Sire Referencing Project for Deer
Featuring: Dr Jason Archer, project leader, senior scientist, geneticist, AgResearch Invermay
Invermay has set up a system that has sped up the ranking of stags on the basis of the growth of their progeny. Essentially a tool to get industry-wide comparisons up and running, and partly funded by FORST money, the sire referencing programme has been successful and is now in a situation where the industry can extend it to comparisons of temperament, seasonality traits and disease resistance.
It isnt difficult to compare the performance of stags within the same herd. The management and environmental influences on them are essentially the same, so any difference in performance is a true expression of genes. However, comparisons between farms are much more difficult because of different environmental influences.
Invermay arranged for a number of farmers from key deer studs to provide semen from their top stags. This was used over several hundred Invermay hinds, as well as on the studs involved. When their progeny were born and raised under the same environmental conditions at Invermay scientists could work out the relative contribution of the stag genetics to their progenys performance and then through a variety of statistical means correct the figures from each stud for the differences in environment as opposed to genetics. This gave a corrected breeding value for each stag compared across all farms and all years in programme.
For the first time last year they provided a list of breeding values for nearly 150 stags around the country, ranking them on how well they performed in terms of yearling weight, thus allowing farmers to make some objective choices about sires.
A new set of breeding values for this year will come out soon, and then next year there will be another set of breeding values including even more stags. Eventually farmers will start swapping stags and semen amongst themselves, and since that will links sire across the farms as well the need for a reference farm will diminish.
Dr Geoff Asher, head of the deer research programme at Invermay, says that the sire reference farm programme has spurred the key players in the industry to link sires together.
If we hadn't had the link farm it would have happened only slowly. It has been tried before but there wasn't the willpower and the drivers behind it in to keep it going, he says.
Concentrating it as a sire reference programme provided the incentive to get it going and it has been very successful.
This approach has been used in other livestock industries. Once the centralised sire referencing herd has been established for a few years, the need for it diminishes and the industry moves away from it to become a bunch of linked herds using link sires.
The project has been partially funded through FORST to get it going. This has allowed the concept to be proven, and the industry can now springboard from this to looking at other things like the genetics of temperament and the genetics of seasonality traits. Any further work will probably have to be fully industry funded, and there is every indication that the industry will pick it up.
It's early days yet but what has happened in all other livestock industries where they have used estimated breeding value (EBV) systems like this is that they got an immediate performance jump followed by positive gains each year, says Asher.
Already the indications are with this one that there will be a significant lift in the performance of the contributing herds. The downstream effects of that which we can't yet measure are what happens in all the commercial herds that buy sires from them.
A good example of the gains that can be made, he says, come from experience with deer antler performance, which is so highly heritable that deer farmers have been able to achieve huge advances in deer antler growth without the need for a sire referencing scheme.
However, antler growth is not much affected by environmental conditions whereas carcass growth is.
So carcass growth, with its lower heritability, requires more standardised systems to ensure that what you are measuring is actually genetic merit and not just the influence of environment. In the past when they bought sires from studs, farmers didnt know whether they were buying superior genetics or simply the result of better feeding, says Asher.
What sire referencing and linked sire systems do is standardise the environment or apply some correction factor that takes out the environmental components.
Other traits
So far the project has focused very strongly on growth traits of progeny in their first year, but the system can be applied to other traits that farmers are interested in. One that is starting now is looking at temperament an important consideration in flighty deer. What is good temperament? One of the problems is if you ask ten farmers what constitutes good temperament you will get ten different answers. Once you have an objective answer, how do you measure temperament? Is it heritable? And once you have some meaningful figures how do they fit into the breeding value system?
Another aspect that the industry is very interested in seasonality genetics deer are strongly influenced by the photoperiodic effect, and that constrains production systems. What genes are involved in controlling seasonal traits, and the genetics of animals be changed so that they calve earlier or grow differently in different seasons?
We now have a system in place into which we can plug any new measurements as science gives them to us. AT the moment its just growth at 12 months of age, which is very important, but very shortly we will be plugging in antler traits, and over the course of time we will be plugging in temperament traits, seasonality traits, traits for disease resistance, says Asher.
By and large the stud breeders are driving this, they realise now that they can't rely on named stags any more. Farmers are coming back to them and saying that they want to know that what they are buying has true genetic merit.
Invermay has set up a system that has sped up the ranking of stags on the basis of the growth of their progeny. Essentially a tool to get industry-wide comparisons up and running, and partly funded by FORST money, the sire referencing programme has been successful and is now in a situation where the industry can extend it to comparisons of temperament, seasonality traits and disease resistance.
It isnt difficult to compare the performance of stags within the same herd. The management and environmental influences on them are essentially the same, so any difference in performance is a true expression of genes. However, comparisons between farms are much more difficult because of different environmental influences.
Invermay arranged for a number of farmers from key deer studs to provide semen from their top stags. This was used over several hundred Invermay hinds, as well as on the studs involved. When their progeny were born and raised under the same environmental conditions at Invermay scientists could work out the relative contribution of the stag genetics to their progenys performance and then through a variety of statistical means correct the figures from each stud for the differences in environment as opposed to genetics. This gave a corrected breeding value for each stag compared across all farms and all years in programme.
For the first time last year they provided a list of breeding values for nearly 150 stags around the country, ranking them on how well they performed in terms of yearling weight, thus allowing farmers to make some objective choices about sires.
A new set of breeding values for this year will come out soon, and then next year there will be another set of breeding values including even more stags. Eventually farmers will start swapping stags and semen amongst themselves, and since that will links sire across the farms as well the need for a reference farm will diminish.
Dr Geoff Asher, head of the deer research programme at Invermay, says that the sire reference farm programme has spurred the key players in the industry to link sires together.
If we hadn't had the link farm it would have happened only slowly. It has been tried before but there wasn't the willpower and the drivers behind it in to keep it going, he says.
Concentrating it as a sire reference programme provided the incentive to get it going and it has been very successful.
This approach has been used in other livestock industries. Once the centralised sire referencing herd has been established for a few years, the need for it diminishes and the industry moves away from it to become a bunch of linked herds using link sires.
The project has been partially funded through FORST to get it going. This has allowed the concept to be proven, and the industry can now springboard from this to looking at other things like the genetics of temperament and the genetics of seasonality traits. Any further work will probably have to be fully industry funded, and there is every indication that the industry will pick it up.
It's early days yet but what has happened in all other livestock industries where they have used estimated breeding value (EBV) systems like this is that they got an immediate performance jump followed by positive gains each year, says Asher.
Already the indications are with this one that there will be a significant lift in the performance of the contributing herds. The downstream effects of that which we can't yet measure are what happens in all the commercial herds that buy sires from them.
A good example of the gains that can be made, he says, come from experience with deer antler performance, which is so highly heritable that deer farmers have been able to achieve huge advances in deer antler growth without the need for a sire referencing scheme.
However, antler growth is not much affected by environmental conditions whereas carcass growth is.
So carcass growth, with its lower heritability, requires more standardised systems to ensure that what you are measuring is actually genetic merit and not just the influence of environment. In the past when they bought sires from studs, farmers didnt know whether they were buying superior genetics or simply the result of better feeding, says Asher.
What sire referencing and linked sire systems do is standardise the environment or apply some correction factor that takes out the environmental components.
Other traits
So far the project has focused very strongly on growth traits of progeny in their first year, but the system can be applied to other traits that farmers are interested in. One that is starting now is looking at temperament an important consideration in flighty deer. What is good temperament? One of the problems is if you ask ten farmers what constitutes good temperament you will get ten different answers. Once you have an objective answer, how do you measure temperament? Is it heritable? And once you have some meaningful figures how do they fit into the breeding value system?
Another aspect that the industry is very interested in seasonality genetics deer are strongly influenced by the photoperiodic effect, and that constrains production systems. What genes are involved in controlling seasonal traits, and the genetics of animals be changed so that they calve earlier or grow differently in different seasons?
We now have a system in place into which we can plug any new measurements as science gives them to us. AT the moment its just growth at 12 months of age, which is very important, but very shortly we will be plugging in antler traits, and over the course of time we will be plugging in temperament traits, seasonality traits, traits for disease resistance, says Asher.
By and large the stud breeders are driving this, they realise now that they can't rely on named stags any more. Farmers are coming back to them and saying that they want to know that what they are buying has true genetic merit.