What is inbreeding and line breeding? Definitions for inbreeding, line breeding, and out crossing vary widely, but often seem to boil down to inbreeding describing the pairing of first generation related animals, such as parent/offspring and sibling/sibling, line breeding describing pairing of animals related in the second to fifth generation, and out crossing referring to pairings that do not have a common ancestor within the first 5 generations.

Throughout the history of animals and humans, line breeding and inbreeding has played many roles. Some of these roles have been very beneficial to the population in question, while others have been very detrimental. Most varieties of purebred animals, including dogs, cats, rabbits, horses, cattle, pigs, chickens, and a wide variety of others, owe their entire blueprint to a foundation of inbreeding. The diversity of size, shape, color, and general appearance between breeds of the same species typically began when an individual displayed a characteristic that made it different from the rest of the population around it, and this trait was encouraged by maintaining the individuals displaying that characteristic (often offspring of that original individual) in a closely knit gene pool. Encouraging these specific characteristics created a wide variety of types of individual animals who were more suited for a variety of climates, purposes, lifestyles, and individual preferences. Lack of care in inbreeding can be very harmful. The European royal families of past centuries have been a perfect example of this. These, or rather, THIS family interbred repeatedly to maintain close blood-ties to other prominent branches. This uncontrolled inbreeding caused many birth defects, reduced fertility, failure of children to survive, and long term negative health issues in the members of royalty.

How is line breeding done? There are several different methods of line breeding that are practiced by breeders working with a variety of species. While listing all of the methods and techniques would be extremely tedious and confusing, it is important to understand a few different styles of line breeding.
The Two Line Method In this method of line breeding, a breeder essentially maintains two separate lines of animals that are line bred for several generations with no input of additional bloodlines. Then, if the breeder decides it is necessary to bring in additional bloodlines to strengthen traits that are not as strong as desired in one family, he chooses an animal from the secondary family that is very strong in the desired traits, and adds that individual into the first family. The end result is two lines that are essentially separate, but do have some connection.
The Baldwin Plan The most important factor in the Baldwin plan is the strict maintenance of a standard of excellence. Any individual who falls below this standard of excellence is automatically removed from the breeding pool. This standard of excellence line is not set in stone, it is reevaluated as needed, often at the beginning of each breeding season. Therefore, animals who were ideal according to the previous standard of excellence may no longer be suitable for the continuation of breeding.
Along with this strict standard of excellence, the Baldwin plan does not just look at the quality of the individual animal, but also the quality of the parents and grandparents of the individual. The ideal breeding animal is one who shows not only the desired characteristics for the standard of excellence, but also shows these characteristics in the family line that produced the animal. The Baldwin plan does not specify the degree of line breeding used to further these means, but these requirements for choosing the breeding stock are the foundation for a plan of line breeding.

Who should consider working with inbreeding or line breeding? Inbreeding and line breeding require several factors in order to be beneficial to the population.

The first is experience. Only an individual who has had vast experience with breeding, owning, and caring for a specific type of animal should consider inbreeding or line breeding. Without an extensive knowledge of what you are looking at and working towards, it is essentially impossible to line breed with any long term positive results.

The second is Determination. Inbreeding and line breeding do not always prove beneficial. To successfully line breed, you must be willing to accept the negative consequences that sometimes occur. Typically, this involves culling an individual who fails to receive the beneficial qualities that you were working towards. In the hedgehog community, this is typically done by removing the animal from the breeding gene pool, and placing it in a pet only environment. In some extremely severe cases, in which an animal is affected to the point that it is unable to have a positive quality of life, this animal must be euthanized. In rare cases, where an unexpected genetic flaw is displayed in the majority of individuals produced from line breeding, the entire results of the pairing should be removed from the gene pool.

The third is good material to work with. To benefit a species in general, which is what your goal should be, you should have a high quality of animals in your gene pool to work with. Animals that display faults should not be the ones considered for line breeding. Neither should animals which display one good characteristic, with everything else about them being mediocre. Only the animals who show exceptional traits essentially across the board should be considered for line breeding.

If an individual does not have these factors available to them, they should not attempt inbreeding. Without these factors, inbreeding is more likely to produce negative results overall than it is to improve the species that is in question.

Misconceptions of Line breeding Many individuals who are not knowledgeable about inbreeding and line breeding automatically shudder at the thought of any breeder who would willingly line breed an animal. They feel that the results of these breedings will be inferior quality, suffer from birth defects, and other horrible fates. This is not necessarily true. Lets discuss some of the misconceptions of line breeding.

Inbreeding is horrible, and causes all kinds of bad results. Done improperly and without the appropriate measures of care, inbreeding CAN be horrible. Breeding two closely related animals together simply because they are there, regardless of quality of the animal, can produce animals that are far below the midline of the quality of the species. Overall, situations such as this can do much harm to the entire species of animal that is being worked with. Genetic flaws such as poor conformation, behavioral problems, reduced health quality, and many others are more likely to be displayed in the offspring of animals who exhibit these qualities.

When done carefully, line breeding can promote the ability of ideal qualities to be passed down to future generations and be used to weed out undesirable characteristics.

Inbreeding Causes Birth Defects. No. Inbreeding is not capable of producing genetic abnormalities or characteristics that are not already present. While it is true that line breeding or inbreeding can bring out problems that are already in the line, it does not create any problems that could not still occur in situations where no line breeding is used. This is why it is important to know the family history of the lines that you choose to line breed, and also be willing to cull out animals who should not be considered worthy to continue in the gene pool.

Any breeder who inbreeds or line breeds is unethical. Not necessarily. A breeder who approaches line breeding carefully with the welfare of the entire species in mind can actually be beneficial to the species. These breeders are careful to choose only the animals that they feel represent the qualities that are important to the species continuation and well-being.

Line breeding in Hedgehogs Up until now, this article has primarily discussed line breeding in general terms involving multiple species. Since this article is geared towards the hedgehog in specific, it is now necessary to narrow our focus to the use of line breeding in hedgehogs alone. The original hedgehog imports were of a similar coloration, close to the gray versions that we currently see. When we originally began breeding them, color variations began to appear. These abnormal color variations were closely bred, often with first generation ties. Thus, the extremely wide range of color varieties that we have today. With a broader availability of hedgehogs carrying the color genes that were originally very difficult to find, it is much easier to produce the rarer colored hedgehogs without extensive use of line breeding.

Because of this original line breeding, the use of line breeding in most current breeding programs specifically for the purpose of coloration is much less common. Only in very rare colorations is it difficult to find an unrelated breeding pair that both carry the potential to produce the desired coloration.

This does not mean, however, that line breeding is never used in hedgehog breeding. In some cases, a certain foundation animal or line is seen to produce offspring that are overall superior to the typical quality of hedgehogs, and even superior to the quality of hedgehogs that is currently considered to be excellent. When this does occur, limited line breeding, typically a single occurrence in a family tree is considered. This is quite similar to the Baldwin plan of line breeding described above. Some of the things that should be evaluated when considering the line breeding, and in fact, ANY breeding even if unrelated are-
Is this animal TRULY superior? Having one wonderful characteristic is not good enough. The entire hedgehog should be evaluated, including color, temperament, form, health status, and all other aspects of quality. Other than color, these other aspects all apply to each other. A hedgehog with less than ideal form may be more prone to some health issues, or less able to recover from health problems that can occur. A hedgehog with lousy temperament is more difficult to evaluate for health, and may make it more difficult to discover some health problems. A hedgehog with poor health may suffer damage to their form due to repeated health problems, and may die at a younger age, making them a less ideal pet. Do the offspring of this animal also display the superior characteristics? Breeding animals that have wonderful characteristics themselves may not pass on the characteristics to their offspring. If a hedgehog is bred and the offspring are typical quality, then that line is less likely to be desirable for line breeding.
Are the characteristics displayed available in other unrelated lines? Even if you have a wonderful animal, who produces wonderful offspring, line breeding is not automatically the best option. Other unrelated lines that you have available to you should be evaluated to see if they would be appropriate matches for the superior animal. If there are other breeding hedgehogs that are available either through your own stock or through another breeder who would be willing to do a cooperative breeding with you, then this should be the preferred avenue.

After these aspects are evaluated, and you are sure that you are mentally prepared for the possible consequences, then you can consider line breeding. The most common usage of line breeding among established breeders who track pedigrees is to pair two animals who come from a single line that each display the ideal characteristics being sought after. Typically, the relationship preferred in these two animals is to have the foundation animal occurring in each pedigree in a manner that would cause the foundation animal to appear twice at around the third generation or further back. Therefore, the foundation animal would usually be the grandparent of each of the breeding pair. This is not a hard and fast rule, however, in some extreme cases it is desirable to line breed to a closer degree.

Careful line breeding can strengthen the passage of ideal characteristics into the next generation, improving the quality of breeding animals available in the future without endangering the lives or health of the current generation or their offspring.
{mos_jb_discuss:21}