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Sunday 19 November 2017

Those who got grass cover right on crest of a wave

Dr Mary Kinston

As we near the end of the first grazing rotation, grass covers are still very variable, ranging from extremely low to on target, and even too high in a few places.

Where pasture covers are less than 300kg DM/ha grass growth will be reduced due to a low leaf area index on the overall farm. In this circumstance, you should reduce daily pasture demand per hectare (cows/ha multiplied by intake of pasture per cow) to a level which is below your projected growth estimate in order to aid grass accumulation.

It is essential where covers are low that you resist commencing the second rotation coupled with a fast rotation, as this will reduce grass cover and grass growth further. You will be left with a situation of low growth which will become very prolonged and expensive to feed your way out of. Where grass covers are less than 300kg DM/ ha, remember that rotations of 30 days instead of the typical 20 days will aid grass growth.

Farmers lucky enough to have got their grass calculations right will now be on the crest of a wave. Getting your timing and grass demand right as you head into the second rotation will have a substantial impact on the pasture quality on offer for the remainder of the spring. No one said grass management is easy, but it is rewarding so make sure you are monitoring pasture covers every week at this stage.

In many cases, this winter and spring resulted in some paddocks becoming patchy due to winter kill of tillers. The cold also highlighted paddocks of poor grass species composition that lacked growth and vigour.

Reseeding has consequently been often mentioned at my discussion groups recently. For those group members who are dedicated fans of grass monitoring, the obvious question has been "so what did it grow last year?" Knowing that answer is easier now than ever if you are competent at using a computer. Many companies, including AgriNet, Kingswood, and Teagasc, offer spreadsheets that calculate this figure for each paddock with ease after a year of grass monitoring.

But don't despair if you are more of a fan of the old-fashioned pen and paper. I use this simple tool called the paddock grazing dairy as shown below. It is illustrated for a sample of paddocks from a farm monitored last year. As each paddock is grazed the date is marked in the next available box.

Using this tool has relevance where you are monitoring your pasture covers and grazing cows on paddocks with higher grass covers rather that just sending cows round in a set rotation.

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Using just a simple grid of your paddock numbers, where you mark down the date when each paddock is grazed, can help you assess each paddock's progress through the year.

Where paddocks are being closed for silage, mark down closed for every full grazing rotation that they are growing grass but are closed off. In this example it is clear that paddock 6 and 8 are substantially poorer in grass growth. It also highlights that paddock 4 is the best followed by paddock 1 and 3. Visually, this tool is very effective and the answer to the reseeding question is obvious.

So if you are not comfortable with the computer but measure grass covers weekly, consider using this alongside your weekly measurements to aid you in your management decisions.

In addition, where reseeding is being considered, make sure you address issues relating to the drainage and soil nutrient status of the paddock to get the best return for your investment.

Mary Kinston is a dairy consultant based in Co Kerry. Email: mary.kinston@gmail.com

Indo Farming