Linebreading VS. Inbreeding

[Dvrom]

What is the difference between line breeding and inbreeding? they sound like just two different names for the same thing. What is everyones thoughts and experiences also what do you benefit?

 

[Bulldaddy]

The way I see it, linebreeding is the intended and controlled crossing of close relatives to perpetuate desirable traits while inbreeding is the unplanned and uncontrolled crossing of close relatives that often perpetuates undesirable traits.  Certain lines of cattle have been developed through linebreeding that are very uniform in kind.

 

[Mainevent]

Here's how it got put to me. Linebreeding is what you call it when you call it when it goes right. Inbreeding is when it goes horribly wrong.

 

[knabe]

The way I see it, linebreeding is the intended and controlled crossing of close relatives to perpetuate desirable traits while inbreeding is the unplanned and uncontrolled crossing of close relatives that often perpetuates undesirable traits.  Certain lines of cattle have been developed through linebreeding that are very uniform in kind.

linebreeding gets rid of undesirable traits, if culled.  too often, too little culling occurs as numbers are too low.

breeding for TH is linebreeding.  it's planned, it's "desirable", uniform and it's controlled.  linebreeding are inbreeding are the same.

 

[nate53]

I guess I thought linebreeding was like a specific bull or cow that was in the pedigree multiple times, like breeding first cousins in cattle, basically you have some cattle you like and and are related to each other just not full siblings or sire-daughter, dam-son matings.  Where as inbreeding is sire daughter, and dam son matings.  This is what I was taught anyhow!

 

[nate53]

So basically the objective to both is consistency, negative problems are more likely to show up if there are any when line and inbreeding are done, more so in inbreeding.  But I think the whole objective is if you have cattle you like and are happy with and you want to stick with that type of animal, you either linebreed or find another herd that is similair to yours and unrelated and breed with them.  Basically breed like to like begets like, the more like like generations you get in the more consistencey, ideally.  Some very sucsessfull programs use linebreeding, don't know to many that inbreed but it is done and purposely in places for a more superior and consistent animal, sometimes it works and sometimes it goes wrong!

 

[Dvrom]

It kinda sounds like a bad idea to me because you can get some messed up calves, is this true? and does anyone know the percentage of good to bad?

 

[BuckJones]

Interesting responses. I thought there might have been more accurate responses given the history of domestication of livestock and the extent to which both methods of selection are used in the cattle industry and even more so in the show cattle industry.

Inbreeding: A systematic program of breeding closely-related animals. This generally refers to father x daughter, mother x son, and brother x sister parings.

Linebreeding: This term is used to describe a less intense program of inbreeding. This generally refers to closely related pairings like uncle x niece and halfbrother x halfsister.

Outcrossing: Outcrossing refers to the breeding of two unrelated (inbred) strains.

I also breed show quality Betta Splendens or "Siamese Fighting fish" and we use both inbreeding and linebreeding extensively.

INBREEDING: Mating of closely related individuals
Pros:
- Produces uniform or predictable offspring.
- Hidden (recessive) genes show up and can be eliminated.
- Individuals will "breed true" and are "pure."
- Doubles up good genes.
- Eliminates unwanted traits.
Cons:
- Doubles up on faults and weaknesses.
- Progressive loss of vigor and immune response.
- Increased reproductive failures, fewer offspring.
- Emphasis on appearance means accidental loss of "good" genes for other attributes.
- Genetically impoverished individuals.

LINE-BREEDING: Mating of less closely related individuals
Pros:
- Avoid inbreeding of very closely-related fish, but the cattle are still "pure".
- Produces uniform or predictable offspring.
- Slows genetic impoverishment.
Cons:
- Require excellent individuals.
- Does not halt genetic impoverishment, only slows it down.

OUTCROSSING: Mating of unrelated individuals within the same breed
Pros:
- Brings in new qualities or reintroduces lost qualities.
- Increases vigor.
- The cattle are still "pure".
Cons:
- Less consistency and predictability of offspring.
- May have to breed out unwanted genes accidentally introduced at same time.
- May be hard to find individuals which are true outcrosses.

HYBRIDIZATION: Mating of unrelated individuals of different breeds
Pros:
- Brings in new qualities or reintroduces lost qualities.
- Increases vigor, may improve immune system and reproductive capacity.
- Introduces totally new traits e.g. color.
- May result in new breeds.
- The offspring are considered "impure" for many generations.
Cons:
- Unpredictable - new traits may not all be desirable.
- Must choose outcross breed whose qualities complement or match own breed.
- May take years to eliminate unwanted traits/loss of type.
- May take years to get consistent offspring.
- Produces many variants not suitable for use in breeding program.

Source: http://www.messybeast.com/inbreed.htm

The link also provides a lot of discussion and good general info.

 

[aandtcattle]

That was an outstanding post BuckJones!  Very informative and definitely answers the age old question of "whats the difference?"  THANK YOU!

 

[aj]

When I was a college boy I got into an arguement with a instructor. He taught....physiology and reproduction of beef cattle(or something like that). My premise was that hybrid vigor(crossbred cows) in general are more fertile. This would be over large populations. Dr. Brower disagreed. He asked" do they ovulate more eggs?" I lost the arguement of course. But I always read about heterosis increases fertility. Is this true? Would the heterosis increase disease resistence or maybe they are more feed effiencient or is there an advantage?

 

[nate53]

Buck, sounds a lot like my post just with textbook defenitions to back it up!!!  (thumbsup)

 

[kfacres]

linebreeding is the concentration at less than 50% of one individual's influence.... Inbreeding is great than a 50% influence...

which would only be likely with a father/ daughter, or mother/ son mating.

 

[BuckJones]

When I was a college boy I got into an arguement with a instructor. He taught....physiology and reproduction of beef cattle(or something like that). My premise was that hybrid vigor(crossbred cows) in general are more fertile. This would be over large populations. Dr. Brower disagreed. He asked" do they ovulate more eggs?" I lost the arguement of course. But I always read about heterosis increases fertility. Is this true? Would the heterosis increase disease resistence or maybe they are more feed effiencient or is there an advantage?

Well, fertility is a function of several factors - health, nutrition, management, soundness etc. Heterosis is literally a condition of having different genes. If the genes you introduce improve the factors of fertility, then it is possible to increase fertility. If the introduced genes worsen the factors of fertility, then fertility will be reduced. I assume the definition of fertility of cattle is the number of live births in a population of cattle.
An instance of increasing fertility as a result of heterosis could be as simple as having a cow that will live longer. All other factors remaining the same(same management/environment, calves every year til death), if you have a cow, A, that will live 4 years longer than another cow, B, then cow A will ovulate 4 times more than Cow B. A genetic factor introduced by outcrossing could be disease resistance.
On the other hand, introduction of new genes could reduce fertility. If I were to introduce TH into a line, subsequent generations of live calves would be reduced by 25% and continued homogenizing would reduce fertility to zero.

You already knew this though.
With my fish, continued line breeding results in increased ammounts of deformities per spawn, less eggs per spawn, less eggs fertilized per spawn, and less eggs hatching per spawn. It also could result in smaller, less vigorous fish as adults. We generally outcross every 3 or 4 generations. I have no experience with breeding cattle yet.

 

[thunderdownunder]

Linebreeding is what they call it when it works.
Inbreeding is when it doesn't work.

 

[aj]

I was always impressed with say the Hubs Shorthorn pedigree's in the 70's anyway. you could go back 3,4, and 5 generations and all the cattle had the Hub prefix. They weren't much for trading cattle anyway. Same way with Sneeds, Dover or who ever.