Video: Highland farm grazes cattle unfenced with GPS collars

Virtual fencing is gathering pace and there are now more than 30,000 collars in use around the globe.

The Girvans of Corrimony Farm, near Drumnadrochit, Inverness, could not graze cattle on their unfenced hill without such innovative technology.

Hours would be spent finding and gathering cows and worrying about overgrazing or damage to Caledonian woodland, explains David Girvan.

But solar-powered GPS collars developed in Norway are enabling the Girvans to keep cattle within a digital paddock drawn on a phone.

The whole system can be monitored remotely in the farmhouse.

Cattle locations show up as red dots or as white-collar symbols, meaning the Girvans know exactly where the cows are at any given time on their extensive farm.

Watch how the collars are used on the farm and read the rest of the report below.

How the farm uses the collars

The farm bought 25 NoFence collars in 2020 for £300 a collar.

This was to enable grazing on the rougher, unfenced parts of the farm in the summer and to help the RSPB wardens manage the Caledonian Forest areas on the RSPB Corrimony wildlife reserve.

To “teach” the cows how to use the collars, the Girvans put the cows on in-bye ground and kept them on one-half of a field for a couple of days.

Every time a cow tried to cross into the other half of the field, the cow got an audio signal. Three increasingly intense audio signals are emitted from the collar, until the collar delivers an electronic pulse.

Cattle quickly learn to associate the audio signal with the pulse and turn around to return to the herd. Each audio signal, electronic pulse and escape is recorded and mapped on the app.

Once pulses abated and the cows were trained to the audio signal, the cows were taken up to the hill.

This summer, a group of 10 cows and calves ran with a bull on the hill in a virtual paddock measuring 250ha (617 acres) in size.

The paddock was drawn on a relatively flat and dry area of ground at about 450m (1,467ft).

Later in the autumn, after grazing the hill, the plan is to put weaned cows on to land at the Corrimony Nature Reserve beside a lochan near some trees.

Next year, David Girvan is considering weaning calves at 140 days as opposed to the more usual 180 days and putting cows out on the hill for longer, targeting weaned calves at the better ground and silage aftermaths.

Maximising the farm

The collars have been the latest development in a system change at Corrimony Farm that has seen David and his father Lindsay ramp up flock productivity by bringing the sheep in-bye and challenging the cows on rougher ground.

Previously, Corrimony ran 1,000 Scottish Blackface ewes and bred them pure in hefted flocks across the hill. The tough conditions meant sheep only reared 80%.

Sheep were brought in-bye, firstly to breed Mules, but this system required too much hard feed, explains David.

More recently, the family started running a closed flock Lleyn-based cross-breeds using rams bought off farm and reared on forage from the MacGowans at Incheoch, Blairgowrie. 

The flock is now run entirely in-bye and scans at about 180% with 15% mortality, on average, each year. 

This system depends on far fewer concentrates than before, and typically saves around 20t/year. 

This is mainly down to rotational grazing, wintering on 8ha (20 acres) of swedes/fodder beet and ensuring lambing paddocks are rested for 100 days so there is enough grass for milking ewes.

However, the new system meant the unfenced hill went largely ungrazed by livestock, barring dry ewes and hoggs.

The collars have opened up the potential to graze hundreds of hectares of unfenced, rough grazing with cows, allowing the best in-bye grass to be targeted at priority groups such as ewes and lambs, and growing cattle.

But David stresses that the right type of cow is vital to make a success of grazing such rough terrain.

“We used to criss-cross Limousins and Angus. They might cope for a short time on the heather, but you’d have to pick the easy-fleshing types.”

The collars are not needed for winter as the Stabiliser cows graze in-bye areas of rough hill, meaning the Girvans know where they are. A pot ale syrup and straw mix (mixed 5:1) is taken to cows daily.

Cows then calve in sheltered fields and heifers or priority animals calve indoors.

Maximising wildlife

The collars allow for exclusion zones to be drawn around saplings or regenerating woodland to avoid damage, explains Mr Girvan.

Grazing cattle can be used to churn up small areas of ground and control vegetation, creating diverse habitats for mammals, insects and birds.

The farm sits adjacent to the Dundreggan rewilding project, which has planted more than 335,000 native trees. RSPB Corrimony Nature Reserve spans some 1,530ha (3,780 acres) of highland hill.

The area is home to black grouse, crested tits, Scottish crossbills and whooper swans, and snow buntings in the winter.

“Areas of ground in between the high hill and the in-bye ground are where cattle really make a difference,” says Mr Girvan. “They can control bracken and open up the soil.

“The RSPB likes to graze ground for a year or two and then move on and rest it. Traditional fencing infrastructure is very expensive, so the collars offer a solution.”