Farm Ireland

Tuesday 12 December 2017

Going back to your grass roots ...

How are you dealing with excessive grass on the grazing platform at present? Do you know what your target pre-grazing cover should be? Are you prepared to pull out paddocks with high covers?

These are the questions doing the rounds at discussion groups -- dealing with a situation not known for at least two years. To work through this period of high-grass growth effectively requires good management.

It is also essential that all relevant figures are available. Are you walking the grazing area once, if not twice, a week? What is the stocking rate on the grazing platform, what length is the rotation and what is the daily allocation of grass DM per cow?

This figure is the target pre-grazing cover -- what use can be made of it? Having the herd going into covers greater than this target suggests that paddocks need to be mowed out and wrapped. Taking out one or two earmarked for grazing in the next two or three days will allow the herd to graze a cover similar to the pre-grazing target.

Some farmers dislike getting in a contractor to wrap less than 10 bales, but don't feel this is expensive or a waste of grass. These bales may be used sooner than expected, if the current surplus turns into a deficit in a month's time.

These wraps contain top-quality material -- they are an extension of the grazing area and will retain their high quality until required. Taking out one or two paddocks will speed up the rotation.

At Kildalton College, a growth rate of 106kg grass DM/day was recorded last week, so in a week, a paddock will have a cover of more than 700kg. Regrowth tends to be of excellent-quality material, with a high usage of grass on the next rotation.

There is also quite a bit of debate at discussion groups whether to cut these paddocks immediately or allow them to bulk up for a week to 10 days.

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Can these paddocks be out of the rotation for the next five weeks? What effect will this have on the grass cover per cow? Grass cover per cow depends on the current stocking rate on the grazing area.

If this figure remains at an acceptable level for the next five weeks until the paddocks are back in the rotation, allow these paddocks to bulk up, otherwise mow out and get back into the rotation immediately.

What is cover per cow? One farmer I met last week had an average farm cover of 700kg/ha and a stocking rate of four cows/ha. This farm cover is on his current grazing area, with all silage ground eliminated from the calculation. This gives him a cover/cow of 175kg grass DM for that week. Is this enough at this time of the year?

Allocating each cow 18kg/day will ensure there is nearly 10 days grass ahead of the herd if current average farm cover is maintained. If the cow's diet is made up entirely of grass, a comfortable cover should be 160-200kg grass DM/cow.

What should farmers do if their cover/cow is a lot higher than these figures? Take out paddocks from the grazing area, allow them to bulk up for 10-14 days and wrap. Getting the cover per cow under control should be a fundamental tool of mid-season grazing management.

Can the stocking rate be increased on the grazing area? Some farmers have their bulling heifers on an out farm -- can these be brought back to some paddocks on the milking area?

While increasing the stocking rate, it will also allow the heifers to be afforded better heat detection, particularly at a time when most farmers are beginning to waver on this score.

Finally, some farmers are finding it difficult to control grass, yet are still feeding 1-2kg of meal in the parlour. Leaving the economics of meal feeding aside, each kilogramme of meal will reduce intakes of grass by a similar amount.

The 1kg of meal/day will increase the rotation length by one day over an 18-day rotation.

Irish Independent