17 April 2019
This technology has been trialled in the current breeding season at Llysfasi College, a Farming Connect Innovation Site near Ruthin.
Farming Connect established the trial to gather data on factors influencing the efficacy of impregnating ewes with frozen semen.
Cervical AI using fresh semen in not uncommon but this technique in combination with frozen semen - an approach which provides farmers with access to superior genetics and reduces risks of importing diseases - is rare in the UK due to poor conception rates.
At Llysfasi, breeding was synchronised in 50 mixed age Welsh Mules ewes from the 1200-head flock.
This group was inseminated in mid-October with semen from performance-recorded Texel and Norwegian White rams at a cost of £37/head for the synchronisation and semen.
The group has now started lambing and the results show that 10% of the group held to AI; the other pregnant ewes are in lamb to a sweeper ram introduced 14 days after AI.
The group that held to AI all produced singles.
Despite disappointing results at their first attempt, the team involved are confident AI conception figures can be improved.
Farming Connect’s Red Meat Technical Officer for North Wales, Gethin Prys Davies, who coordinated the trial, says data suggests that the timing of insemination and the diluent used could be key to achieving higher conception rates.
“The initial plan was to start inseminating 55 hours after the removal of the CIDRs (devices to increase blood progesterone concentrations) but we found the ewes were coming into heat quicker than anticipated - 37 ewes were marked by paint from the teaser ram after 50 hours,’’ he explains.
“As a result of this, we brought the insemination time forward from 3pm to 12 noon, 52 hours after the ewes were injected.
“The results suggest that this revised time was still too late, and we should have gone earlier as four of the five ewes which held to AI were inseminated between 52-53 hours.’’
Mr Davies says Farming Connect will repeat the trial in the next breeding season, with changes introduced to reflect the data gathered this year.
“Innovative projects always carry risk,’’ he says.
“The end goal is to develop this technique to a point where it is commercially viable for the farmer.
“We are not there yet, but this has given us a true sense of optimism and excitement for the future progress in sheep breeding.’’
Llysfasi farm manager Dewi Jones says the farm had been pleased to be involved in the trial.
“If we can make cervical AI with frozen semen work, it is potentially a way of speeding up genetic progress in ewe flocks as has been achieved in the beef and dairy industries,’’ he says.
The insemination at Llysfasi was carried out by Alwyn Phillips who has used cervical insemination in combination with fresh semen since 1983 on his flock of performance-recorded Texels and Poll Dorsets.
Mr Phillips, of Penygelli Farm, near Caernarfon, had visited Denmark and Sweden, two countries which achieve high conception rates using frozen semen, through the Farming Connect Management Exchange programme.
In Wales, most ewes in AI breeding programmes are inseminated laparoscopically but this is a high cost and invasive procedure with associated risks.
Scandinavian countries have become world leaders in the cervical insemination of sheep using frozen semen because laparoscopic AI is prohibited.
If cervical AI conception rates in the UK can be improved – Scandinavian countries achieve 50-70% – Mr Phillips says it could be cheaper for farmers to buy semen from proven rams than to invest in a stock ram which may not improve the flock and, in some cases, might have a brief working life.
Whilst the beef and dairy industry have made significant advances with introducing superior genetics into herds, there has been limited progress in the sheep industry.
Mr Davies says RamCompare, the UK’s first commercial national progeny test for terminal sire rams, in combination with frozen semen and AI, could be a turning point.
“To buy a ram in the top 1% is not financially viable for most sheep farmers but buying several straws from a proven ram could be a cost-effective way of introducing superior genetics into the flock,’’ he says.
Timeline of the trial at Llysfasi
Day 1
The selected ewes were turned out to grass for 18 days with a vasectomised ram fitted with a raddle to establish if they were cycling naturally.
Day 18
CIDRs were inserted to synchronise breeding
Day 30
The CIDRs were removed at 8am and the ewes injected with an oestrus synchronisation product, PMSG. At 6pm, the teaser ram was re-introduced to the group, this time fitted with a different paint marker.
Day 32
At 12pm, 52 hours after the CIDRs were removed, the ewes were inseminated, starting with those that were marked first by the teaser ram. Ewes were inseminated once with semen from a performance-recorded Texel ram.
Day 46
A fertile Suffolk ram - easily distinguishable from a Texel - was introduced to the group to ‘sweep’ ewes that did not stand to AI.