The benefit of improving genetics in hill rams has a far wider reach than just the hill sheep sector and can also bring about major improvements in the national ewe flock.
This is because the hill sheep sector is a breeding ground for replacements with good maternal genetics.
This message was delivered by Sheep Ireland manager Kevin McDermott during part one of the Teagasc hill sheep conference, which took place online last Wednesday.
Kevin said that 19%, or 15,656 rams from a total of 82,055 rams, were recorded as hill breeds on the Department of Agriculture 2019 annual sheep and goat census. A further 9% were classified as hill crosses.
The percentage of breeding ewes classified as hill and hill-cross ewes is far greater at 49% of the national ewe flock.
Kevin said that there is phenomenal opportunities to drive genetic gain in this area, with hill sheep systems slow to partake in the national breed improvement programme.
Viewers of the conference were told there are currently only two hill flock books set up in Ireland, both of which have been established in the last 12 months.
These are the Donegal Wicklow Cheviot Breeders and the Mayo-Connemara Blackface Sheep Society.
Kevin said the move by these two societies to form a flock book will unlock the potential to bring about significant advances in genetic gain, while also ensuring superior bloodlines are not lost.
The first step is collecting ancestry information on rams which have been bred to excel in the environment in which they are farmed.
Recording parentage information will protect important bloodlines and prevent them from being diluted down by crossing with inferior breeding strains or from inbreeding.
Once a flock book has been established, other attributes can be included in ram selection decisions, such as longevity traits, with a specific focus on how long a ram and its progeny will maintain a full mouth for example, how good of a milk yield its daughters will have or how fertile his daughters will be.
“The only way to predict these traits with a certain level of reliability is to collect data on their known ancestors and combine this into a central database for the breed where they can be analysed. A prediction on the future performance of the progeny can then be made.”
There have been several attempts to establish flock books across a number of hill sheep breeds in the past, but these have not proven fruitful.
However, Kevin said that these false starts were at a more difficult time where the same breeding tools were not available, with several advancements in recent years providing for much greater success this time round.
There is also the potential where parentage was recorded incorrectly or not recorded at all to be identified.
The potential of this increases greatly as more records for a breed are incorporated into a flock book.
At present, 8% of purebred lowland animals genotyped had an incorrect sire recorded, with this rising to 8.5% for ewes.
Kevin said there is no reason to think these figures are any lower in a hill sheep context, with a strong possibility they could be higher.
Kevin presented data which shows that based on the number of animals genotyped in the previous two years, there appears to be a higher percentage of scrapie type-3 animals identified in the hill breed when compared with the results from the lowland ewe flock. This is detailed in Table 1.
However, it should be pointed out that the data set for the hill sheep breeds is small and it does not convey that they are more prone to scrapie. Rather, it shows the merit of collecting higher volumes of data and informed breeding decisions.
Kevin said the range of genomic inbreeding typically ranges from 0% to 13% in the sheep genotyped to date.
Therefore, he said breeders and farmers need to be aware of its threats and avoid it.
Inbreeding tools developed by Sheep Ireland can help to avoid the chance of inbreeding.
Kevin said this cuts down significantly on the length of time it takes to assess animals on certain attributes, with genomic evaluations, which were launched in 2020, increasing the average accuracy of genotyped animals by 17%.