Cross Bred Tups - Any good?

[M-J-G]

There seems to be a notion in some people's minds that using a pure bred sire gives some kind of assurance that progeny will be consistent.

As @Ysgythan has said, the more inbred an animal is the more variation can be avoided, and in theory breeding pure is closer to in-breeding than crossing.

However, if two animals from within the same breed are of very different types, or are a total outcross, the variations in resultant generations can be as extreme as using a mismatched crossbred, and a lot more extreme than if said crossbred is made up of two animals of very similar type.

As for the theory of the mule being an example of why crossbreds haven't caught on, take a look at the two parents of the mule, they are not of a type, so it's unlikely that two breeds as different as a Blackie and BFL would breed consistently if used on a mongrel.

But cross a Blackie with a Swale, and the resultant progeny would breed more consistently due to there being more similar in type.

 

[glensman]

He sells pure tups...

I know........

 

[Ysgythan]

I know........

Ah good, wasn't sure I'd mentioned it.

 

[Woolless]

A self portrait

Led Zeppelin IV?

 

[MRT]

Led Zeppelin IV?

Just me with aaaaaall the stick I get for breeding a smaller terminal sire

 

[newgeneration]

There seems to be a notion in some people's minds that using a pure bred sire gives some kind of assurance that progeny will be consistent.

As @Ysgythan has said, the more inbred an animal is the more variation can be avoided, and in theory breeding pure is closer to in-breeding than crossing.

However, if two animals from within the same breed are of very different types, or are a total outcross, the variations in resultant generations can be as extreme as using a mismatched crossbred, and a lot more extreme than if said crossbred is made up of two animals of very similar type.

As for the theory of the mule being an example of why crossbreds haven't caught on, take a look at the two parents of the mule, they are not of a type, so it's unlikely that two breeds as different as a Blackie and BFL would breed consistently if used on a mongrel.

But cross a Blackie with a Swale, and the resultant progeny would breed more consistently due to there being more similar in type.

Agree with what you say about some crosses being similar, but may of the popular crosses are being touted as the best of both type animal, but could throw also worst of both!!
I've seen blueface x texel very popular selling really well in this area - hardly similar breeds!
Charollais x beltex one for length and growth the other for carcass very different animals
Suffolk x beltex Very different breeds
Lleyn x charollais one maternal one terminal
The science of genetics will dictate that there is a 50% chance of inheriting any of the parental genes and therefore a 25% chance of it being expressed!! The variation in vastly different parents has to mean that the offspring will vary greatly!!

 

[M-J-G]

Agree with what you say about some crosses being similar, but may of the popular crosses are being touted as the best of both type animal, but could throw also worst of both!!
I've seen blueface x texel very popular selling really well in this area - hardly similar breeds!
Charollais x beltex one for length and growth the other for carcass very different animals
Suffolk x beltex Very different breeds
Lleyn x charollais one maternal one terminal
The science of genetics will dictate that there is a 50% chance of inheriting any of the parental genes and therefore a 25% chance of it being expressed!! The variation in vastly different parents has to mean that the offspring will vary greatly!!

Those who tout such consistency from extreme genetic combinations, be that crosses or pures, are either mating the crosses to pure animals, very lucky or talking nonsense. Genetics don't work that way in the long term.

As said before, this is not limited to cross bred animals. The same genetic science applies to pure and crossbreds alike, in that, the greater the variation the more obvious it is when it's expressed.

Take a leggy plain animal and mate it to a small muscular one of the same breed and you will get just as much variation as if you had crossed two breeds with such physical differences.

In this case where two pures of different extremes, the progeny off the result could be more varied than those off a crossbred from two animals of a very similar type.

In reality if you mix extremes the results are more varied, be that in a pure or crossbred. Cross breeding offers more variation, but pure breeding offers no more guarantee than a strategic cross.

 

[gatepost]

It is interesting to look at the genome map of the different ''breeds'' as we know them and see were they overlap heavily or for some hardly at all, however if a ''pure bred animal is crossed with another of the same breed but maybe with bigger ears, the 80% of genes for other traits that they share should breed true for those traits( % just plucked for sake of argument) if you take animals with very different genetic backgrounds even with a small overlap of genes then much more difficult to produce consistent progeny, too many different genes floating about any of which could be inherited.

 

[Nithsdale]

It is interesting to look at the genome map of the different ''breeds'' as we know them and see were they overlap heavily or for some hardly at all, however if a ''pure bred animal is cross with another of the same breed but maybe with bigger ears, the 80% of genes for other traits that they share should breed true for those traits( % just plucked for sake of argument) if you take an animals with very different genetic backgrounds even with a small overlap of genes then much more difficult to produce consistent progeny too many different genes floating about any of which can be inherited.

Isn't that why Mule cross breeds are called Mules? - both parents are so different, genetically, that you can't breed the cross 'pure' as it is effectively an unstable cross. Even though the cross consistently breeds true to 'type'.

Basically - if you've ever had a Mule tup/rig serve Mule ewes/lambs... you soon realise it throws some perfect Mule looking lambs, and some Blackie (or which ever dam was used) looking things - and everything else in-between!!

 

[CharcoalWally]

A big problem in the sheep terminal sire breeding business is that a lot of the 'top' breeders don't have a commercial ewe on the farm(except embryo recipients).

This played a large part in the downfall of the Suffolk breed up here @sheepwise as you and I both know, which then led to opening the door to let your breed in to get established.

This is why you can never get complacent - someone else is always waiting to pick up from where you failed.

 

[Roy_H]

Those who tout such consistency from extreme genetic combinations, be that crosses or pures, are either mating the crosses to pure animals, very lucky or talking nonsense. Genetics don't work that way in the long term.

As said before, this is not limited to cross bred animals. The same genetic science applies to pure and crossbreds alike, in that, the greater the variation the more obvious it is when it's expressed.

Take a leggy plain animal and mate it to a small muscular one of the same breed and you will get just as much variation as if you had crossed two breeds with such physical differences.

In this case where two pures of different extremes, the progeny off the result could be more varied than those off a crossbred from two animals of a very similar type.

In reality if you mix extremes the results are more varied, be that in a pure or crossbred. Cross breeding offers more variation, but pure breeding offers no more guarantee than a strategic cross.

A farmer I know was very taken by Salers cattle but he thought them quote: "A bit long in the leg for my liking" so in an effort to bring their bellies a bit closer to the ground he crossed them with Sussex. In true Mendelian fashion he got some with long legs and some with short legs but none with 'middle sized' legs.