  

 

During June, you should identify 2–3 (or more) paddocks that have poor quality grass and remove them from the grazing rotation, preferably as silage.  Hopefully, the month of June will be a better month for making round bale silage.  Round bale silage is a preferable option than topping as topping wastes feed.

Remember you need cows to graze leafy grass (around 1,400kgDM/ha).  Growth rates should average around 65-70kgDM/ha/day during June and this means you should have a grazing rotation of about 20 days. The aim is to keep a farm cover of around 160-180 kg DM/cow.  Of course, using the grass wedge is also a very good guide to try to keep the right grass in front of the cows.  

 

Milk yield should not drop by more than 10% per month after the peak is reached.  Milk protein should increase through the season.  However, milk protein content can dip during June.  This is mainly due to reduced grass quality i.e. more stem.  So every effort must be made to grow and graze leafy grass.

 

Sulphur “The 11th Hour”

Sulphur deficiency arises during the summer months and to prevent this you need to apply 15-20 units/acre to every paddock by the end of June.  Applying ASN (26%N & 14%S) now at 1.5 bags/acre will meet both your yearly Sulphur and monthly nitrogen requirements. Alternatively, CAN+S applications needed to have started in early May to get enough Sulphur out by the end of June. 

 

Fertiliser

Grazing ground requires about 30 units of N/ac.  However, where 1st cut silage area is coming back into the grazing rotation, apply about 40 units N/ac.  

 

Normally 80 units N/ac is required for 2nd cut silage.  Normally 2,000 – 2,500 gallons of slurry/ac is required for 2nd cut silage to meet P & K requirements. Every 1,000 gals of good quality slurry is almost equivalent to 1 bag of 0:7:30/ac but where soil fertility is poor, the value is lower. With most silage ground having poor soil fertility, some additional P and K fertiliser (1 bag of 0:7:30/acre) will need to be applied to silage ground.