Breeding Herd Foundation GuidelinesWhen the perpetuation of a domestic animal falls solely into the hands of a breeder, and is far removed from the laws of natural selection, the knowledge and responsibility put into practice by that breeder is paramount. We have seen how hip dysplasia in purebred dogs, HYPP in Quarter horses and malocclusion in the domestic chinchillas can affect a far greater percent of the breeding population than would ever be afflicted in nature. A breed can be degenerated extremely fast. The elimination of genetic disease and breeding soundness should never be sacrificed for the attainment of singular desired traits. With these things in mind, this article will point out some important breeding basics pertaining to the foundation of a domestic chinchilla breeding program.
When deciding to take on the responsibility of breeding
chinchillas, the breeder needs to pay close attention to several factors
including conformation, color, fur quality, temperament, and size. The
selection of a herd's foundation stock is critical. Foundation animals
often have more influence on the future of the herd than any selected
later, as they will in all likelihood appear in most of the herd's pedigrees.
Buying mature chinchillas (9-15 months) at this particular time may
prove to be a great aid. Several reasons for this are:
Chinchilla conformation depends largely on strain influence (i.e. Brevicaudata, Lanigera, or Costina). Brevicaudata chinchillas developed at higher elevations, at around 15,000 feet elevation. They were known for being large with short ears and tails, and having docile temperaments. Pure Brevicaudatas generally have a brownish cast to their coats, and can have a wavy-type fur. Costinas developed closer to sea level, have longer ears and tails, and tend to have a pointy head and body. They tend to be a little more high strung than their Brevicaudata cousins. Costinas are largely responsible for contributing the desirable blue hue that is so complimentary to all color mutations. Lanigeras developed at moderate elevations, and have traits that fall somewhere between the other two in characteristics. Almost all domestic chinchillas are classified as Chinchilla Lanigera, and have genetic markers from all three strains, but some tend to show a stronger influence from one strain than another. Certain mutation colors developed from herds with a high percent genetic influence from particular strains. The Gunning black velvet, for example, mutated in a herd with heavy Brevicaudata influence.
The "Standard" grey (agouti) chinchilla is the natural and original color of the chinchilla. It is nearly impossible to place too much emphasis on the importance of high quality standard lines in any standard or mutation breeding herd. The high quality standard is the backbone of quality and hybrid vigor.
All other colors are mutations which have mutated at random in the herds of domestic chinchilla breeders, and perpetuated. The three most common dominant (meaning the gene for this color is dominant over standard) mutation colors are the Wilson White, Tower Beige, and Gunning Black (or black velvet).The three most common recessive color mutations are ebony or charcoal (this is not actually one color gene, but a combination of several color genes that have mutated in different herds, and in general is safest treated like a recessive), sapphire, and violet. There are also many hybrid combinations in which the animal shows several different colors. Some common examples of these are pink white (white and beige), TOV beige (beige and black velvet), tan or pastel (beige and ebony), TOV violet (violet and black velvet), and TOV sapphire (sapphire and black velvet). (*Note: Since the Wilson white gene is an incomplete dominant gene, often the recessive color shows through, hence the white mosaic and silver. Solid white, white mosaic, and silver all share the same phenotype. The genetic variance in color coat pattern is responsible for the different appearing animals.)
When breeding dominant color mutations it is important to keep in mind that there is a lethal factor associated with both the black velvet and the white color genes. Neither of these two colors can exist in the homozygous form. Beige can be homozygous, however, and the result is the homozygous beige animal. When black velvet is bred to black velvet, the result is 25% less offspring produced. The same case exists when white is bred to white. Also, the same rule applies when any black velvet hybrid is bred to another black velvet hybrid (i.e. TOV white to TOV ebony), or when any white hybrid is bred to any other white hybrid (i.e. pink white to violet/white mosaic). Note: there is no lethal factor involved with a Wilson White to Gunning Black cross (i.e. white mosaic, pink white, etc... to a black velvet, TOV ebony, etc...).
For a recessive color to be seen (to appear in the phenotype), that animal must carry the genes for that color in the homozygous form. This means that all sapphires and all violets are homozygous for that particular color. If the recessive gene is only heterozygous, then the animal will be a carrier. A standard, violet carrier, for example, will appear standard, but will carry the recessive violet gene and can produce this recessive violet color if bred to another animal carrying the violet gene. Considering that recessive genes in the heterozygous form are not visibly apparent, it is very important to know the ancestry of you breeding animal. A black velvet carrying the violet gene is often not the quality or as good of a black velvet producer as a pure black velvet, when bred back to pure standards or other dominant color mutations. Also, the quality of the recessive colors has not yet reached the quality of the standards, or even the dominant mutation colors. It is important to cross all colors back into a good standard line every few generations to maintain the quality of that color. Constantly breeding mutation to mutation will degenerate the size and quality of the herd.
Despite whether the chinchillas being bred are standard grey, or color mutations, they should have a clear or blueish tint to their coats, and no red cast. To clearly view color it takes a well trained eye and the proper lights; a specific full spectrum fluorescent light bulb configuration. Keep in mind that there are both environmental and genetic factors which can affect clarity of color. Beige chinchillas, for example, will almost always oxidize and develop an orange tint over time due to environment. You need to be aware of the type of clarity your standards and mutations tend to throw. Chinchillas should have very white bellies, showing no creaminess and no brown tip on the white hairs, especially between the front legs. This grey/brown tip often indicates the presence of the charcoal or ebony gene in the background of the animal. This is undesirable unless that animal will be going into breeding with other ebonies or ebony hybrids. Chinchillas with the black velvet gene should show complete silky textured veiling from the tip of the nose to the base of the tail with little to no break in veiling at the back of the neck, or elsewhere. It can take a year or more for a chinchilla with the black velvet gene to completely get its veiling. Also, black velvets, males in particular, tend to be slow to mature and often are slow to breed. Beiges should be blue-beige, not orange. Whites should be true white, not yellow or creamy. Ebonies should be blue-black, not red. Sapphires tend to be true to their color, but the whiteness of the belly should be watched. Violets should be clear, and their bellies must be watched very carefully, as they tend to be creamy or yellow. The other mutations like recessive beige and albino are so rare or obsolete that they will not be discussed in detail at this time. All other colors (i.e. pink white, TOV beige, tan) are merely hybrids (phenotypic combinations) of the colors mentioned above, and clarity should be watched in them as it is in the non-hybrid mutations.
Temperament should always be considered when selecting animals for breeding. Temperament gets passed on through both heredity and environment. Chinchillas should not bite or be excessively high strung under normal circumstances. Extremely nervous animals also tend to be "fur chewers," and although there are several reasons why an animal may chew, chewing is considered to be largely hereditary. Fur chewers will chew off the hair around their hips or sides on one or both sides. They can chew from time to time, regrowing hair completely in the mean time, or chew constantly.
Chinchillas, being quasi rodents, are afflicted by malocclusion (bad fit of the teeth) like their rodent cousins. Malocclusion is quite often hereditary, and should be strictly culled from the breeding program. Experienced lifelong breeders tend to agree that the genetics involved with malocclusion is most likely a combination of genetic factors (which could also include some environmental factors) rather than one simple gene. DNA seaches for the genes involved in malocclusion in lab animals like mice and rats has proven that the set of genetics involved in malocclusion is elusive. However, this does not mean that practical and effective means of minimizing malocclusion do not exist. If a breeder will study his or her herdbook, they will find that quite often, their maloccluders trace back to one or a small related group of chinchillas. Steps should be taken to cull or minimize this bloodline. Also, outcross, outcross, outcross!... especially to good quality standards. Chinchillas should not be inbreed, nor should they be closely linebred under any but the most controlled circumstances.
In general, female chinchillas are larger than males. It is important that the females are roughly equal in size or larger than the males they will be bred to. This will result in fewer complications when littering, and can have both a positive genetic and environmental size influence on their offspring. A general guideline for good breeding weight for high quality standards is 1 pound 7 ounces to 1 pound 12 ounces, with more leniency for high quality males lacking this particular attribute. Dominant mutations tend to be slightly smaller, and recessive and hybrid mutations tend to be smaller still. It is very important to let females attain their full size before they are put into breeding. Some chinchillas don't reach their full size until 10-12 months of age, and possibly even longer longer, up to 15 months. If bred too early, females will often not reach their own full size, and will tend to have smaller kits always. Males need to attain their full size before being selected for breeding primarily so that the breeder can be assured that he will be adequate size and quality himself. All and all it's well worth the wait to let chinchillas mature fully before putting them into the breeding herd.
As hobbyist show chinchillas have risen in popularity over the past decade, there has been a lot of interest in exceptionally large chinchillas. Keep in mind that extra large chinchillas are more likely to be sluggish producers than somewhat smaller chinchillas. Also, extremely rapid growing chinchillas are more likely than slow maturers to malocclude. Larger is not always better.
Whether your "herd" is just a few chinchillas, or several destined to become hundreds, the benefit gained by their breeder's understanding of the even the basics is immeasurable. By starting out with quality chinchillas, a breeder will be decades ahead of one starting out with mediocre or poor animals. The latter will spend a countless amount of time and effort to produce the quality that other breeders have already produced.
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