Grazing efficiency to improve margins

As milk prices have recovered to a more sustainable level, the importance of producing cheaper milk from grazed grass will still be key to improving margins this grazing season.

With elevated concentrate prices, supplementation through the grazing season will need to be carefully managed. Not only spring calvers can make efficient use of grass; higher yielding herds can still target higher milk yields from grazed grass through careful management of either grazing the whole herd or part of the herd.

The potential yield and margin gained by grazing can be substantial, however this isn’t a case of simply opening the door and letting the cows out! Careful management and paddock layout need to be considered long before turnout.

Grass is a great feed with huge potential to reduce bought-in concentrate, however maintaining this quality of high energy and protein requires attention to detail, especially early season, to ensure this quality is kept through mid and late season. The downfall for many is that intakes of grass are restricted due to unpalatable poorly managed swards and we turn to buffer feeding to increase the DMI. Greater early season management of your pasture could mean an extra 4litres/cow/day from grass later in the season.

Key tips for early grazing management

  • Turn out as soon as ground conditions allow. Grass is at its best in April and May but quality is highly influenced by grazing in March and removing winter growth.
  • The recent heavy rain may delay turnout. Don’t compromise the paddocks through heavy poaching as this will only lead to reduced DM yield through the season.
  • The first rotation should be completed by at least mid-April. The grazing platform should be allocated accordingly up until the desired date.
  • Set up a rotation and grass wedge from the outset, but remember that the length of the rotation will depend on grass growth. The optimal grazing point is when the sward reaches the three leaf stage (2800kg DM/ha). The intervals between grazings will be less in April and May than during the rest of the season.
  • Grazing platform layout is key; tracks should have already been placed to reduce poaching when accessing paddocks.
  • Ensure there is adequate water supply to each paddock.
  • Graze hard early on and take residuals down; this will help to maintain grass quality for the rest of the season and increase DM yield on the whole farm.
  • The size of the grazing platform can be calculated roughly using the following stocking rates in figure 1. In March this can include a portion of the planned silage area.
  • Don’t be reluctant to remove excess grass as silage and introduce additional grazing area or feed silage when grass is in short supply.
  • Graze in 12 or 24 hour breaks, turn cows into fresh paddocks at night, this is when it’s at its highest DM and sugars.
  • Supplementary Magnesium will be required.
Figure 1- Stocking rates/Ha through the season

Monitoring grass growth and managing your rotation is key to getting this right, especially early in the season.

Measuring grass using a plate meter weekly and recording this data on a grass management software, such as Agrinet, will be a valuable tool in decision making through the season.

Knowing how much grass you have available and estimating rotation length can give you the confidence to take surplus grass out of the rotation or increase the grazing platform – or being able to buffer if there is a deficit.

Figure 2- Grass Wedge from Agrinet (grazing)
Figure 2- Grass Wedge from Agrinet

Inputting your weekly data into Agrinet will produce a grass wedge (as seen in figure 2), this will show you your demand line and your target pre-grazing cover once you have entered your rotation length. This will be a great guide and management tool to make the most of your grass.

Supplementation at grass

Depending on the type and stage of lactation of the cows, supplementation at grass will probably be necessary. Feeding concentrates at grass can have an effect of increasing DMI and gaining more milk and also substituting forage DM if grass is in a deficit.

Concentrates have a substitution factor of 2:1 when fed with grazed grass, meaning for every kg of concentrates added to the diet they will eat 0.5kg DM less grass, meaning that at grass 1kg concentrates= 1kg Milk (when concentrates are 20p/kg and milk will be 28p/kg, these marginal litres can be worth chasing depending on milk contract and seasonality). Feeding more than 6kg at grass means the substitution factor drops and it can become uneconomical to feed more.

When grazing high yielding Holstein cows, careful consideration should be given to which cows within the herd can make sufficient use of grass. Grazing mid lactation and beyond (in-calf cows) can be done successfully without the need to buffer feed. Buffer feeding reduces the efficiency of grazing by making these cows lazy.

If you would like any further details and advice for the coming grazing season please contact one of the Dairy Technical Team.

Iwan Vaughan
Senior Dairy Specialist

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