Breeding blue-eyed white Lionheads has proven to be quite the journey for me since I started my project with this variety four years ago. Challenging, but also very rewarding, the BEW variety requires ample patience in addition to a solid understanding of genetics, because of the intricacies of the Vienna gene. This is an updated version of my article that was published in the Mane Musings in 2013.
Establishing a Breeding Program and Vienna Genetics
A blue-eyed white breeding program should be treated like a completely different breed from your other Lionhead colors in a sense, because you cannot use animals from your BEW program with other color lines. Additionally, you do not necessarily want to cross any color into your BEW program either, without careful consideration. Breeding your BEWs to a colored rabbit should only be done to improve the type/mane/etc. in your BEWs and then all resulting offspring are Viennas and should be treated as such. Having a Vienna color breeding program will mean that you have many non-showable bunnies popping up, so make sure you have a plan to move them on when needed. Breeding BEWs is a one-way street. Other colors can go in, but you cannot take rabbits from your Vienna line and put them in a non-Vienna breeding program.
It is important to understand the terminology used by BEW breeders.
BEW – stands for blue-eyed white. It is a pure white rabbit with bright blue eyes.
Vienna Gene – Expressed as “V” (regular) or “v” (Vienna).
VM – Stands for Vienna Marked or “Mismark Sport”. It is when a rabbit carries the Vienna gene and shows it in spots of foreign color in the coat. This is never showable.
VC – Stands for Vienna Carrier. A rabbit that carries the Vienna gene but does not show it. These are the most important to clearly identify as Viennas to your customers and in pedigrees. You do not want someone thinking that their Lionhead is just a regular solid colored rabbit and then get the Vienna gene spoiling their color down the road.
The genetics of a BEW are as follows:
----------VV – “regular”, non-Vienna rabbit. Most Lionheads are VV and do not have the Vienna gene.
----------vv – blue-eyed white. It takes two copies of this gene to be a BEW.
----------Vv – Vienna Mismark or Vienna Carrier. One copy of this gene may or may not show up in the rabbit’s phenotype.
The Vienna gene is a masking gene
like REW. All the dashes in the genotype
are unknown genes that vary by the rabbit.
Like REWs, you can have BEWs that are genetically torts, chestnuts, otters,
harlequins, or any variety of colors hiding behind the white. Many BEWs do hide some of these more unusual
BEW eye color also changes from kits to mature animals. When the eyes first open, they look very dark - almost black. As they mature, the color slowly brightens. At what age the eye color stops changing varies somewhat by the line, but many do by around 4 months of age.
Working with VMs and VCs
When you breed BEWs, unless you are only crossing BEW to BEW, you will likely be working with VMs and VCs. The Vienna gene has incomplete dominance, so if a rabbit carries one copy of the gene, the color expression can “turn off” or “turn on” by mere chance. A VM can be very subtle like a colored rabbit with a speck of blue color in the eye and a white toenail, or it can be more dramatic with a blaze, color on the neck and shoulder, and white feet, for example. Although the markings are somewhat random, they still tend to follow a pattern of typical depigmentation. Blazes and nose spots of many different shapes, blue or partially blue eyes, neck and shoulder markings, and white feet tend to be the most commonly seen markings. Eye color on VMs varies just as the spotting does. It is often regular colored (brown or blue-gray), but can also be pure blue, or very often partially blue or odd eyed.
VMs or VCs can be very valuable in a herd. Many BEW breeders will occasionally bring in a non-Vienna rabbit of compatible color genetics to improve quality and bring in new blood. It takes at least two generations working this way as the first generation of kits will all be VMs and VCs. Vienna-marked and carriers can be bred to a BEW for BEW offspring or with each other to achieve the same goal. I do not recommend breeding a VM or a VC to a non-Vienna rabbit because you will not get any BEWs and the number of VMs will be too small to make the cross worth it. Some of the kits produced will not carry the Vienna gene at all and these cannot be told apart from VCs without test breeding first.
Purple Eye Effect
There are several causes of a purple eye effect in BEWs. This happens when additional factors contribute red to the eye color and, in combination with the existing blue, can look purple overall.
A ruby cast is a common cause of purple eyes. Shaded varieties that have a ruby cast to their eyes like siamese sables, sable points, and smoke pearls will cause this in addition to chocolate varieties such as chocolates, lilacs, and chocolate torts. Homozygous Vienna genes mask everything, but for some reason do not mask this ruby cast and it will show right through the blue eyes. The eyes resemble a red eye in a photograph from camera flash - but in real life. The ruby cast can be described like a translucent red film in the pupil of the eye and it is somewhat reflective. This effect is sometimes described as purple eyes and it spoils the look of a blue eye considerably. The recessive nature of these genes make it important to not only stay away from breeding in these animals with ruby cast, but also ones that carry for it. A black that carries chocolate, for example, can still introduce these genes in your BEW herd.
BEWs can also have a different purple effect in the eye, not to be confused with the ruby cast effect from chocolate or shaded. These eyes are blue with visible red/purple veins in them, and are believed to be caused by lack of pigmentation in the iris. If you look at the brown eyes in some rabbits, you will see that some are very dark and uniform and others are lighter or possibly have somewhat uneven coloration. This is the same lack of pigmentation being expressed in a more subtle manner in other colors than BEWs. By selecting away from the latter coloration, the purple veining will disappear and the eyes will be a uniform, brilliant blue.
Other Genes Avoided
There are also several colors that many BEW breeders will avoid, not because they damage BEW color, but because they make color identification much more difficult.
The first of these colors is REW which is another masking gene. You can have a rabbit that is genetically blue-eyed white and ruby-eyed white at the same time, but they have ruby eyes because REW will cover patterns in all other loci. Because of this masking, you do not know if the rabbit genetically is a BEW, a VM, VC, or even non-Vienna depending on the breeding they are out of. It also makes your chances of getting actual BEWs in a litter slimmer when some of them are double masked with REW.
The next color that many BEW breeders avoid is broken. In some crosses, many breeders will depend on retaining VMs rather than non-marked babies so that they know they carry the Vienna gene and broken can mask this very well as it is white on white.
If you breed BEWs, it is very important to inform all buyers of any BEW, VC, or VM rabbits. This should be clearly marked in the pedigrees and I tattoo a “V” in the ear of any rabbit from my Vienna line whether it is a BEW or not. There are terrible stories of entire breeding programs being destroyed because the Vienna gene was lurking behind colors and the breeder was unaware of its presence. Anyone who raises and breeds rabbits with the Vienna gene needs to understand how damaging it can be if not carefully controlled in its own program. They also need to ensure that their buyers understand this as well.
Misconceptions with the Vienna gene:
Possibly more so than with other colors, there are many misconceptions with the Vienna gene and BEWs in general.
· It is a myth that BEWs are blind, deaf, or have seizures. This may have been the case early in the development in some breeds due to heavy in-breeding, but it is no longer a problem at all. I have never heard of this being an issue in the Lionhead breed.
· Dutch colored rabbits are not caused by the Vienna gene. Although the blaze and other patterning in a VM may closely resemble Dutch patterning, they are completely unrelated genetically. VMs are sometimes called “Dutch-Marked” which may lead to further confusion.
· A white rabbit with blue gray eyes or brown eyes is an ermine or frosty with extremely light color. Usually you can find these faintly colored hairs on the ears and a BEW would never have them. A white rabbit with blue gray eyes can easily be mistaken for a BEW.
· VMs are not brokens and cannot be shown or bred as such. Using a VM as a broken in your breeding program will be devastating. If it is out of Vienna lines, do not cross it with your other colors.
· Although REWs and BEWs are both white, they are not at all related.
· REW does not cause a purple eye effect. REWs that are hiding chocolate can pass chocolate which produces this ruby cast or ones that have the genetics for light eye pigmentation can produce the visible vein effect, but the REW gene itself does not damage color.
· No other color genes appear to affect BEW color including dilute and chinchilla. BEWs with these genes behind them have blue eye color equal to ones that do not.
With striking blue eyes and a pure white coat, BEWs are a stunning variety with increasing popularity and interest. This is not a variety project that should be undertaken without a solid understanding of the genetics behind it. Careful and responsible breeding of the Vienna gene is essential to a successful and rewarding line of blue-eyed whites.
Other than show bunnies, it is health-wise okay to breed a BEW with a Harlequin, for example, right? Breeding for pet reasons only. Thanks for your help.ReplyDelete
There are no health issues with breeding BEWs and harlequins together.ReplyDelete