How leading breeders are speeding up genetic gain in Texels

Using embryo transfer (ET) together with a synchronisation programme is helping a renowned Texel flock speed up genetic gain.

The Clark family, consisting of brothers Alan, Andrew and David and mother Helen, are well known for breeding leading females, ram lambs and shearlings from their 60-strong Garngour, Teiglum and Clark flocks, which run together in Lanarkshire.

They have achieved prices up to 70,000gns – for the ram lamb Teiglum Young Gun in 2016 – and have realised several more five-figure sums for their stock.

The Clarks use ET on a number of their top females every year, with a handful of ewes flushed twice.

Farm facts

  • 600 head of commercial ewes, mostly Texel-crosses
  • 60 pedigree Texels
  • Flushing 20-30 Texels a year
  • Farming 526ha
  • Sold ram lambs up to 70,000gns and shearlings to £29,000
  • Only the best ram lambs are offered creep to get them in top condition for sales at Carlisle and Lanark. Twin lambs are introduced from about two weeks old and singles when needed.

Female selection

Only the best females are selected to flush, and they must be from good, trouble-free families. The aim is to breed a balanced type, with good conformation as well as breed character.

Alan says: “We are breeding for the pedigree market, but ultimately every animal we produce needs to be able to perform commercially.”

See also: What to consider if you want to AI sheep

Conception rates have been as high as 80% in the younger females, with last year’s average 77%.

On average, six embryos are obtained from each donor ewe flushed.

Three Clark brothers on the farm

David (left), Andrew and Alan Clark

Home-bred recipient ewes from the 600-head commercial ewe flock (Bluefaced Leicester cross Texel) are used as they are milky ewes with good mothering ability.

Most recipients are one- or two-crop ewes that have successfully held and produced good lambs previously. The rest of the commercial flock is bred to Texel rams, to produce finished lambs off grass.

Synchronisation programme

Embryo transfer speeds up a flock’s genetic gain by breeding more progeny from the best ewes.

The donor ewe is super-ovulated using hormones, so she produces more eggs than usual at a synchronised mating.

Fertilised embryos are flushed from the donor ewe and transplanted into suitably synchronised recipient ewes to establish a surrogate pregnancy.

Two people inserting progesterone device into a ewe

Inserting a CIDR Ovis device using an insertion tool

Synchronisation is used in both the donor and recipient ewes (see timeline box).

After consulting with their vet and breeding company, the Clarks switched from using sponges to a T-shaped progesterone device called CIDR Ovis which mimics the natural progesterone of the sheep.

They say it is easier to insert and remove compared with sponges but that the timings are different, so it is important to follow the exact guidelines.

Ewes are flushed in September and October to lamb in March-April. The Clarks work with a specialised breeding company which performs all the ET and AI work.

Management of ewes

Donor ewes are managed carefully in the run up to flushing. They are housed for a period of a few weeks in summer and fed hay and water in order to get them in the correct body condition.

They are then turned out on to silage aftermaths and at the time of insertion both the donor and recipient ewes are fed a high plane of nutrition.

The diet for donors and recipients at insertion consists of 50:50 beet pulp and oat mix with an energy of 13-14ME. They stay on that until the point of flushing.

During the first few weeks, recipients are grazed in surrounding fields as a group to keep them settled, which helps embryo development.

It can be costly to carry out ET work, but the Clarks say the cost is justified on their farm.

Alan says: “It can be a lot of money, but we are getting the return by being able to sell more top-pedigree animals at the sales and privately. Synchronisation also allows you to lamb when it suits you.”

Is synchronisation right for me?

Synchronisation isn’t reserved for the elite pedigree breeders. It is something that can benefit commercial producers wishing to reap financial rewards by marketing their lambs earlier.

Bringing forward the breeding season, to tup in the summer and lamb in late December or early January, means farmers can get lambs away by April and May.

Figures from AHDB show that lambs sold in April and May generate on average 21% greater return over those sold in the summer months, giving a possible extra £18 per 45kg lamb.

In addition, synchronising oestrus and then using AI gives farmers access to superior rams without the initial purchase costs and accelerates flock genetics. A top terminal sire can add £3.50 sale value a lamb/year.

Timings of synchronisation and insemination with T-shaped progesterone devices

  • One CIDR Ovis device is inserted into the vagina of each ewe.
  • The vaginal insert is left in position for 12 days, followed by an injection of equine chorionic gonadotropin (eCG) hormone at device removal.
  • The onset of oestrus occurs within one to two days after removal of the insert, at which time animals are inseminated.

Synchronisation methods compared



Chronogest sponge


Active ingredient


Flugestone Acetate 0.20g

Progesterone 0.35g

Withdrawal (meat)

0 days

2 days (after removal)

0 days


Vasectomised male

Vaginal sponge

T-shaped vaginal device


Induces oestrus

Induction and synchronisation of oestrus and ovulation

Induction and synchronisation of oestrus and ovulation


14-17 days followed by entire male

14 days followed by injection of eCG*

12 days followed by injection of eCG*

Pack size








*Equine chorionic gonadotropin, formerly known as PMSG

Source: Kirsten Williams, SAC Consulting beef and sheep consultant