How to set up rotational grazing on your beef farm

Rotationally grazing beef cattle is becoming more popular as people strive to maximise output from forage.

It is not a precise science, but there are key points farmers need to bear in mind to make it work.

Gareth Davies from Gareth’s Grassland Advisory Service talks us through the main questions beef farmers may have.

Unlike dairy cows, a beef herd includes growing animals, so weights are continually increasing. This means working out grass demand is trickier.

For a cow with a calf at foot, assume a dry matter intake of 15-16kg/day. When a cow is not suckling, budget for 11kg DM/day.

For the suckling calf, a dry matter intake of 2.5% of the calf’s liveweight should be allocated; a 200kg calf will therefore eat 5kg DM/day.

Taking this calculation into account, the cow together with the calf will need an allowance of 21kg three months after birth.

How do I calculate pre-grazing pasture cover?

Cover is the amount of grass, dictated by height and density, that is available for cattle to graze.

To maximise weight gain in a growing animal – achieved through grass intakes and cow milk – it is vital to provide cattle with the best quality of grass daily.

Keep the herd on a three-week rotation during the grazing season, as this matches the grass growth at this point in time; this equates to a grass cover of between 2,700-3,000kg DM/ha, which can be calculated using a rising plate meter.

To maintain this required rotation length, match the stocking rate to annual grass production – for instance, if the area is only capable of growing 8t DM/year, stocking rates must reflect this.

If growth gets ahead of the rotation, covers can be controlled by taking fields out of the rotation for making big bale silage.

See also: Promising weight gains made from grass in dairy beef study

Using a plate meter allows a figure to be attached to grass covers. There are two types of plate meter – mechanical and electronic – and both measure grass cover in terms of kilogramme of dry matter a hectare. They provide comparable and quotable results that can then be shared with other farmers and advisers.

Monitoring field cover and average farm cover on a regular basis allows potential grazing surpluses or shortfalls to be identified and addressed before they create problems.

How do I know what residual should be left after grazing?

If you get the pre-grazing covers right, the herd will happily graze down to 1,500kg DH/ha, the height of a golf ball.

Once animals have adapted to the system, they will learn what they need to do before they are given fresh grass.

Measuring covers and calculating demand allows you to accurately graze cattle for the required period of time.

One of the key points of efficient grazing is to always graze down to the correct residual and this is achieved by turning cattle into the right grass cover and the appropriate area for the stocking rate.

Cows should be removed from a field when the sward reaches the target post-grazing point – a field cover of 1,500kg DM/ha or a sward height of 4-5cm. 

Access to water is generally the limiting factor – rotational grazing is not going to work if there is only a single water trough wedged in the corner of a field.

Any water system must be well designed, with troughs placed in a position where they can be accessed from each section of a subdivided field.

A simple mobile water tank is often a useful tool.

There are push-and-fit connections that can be used to fit a trough to a pipe and that trough can then be moved around with the rotation.

A water bowser and tractor is also a simple way to deliver fresh water to cattle.

What are the fencing options?

Mr Davies advises using whole fields as a starting point if they are of a suitable size – preferably no greater than 2ha – but electric fencing allows stocking density to be adjusted so grazing pressure can be controlled in bigger fields.

An electric fence system needs to be well laid out, but once it is done it reduces overall fencing costs.

Solar-powered energisers are useful for electrifying fences in remote areas.

What are the rules around footpaths?

Electric fencing and subdivision mostly allow cows with young calves to be fenced off from the footpaths. 

Make sure the fence is on your field, not on the footpath itself.

Check your local authority’s definitive map to see whether the footpath is marked as a certain width. If not, allow a width of at least two metres.

If using electric fencing, erect warning signs and make sure it is insulated where it runs close to the path.

And always make sure you know the rules when running bulls and cows on footpaths.