Artificial Insemination (AI) is commonplace in suckler and dairy herds, but its use is more limited in sheep flocks due primarily to prohibitive costs and variable success rates.
Last Saturday, the Irish Farmers Journal visited A Farmer Writes contributor Brian Nicholson to see laparoscopic AI in action. The farm, located in Johnstown, Co Kilkenny, is taking part in the central progeny test (CPT) programme run by Sheep Ireland.
The CPT programme is in its sixth year using AI, with in excess of 2,000 ewes inseminated per year. The process is no easy feat, especially when you take into account rams also have to be quarantined and trained to deliver semen for four weeks before inseminating.
As Eamon Wall from Sheep Ireland explains, the practice is worth the effort, as it delivers invaluable breeding information that is central to improving breeding in the national flock.
Background to CPT
The aim of the CPT programme is to improve the accuracy figures for the €uro-Star index and to help accelerate the rate at which top genetic sires are identified, based on performance data of a ram’s progeny on commercial farms.
Since 2009, the programme has used semen from rams on commercial flocks that have a very high standard of animal performance recording.
In the early years of CPT, the goal was slightly different to the current one. The primary aim was increasing the amount of information across all the bloodlines (high- and low-starred rams) in order to create genetic linkage across all the breeders in LambPlus. This goal was deemed to be at an acceptable level after 2013 and so the criteria was changed to try to identify the best bloodlines for breeding replacement ewe lambs.
Eamon says the reason behind using high-index rams is that their progeny’s performance can be scrutinised at a commercial level and the data obtained from these farms can be fed back to the animals’ indices. This increases the reliability of important production traits and identifies top-performing animals that will improve breeding in pedigree and commercial flocks.
“Our hope is that by proving the ram’s accuracies in the CPT, we can then go further down the line of promoting the use of those rams to pedigree breeders,” explains Eamon.
The main reasons AI is used for the programme are:
The number of progeny each ram produces is increased hugely compared with natural service, which means better data can be obtained.
Having ewes lambing down in a short period means the data selected for comparing progeny performance is much more accurate, as each lamb should be subjected to the exact same conditions (removes any environmental bias caused by a significant spread in lambing dates and aspects such as weather and grass availability).
Brian Nicholson says one of the main reasons he joined the CPT last year was because he likes the idea of a very condensed lambing period.
This year, he is going to inseminate 500 ewes artificially and with an almost 80% fertilisation rate from the AI service in 2014, he expects over 400 ewes will be lambing over a 10-day period next spring.
“Having a compact lambing period by synchronising the ewes means I can plan labour much better at lambing time,” Brian says.
He also likes the fact that high replacement index rams are being used on his flock.
“This should help increase the genetic merit of my own lambs that I will be keeping on the farm for breeding.”
Brian keeps meticulous records at lambing time by electronically tagging lambs once they are born and matching these lambs to their mothers on a sheep management system.
He records key data such as lambing difficulty, birth weight and weight at 40 days, 100 days and 150 days (unless already sold).
By using electronic tags and a computer recording system, Brian knows the sires and dams of each lamb and he will base sire and dam selection the following year on the performance of those lambs.
Brian’s recording skills in turn help the CPT programme because he will pass his lamb’s performance records on to Sheep Ireland. It will be able to see how each ram’s progeny performed and even more farmers will benefit from the data produced, as it will improve the accuracy of the €uro-Star indices.
There are various methods of AI available, with the most common being laparoscopic AI, with some cervical AI now being used. Laparoscopic AI is used for the CPT programme and is seen by Sheep Ireland as the most suitable practice to optimise fertilisation rates.
Watch a step-by-step video of the process below:
The timeline for synchronisation and laparoscopic AI on Brian’s farm is as follows:
3 October: Approximatively 250 ewes were implanted with a progesterone sponge in the vagina (two weeks before AI took place). The sponges were inserted to synchronise cyclic activity of the flock. Brian inserted the sponges himself using a special tube and syringe.
15 October: The sponges were removed by giving a firm and slow pull to the strings attached and the ewes were injected with PMSG at a rate of 400iu/ewe. The PMSG was used to increase ovulation rates and in turn hopefully increase the litter size of the ewe if she was successfully mated.
16 October: The ewes were kept indoors and were given restricted access to forage and water for 24 hours to prepare for laparoscopic AI. Rams were in the shed next door to create the ram effect. The rams’ natural male pheromones help to set off the ewes’ reproductive systems and complements the effect of the removal of the progesterone sponges.
17 October: Sheep Ireland transported rams rated as five-star on the replacement index to the farm (these rams were sourced from private breeders and put in quarantine for a month in advance). During this quarantine, rams were trained to produce semen for AI. Twelve rams were selected for breeding for Brian’s flock from the Texel, Belclare and Suffolk breeds.
On the day of AI, Ronan Gallagher from Prostar Genetics, Co Sligo, took fresh semen samples from the rams present. This semen was used to serve the 250 ewes that were brought into heat following sponge removal two days previously. A ram was selected from the six present and let into a pen with a ewe in heat. As the ram went to mount the ewe, an artificial vagina connected to a plastic collector and tube was used to collect the semen.
Ronan says generally over one millilitre of semen collected from a ram is a good quantity in one jump.
Once collected, he takes a small sample of the semen and puts it under the microscope. He grades the semen from one to five on factors such as motion, viability and vigour, with five being the best quality.
Good-quality semen is diluted with a dilutant made up primarily of egg yolk to increase the amount of ewes the semen sample can cover. One millilitre of semen from the ram can be diluted to 10ml and this will easily cover 50 to 60 ewes.
The semen and the dilutant were stored in a warm water bath at body temperature of 35°C.
All the ewes were given a sedative to relax them before the procedure was carried out. Just before AI, the ewe was put up on a special trolly to keep her as steady as possible before work began and make her abdomen freely accessible.
The ewe was clipped and surgically prepared. A small incision was made on the left and right hand side of her stomach. On the left, a 10mm trocar was used to make the incision a couple of centimetres in front of her udder and on the right, a 5mm trocar was used. On the left, the scope was put in and connected to a light source and acted as a mini camera.
Gas was also pumped in this side to help displace the stomach, bladder and intestine so that it was easier for Ronan to see the womb.
Once the way was clear, the AI gun was placed into the right-hand side and 0.1ml of semen was injected into each uterine horn. The two trocars were removed and there was no bleeding whatsoever.
The insertion sites were tiny and there wasn’t any need for a stitch.
Antibiotic spray was used on the sites and ewes were given an antibiotic injection to prevent any risk of infection. The remaining 250 ewes were serviced a few days later with the same procedure.
Research carried out by Áine O'Brien of Teagasc shows that it is possible to select breeding lines with a lower prevalence of important production traits.
The concept of breeding healthier sheep was discussed by Áine O’Brien of Teagasc at the recent Sheep Ireland/ICBF genetics conference to celebrate 10 and 20 years in existence.
Three traits were highlighted – lameness, dagginess and mastitis. All three fit the criteria of being including in a breeding goal which, according to Áine, include being socially or economically important, exhibit genetic variation and are measurable on a large scale or correlated with a trait that is.
The phenotypes used to record dagginess is a score system ranging from one to five while lameness is recorded as no evidence or lameness or any sign of lameness.
A similar approach is used for mastitis, with no evidence of mastitis or evidence of existing or historic mastitis.
Looking at dagginess in isolation the current prevalence recorded by Áine was 30.2% of adults and 22.2% of lambs but there is significant variation between sires from as low as 0% prevalence to 75% prevalence. There was a similar trend for lameness with a spread of 0% to 45%.
The data was extracted from 39,315 records across the five main breeds Belclare, Charollais, Suffolk, Texel and Vendeen.
Heritability estimates were recorded at 14% to 15% for dagginess while lameness was estimated at 6% to 12% and mastitis at 4%, although the low heritability could be influenced by a lower recording rate due to the possibility of ewes being culled or dying with the cause not recorded as mastitis.
Áine summed up by highlighting that we have the tools to breed healthier sheep and therefore we should now be using them.
As such, dagginess and lameness are now included in the terminal index (1.15% for dagginess and 0.11% for lamb lameness) and replacement index (0.17% for dagginess, 0.02% for lamb lameness and 0.04% for ewe lamness). This is a first in sheep breeding programmes and further research is taking place in other relevant health traits.
The PAC chambers can collect samples from 12 sheep and can be brought direct to the field to minismise disruption to normal behaviour.
Sheep Ireland celebrated 10 years in existence with a combined conference held last week in Athlone with beef counterparts the Irish Cattle Breeding Federation (ICBF) which is coincidentally celebrating 20 years working in beef breeding in Ireland.
The conference delivered a number of presentations which reviewed milestones of the last 10 years, while also looking ahead to Sheep Ireland’s plans for sheep breeding in Ireland.
Setting the scene, Tim Byrne from Abacus Bio Limited said that Sheep Ireland started in an era of low performance recording and a focus on driving progress in terminal traits.
This, he said, came initially at the expense of maternal attributes, with the replacement index caught in a downward trend that remained as such until 2014.
A change in the makeup of the replacement index and a greater focus on maternal attributes has brought about significant change, with the average replacement index set to come into positive values in 2019, as reflected in Figure 1.
This also demonstrates another challenge highlighted by Tim that significant improvement is needed in maternal traits. Meanwhile, growth and lambing have not been affected by the change in emphasis and have also recorded improvement in recent years.
Benefit to farmers
In terms of what this has delivered to farmers, Tim said the proof is in the performance of animals rated as four and five stars on both the replacement and terminal indices.
He presented data that showed five-star animals recording lamb mortality of 9.5% compared with 10.7% for one-star rated animals. There is a 0.05 difference in the number of lambs born in favour of five-star animals (1.97 v 1.92) while five-star ewes have a mature weight of 76.8kg, which is 1.9kg lighter than their one-star counterparts.
In terms of the terminal index, lambing difficulty for five-star animals is shown to be 4.9% lower at a value of 18.2%, while progeny of five-star parents were shown to have a 2.1kg higher weight at day 40 (20.2kg v 18.1kg), with this difference holding through to weaning and delivering a weaning weight of 34.5kg compared with 31.9kg.
Tim said that, in economic terms, the benefit of using five-star genetics is worth €5 per ewe for commercial flocks and €20/ewe for pedigree flocks.
He heralded breeder participation in the LambPlus scheme and an increase in the volume of commercial data being fed into evaluations as driving this gain through identification of superior genetics.
The number of LambPlus breeders stands at over 700 flocks, with the greatest gain fuelled by the Department of Agriculture’s Sheep Technology Adoption Programme in place between 2012 and 2015, with momentum continuing to build despite the absence of a targeted scheme.
The volume of commercial data recorded has improved in the last four years, but still remains small in the context of the national sheep population, with records in the region of just 17,500 lambs.
This is one of a number of challenges highlighted by Tim as required to underpin future breeding progress.
Traits included in genetic evaluations in the future should include age at slaughter, lamb vigour, mothering ability, mastitis, ewe productivity (number of lambings) and greenhouse gas emissions.
Along with this, Tim says there needs to be more routine genomic parentage assignment and greater use of genomic evaluations.
Across-breed evaluations have been talked about for some time, but have still not been introduced. This was highlighted as a priority area for future developments, along with a system of incorporating and comparing international economic breeding values with greater ease.
The use of non-recorded rams, estimated as comprising 75% of rams used, is seen as a major barrier to extending the use of superior genetics into the wider national flock, while a lack of factory data from commercial animals was highlighted as limiting the recording process.
In a wider context, global market uncertainty and adoption of consumer traits, such as eating quality, is a challenge for sheep sectors across the world.
Closer to home, Tim says a review of the overall industry direction that could take the form of a new Malone report would deliver greatly.
Teagasc’s Fiona McGovern presented the first look at new research looking at greenhouse gas emissions (GHG) in sheep.
GHG emissions from agriculture are already facing closer scrutiny and, as such, it is important to be able to firstly accurately quantify how sheep fare in terms of the amount of methane produced in light of their feed intake and then establish if there is variability in production across animals so that feed intake and methane emissions can be integrated into future breeding programmes.
The final step is international genetic analysis of predicted feed intake and methane emissions.
The research is taking place under the Greenbreed banner, which will also be tackling the same challenges in other livestock enterprises.
For sheep, it will take place initially in the Irish and New Zealand Across Country Comparison (INZAC) trial flocks.
Portable accumulation chambers (PAC) have been imported from New Zealand and will allow this data to be collected in the field by simply housing animals in the chamber for short periods of time.
The phenotypes currently measured will now extend to feed intake, feed digestibility, rumen microbial profile and methane output.
College lecturer David Coen addresses students from Ennistymon CBS, Co Clare at a careers open day in the Salesian Agricultural College, Pallaskenry, Co Limerick. Photo O'Gorman Photography.
Sheep Ireland breeding advice for selecting rams has always centred on judging an animal on a combination of physical traits and predicted breeding performance.
At last week’s genetics conference, head of sheep enterprise at Salesian Agricultural College David Coen told those attending that were it not for access to genetic evaluations, a ram that is now excelling in the flock could have met a premature end.
David said that in 2015 the flock purchased a Belclare ram, Kilflynn Amigo MN1511041, which at the time had a good replacement index value of €1.22, but could have been characterised as not possessing superior physical attributes.
He explained: “The ram was a triplet that weighed in the region of 45kg. He had sound physical attributes in terms of legs, feet, teeth, conformation, etc, but was light and looked to some to be closer to a factory ram than a breeding ram.
“We decided to take a chance on his genetics and have been hugely rewarded since,” he said.
The purchase of the ram coincided with the flock putting much more attention into data recording.
David explains that there has been a sheep flock in the college for over 60 years, but that there was very little data recording taking place until recent years.
The flock joined Sheep Ireland in 2016 with the aim of establishing current performance and identifying the best- and worst-performing ewes.
Ewes were assessed on breed, age, weight, body condition score, etc, with this information used to develop a primary profile.
In 2016, ewes were artificially inseminated to Central Progeny Test (CPT) sires. This gave the opportunity to evaluate the flock against linked flocks, while the collection of higher volumes of data helped to increase the accuracy of genetic evaluations.
Kilflynn Amigo was then widely used in the flock in 2017. Figure 1 shows the average replacement index of females in the flock, with a complete turnaround achieved in the last six to seven years.
David explains that ewe lambs have followed a continuous upward trajectory, with ewe lamb replacements possessing a higher value than the average of mature ewes, demonstrating that the flock is moving in the right direction.
The average replacement index of females in the flock was €0.195, with an accuracy of 40% in 2018.
The average replacement index of females lambing down in 2019 is €0.915, with 42% accuracy.
The jump in the replacement index value has been underpinned by Kilflynn Amigo’s genetic evaluation soaring in 2017, with the replacement index value now standing at €4.86, while the terminal index has increased to €2.01, with the accuracy of predictions now at 78% and 81% respectively.
The increase has been such that the ram has been used in four pedigree flocks in 2018 and through the CPT flocks.
This is a situation David is particularly pleased about: “For our flock to continue to record progress, we need access to superior genetics, which are becoming harder to source.
“It is important that pedigree breeders utilise the best genetics to make this happen and we are glad to be in a position to be able to help.”
Five-star genetics delivering
The flock is now starting to deliver on some key performance indicators. A higher daughter milk yield potential is delivering in higher output, with ewes rated as four and five stars for daughter milk achieving a litter weight at 40 days of 7kg higher than one-star ewes and 2kg higher than three- and four-star rated ewes.
The lamb survivability rating of ewes has also improved, with over 106 ewes rated five-star for lamb survivability, while there are 43 four-star ewes, 36 three-star ewes, 29 two-star ewes and 33 one-star ewes.
David believes this is contributing to lower lamb mortality, which has improved from 13.03% in 2016 to 11.75% in 2017 and 9.49% in 2018.
David concludes that management still remains vital to flock performance, but that without recording performance you will not be able to make decisions that will influence management practices with any degree of accuracy, while there is also the risk of losing the flock’s best genetics.