Inbreeding

[Oubuffel]

Hi Everyone
Just a quick question:
If a bull X was line bred or inbred to the extent that a physical abnormality or abnormalities are present, and we combine X with a completely non related cow Y, would X's physical abnormalities be carried over to calf XY or would Y have "neutralised" these defects, subsequently producing a healthy and completely normal looking calf (XY)?

 

[sstterry]

I do not know that "neutralize" is the proper term. Usually, genes that cause abnormality are recessive, meaning two must be present to cause an abnormality. Both parents must be carriers of the gene for a calf to be abnormal. If both parents are carriers, then on average one out of every 4 calves will manifest the abnormality.

There more on here that are more knowledgeable about genetics than I am though. Hopefully, they will give a more complete answer.

 

[FungusProudKY31]

Not likely unless you exposed a genetic defect in the bull and the cow is also a carrier and transmitter of those genes. Most complaints on inbreeding: less growth, infertility, sterility, ...

 

[Dsth]

my question is why you would use bull X for breeding. even if the calf looks normal, it will carry the defective gene and could reemerge in later generations.

 

[Oubuffel]

I do not know that "neutralize" is the proper term. Usually, genes that cause abnormality are recessive, meaning two must be present to cause an abnormality. Both parents must be carriers of the gene for a calf to be abnormal. If both parents are carriers, then on average one out of every 4 calves will manifest the abnormality.

There more on here that are more

knowledgeable about genetics than I am though. Hopefully, they will give a more complete answer.

Hi Sstterry!
Thanks for your reply. I agree. In this case the recessive genes were probably present in both the sire and dam of X. Lets say that Y is definitely a non carrier of this recessive gene. The question is, is there any chance that the abnormalities seen in X would or could be carried over to XY?

 

[Oubuffel]

my question is why you would use bull X for breeding. even if the calf looks normal, it will carry the defective gene and could reemerge in later generations.

Very true. You have a good point. Still, more defective genes are probably present everywhere we look (in their recessive form). So if XY does carry the defective gene seen in X, but not in it's dominant form as seen X, would it matter?

 

[Dsth]

i

Very true. You have a good point. Still, more defective genes are probably present everywhere we look (in their recessive form). So if XY does carry the defective gene seen in X, but not in it's dominant form as seen X, would it matter?

it would matter. not a matter of if XY carries the defective gene; bull X has both recessive genes so he will definitely pass the gene on to all his offspring. if his offspring mates with another carrier, 1 in 4 will show the same defect.

 

[SBMF 2015]

The best way to solve this problem is to sell bull X and buy a bull of a different bred than the cows. Cross breeding eliminates most genetic problems.

Welcome to CT!

 

[Son of Butch]

Hi Everyone
Just a quick question:
If a bull X was line bred or inbred to the extent that a physical abnormality or abnormalities are present, and we combine X with a completely non related cow Y, would X's physical abnormalities be carried over to calf XY or would Y have "neutralised" these defects, subsequently producing a healthy and completely normal looking calf (XY)?

As SBMF pointed out, a non related cow of a different breed would eliminate next generation abnormalities (but all offspring would be carriers)

Without testing to know for sure, a non related cow of the same breed may well be a carrier of the same defect without exhibiting the trait herself.

The most insidious abnormalities of inbreeding are fertility related, in example daughter looks normal, but has low functioning ovaries.
There is a correlation between Sire testicle size and Daughter ovary size and fertility.

 

[GoWyo]

Cross breeding hides genetic problems until you breed carrier to carrier.

 

[Little Joe]

Just curious as to why you would want to breed inferior genetics? It might work out fine for you but on my place anything that could go wrong with that would so I wouldn't want to take a chance.

 

[SBMF 2015]

Cross breeding hides genetic problems until you breed carrier to carrier.

In a commercial terminal breeding program the % is pretty slim. I bought several reg Angus cows cheap at seed stock sales because they are curly calf carriers. I cross them with horned Hereford bulls. Any F1 daughters worth saving end up being bred to Charolais bulls from their 2nd calf on. All of those calves go in our feed lot.

 

[GoWyo]

So long as you know they are carriers you can manage them. Clubby breeders do it all the time with PHA and TH. In those cases, the fact that one of the parents is a carrier seems to lead to certain desirable traits (bone and hair), but an affected calf is not viable. Curly calf carrier cows should eventually die out so long as no carrier bulls are used.

 

[alacowman1]

Very true. You have a good point. Still, more defective genes are probably present everywhere we look (in their recessive form). So if XY does carry the defective gene seen in X, but not in it's dominant form as seen X, would it matter?

Likely never notice it..I used a predestined son that was most likely a DD Developmental Duplication carrier..didn't find that out till I was knee deep in with him..no problem on my herd...thank the Lord...though I have replacements from him,that would be at risk in the future...if I don't do my home work..my last Bulls sire ,was highly line bred..

 

[Oubuffel]

As SBMF pointed out, a non related cow of a different breed would eliminate next generation abnormalities (but all offspring would be carriers)

Without testing to know for sure, a non related cow of the same breed may well be a carrier of the same defect without exhibiting the trait herself.

The most insidious abnormalities of inbreeding are fertility related, in example daughter looks normal, but has low functioning ovaries.
There is a correlation between Sire testicle size and Daughter ovary size and fertility.

Thanks Son of Butch, I appreciate your input. What you mentioned about the correlation between testicle size etc. is something I've always found intriguing. I'm planning on posting a new thread on the topic. Please be on the lookout for it and perhaps tell us more about the correlation you've mentioned?