Correcting residuals and undoing the damage from the wettest April in a hundred years

grazing after mowingApril was extremely wet and in such conditions it is very difficult to achieve good residuals, be it that cows struggle to graze well in these conditions or as in many cases cows had to come in. This is linked to the time of year, grass being at its most productive in terms of growth has meant high residuals and cows now trying to graze covers that are too high to get good utilisation. If this is not corrected then potential grass growth and quality will suffer in the following months.

As an example at a farm in Gloucestershire yesterday, the cows were grazing a sward of in excess of 3500kg DM Ha and not utilising it well, but silage aftermaths are ten to fourteen days away so what to do?

The cows need to graze something so cutting the pasture that has got ahead for silage will leave no pasture ready to graze. One option is pre-mowing, wilting and grazing, this reinstates a good residual (so important for quality in subsequent rounds), it also means the cows will fully utilise everything. Once the grass is cut and wilted cows will even eat the grass around cow pats that they would normally leave and any headed grass. So with this technique we can get very good utilisation, correct the residual and get grass back under control. We can also potentially get higher dry matter intakes as I have seen on some farms with yield advantages, this being because the cow can eat more dry matter in a set period of time as the grass is drier.

So how to do it? Mow a day at a time and watch the weather. For cows that are new to this only cut when dry as they will tend to leave it if it is wet (some herds which have used this technique for a while can get cows to eat wet mown material). Then just mow enough for the feed, be that one or two feeds. If you mow too much they will leave it and it will look as if it hasn't worked. As they will eat everything and won't leave anything be aware they may need a slightly smaller allocation than if they were grazing.

Most people mow in the afternoon for the following day's grazing (no more than this as once grass is cut it is deteriorating) but I do know of producers cutting just before the cows go in with no ill effects. Just like with silage the stomata of the plant remains open for about four hours post-cutting and this is the time most moisture is lost, so maybe mow four hours pre-grazing to get the wilt at a minimum. Just make sure you don't give them too much as you do not want lumps left all over the place suppressing regrowth.

Set your mower low, you are trying to recreate a 5cm residual, do not worry about any muck from previous rounds, the mower will go over the top and any contamination is very minimal. Another tip is persevere, if your cows have never come across this they may turn their noses up for the first day or two as they are not used to it; but they will get the hang of it, let them go out with an edge to their appetite, cows that are full of buffer will use it as bedding! So an edge is good. Most people who have said this technique did not work probably haven't persevered with it for a few days or fed too much buffer or allocated too much. One producer in Wiltshire with a 10,000 litre herd turned his herd onto pre-mown and wilted grass for the first time ever and they got straight into it as if that was how they always grazed.

Some may say what about cost and bother of doing this? Well in terms of bother and effort most swards need pulling back into shape after April and this is a good way of doing this. Also, the difference between well managed grass at 12 ME and sub standard (which is grass that is not pulled back into shape will be) at 10.5 ME is 3 to 4 litres per cow per day on any dry matter intake, so it pays. In terms of cost one of the discussion groups I work with costed out one of the members cutting wilting and grazing at 10p a cow per day with labour at £12 an hour plus diesel etc. I would suggest this gives a good return on your investment. The photograph show cows which have completely cleared the pre-mown grass and the residual is ready to regrow quality material.