Interesting the increase in autoimmune disease in dogs. There is thought to be a normal inherited basis to this, but also it's increase is now linked to pedigree breeding per se in that breeding within a closed gene pool results in increasing homozygosity of genes... in other words, an increase in inbreeding.

The genes most concerned with the immune system belong to a haplotype known as the Major Histocompatibility gene Complex (MHC) and a reduction in diversity here is what's thought to be specifically connected with the increase in immune mediated diseases.

The concept of pedigree breeding ie breeding within a closed stud book, is relatively new, little more than a century old and the benefits of hybrid vigour in crossbreeding are now seen in agriculture (animal and plant breeding) and zoo keeping as well as domestic pet breeding.

50 years ago dogs took themselves off for a walk!!

my mums dog..... lol

Really so what cattle have been cross bred solely for hybrid vigour ? come to that what wild animals have been crossed in zoos for hybrid vigour ?

I've got loads of farming friends & yes they do cross breed cattle & sheep but not for hybrid vigour as it is always F1 or f2 generations only & usually to produce a type of meat for the marketplace. Some cows have implant fertilised eggs of other breeds as the biological parents are not in the same country etc Some pigs are also cross bred but again only for the meat production & not hybrid vigour.

There is the Chillingham Herd of Wild Cattle that have been inbred for 100s of years yet don't have any major health problems.

Plants yes they do cross breed, rarely for hybrid vigour mainly to produce new types of plants bigger & better than the parent plants

I think they were happier then but not really looked after as well

My first BC (Glen) passed away in 1969, aged 19. Even then, this was thought to be quite unusual, but it was down to two things, I think - better food, and better vet care. As he was a rescue, we never knew his parents, but I'd be prepared to bet that they had nothing like the lifestyle he did. He was more like a member of the family, and not "just the dog" (except, of course, when he misbehaved, when he became "That bl@@dy dog!). I do think that by becoming pet animals, some dogs have traded their freedom for reliably good food and shelter.

Incidentally, I noticed that ole Crufty used to sell Spratt's Dog Cakes. Anyone else suspect that these were the antecedents of Bonios (which used to be made by Spratts before they were Nestle-Purina)?

Snorri

Interesting - guess it depends on the individual dog and owner
Dont think you had separation angsiaty back them cos dogs were not left alone in the house

I have been interested in the age dogs lived to than and now for a while
If we are doing so well for them with all our vet treatments and fantastic foods are they living longer??

My grandads dog lived well into its teens - and that was considered normal - but now I am out on walks and see someone with a dog and they say ' he is really getting old now he is 8!!'
He also roamed where he wanted when they were at work (the next door neighbours collie herded him home when they wanted him back) had his ice cream from the van every night, had no injections worm or flea treatment and ate kennomeat

(Ben is making me say that 100 years ago he wouldnt have got to go to agility classes so that almost makes up for me going to work)

Do you mean species crossing? If so, this isn't for hybrid vigour, or at least not with any connection to improving the species, as most crosses of this sort are infertile. The use of hybrid vigour in wild species breeding is facilitated by the introduction of new 'blood' from unrelated animals of the same species into zoo breeding programmes to offset inbreeding depression.



Hybrid vigour has greatest effect on the F1 generation, less so in F2. Any subsequent breeding back into the parental breeds will reduce the effect.


Inplanting has no significance here as the host animal has no genetic input.

Increase in meat production is just one of the results of hybrid vigour. Sheep, cattle, pigs etc also show increase in fecundity, disease resistance, fleece production etc. Just do a search on this, and the term 'heterosis' to see what this is about.

Here's one quote -

Many years of research with many animal species has clearly documented that vitality and fertility characteristics improve with crossbreeding. Crossbreeding of pigs, sheep and beef cattle is a standard practice. Until recently, little consideration has been given to crossbreeding dairy cattle. Although research from the 50s to the 90s showed that crossbred dairy cattle were vigorous and fertile animals. Now, many research organizations are evaluating crossbreeding.

http://www.extension.umn.edu/dairy/d...06-Johnson.htm



Yes, I've been to see these cattle, really interesting and similar phenomenon to the Isle Royale (sp?) wolves. The big difference here is that natural selection is in place ie onlt the fittest survive to breed and pass on their genes. A far cry from domestication where selection is based on a percieved image of fitness as we use in modern dog breeding.

One major drawback in a small population such as the Chillingham herd is that, if a disease or condition that they had low natural immunity to did strike, there would be very little chance of herd recovery. A larger, more diverse herd/breed would have the genetic capacity to cope. And one result of this closed gene pool that I was told at the time, is that they have retained their ancestral dietary habit of eating only grass or hay, refusing concentates even in times of hardship. This has been a major worry for the herd keepers as they have had substantial losses in severe winters.


"Bigger and better" is caused by hybrid vigour. Exactly why this crossbreeding is done