Achieving high yields with rotational grazing

Rotational grazing may not seem like the obvious management choice for a herd of 10,000-litre Holsteins, but a Kent farm is saving £82.08 a day by focusing on grass intakes. Gemma Mackenzie reports

Achieving a 10,000-litre herd average and reducing protein costs by using grazed grass go hand in hand at Home Farm, Sevenoaks, Kent.

Speaking at a DairyCo farm walk, herd manager Richard Evans explained that grazing was a significant cost-saving exercise for the 144-cow autumn block-calving herd, that yields 3,445 litres from forage.

“I’m trying to get the best of both worlds – I want to maintain yields and get more from grazing. I’m looking at the margins and costs involved in the system, and I believe on a p/litre basis, it’s cheaper to put the cows outside if you have got the grass. The aim is to reduce costs from turn-out in March to drying off at the end of June.”

Grazing cows also allows significant savings in labour costs at Home Farm, which is tenanted by William Westacott and his wife. “We need two to two-and-a-half people working over the winter, when the cows are inside, but in the summer I can do it all on my own; the decrease in labour units is significant,” says Mr Evans.

Ration

Mr Evans said: “We start calving at the end of August, and in-calf heifers calve about five days after the cows. Because of the lack of grass, we calve outside and then house them straight away after calving.”

During the winter the cows are fed a TMR ration of M+28. The ration consists of 30kg maize silage, 10kg grass silage, 3kg rapemeal, 2kg wheat distillers, 0.5kg straw, 0.25kg protected fat supplement, 0.02g of a mycotoxin adsorbent and 0.01g acid buffer.

Turnout in the spring is when grass growth can support 5kg DM/cow/day, with a target to get the cows out twice a day to achieve intakes of 11kg DM/cow/day.

“When we put cows out we start pulling back on the protein in the TMR and gradually reduce the level of wheat distillers and rapemeal. There’s an abundance of protein in grazed grass, so it makes sense to cut levels down in the ration.”

Current grass growth has allowed the farm to cut distillers and rapemeal completely out of the ration, but depending on grass availability, the ration will be tweaked accordingly throughout the season.

“The aim is to just buffer feed with maize in the troughs,” said Mr Evans.

Grazing

Mr Evans said cows adapt quickly to the system, but supplementing the grazing diet is key to maintaining high yields.

“Average yield a cow did drop by 2 litres/day over the first 31 days from turnout, but the financial benefits are probably double.

“Because of the size of the grazing platform we have got – 30ha split into 12 paddocks – we will never get enough kg DM intake a cow from grass alone, so we still supplement them in the parlour to yield. The system is based on grass growth rates and demands,” he added.

Grass growth is assessed using a plate meter and cows enter a field at 2,700kg DM/ha with the aim to graze down to 1,500kg DM/ha.

“We are not trying to create a grazing system here, it’s a cost-reducing exercise, because we have a resource which is very high in protein – why not use it?”

 

COST SAVINGS AT HOME FARM FROM GRAZING COWS    
   Per cow/day  herd/day
 Conserved forage savings  £0.61  £87.84
 Concentrate (straights) savings  £0.54  £77.76
 Total savings  £1.15  £165.60
 Milk losses  £0.58  £83.52
 Financial benefit  £0.57  £82.08
* A month after turnout this amounts to a £3,296 saving for the herd – without costing reduced labour and bedding.


Expert’s viewpoint

DairyNZ technical adviser John Roche shared his views on how grass can be used more in high-yielding herds.

  • When assessing grass growth by eye, it’s worth spreading the grass out and pulling out a tiller to have a look at it
  • If your cost of production is high, you need to question whether grass is worthwhile for you
  • Aim for 1,500kg DM/ha residuals to promote longer grazing rotations – this is roughly 4cm grass growth
  • Aim for a grazing wedge on a 20-day rotation – this will help you get the cows out earlier
  • The appropriate infrastructure – water troughs, tracks, electric fencing etc – needs to be in place
  • If adopting this approach, be prepared to put the cows outside as soon as the grass growth is ready – don’t be tempted to keep feeding them with the mixer wagon and get behind a few days on grazing

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