Line breeding is a process that is used in order to concentrate the numbers of genetic traits present within a population of rabbit. Unlike inbreeding, which is random and has no plan to the breeding of rabbits that have a shared ancestor, line breeding is a method that intentionaly breeds rabbits that share a common ancestor with the rabbit to be breed. Breeding rabbits in this manner allow for the increase in the presence of specific trait within the litters that those rabbits produce.
However, if line breeding is performed incorrect, the trait selection process may lead to inbreeding depression, which can lead to the reduction of the number of kits that is born by those rabbits, and the weakening of the surviving rabbit. One method of performing line breeding is known as a buck to grand-daughter method. This method involve breeding a foundation buck to an unrelated doe to produce a daughter of the buck.
How to Line Breed Rabbits Safely
The daughter can then be bred to a different, unrelated doe to produce a granddaughter. Finally, the breeder can breed the original foundation buck to the granddaughter. The genetics of the foundation buck is present within the granddaughter, allowing for the trait associated with that buck to be “fixed” within the line of rabbits that are bred to the granddaughter.
Beyond this method, there is others that can be performed based off the goals of the breeder. Methods that can be used include breeding half-siblings, which are offspring of the same father but different mother; beginner often use this breeding as it spreads the genetic risk of inbreeding. Other methods include breeding cousins to one another, which is often used in situation where a slow breeding plan is desired.
Both of these method can be best understood through the mapping of the breeding plan using a pedigree tree diagram. Such a pedigree tree will reveal any breeding “loops” within the plan, which often determine the number of time that the breeding of cousins or half-siblings should occur. The process of line breeding require the selection of rabbits based on certain traits.
The traits may be physical, such as the weight of the rabbits at eight week of age, the number of live kit born by does of a litter, or the temperament of the rabbits (calmness). Such a selection process is very strict, as some rabbits may need to be “culled” from the breeding line due to their lack of meeting the standard that are required for breeding. In addition to the breeding of rabbits, the breeder must also keep the record of those rabbits.
The weights of the rabbits at three, five, and eight week of age should be recorded, as should the details of each of their litters, and the score for the handling of each of the rabbits. These records will allow the breeder to ensure that the line breeding program is successful, as well as to recognize potential problem within the breeding line. Failure to keep such records, however, can lead to the unintentional introduction of genetic defect to the breeding line.
Within the line breeding process, it is important to recognize the signs of inbreeding depression. Inbreeding depression is exhibited by the reduction of the number of kits born by does, the increase in the number of “runts” within litters, the decrease in the interest that buck have in does, and the development of physical defect in the rabbits. Should any of these trait be exhibited by any of the breeding rabbits, an outcrossing should be performed with an unrelated buck.
The introduction of new genetics into the breeding program through outcrossing result in the development of hybrid vigor, which increase the size and survival rate of the rabbits. Certain mistake should be avoided within the line breeding process, however. One mistake is attempting to use only one breeding method.
Another is breeding too young rabbit; does should be bred at five or six month of age, and bucks should not be bred more than five service per week. Additionally, tattoos should be used to identify each of the breeding rabbits, and breeding and nesting schedule should be establish and followed. The avoidance of these mistakes will ensure the success of the breeding program and the maintenance of a productive herd of rabbit.