Farm Ireland

Sunday 25 February 2018

Add two days to your grazing rotation

It is vital that the majority of our autumn milk is produced off grass
It is vital that the majority of our autumn milk is produced off grass

Building autumn covers of grass can be a tricky business. If you don't build enough grass, cows will end up eating too much expensive meals and silage in the month of October. And if you build up too much grass then you run the risk of leaving a butt of old grass through the winter which is a waste of good feed and will also impact heavily on next spring's grass quality.

With milk prices being where they are, it is vital this year that the majority of our autumn milk is produced off grass. Grass costs 7c/kg to produce, silage 15c and meal 25c approximately, so obviously we want as much as possible of the stuff that costs 7c in our cow's diets this autumn.

Grass growth generally tapers off at the end of August, typically dropping below 60kgs growth per day, and it further tails off further as we head into October, dropping to below 40kgs per day. Therefore, the grass we graze in October/November has to be grown in September and this won't happen by accident.

Rotation length

Rotation length needs to increase by two days per week from now on.

Most farmers try to determine the rotation length by trying to remember when the cows were last in today's paddock, which gives a good indication, but a better way is to divide the amount of ground the cows are eating on a daily basis into the total ground available. If you have 100ac available for the cows and they are eating 4ac per day, then your rotation length should be 25 days. At the end of August they need to be eating only 3.3ac per day.

Adding two days per week to the rotation length can happen in two ways - increase the supply of grass or reduce the demand.

Increasing grass supply

Also Read

Some may have aftergrass entering the system now, which will automatically increase the supply of grass available. All others have to depend on fertiliser. The closing date for spreading chemical fertiliser is four weeks away on September 15. Those of you who are stocked at greater than 2.5Lu/ha need to blanket spread the farm twice in this period. Those of you who are lower stocked should go with one application in the next fortnight as the response to nitrogen will be higher in August than in September.

Decreasing demand

There are numerous options to reduce demand. The first area to look at is stocking rate. All calves and heifers should be sent to outside blocks now. Scan all milking cows and determine those that are not in calf. Perhaps there may be a market to sell these while milking? An ad online or in the paper will soon find out. Low yielders, thin cows, lame cows, mastitis cows could be dried off and sent to an outside block of ground.

Feeding extra meal may be necessary for some, but it should be a last resort. High quality baled silage should be introduced before resorting to meal, but on some very highly stocked farms, it may be necessary. A very basic three-way mix will be adequate in most instances.

Ground conditions are good in most areas at present, so graze out paddocks as clean as possible now because it may not be as easy to do it the next time round. This avoids grass being wasted and sets the farm up for the final autumn grazing and also for the first spring grazing.

For those on heavy soils, build as much grass as possible on your drier fields - the ones you know you will be able to graze in October. Graze the heavier fields now while the going is good.

So how are you going to add two days to your rotation length this week?

Put a plan in place now, otherwise it could end up being a very expensive winter.

Joe Kelleher is with Teagasc, Newcastle West, Co Limerick

Indo Farming

More in Dairy