Hey folks,
There are a few threads relating to this, so I thought I'd put in what I know on the subject.
Netherland Dwarfs and Peanuts.
Peanuts can result from breeding Netherland Dwarfs and in many cases Miniature Lops too. These days many Lionheads seen in the pet trade also may be capable of producing peanuts.
A peanut is generally the size and shape of a whole peanut. The youngster is always poorly formed and will die of dehydration and starvation after a few days due to a malformed soft pallet meaning it cannot suckle successfully. The record survival of a peanut was around 3 weeks, and that was with intensive nursing. The genetics behind the production of peanuts is very simple and they are easily avoidable by mating "good" Nethies with "big" Nethies.
The Genetics:
Your average rabbit will, within the locus for size/shape, have the genes dwdw. There is a mutation of this gene which is dominant and causes the Nethie shape, and that is Dw.
A Netherland Dwarf that you see on the show bench will have one of these mutated genes, and will be Dwdw. When you mate two of these rabbits together there are three possible outcomes:
dwdw - Norma or false dwarf (25%)
Dwdw - "True" dwarf (50%)
DwDw - Peanut (25%)
False dwarf kits from Nethie parents will often pass as true Nethies when being sold to the general public as decades of selecting for the cobbiest rabbits has resulted in a more rounded shape, hence the name false dwarf. Breeders often call these "big ones" or "big ugly ones".
Many breeders of Netherlands in these times will no longer carry out these matings. Instead they take a "big" doe from Nethie parents (she will carry the genes for good show Nethies) and a show buck and mate them together. This type of mating will give 50% normal and 50% true dwarf, a peanut free litter.
Cross Breeding
In most cases, cross breeding does not present an obvious problem.
Having said that, there is one cross mating that there is a particular problem with and this is the crossing of Lop breeds with normal breeds. Lop rabbits have a different shape of skull to normal rabbits, and that adorable "one ear up, one ear down" look in cross breeds is caused by a distortion of the skull which be a major cause of malocclusion. This is not something new, either - Darwin studied the subject and has drawn a diagram of an affected skull which you can see clearly shows the distortion:
The article can be found here:
http://pages.britishlibrary.net/charles.darwin/texts/variation/variation04.html
If you are a biologist, genetisist or just interested then it is worth a read.
There are other similar cases where a cross is not a good idea at all. For instance, I once had a Swiss Fox doe who although long coated was very easy to look after. Brushing once a fortnight was fine most of the year and every other day during the spring moult. She escaped one day when my Satin buck (also easy to look after) was running around and it just happened that he carried the gene for long hair. I had not known this before the incident, but the appearence of a long haired baby shows this was the case. The resulting kit grew to be an amazing, beautiful animal who requires brushing at least every day and is still knotted, requiring clipping every summer to remove the accumulation of tangles. Both parents has easy coats - but just look at the offspring, an impossible coat.
Inherited diseases are also more avoidable in a breeding "program" which they are not in cross breeding. Rabbits with, say, malocclusion (a problem we are all familiar with) are capable of producing a kit with apparently normal teeth. If you then get this rabbit from a pet shop, how are you to know that its parents are diseased and that this rabbit will produce babies with this problem? You are not - so that whilst you may think you are breeding two perfectly healthy rabbits together you get malocclusion in the litter.
Inbreeding itself presents few problems in rabbit populations - take wild rabbits as an example. I cannot remember the figures, but a warren of rabbits may not see fresh blood for many years so that all breeding is in breeding and this does not cause problems. The problem is, in fact, recessively inherant disease which is "brought to the surface" through this inbreeding. After a point, those lines with disease will be obvious as will those without and the health of the population can be improved. This occurs in the wild too - those lines carrying deseases begin to die out as the disease begins to show.
In essence, the crossing of breeds may not be problematic if you know the line of both parents well and you are very familiar with the potential problems presented by each breed so that you can establish whether or not the mating is "safe". I would never recommend crossing Netherlands, any Lop breed or unusual coated breeds with any other breed.
-------------------------------------------------------------------------------------
I hope that was reasonably understandable. If you have any questions, just ask! I can go into a lot more detail on many of these topics.
There are a few threads relating to this, so I thought I'd put in what I know on the subject.
Netherland Dwarfs and Peanuts.
Peanuts can result from breeding Netherland Dwarfs and in many cases Miniature Lops too. These days many Lionheads seen in the pet trade also may be capable of producing peanuts.
A peanut is generally the size and shape of a whole peanut. The youngster is always poorly formed and will die of dehydration and starvation after a few days due to a malformed soft pallet meaning it cannot suckle successfully. The record survival of a peanut was around 3 weeks, and that was with intensive nursing. The genetics behind the production of peanuts is very simple and they are easily avoidable by mating "good" Nethies with "big" Nethies.
The Genetics:
Your average rabbit will, within the locus for size/shape, have the genes dwdw. There is a mutation of this gene which is dominant and causes the Nethie shape, and that is Dw.
A Netherland Dwarf that you see on the show bench will have one of these mutated genes, and will be Dwdw. When you mate two of these rabbits together there are three possible outcomes:
dwdw - Norma or false dwarf (25%)
Dwdw - "True" dwarf (50%)
DwDw - Peanut (25%)
False dwarf kits from Nethie parents will often pass as true Nethies when being sold to the general public as decades of selecting for the cobbiest rabbits has resulted in a more rounded shape, hence the name false dwarf. Breeders often call these "big ones" or "big ugly ones".
Many breeders of Netherlands in these times will no longer carry out these matings. Instead they take a "big" doe from Nethie parents (she will carry the genes for good show Nethies) and a show buck and mate them together. This type of mating will give 50% normal and 50% true dwarf, a peanut free litter.
Cross Breeding
In most cases, cross breeding does not present an obvious problem.
Having said that, there is one cross mating that there is a particular problem with and this is the crossing of Lop breeds with normal breeds. Lop rabbits have a different shape of skull to normal rabbits, and that adorable "one ear up, one ear down" look in cross breeds is caused by a distortion of the skull which be a major cause of malocclusion. This is not something new, either - Darwin studied the subject and has drawn a diagram of an affected skull which you can see clearly shows the distortion:
The article can be found here:
http://pages.britishlibrary.net/charles.darwin/texts/variation/variation04.html
If you are a biologist, genetisist or just interested then it is worth a read.
There are other similar cases where a cross is not a good idea at all. For instance, I once had a Swiss Fox doe who although long coated was very easy to look after. Brushing once a fortnight was fine most of the year and every other day during the spring moult. She escaped one day when my Satin buck (also easy to look after) was running around and it just happened that he carried the gene for long hair. I had not known this before the incident, but the appearence of a long haired baby shows this was the case. The resulting kit grew to be an amazing, beautiful animal who requires brushing at least every day and is still knotted, requiring clipping every summer to remove the accumulation of tangles. Both parents has easy coats - but just look at the offspring, an impossible coat.
Inherited diseases are also more avoidable in a breeding "program" which they are not in cross breeding. Rabbits with, say, malocclusion (a problem we are all familiar with) are capable of producing a kit with apparently normal teeth. If you then get this rabbit from a pet shop, how are you to know that its parents are diseased and that this rabbit will produce babies with this problem? You are not - so that whilst you may think you are breeding two perfectly healthy rabbits together you get malocclusion in the litter.
Inbreeding itself presents few problems in rabbit populations - take wild rabbits as an example. I cannot remember the figures, but a warren of rabbits may not see fresh blood for many years so that all breeding is in breeding and this does not cause problems. The problem is, in fact, recessively inherant disease which is "brought to the surface" through this inbreeding. After a point, those lines with disease will be obvious as will those without and the health of the population can be improved. This occurs in the wild too - those lines carrying deseases begin to die out as the disease begins to show.
In essence, the crossing of breeds may not be problematic if you know the line of both parents well and you are very familiar with the potential problems presented by each breed so that you can establish whether or not the mating is "safe". I would never recommend crossing Netherlands, any Lop breed or unusual coated breeds with any other breed.
-------------------------------------------------------------------------------------
I hope that was reasonably understandable. If you have any questions, just ask! I can go into a lot more detail on many of these topics.
