Mid-season grazing and planning for the autumn

With the ongoing situation with farm gate milk prices, many producers have turned to including grass within the diet for the whole or for a proportion of the herd.  As we now approach mid-July, milk from grass has now started to decrease. By the end of June over 50% of this year’s grass growth has taken place.

If this sward has not been grazed down well enough in the spring a lot of dead material will be rotting away in the base of the sward. Although the cow will still graze the top nutritious leaves the amount of grass available for the cows could be 30% less than you think.

Milk Prices

Maybe now as there are a few signs that milk prices may slowly start to increase going into the autumn, it is essential that milk from grass isn’t overestimated as milk yield will drop and cows could lose too much body weight.

A loss of 0.5 body condition score at this time will result in a potential milk yield loss of 2 litres per head per day in the first 3 months of winter, as feed energy is used to replenish body condition. Depending on your milk contract and seasonality maintaining or increasing production into the autumn could be advantageous. Maintaining grass quality and supplementary feeding will be key to achieving this.

Grazing Quality

As many pastures or paddocks are now being grazed for the 6th/7th/8th rotation, grazing quality would have become poorer depending on the residuals the cows have been leaving. Whatever the situation there should be a management decision made to freshen up the pasture and increase the potential milk produced off the pasture. To hold grass quality these management decision should have been taken earlier in the season (early June), however if nothing has been done to date action must be taken now.

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Figure 1- Average GB Grass Growth Rates (Trouw Nutrition)

Figure 1 and Figure 2 shows the average GB grass growth rates through 2016 so far compared to last year, although having a slow start in the Spring, there was an explosion of growth through May and early June. However, grass growth has started to slow down the last 3-4 weeks, with slightly colder and wetter weather the plant has now become stressed and has matured and thrown up a head, meaning potential milk from forage will be reduced. The wet weather has also affected dry matter intakes (DMI) of grass which is increasing pressure on production.

Overcoming Grazing Problems
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Figure 2 – Average Monthly GB Grass Growths (Trouw Nutrition)

Many farmers revert to topping the old grass which has thrown up a head and also top rejected grass around dung patches. However, all this achieves is shredding of the grass and dropping it back onto the pasture. The paddocks will green up and look better but the cows will still refuse to eat down to the required residuals due to the rotting grass left behind and you will be in the same situation.

Many others will be reluctant to cut/top grass this time of year in case it dries up and they become short of grass for the cows. Increasing the grazing platform by bringing 2nd cut aftermaths into the rotation will help this issue and offer better quality grazing. Buffer feeding is also an option if grass becomes short, this will be discussed later.

 

Options to freshen up pasture:

  • Pre mowing- This should have ideally be done through early/mid-June, However there is still an opportunity to do it if nothing has been done or you have been topping up until now. Mow the allocated daily grass in front of the cows every day, this will achieve higher intakes of grass from the cows, and also freshen up the pasture and allow for aftermath grazing 3 weeks later or depending on rotation length.
  • Increasing the grazing platform-as many are planning or have taken second cut, if the aftermath is able to be included in the grazing rotation is there an option to leave the older grazing pastures of for long term silage as these will then be freshened up for late season grazing, or even take the stale pasture out as short term silage and bale this as rotation length increases when grazing 2nd cut aftermath.
  • Mowing after the cows and collecting grass in big bales – this is not ideal as there will be a high risk of manure contamination, however it will remove all the old grass and allow fresh regrowth to recover.
  • At no time should the paddocks be topped after grazing to control grass- this just shreds the grass and lies it back down on the surface where it is allowed to rot and deters the cows from eating as low on the next rotation.
Buffer Feeding

To maintain production from grass, buffer feeding can be a valuable tool to increase DMI and leading on to maintained body condition and increased milk yields. However buffer feeding can make cows lazy at grazing and make them reluctant to graze down to the required residuals as they are filling up or waiting for the buffer.grazing grass

As well as having a negative effect on grass quality, buffer feeding poorer quality grass silage can increase NDF intakes, which also has a much lower ME than grass, this in effect will reduce total forage DMI and lead to reduced ME intakes having a negative effect on production.

Buffer feeding should be targeted at the cows which require it if possible into late season grazing, as long as grass quality has been managed. Any high yielding (8,500 litres annual yield) cow which calve from early August onwards should have restricted grass within the diet and increase buffer and dry feed. This will maintain DMI and limit body condition loss on poorer late season grass. Late lactation cows can utilise grass within the diet through this period.

  • If grazing a AYR herd as one group- feed 3-4kg DM of forage as a buffer and include some concentrates or equivalent to increase energy intakes, work out M+ of the diet and feed accordingly in the parlour. Buffer would have to be increased into late season (September and October)
  • Partitioning high/fresh cows can be kept indoor at night and allowed to graze in the day, if there is access to an automated segregation gate, this can become a very useful tool. This allows for the cows to be grazed as one group in the day and only the lows being sent out at night to mop up the pasture, allowing the fresh cow’s access to good quality higher DM feed.
  • Splitting the herd into highs/fresh and lows will allow for easier management with the fresh cows being kept indoor from early/mid-august onwards.
  • Autumn calving – All cows calving down from August-October, should be kept indoors from the beginning of lactation, and take full advantage of grazing earlier the following season, depending on grass quality in late season perhaps a proportion of the diet cold be grass but this would have to be managed carefully.

When buffer feeding the choice of buffer is very important, feeding good quality grass silage, this can be slightly more fibrous but no lower than 10.5 MJ/kg ME. Feeding wholecrop or maize silage would be advantageous in getting more starch and glycogenic energy into the cows.

In terms of concentrate inclusion, balancing the diet up with protein, starch and sugars either with a blend or moist feed but also keep in mind the purchased feed cost per litre.

If you would like to have a look at your grazing management and late season planning in more detail please contact one of the dairy specialist at Wynnstay.

Iwan Vaughan

Dairy Specialist

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