Pastures can lose quality as they get older. Although the fields are still covered with grass it is not certain that farmers are still getting maximum output from their pastures. In many modern dairy  systems it is crucial to maintain maximum output from the grassland. If not, the fields will produce less dry matter and also the forage quality will become insufficient, resulting in higher (additional) feeding costs per cow. It therefore is important to renovate pastures as soon as they start to lose quality.

 

 

When to renovate?

• If one or more of the following problems appear during the growing season:
• water remains on top surface during growing season
• the grass shows slow regrowth
• the grass is heading continuously
• the botanical composition consists of less than 75% good grasses
• cows have difficulties to maintain their milk production level

If one or more of the following conclusions can be drawn from the silage analysis:

• the total dry matter yield is too low
• the crude ash content is too high
• the digestibility of the organic substance is lower than 70%
• disappointing feeding value despite good ensiling technique

What are the costs and benefits of pasture renovation?
For the renovation of one hectare grassland we can use the cost indication below.

 

Spraying old sward (including product)	25
Rotary cultivating (5cm)	100
Ploughing (with land packer)	113
Levelling out	pm
Seedbed preparation & sowing	90
Seeds	110
Total costs per hectare	438 Euro
(Costs are based on a Dutch situation)

 

 

After renovation, the improved field offers a better botanical composition of the sward, better sward density and increased dry matter yield and feeding value. What this will mean in economic terms for the farm is presented in the next table.

 

Yield

Old sward/ha	kg DM/kg dm	VEM*)/ha	kVEM
60% good grass	12.000	980	7.056
20% weed grass	8.000	790	1.264
10% weeds	4.000	750	300
10% bare soil	0	0	0
Yield per hectare	9.200		8.620
New sward/ha	kg DM/kg dm	VEM/ha	kVEM
90% good grass	12.000	980	10.584
4% weed grass	8.000	790	253
4% weeds	4.000	750	120
2% bare soil	0	0	0
Yield per hectare	11.280		10.957
Difference:	2.080		+2.337

*) VEM= energy value per kg dry matter feed product Fresh grass (normal cut) has an avarage feeding value of 930
*) VEM= energy value per kg dry matter feed product Fresh grass (normal cut) has an average feeding value of 930 VEM/ kg dry matter. Converted into foreign energy systems this will be:

     930 VEM = 6.7 MjNel
     930 VEM = 0.85 NFE
     930 VEM = 10.9 ME

 

What is the effect of grassland renovation?

• Increased dry matter yield per hectare resulting in lower costs for purchasing concentrates or forage  products.
• Better forage quality (VEM) per kg dry matter (palatability + digestibility)
• In this example: + 2337 kVEM per ha
• An added value of (2337 kVEM x 0.15 ct/ kVEM) = 350 Euro/ha
• Better dry matter intake by the animals

 

Comment
If the condition of an old sward is even worse than in this example the return of investment will be much faster.