How much heterosis is lost?

[farmer41]

I've got some Simangus cows I currently have a Hereford bull with. I know that gives me maximum heterosis in my calves...but if I keep heifers and Breed them back to a Gelbveih for example bow much heterosis is lost with the 3 breed cow vs a 2 breed cow?

 

[WalnutCrest]

You gain heterosis.

If you rotate among a two-breed cross, your heterosis will stabilize at about 66%; with three breeds, it'll stabilize at 83%.

 

[cbcr]

If your cows now are Simangus you have 2 breeds (Angus and Simmental), if they are the result of breeding an Angus to a Simmental then you have 100% hybrid vigor. If they are bred to a Hereford bull, the resulting offspring again will have 100% hybrid vigor. As in your question, if you were to retain heifers and breed them to a Gelbvieh again you would have 100% hybrid vigor.

Now you have animals that are the result of 4 breeds, if you were to keep replacements from these and then cross them with Angus, keep replacements from this mating and breed them to Simmental, keep replacements then breed to Hereford, keep replacements and breed to Gelbvieh this would be a 4 breed rotational cross. You would have a 93% retention of hybrid vigor.

If you were to have animals that were a composite of the four breeds each contributing 25% and breed those animals you would have animals that would have 75% hybrid vigor.

Please go to this link on our website, we have a chart there that shows the amount f hybrid vigor resulting from various breeding scenarios. http://compositebeef.com/why-composites.html

 

[farmer41]

Thanks for the info. I was afraid I lost more than that after the F1 cross. Thats great. I've got the Simangus cows bred to Hereford bulls and some Brangus cows Bred to Hereford bulls. I'll keep heifers out of these. What would be the % heterosis if bred back to an Angus bull compared to a different such a Gelbveigh or Charlois

 

[3waycross]

Thanks for the info. I was afraid I lost more than that after the F1 cross. Thats great. I've got the Simangus cows bred to Hereford bulls and some Brangus cows Bred to Hereford bulls. I'll keep heifers out of these. What would be the % heterosis if bred back to an Angus bull compared to a different such a Gelbveigh or Charlois

If you go back you lose heterosis.

 

[farmer41]

I realize I lose some heterosis but how much using an Angus bull compared to a totally different breed. I'm talking about the heifers I will keep out of the Simangus/Hereford cross and the heifers out of the Brangus/Hereford cross

 

[farmer41]

Never mind. After rereading back through Cbcr's post I should get 93% heterosis.

 

[WalnutCrest]

Some of the amount of loss of heterosis would also relate to how closely related the new Angus genetics are to your original Angus stock.