Inbreeding /Line breeding

[Akcattle]

Does anyone have experience breeding half siblings? We have 8 yearling heifers all from same sire and 1 yearling bull from that same sire. Thinking about turning the bull in with these heifers because he is smaller framed and comes from a good cow. Hoping to achieve smaller/ easy calving calves from these 8 heifers without having to AI this year and put the bull to use at the same time.

Has anyone seen unsurvivable defects or genetic traits from doing this? Never tried any inbreeding or line breeding before so we are nervous to try it on 8 heifers at once.

 

[Son of Butch]

No experience and I've only seen a few [all were holsteins]
No unsurvivable defects...but genetic defects could cause early terminated pregnancy and who would know?

Of the 1/2 sibling mating results I've seen only one with a weird appearance, she was under sized with an over sized head,
she had shoulder problems and her forelegs were short and very bowed.
She grew to adulthood and entered the milking herd...I'm sure she was culled during her 1st lactation.
That was when I saw her and at that time she moved as though she was a very old cow.

Over 20 yrs ago Select Sires had a bull from 1/2 sib mating that made it into their proven line up.
A son of Norcroft Elevation Ella EX-97 sired by her 1/2 brother Marshfield Elevation Tony VG-88
IF I remember correctly he scored VG-85 and ended up being ok but a bit of a disappointment given his parentage.

I also saw result of a mother x son mating. (the sire was a Big name A.I. sire)
That son entered a private limited A.I. proving program, he looked normal, but his daughters performance was poor
and he was sent to slaughter.

 

[Nesikep]

Wow, there's a lot of opinions on this... I'll try and give you the facts the best I can..

line breeding concentrates genes... Many defects are recessive, meaning they'll only show up if BOTH parents are carriers, and line breeding can expose such defects. If there are no recessive defects in the animals, you shouldn't have any problems. Of course the same happens with GOOD traits, they get concentrated as well, and the end result is consistency in the offspring.

I usually don't keep calves from first timers, and in my case I'd probably go for it... The heifers that milk better will still make better calves than the ones that don't, so you can compare the heifers performance to each other.

I have bred father-daughter MANY times and never had an ounce of trouble, I had one that looked so good last year I kept her as a replacement, and it's looking like I'll be keeping another this year...

I don't see it as something you should be afraid of at least!

 

[Herefords.US]

Does anyone have experience breeding half siblings? We have 8 yearling heifers all from same sire and 1 yearling bull from that same sire. Thinking about turning the bull in with these heifers because he is smaller framed and comes from a good cow. Hoping to achieve smaller/ easy calving calves from these 8 heifers without having to AI this year and put the bull to use at the same time.

Has anyone seen unsurvivable defects or genetic traits from doing this? Never tried any inbreeding or line breeding before so we are nervous to try it on 8 heifers at once.

I've tried half sib matings with several of my bulls with good success. Also some sire/daughter matings and son/mother matings. You learn more about your breeding program through doing these kind of matings in a purebred herd.

The calves from half sibs will generally be a little smaller at birth than the same bull's calves from other cows in my experience. And some of my best successes have come from the half sib matings.

The key to successful linebreeding is whether you have generally fault free cattle and cattle with no genetic disorders. If you have cattle that have known genetic disorder carriers close up in their pedigree, and they haven't been DNA tested for the disorder, then I wouldn't recommend linebreeding them until you have them tested.

George

 

[WichitaLineMan]

Probably the most used and most influential Angus bull of the last 30 years was a half brother half sister mating.

N Bar Emulation EXT

 

[WichitaLineMan]

Take a look at this link and let the number of progeny sink in on you for a moment!!

over 17,000 daughters with a WW turned in to the AAA.

Incredible

http://www.blackgrove.com/sires/NBarEmulationEXT.html

 

[WalnutCrest]

I try to study the breeding practices of people outside the world of cattle to try to learn what other successful people do to be successful ...

There was a breeder of German Shepherd Dogs from the 1940s to 1960s who was so successful at breeding champion GSDs (and at a little self-promotion along the way) that he became known as Mr. German Shepherd. He was always tinkering with different inbreeding, linebreeding, outcrossing ideas. Given the short generational cycles of dogs, and the multiple offspring per litter, he was able to do quite a bit of tinkering in a relatively short amount of time. Over time, he became convinced of a variety of approaches to formulaic prepotency ... all of which were predicated upon having EXCELLENT specimens to start with.

With excellent dogs as a starting place, he performed a variety of half-sibling, mother-son, father-daugther, aunt-nephew, uncle-niece, grandfather-granddaughter, grandmother-grandson breedings ... and he would then assess the prepotency for transmitting the desired traits of the offspring of those pups ... based solely on their ability to pass on the desired traits to the next generation.

As a result of all of his tinkering, he found that taking a extraordinarly high quality female ... and breeding her to a similarly phenotyped (but largely unrelated) male ... and do it repeatedly until you have a female who represents the best of what that pairing could reasonably afford you to experience ... and then, breed that female back to her mother's father until you had a MALE offspring who was confirmed prepotent for the traits of the maternal grandfather.

He claimed that this approach was more effective at establishing prepotency from one generation to the next than half-sibling to half-sibling.

***********************

I've also looked into the breeding practices of top breeders of racing pigeons.

Why?

Because they tightly breed, and then test the progeny for actual real-world performance (time trials, the faster the better) in their environment under their management.

There are some similarities and overlaps in what they do and what our GSD-breeding friend found ...