College flock pits Mules against terminal crosses

Early results from a trial at a leading vet college farm comparing Mules with three-quarter and seven-eighths-bred continental lowland ewes have shown one breed could have a slight edge.

The Royal Veterinary College (RVC), which owns Boltons Park Farm, near Potters Bar, Hertfordshire, has found the continental-type “lowland” ewes have, unsurprisingly, produced better carcasses.

But the North of England Mules have had better weight gain and lower lamb mortality.

Farm manager Graeme Webster, along with shepherd Aimee Bailey, started a breed comparison trial this year to see which sheep would come out on top.

See also: Mule breeder builds flock health to keep market share

“We are trying to do everything we can on the management and diet side to really see what we can get out of the sheep,” says Mr Webster (see below, Boltons Park Farm: High input system).

While profit is an aim at the farm, with school visits and outreach activities taking place each year, along with more than 16,000 student teaching hours a year on the farm, day-to-day management has more staffing and planning challenges than a typical lowland sheep flock.

Farmers Weekly will follow progress and see which breed ends up on top.

© MAG/Michael Priestley

Breeds

The two flocks are North Country Mules – a Swaledale sired by a Bluefaced Leicester – and continental ewes, which are a mix of Suffolk-, Texel- and Charrollais-crosses home-bred from Mules.

The farm runs a system producing lambs from terminal sires, and is using the data to see whether it is worthwhile retaining any continental-cross sheep, following improvements in the farm’s replacement sourcing policy for Mules.

Historically, about 60 ewe lambs were kept from the first draw of lambs and a similar number of North of England Mules was bought in from an agent.

Graeme Webster @ MAG/Michael Priestley

Biosecurity

However, this resulted in a maedi visna (MV) outbreak, lameness issues and sheep scab, all things that Mr Webster has controlled since he started managing the flock in 2019.

“When I first came, we bled the entire flock to test for MV and it was in about 5% of the ewes. We tested thinner sheep for Johne’s and checked for caseous lymphadenitis (CLA) as well, but the main issue was MV.

“The issue was buying from unknown multiple sources – we had a group of 100 Mule shearlings and 10 different UK numbers.”

The breed comparison trial is going to look at Mules bought from Cumbrian breeder Jonathan Hodgson, High Borrans, near Ambleside, who is monitoring his sheep for MV.

Mr Webster says having a known source of sheep and a breeder he trusts is important.

He believes Mules are potentially good sheep but cannot realise their potential if they are limited by disease, which is why a strict quarantine protocol is in place sourcing from a single flock (see Quarantine and biosecurity policy).

Results so far

At scanning, the twinning rate for the shearling Mules was 3% ahead of the shearling continentals, at 70%.

Lambing inside with the aid of veterinary students means there is plenty of labour to help with fostering, so the system does not rely on a high twinning rate.

“The continentals scanned better,” Mr Webster says. “But mortality and barren rates were lower in the Mules, so the actual numbers of lambs sold will be interesting to see.”

When all lambs are slaughtered, an economic income on each ewe will be calculated to determine which sheep are earning the business most money.