Breed associations and genetic defects

[LLBUX]

Should breed associations prevent/revoke registration of animals known/demonstrated to be carriers of genetic defects such as(but not limited to) Th and PHA?

I vote Yes

 

[twistedhshowstock]

I think they should require that all animals be tested and their status listed on their papers.  I think carriers of genetic deffects should be allowed to register with the carrier status noted on papers.  However, I do not believe that individuals that are Homozygous for genetic deffects should be allowed to register.

 

[kfacres]

I think they should require that all animals be tested and their status listed on their papers.  I think carriers of genetic deffects should be allowed to register with the carrier status noted on papers.  However, I do not believe that individuals that are Homozygous for genetic deffects should be allowed to register.

I cannot think of any lethal genetic defect in cattle, where a homozygous one lives to birth, or shortly after birth .  I just don't know about it not being natural for them to die...

 

[DL]

I think they should require that all animals be tested and their status listed on their papers.  I think carriers of genetic deffects should be allowed to register with the carrier status noted on papers.  However, I do not believe that individuals that are Homozygous for genetic deffects should be allowed to register.

I cannot think of any lethal genetic defect in cattle, where a homozygous one lives to birth, or shortly after birth .  I just don't know about it not being natural for them to die...

While most lethal recessive defects result in early demise (by definition ) not all recessive defects are lethal - Fawn calf syndrome (FCS) AKA contractural arachnodaactly (CA) is an autosomal recessive genetic defect in Angus cattle that is not always lethal; in fact some homozygous critters go on to reproduce; double muscling (DM) is considered a genetic defect by some breed associations (Angus) but not all - homozygotes are not (necessarily) born dead directly from the disorder but may die as a result of dystocia

As I have said a billion times before I think the use of carrier bulls is a bad idea - as long people believe that they cannot get a winner without using carriers - carriers will continue to be used. Breeders of seedstock should not IMHO multiply carriers -

 

[twistedhshowstock]

I think they should require that all animals be tested and their status listed on their papers.  I think carriers of genetic deffects should be allowed to register with the carrier status noted on papers.  However, I do not believe that individuals that are Homozygous for genetic deffects should be allowed to register.

I cannot think of any lethal genetic defect in cattle, where a homozygous one lives to birth, or shortly after birth .  I just don't know about it not being natural for them to die...

Who said anything about lethal. The post was about genetic defects in general.  There are numerous genetic deffects that can be tested for that are not necessarily lethal in the homozygous state.  They are a concern because of the potential and high likelihood that they will be lethal, but as stated above it is not ucommon for homozygotes to go on and lead normal, productive lives without ever showing sign of the deffect they carry.

 

[DL]

Who said anything about lethal. The post was about genetic defects in general.  There are numerous genetic deffects that can be tested for that are not necessarily lethal in the homozygous state.  They are a concern because of the potential and high likelihood that they will be lethal, but as stated above it is not ucommon for homozygotes to go on and lead normal, productive lives without ever showing sign of the deffect they carry.

What you say twisted is not entirely true

It breaks down like this
HOMOZYGOTES for ....
TH --> LETHAL

PHA ---> LETHAL

OS (Osteopetrosis AKA marble bone) ---> LETHAL

AM (arthrogryposis multiplex) ---> LETHAL

NH (neurohydrocephalus) ---> LETHAL

MA (alpha mannosidosis) ---> LETHAL

IE (idiopathic epilepsy ---> LETHAL (die from grand mal seizures early in life)

FCS (AKA CA) ----> may die at birth due to inability to stand and nurse; may survive with great assistance; may survive without help but can be identified by by abnormal musculature and poor growth - meat is off flavor - not really a "normal productive life"

DM - homozygotes often require c-section or may be born dead because of excessive muscling; a defect in some breeds a bonus in others

DWARFISM - different types some compatible with relatively normal life (Long nosed dwarf and proportional dwarf) some compatible with early demise (snorter AKA bulldog dwarf)

SYNDACTLY (AKA mule foot) not lethal but highly undesirable

Inherited Congenital Myoclonus - euthanasia recommended at birth

and in dairy cattle
Brachyspina syndrome, Complex vertebral malformation, Perosomus elumbis ---> LETHAL


So you see most of the recessive genetic defects are not compatible with a normal healthy life and many are LETHAL

 

[twistedhshowstock]

Who said anything about lethal. The post was about genetic defects in general.  There are numerous genetic deffects that can be tested for that are not necessarily lethal in the homozygous state.  They are a concern because of the potential and high likelihood that they will be lethal, but as stated above it is not ucommon for homozygotes to go on and lead normal, productive lives without ever showing sign of the deffect they carry.

What you say twisted is not entirely true

It breaks down like this
HOMOZYGOTES for ....
TH --> LETHAL

PHA ---> LETHAL

OS (Osteopetrosis AKA marble bone) ---> LETHAL

AM (arthrogryposis multiplex) ---> LETHAL

NH (neurohydrocephalus) ---> LETHAL

MA (alpha mannosidosis) ---> LETHAL

IE (idiopathic epilepsy ---> LETHAL (die from grand mal seizures early in life)

FCS (AKA CA) ----> may die at birth due to inability to stand and nurse; may survive with great assistance; may survive without help but can be identified by by abnormal musculature and poor growth - meat is off flavor - not really a "normal productive life"

DM - homozygotes often require c-section or may be born dead because of excessive muscling; a defect in some breeds a bonus in others

DWARFISM - different types some compatible with relatively normal life (Long nosed dwarf and proportional dwarf) some compatible with early demise (snorter AKA bulldog dwarf)

SYNDACTLY (AKA mule foot) not lethal but highly undesirable

Inherited Congenital Myoclonus - euthanasia recommended at birth

and in dairy cattle
Brachyspina syndrome, Complex vertebral malformation, Perosomus elumbis ---> LETHAL


So you see most of the recessive genetic defects are not compatible with a normal healthy life and many are LETHAL

I dont see how that changed what I said? I said the concern was with the potential and high likelihood.  I know that most genetic deffects are not compatible with a normal healthy life, if they were compatible with a normal healthy life we most likely wouldnt be as concerned with them.  What I was saying was that while yes it doesnt happen all that often, it is not all together uncommon for animals that are homozygotes for some of the genetic deffects to live normal healthy lifestyles. While some of them like TH/PHA will always be lethal within a short time of birth in the homozygous state.

 

[shorthorngirl2010]

Red gene carrier...
Wild type color gene...

;D

We all know the AAA has taken the initiative and set rules regarding the carrier status of all known defects, and that being said, I can see & understand both sides of the argument... Personally, I like that they don't allow papers to be issued to carriers [of AM/ NH/ CA/ ect.], it's their way of keeping 'clean' pedigrees.  Then again, it's nerve racking while waiting for those test results to come back in <cowboy>

-Sam

 

[Gators Rule]

My opinion may not be considered "liked" by some, but I think for the long term viability of any breed, or "discipline" (dairy, club calf, etc) which may include several breeds (composites or crosses), we should strive to remove genetic defects in the same manner as AQHA finally handled Impressive's HYPP genetic defect.  It is being handled over time, so as to not put those folks out of business overnight, and allow them to shift their breeding direction...

David