Linebreeding cattle

[RD-Sam]

I have a question about linebreeding cattle, in dogs you tend to loose size when doing tight linebreeding, does that happen in cattle? I had read that most people try and keep the factor under 6% for cattle, is this what is generally accepted with most breeds? The mating I was looking at was about a 4% factor, just wondering what I might expect in regards to the size, or frame score?

 

[dun]

I don;t know, but in crossbreeding if you breed one half of an F1 back to one of the parent breeds you will lose some size, repeatedly breeding back to that same breed in theory decreases it more.
I've seen the breeding back deal decease the size of the offspring but don;t really know if it's the breed regression thing or because we've selected more moderate framed bulls.
The vet bred 3 or 4 generations of EXT daughters back to EXT and the last generation heifer was a tiny little dink.

 

[RD-Sam]

Did the frame size just decrease, or did you loose muscle mass too? I guess what I am trying to say is was it a balanced decrease in size, or did the frame get smaller and they retain alot of muscle?

 

[dun]

Did the frame size just decrease, or did you loose muscle mass too? I guess what I am trying to say is was it a balanced decrease in size, or did the frame get smaller and they retain alot of muscle?

In the case of the EXT there wasn;t any physical apparent difference from one generation to the next other then size. They were lighter muscled buy proportioned the same as the preceding generations.
With the F1s we gained muscle, but that was a property of using heavier muscled bulls.
MARC may have some data on the breeding regression thing, I know I had gotten a lot of data on it but can;t remember if it was from MARC or the university studys

 

[RD-Sam]

Thanks, you have been very helpful!

 

[redcowsrule33]

The experiment's been done, we call them Lowline cattle.

http://www.ansi.okstate.edu/breeds/catt ... /index.htm

The picture says a thousand words.

PS Don't tell Lowline guys they have inbred Angus, they don't like it. :devil2: Nice cows, just not my type.

 

[DOC HARRIS]

I have a question about linebreeding cattle, in dogs you tend to loose size when doing tight linebreeding, does that happen in cattle? I had read that most people try and keep the factor under 6% for cattle, is this what is generally accepted with most breeds? The mating I was looking at was about a 4% factor, just wondering what I might expect in regards to the size, or frame score?

SAM-


As I have attempted to explain to you in the past 6 months, when you concentrate (line breed) genetics, you will exacerbate the traits and characteristics - which is the purpose of linebreeding. So far - so good!

BUT - IF you go to far afield with the units of measure ( + or - of EPD's) to the extreme, you are asking for genetic trouble! Take Milk traits and Calving Ease, or Birth Weight, for example. Milk +36 and BW -5.0. Retaining heifers with these EPD's, and consistently following this protocol will result, eventually (two or more generations down the line) in DECREASED musculature appearing in the progeny - OR FUNNEL BUTTS! You can hope, and wish and assume and pray and overlook reality of Genetic Inheritance truths, but you WILL reap the whirlwind of achieving FUNNEL BUTT cattle from those breeding actions if you continue to repeat the same actions.

My philosophy is - "MODERATION IN EVERYTHING" and that includes sensible concentrated genetic matings. Linebreeding is a wonderful tool - IF - it is used with common sense and knowledge of what you are doing.

DOC HARRIS

 

[RD-Sam]

Hi Doc, I understand about passing on traits when linebreeding, I was mainly interested in what happened in regards to size in this instance.

Since you touched on EPD's, what is the range that you feel is acceptable for keeping and breeding cows in these categories? BW,YW, Milk, CED, CEM, $EN.

 

[RD-Sam]

The experiment's been done, we call them Lowline cattle.

http://www.ansi.okstate.edu/breeds/catt ... /index.htm

The picture says a thousand words.

PS Don't tell Lowline guys they have inbred Angus, they don't like it. :devil2: Nice cows, just not my type.

Those appear to have somewhat exaggerated features, I was wondering about that, because I have seen that in dogs when tight line breeding and inbreeding. Look at the bone on that one, looks like alot for that size of a cow, also the exaggerated features on the head.