Ground conditions

After a wet couple of days, ground conditions for early grazing are challenging. The good news is that dry and colder weather is forecast, so that will make the job easier. Is it worth the hassle?

OK, the numbers calved are small and area grazed per day is small, but it all adds up. Putting grass in the cows’ diet will increase cow performance, reduce feed costs and reduce the period of negative energy balance after calving.

Even good quality silage reduces milk production, especially protein percentage, so the less silage fed to freshly calved cows the better. There is also a knock-on effect of feeding silage to freshly calved cows in spring – protein percentage will be suppressed for weeks after the feeding event.

Under Irish conditions, feeding some silage will be inevitable as ground conditions just won’t be suitable for grazing all of the time.

On some farms they won’t be suitable for grazing for another few weeks, and no amount of management will change that. However, there are plenty of farms where early spring grazing can be practiced but isn’t.

Making this management change will bring about huge benefits to farm performance and cost structure.

Allocating grass

This is a key skill for all dairy farmers, particularly in spring. There are a few methods, but the most accurate in spring is as follows;

  • Work out how many cows are grazing and how much grass they are eating in the 12 hour break, for example 15 cows eating 6kg is a total demand of 90kg.
  • Work out how many square metres are needed to give 1kg of grass dry matter. To do this, divide the cover into 10,000. For example, a cover of 900kg into 10,000 is 11.1m2 /kg of dry matter. The higher the cover of grass, the lower the number of metres to get 1kg of dry matter.
  • Multiply this number by the demand to work out the total allocation. So in this case, 11.1 multiplied by 90kg is ~1,000m2. This is how much area you need to give the cows.
  • To work out where to put the fence, measure the length of the paddock and then divide this into 1,000. For example, if the paddock is 75m deep, the strip wire should be placed 13m wide.

    • Allocating the grass is only half the job. The amount of area being allocated needs to be tweaked daily as cow intakes change constantly, and so too does the amount of grass in the paddock.

    Farmers should be looking at post grazing heights and changing the allocation accordingly.

    Fat cows

    In the main, dry cows are in very good body condition score (BCS) as they had a long dry period eating good quality silage. While this is an asset, it’s also a bit of a liability, because research shows where there is excessive BCS loss, fertility is impacted.

    Cows in too good BCS at calving have more to lose. Metabolic disorders like milk fever and ketosis are more prevalent when cows are too fat. Feeding more magnesium pre-calving is a good preventative measure against milk fever.