50 years of research on Scottish hill farms

Kirkton and Auchtertyre are two research hill farms for Scotland’s Rural College (SRUC) near Crianlarich, around six miles northeast of the northern tip of Loch Lomond, within the Loch Lomond and Trossachs national park.

The farms have been run to support hill farming for over 50 years, with a focus on improving the productivity of hill units and increasingly on the environment and biodiversity.

Farm overview

Stretching to a combined 2,200ha, Auchtertyre and Kirkton are contiguous hill farms, with 50ha of ploughable in-bye and around 150ha of ground which has been historically improved and is now fenced permanent pasture fields.

Most of the high hill ground on Kirkton is ring-fenced, but the high hill ground on Auchtertyre has no perimeter fence.

The farm runs around 1,400 breeding female sheep across the units

Not only does the land type pose a challenge, but the farms record an average of 2.6m of rain each year on the lower ground and even more on the high ground. On top of that, the grass growing season is short.

The farm runs around 1,400 breeding female sheep across the units, broken into two main flocks. Running parallel flocks allows the staff to study how the different sheep perform.

Kirkton flock

For the last 10 years, Kirkton has hosted two 200-head Scottish Blackface flocks (one selected on high genetic merit for 20+ years and one on average genetic merit) and a Lleyn flock that are all run together for most of the year to ensure similar environmental conditions.

This year, the Lleyn and Blackface sheep will crossbreed to capitalise on hybrid vigour and compare and contrast performance

The 200-head Lleyn flock (high genetic merit) was established to compare the performance of the more productive Welsh breed in a harsh hill environment. All three flocks use the Agriculture and Horticulture Development Board’s (AHDB) Signet breeding indices to identify replacements.

This year, the Lleyn and Blackface sheep will crossbreed to capitalise on hybrid vigour and compare and contrast performance.

Auchtertyre flock

The Auchtertyre farm hosts a typical Scottish Blackface high hill flock of 650 ewes, which spends most of the year out on the hill and has a focus on productivity and environmental benefit.

The flock was removed in 2008 following an enzootic breakdown and re-established soon after using surplus females from Kirkton and a few ewe lambs sourced from accredited, high-health status Blackface flocks.

It was challenging at first to reintroduce a hefted flock to the hill, due to the extensive nature of the area with no boundary fences, but, after a few years, the flock has hefted back well.

In addition to providing valuable production data, the flock is also being used to investigate blackloss

At its peak, this upper glen on the farm held 800 ewes, which had to be fed regularly with bought-in feed. The SRUC team feel the current stock level strikes a good balance between environmental impact and farm output.

In addition to providing valuable production data, the flock is also being used to investigate blackloss – the unexplained losses of lambs.

The team is keen to know how big an impact the photosensitisation condition known as plochteach or yellowses has on the sheep.

Coping with conditions

The wet weather on the farm means that the in-bye fields cannot be grazed heavily over winter and experience has shown forage crops are unsuitable.

While total rainfall has not increased in recent years, there are more extreme weather events.

The farm usually applies around 120t of lime every three years

The wet conditions mean it is a challenge to keep the pH of the soil above 5.8, with most of the ploughable land between pH 5.0 and 6.0 at the moment.

The farm usually applies around 120t of lime every three years (at 5t/ha) to those fields that have a pH below 5.8 to maximise the growth of the grass.

Grass management

Over the years, the farm has been improving its grassland management.

Farm manager Ewen Campbell said: “A ryegrass-white clover mix with cocksfoot, timothy and red fescue has been used in the reseeding. However, within three to four years, native grasses, in particular Yorkshire fog, usually take over.

“The number of bales of silage per hectare varies greatly from year to year, depending on the growing conditions, but tends to peak in year two after reseeding at around 30 bales/ha before dropping to around 20 bales/ha in subsequent years.”

Reseeding each field every three years is not an option for the farm or any conventional hill farm, so they are currently looking at longer-term options.

Later lambing

Lambing starts in late April/May when rainfall is lower and normal growth is capable of sustaining ewes and lambs.

All lambs at Kirkton and most at Auchtertyre are tagged at birth, allowing lifetime performance to be followed.

Each lamb will have data on growth rate, parentage, birth date, litter size, birth weight, any fostering details (Kirkton flock and some parts of Auchtertyre), birthing ease (Kirkton flock only), growth rate, ultrasound fat and muscle depths at weaning (Kirkton), carcase weights and grades (Kirkton male lambs, except selected breeding stock) disease and medicine use along with dates and reasons for deaths or culling.

Ewe information includes number of lambs scanned, born and reared, lambing ease (Kirkton flock only), maternal behaviour (Kirkton only), maternal ability (weight of lambs reared), weight at key points throughout the year, body condition score at key points throughout the year, age/longevity, disease and medicine usage, dates and reasons for any deaths or culling.

For tups (rams), information is broken down to the number of lambs sired, performance of lambs sired, disease and medicine usage, age and the dates and reasons for any deaths or culling.

The sheep are single-sire mated at Kirkton and extensively recorded at birth so that a full genetic history and detailed lambing data can be collected. The Auchtertyre flock mob-mate, with DNA testing used to identify parentage.

This allows the proliferation of the sires used in the multi-sire groups at Auchtertyre to be assessed.

For example, in one year, where a group of three tups was put to the hill with 131 ewes, the top-performing tup sired 87% of the lamb flock from these ewes while the poorest performer sired only one lamb.

Gathering challenge

Collecting this data is not always easy in hill flocks. Kirkton, which is fully fenced, can get a pretty full gather in three or four hours with three shepherds, one quad and seven or eight dogs.

However, the unfenced Auchtertyre typically takes two days and, with four shepherds and two quad bikes, results in only around 80% of the sheep in the pen.

This is not a unique issue for the farm, with many highland farms struggling to gather their sheep as labour becomes scarce and more sheep farms disappear.

These blackloss sheep can often never return

If neighbouring hills are also stocked with sheep, then your own flock will usually stay in place, but if nearby flocks are taken off the hill, then your own ewes will spill out on to other hills and disappear.

These blackloss sheep can often never return. However, others may come back after some time, often carrying an extra fleece since they missed the clipping gather.

Both flocks are gathered about nine times per year for weaning (August-September), dipping and dosing (October), tupping (November), fluke dosing (January), scanning (February), vaccinating (March), lambing (April), marking (June) and shearing (July).

February scanning

Individual ID tags on the ewes are used to help decide which ewes need extra feeding before lambing.

Each time the sheep are handled, they are automatically weighed so each ewe has a record of their weight from their time on the farm.

The Kirkton flock will be assessed on age, body condition score and weight before allocating into winter feeding groups.

Ewes are expected to lose around 3% to 4% body weight from before to after tupping, then an additional 4.5% to 6% to pregnancy scanning. Any sheep losing more than this is put into a field for extra feeding, with high-protein ewe rolls.

All 1,400 ewes have access to high-energy crystalyx tubs, with 10t used over winter.

Across both flocks, ewes scanned with twins or triplets will also be kept in and fed with concentrates. The ewes scanned for a single lamb are returned to the hill, with access to feed tubs.

Hay is also made available when there is snow on the ground or if grass runs short.

Flock scanning rates

The Auchtertyre high hill flock scans 90% to 110% on average, with a barren rate of 8% to 14%.

The number of lambs which are weaned can be as high as 85% in a good year, while it can be 50% in a poor year.

The Kirkton high-index Blackface flock has had scanning rates of 130% to 140%, with the average-index Blackfaces around 110% to 130%.

The weaning rate for the two flocks is usually in the region of 110% and 105% respectively.

The Lleyns are scanning around 130% to 140%, and weaning around 113%.

However, in 2017/2018 the Lleyn performance suffered after two of the sires used in the single-sire mating groups failed to work properly, which was then followed by the bad weather associated with the Beast from the East.

These factors saw the scanning percentage drop to 105%, with a further 21% of the lambs born alive lost before weaning (weaning 72% based on number of ewes to the tup).

Head of department, integrated land management, Hill & Mountain Research Centre Davy McCracken said: “Over a 10-year period, we would expect the Lleyns to do as well or better than Blackfaces, but in poor or bad weather like the Beast from the East, they crashed.”

In the coming years, they are looking to crossbreed the two breeds to combine the higher prolificacy of the Lleyn and the hardiness of the Blackface.

Lamb deaths

The biggest area of improvement for the Auchtertyre flock is not to continually drive scanning rates, but to ensure the maximum number of lambs scanned come to market. “When possible, we try to get unexplained deaths investigated by post-mortem. Most of the known lamb deaths or culls are those associated around lambing time and shortly after birth, such as dystocia and hypothermia. However, a large proportion of the lambs lost from this high hill flock are never found, so reasons for death are unknown,” said Ewen Campbell.

A PhD student is investigating black loss of lambs from Scottish hill farms, which it is hoped will help provide some insight into how these numbers can be reduced.

Ewe deaths

The average ewe mortality in Auchtertyre is around 13%, whereas for Kirkton it is around 6%.

The top reasons for ewe culls and losses include those culled for tooth loss, poor body condition and reproductive or udder disorders.

The Kirkton flock has moved away from culling after the fourth crop of lambs to improve the flock’s environmental impact

A big proportion of losses are recorded as missing or presumed dead, as it is difficult to find ewes that have died on the hill in time for a cause to be determined.

The Kirkton flock has moved away from culling after the fourth crop of lambs to improve the flock’s environmental impact and only removes a ewe from the flock once she fails on other metrics. There are now ewes in their eighth or ninth crop of lambs.

The biological efficiency of ewes does not appear to fall off until around eight or nine years old, with seven-year-old ewes producing lambs with liveweights comparable to younger ewes (~27kg by weaning in August) regularly.

Finishing lambs

All the lambs are finished on farm, which is unusual on such farms, but necessary to provide the best data for breeding decisions. Lambs tend to be slaughtered in batches at a local abattoir between September and January, with most away before Christmas. Lambs are drawn for slaughter at 36kg for Lleyns and 38kg for Blackface.

Over 90% of Lleyn lambs grade as U or R for conformation, whereas over 75% Blackface are graded R. Blackface lambs finish a few days later than Lleyns, on average, and have slightly lighter carcase weights (by around 1kg) and a lower kill-out of 45%, compared with 48%.

Individual feed intake preliminary results suggest the Blackface lambs have higher daily feed intakes, but lower average daily liveweight gain compared with the Lleyn lambs, suggesting poorer feed efficiency in this system. This will be tested further this year.