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How genetic theories can work for cattle breeding. Most breeding programs consist of three different systems of breeding your cows. They are inbreeding and linebreeding which is a form of inbreeding. The second is crossbreeding where you cross family lines. And the third is crossbreeding where you cross breeds.
If linebreeding is a form of inbreeding what is the difference?
What is happening in a line-breeding program is you are trying to concentrate the genetic characteristics of one individual rather than the genes of several animals in a family. In a linebreeding program you look at a common ancestor back through the pedigrees. Through the process of inbreeding you may have four or five common ancestors. You would never use a full brother X full sister mating in a linebreeding program.
Linebreeding and inbreeding programs are really the only true way you can make any type of genetic progress in any breed of cattle. If you are making outcrosses in your breeding programs you cannot predict how your cattle will breed. For example if there is a line-bred bull that stamps every calf he sires but is not available to you there is a high probability a full brother will produce very similar as the brother does because of the concentration of the one sire in his background. However if that brother is not a product of a line-breeding program the chances of any consistency is very slim. Line-breeding creates paternal gene pools. Paternal gene pool if proper selecting is used dominates the progeny produced.
The objective of line breeding is to produce superior breeding bulls. Superior breeding bulls are those that possess a large proportion of superior genes for a desirable trait or traits in a homozygous state. Bulls that will breed true are a measure of a successful line-breeding program.
What must I do to set up a successful line-breeding program? The first thing is to identify a superior individual which to base your program around. You will need some numbers of females and time for selection and to carry the program to completion.
You determine the bull you start with because he is outstanding in appearance and better in most characteristics than the average of the herd or breed. You would need to start with a bull because he has more progeny to work with in each generation. In the process of breeding you would be testing for recessive genes by mating him with a large population. You would then want to breed him to 30-40 of his daughters for the acid test. A detrimental recessive gene would express itself in fragility, lack of body composition; low utilization of forages and would manifest itself in the homozygous state and would not show up in the heterozygous state. If after the 30-40 daughters have calved and no harmful traits show up there is a 95% probability he is carrying no detrimental recessive genes.
100 cows not closely related would be good to begin a line-breeding program. They would provide a wide genetic base you would need for the extensive job of selection that must be done for success. Culling and selection is the elusive secret in making genetic frequencies for progress. Without culling and proper selection gene frequency stays the same and reduces the bull’s ability to pass on their desirable traits to the next generation. The goal of line-breeding is to produce bulls which will breed true, and to do this you must increase gene frequency with each generation.
How do I select for traits? If you select for single traits you will make twice the improvement in that trait than you would if you selected for four traits. What needs to be done is to determine what genetic traits are of economic importance to you. If the animal does not express the traits for the economic improvements you need then he/she should be culled. Animals should be compared with each other phenotypically and in production with that of the average of the herd in the traits you are selecting for to maintain a standard and for correction.
Line-breeding has the advantage over inbreeding. In-breeding will concentrate more of the detrimental recessive genes. Every common ancestor will have some detrimental recessive genes. Therefore the more individuals you concentrate into a pedigree that are in-breed, the higher the chances are that the detrimental recessive genes will bring expression to the progeny produced.
Another advantage is predictability. The in-bred may carry 3-4 common ancestors that are all in-bred and each may possess some detrimental recessive genes, where as the line-breed individual has a concentration of one in-bred individual bull. This will make your degree of predictability greater. In line-breeding you can recognize a defect and correct it in the process of breeding. For example you may have an animal with a narrow, shallow heart girth which makes the animal a high maintaince animal or a small loin. You would simply breed to females with a strong heart girth and large loin’s to correct the deficit.
Some of the most common misconceptions about line-breeding are, some think they are creating new genes, however you are not, you are bringing together the genetic expressions you have selected and breed for. New and different individuals will come from the combinations you have put together. You do not remove the detrimental recessive genes when you outcross. You just cover them up. You buy a high priced bull or use semen from a high EPD bull and his traits never are expressed as you expected. That is because he was a heterozygous bull rather than homozygous bull.
The disadvantage to line-breeding is you lose most all hybrid-vigor effect. Hybrid-vigor is usually expressed in areas like growth, fat, feed conversions carcass traits and other forms of production. With losing these traits why would you line-breed? Genetics is the only tool we as cattle men/women have for improvement for selection of quality and performance of our cattle. You can’t change genes you can only change the frequency of them. Line-breeding or in-breeding is the only way to concentrate genes for the volume of change required to bring about the change our cow herds need and for passage of desirable traits to the next generation.
There is a movement back to grass finishing beef in America. The heterozygous genetics that dominate our pastures and feed lots systems are not genetics that consume our grasses, finish and produce the quality of red meat we desire or can produce. The energy level requirements are a genetic factor and we have selected through heterosis breeding, mainly crossbreeding through the different breeds to accomplish grain genetics that are prevalent in our system today.
We as grass finishers must within our own cow herd began to concentrate the genetics of a superior bull in our cow herds to accomplish the quality and taste the consumer demands.
My encouragement to you is fear not, move away from the status-quo, began thinking for your self, there are a few bulls that semen is available to begin the gene pools you/we need, then the utilization of your forages will began to improve and as you select for other quantitative quality traits sustainability and profitability will improve. The commercial cows you have qualify to build a line-bred gene pool with. There are a few superior cows in every herd of commercial cows. Recognize those cows and began the legacy of your-self and leave a legacy for your children and children’s children. Remember grass is all you have to sell and you can only make a profit with the right kind and type of bovine grass genetics!
Visit us at: http://www.bovineengineering.com/
About the Author:
A specialist in reproductive biology of cattle, Gearld Fry has more than forty years' experience in artificial insemination (AI), embryo transfer (ET), linear measuring of livestock, carcass ultrasound techniques, breeding soundness examinations of bulls (BSE), and collecting semen. For twenty-five years, he ran his own reproductive center in Rose Bud, Arkansas, and has developed a reputation of being able to solve reproductive problems in cattle. Visit his website at www.bovineengineering.com.
Gearld has been a consultant with most of the larger grass-finished meat companies and has extensive experience evaluating live cattle for meat qualities using ultrasound and linear measurement. Several times each year he runs educational cattle schools, usually honing in on animals suitable for Grass Fed.
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Improvement Through Linebreeding