The Science and Art of Upgrading – Foundations

ValaisBlacknose

Until it becomes possible to import embryos or animals with a pure genetic heritage behind them, all new breeds are subjected to the upgrading process. The Wensleydales have gone through it, the Teeswaters have gone through it, as have the Zwartbles, the Gotlands and several other breeds that didn’t have the benefit of having pure foundation stock imported into the US. It sounds relatively simple and straightforward – select a foundation breed, artificially inseminate it, and voila – you have offspring with 50% of the genetic information you are interested in. Do that a few more times until you get to 96% or 98% blood percentage and you have an almost purebred individual, right? Unfortunately, its just not that simple.

Regrettably genetics just don’t find themselves constrained by simple division. How a gene parses data, and their attendant characteristics is a biological roll of the dice. Sometimes you hit the jackpot, many times you don’t. And when you are working with a new set of genetics, the learning curve is particularly steep because you have no idea if you are dealing with characteristics that run the gamut from dominant, to co-dominant to recessive to epistatic to anything in between. You can dedicate lifetimes to learning all about genomes and still be surprised, and in the case of the Valais Blacknose, we’ve never worked with anything like this, and haven’t a clue how its all going to work out.

So where exactly does that leave us – with a whole lot of guesses and not a lot of solid information. And realistically, even empirical observations are going to take time to develop enough “examples” to draw really solid conclusions from. So what does that mean from an Association standpoint? It means that we probably shouldn’t write in stone what we will accept the first time out the gate and give folks an opportunity to figure out what best meets their goals, and that we should be keeping very detailed and accurate records along the way so that we can refer back 3 – 5 years  and mine through all that experience to some useful conclusions.

Which brings us to our first set of decisions – the breed up guidelines.

In looking at all the characteristics that make up a good sheep several come to the forefront as being pretty important to most breeders – they need to be useful and have value, they need to stay alive, and they need to be something that can be reasonably managed with normal practices without excessive cost; which basically equates to the usual list of suspects: physical type, feed efficiency, growth rate, temperament, mothering ability and prolificacy. We will forget the cost part of the equation for the time being as imports by definition are ridiculously expensive and generally not at all cost effective. Its a labor of love – or maybe a love of labor, either way, nobody gambles like a farmer.

In making a guess about which foundation breed(s) are going to give you the most similar  type in the fewest generations –  which admittedly is a pretty important thing for the worlds cutest sheep –  there is some pretty low hanging fruit out there – they look an awful lot like Scottish Blackface Sheep. There could even be some common ancestors somewhere back in those historical pastures, but by no means is that a slam dunk.

There are a number of sheep out there that have at least some similar characteristics – a number of  F-1s are currently incubating in Shetlands and  Dorpers,  as well as Teeswaters, Gotlands, Babydoll Southdowns and various cross bred animals. All have their pros and cons, depending on what your focus is, and we have no real empirical information on how Valais Blacknose Rams will cross on any of them.

But wait, you say – yes we do – they’ve been using  Scotties as a foundation animal in Scotland, we know what they do! That’s partly true, they have been using the UK Scotties in Scotland.  US Scotties, while similar have been Americanized in ways that we really can’t even begin to guess. We know from experience that our country is so large, with such a tremendous diversity in environment, forage and geology, that even moving animals from one side of it to the other can pose significant challenges and result in fundamental changes in type and performance in just a few generations, let alone moving to a different continent. It also means that an animal that has been heavily selected in an extreme environment may not be well suited to many areas in the US and may result in more issues than benefits for some breeders. Because those sorts of issues don’t really promote a wide genetic diversity with the ability to readily adapt to the US production environment and meet all the other tick marks on our wish list, that didn’t seem like a good place to wedge the bar.

There are two very different schools of thought about how to breed up. One involves picking a very similar breed and building on those genetics to incorporate them in an acceptable way into future generations of the animal you are trying to create. The other is to take an animal that is as different as possible and continue to select away from those traits with subsequent infusions of the breed you are working toward so as to remove the base animal entirely and purify your desired genetics.

In both cases the trick is getting the genetics to line up in a way that produces the desired result. A difficult proposition when semen is expensive, AI is difficult and the number of sires is highly limited. Since we are relying on a genetic roll of the dice, the best way to achieve reliable results is to do that alot and find the best results in each group. Further, we realistically don’t have the ability to simply infuse new genetics as a way to correct latent recessive defects exposed by the level of inbreeding/linebreeding necessitated by the extremely limited import pool, so careful selection criteria and heavy culling of unacceptable stock are critically important for the viability of the genetic population. The best, and possibly, the only realistic way to do this is sharing information, utilizing the best genetic specimens from across the country to continue to advance the US breeding pool toward the breed ideal.

To that end, the Association is working toward a centralized record keeping model that collects and organizes individual records for access by all members. Inclusion of foundation breed information, photos, birth weights, rates of gain, prolificacy and other metrics are intended to help breeders by sharing the experiences of other breeders in a complete and standardized way. It may eventually be appropriate to move to NSIP for certain values, but such future decisions will be better evaluated when more information regarding animal performance is available. So for now, the model remains performance rather than method based, with a focus on detailed records, information sharing and an eye toward a more structured future when we have more information available to better inform future decisions.

 

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