IMF and Weights

[MikeC]

Wouldn't castrating affect IMF? Not to mention artificial hormones. Is IMF as hereditary as BW, WW, and YW?

Walt

Steers marble better than bulls, so I'd assume that castration affects IMF. But I'd sure like to see some research.

Age of castration has an effect also:

http://www.joe.org/joe/2006april/rb5.shtml

 

[KMacGinley]

Wouldn't castrating affect IMF? Not to mention artificial hormones. Is IMF as hereditary as BW, WW, and YW?

Walt

Steers marble better than bulls, so I'd assume that castration affects IMF. But I'd sure like to see some research.

Age of castration has an effect also:

http://www.joe.org/joe/2006april/rb5.shtml

Some research???? I think it is a given that testosterone lowers marbling, and since castration removes the vast majority of testosterone sources, maybe there might be a positive correlation between steers and a lack of testosterone promoting increased marbling. Or would that be a negative correletion? Would the removal of the testes be a negative experience for the animal?

 

[KMacGinley]

Doc: When you talk about highly heritable traits, how high are we talking?

While I am respectful of the role of genetics in producing quality animals, I also know that Management plays a much larger role overall.

For example: Implanting cattle lowers marbling scores.

Proper nutrition: cattle need to gain over 1.7 lbs per day for marbling to occur.

I suspect that cattle that wade through mud may be less tender than cattle that don't.

Stessing cattle on loading and transporting to the slaughterhouse may effect tenderness.

Those are my thoughts anyway.

 

[waihou]

I would be more inclined to think that the "well-muscled cow with low BW and very high Milk EPD" is manifesting phenotype traits, and not necessarily legitimate reproducible Genotype characteristics. It will NEVER show 100% of the resulting expectations that you would like to see! Another justification for not selecting for one trait only! Don't put all of your 'eggs' in one basket! I would not bet on a 'freak' of genetics resulting in the perfect answer for your breeding bull. His EPD's might be as mixed up as a bowl of Jello, but you wouldn't really know until he was bred to a 'bunch' of cows - and you wouldn't really KNOW even then!

and "keep an eye on her inter calving period"

Many thanks DOC and Knersie for your words of wisdom.

The cow in question is a '98 born on her eighth lactation. She has been a consistent performer since first calving at 22 months. That bull calf went to another stud and performed creditably for 4 seasons, ranked highly for producing low birth weight calves suitable for dairy heifer mating. We kept her second calf to use over a few heifers before selling him and one of his daughters is still in our herd. The cows mother, now 14 has a milk EBV of +12 this year.
Whilst not a particularly well muscled cow herself, I would call her moderate, her calves seem to get better and better. This years being no exception, and an improvement on the last two. She has consistently weaned the top or near to best calf each year. Her milk EBV has an accuracy of 69% (It is +15 this year, was +16 last year!) and her birth weight EBV is +1.4kg, breed standard +2.5kgs accuracy 79%. Her breeding interval after 8 calves is 369 days!

I realise this breeding game is very much a lottery and you never know just what will happen, but at least with EBV's and dna testing we can be slightly more confident in the outcome!
Her Genestar results are 8/8 tenderness 7/8 feed efficiency and 0/8 marbling. Now theres an interesting link ;-)

By the way said cow has only had two heifers, the first is black , and calved at 17 months-a forward wee girl whilst still unweaned-but she is now on her second calf and has done them both well.

Now I know most of you guys with Limo or Charolais blood will say this guy isn't that well muscled-but for a grass fed Murray Grey at 5 months I think he is developing nicely.
His first day tied up, alongside his dam, in preparation for our local show in 3 weeks time.

 

[Tom Underwood]

I believe there is a negative correlation between growth and IMF. I also believe there is a negative correlation between tenderness and growth. Further, in some lower growth cattle, there is less of a correlation between IMF and BF. In other words, there once were some slow-growing, marbled, muscled cattle that produced great-tasting beef.

Interestingly, when I breed 1950's Hereford genetics to modern Herefords, some of the calves grow close to modern calves, but have the look of the 50's calves. Others grow like the 50's calves (not much at all). The results appear to be somewhat random - not tied to EPD's. My guess is that some exhibit more heterosis than others. I look forward to the ultrasound results among the various calves next spring, as well as the knife and fork test the following year. Of course, I run the experimental herd with the best contemporary genetics - its always good to have a control group.

 

[DOC HARRIS]

Doc: When you talk about highly heritable traits, how high are we talking?

While I am respectful of the role of genetics in producing quality animals, I also know that Management plays a much larger role overall.

For example: Implanting cattle lowers marbling scores.

Proper nutrition: cattle need to gain over 1.7 lbs per day for marbling to occur.

I suspect that cattle that wade through mud may be less tender than cattle that don't.

Stessing cattle on loading and transporting to the slaughterhouse may effect tenderness.

Those are my thoughts anyway.

Mac-

The ratio of Heritable traits is a comparative variable ratio within the heritability factors themselves. To even place a figure is subjective in itself, but here are a few traits and figures that are at least a beginning. And I agree with you that there are so many different conditions and occurrances that will effect different animals in different ways that it is almost ludicrous to rush around like a chicken with it's head off trying to cover every contingency.

I don't remember where or when I got this.

TRAIT- - - - - - - PERCENTAGE HERITABLE

Low Heritability
Conception rate 0-10
Calving Interval 0-10
MODERATE HERITABILITY
Milkiing ability 15-25
Calving Ease 10-40
Gestation Length 30-40
Cancer eye susceptability 25-30
Birth Weight 35-40
Weaning Weight 25-30
Weaning Confirmation Score 20-25
Post Weaning Daily Gain-Pasture 30-35
Post Weaning Feed Conversion 35 40
Slaughter confirmation score 35-40
Dressing Percentage 35-40
Percentage retail product 25-30
MODERATE TO HIGH HERITABILITY
Scrotal Circumference 40-55
Postweaning Daily Gain 40-45
Postweaning Daily Feed Consumption 50-55
Final feedlot weight 50-55
Yearling weight 50=-55
Ribeye area 60-65
Fat thickness 40-55
Marbling score 40-45
Tenderness score 50-60

NOTHING IS SET IN CONCRETE

DOC HARRIS

 

[smnherf]

So if lower testosterone bull produce higher IMF ultrasound scores, aren't we involuntarily selecting for lower libidity bulls in our quest for that high IMF score? Then with the high degree of artificial insemination of such sires are we in danger of having a bunch of bulls that really don't care or not if they breed a cow or not?

The last couple years I hear more and more of "my black bulls don't want to breed cows". Or is something else going on?

Brian

 

[Txwalt]

So does everyone agree that castration improves IMF? Implants hinder IMF?

Walt

 

[DOC HARRIS]

I can't answer post for a while folks. I am off to the Emergency hosp. Got surgery scheduled in a couple of weeks. Hiatal Hernia.

Talk to you later.

DOC HARRIS

 

[SEC]

I can't answer post for a while folks. I am off to the Emergency hosp. Got surgery scheduled in a couple of weeks. Hiatal Hernia.

Talk to you later.

DOC HARRIS

God bless you Doc, hope all goes well!

 

[SEC]

I would be more inclined to think that the "well-muscled cow with low BW and very high Milk EPD" is manifesting phenotype traits, and not necessarily legitimate reproducible Genotype characteristics. It will NEVER show 100% of the resulting expectations that you would like to see! Another justification for not selecting for one trait only! Don't put all of your 'eggs' in one basket! I would not bet on a 'freak' of genetics resulting in the perfect answer for your breeding bull. His EPD's might be as mixed up as a bowl of Jello, but you wouldn't really know until he was bred to a 'bunch' of cows - and you wouldn't really KNOW even then!

and "keep an eye on her inter calving period"

Many thanks DOC and Knersie for your words of wisdom.

The cow in question is a '98 born on her eighth lactation. She has been a consistent performer since first calving at 22 months. That bull calf went to another stud and performed creditably for 4 seasons, ranked highly for producing low birth weight calves suitable for dairy heifer mating. We kept her second calf to use over a few heifers before selling him and one of his daughters is still in our herd. The cows mother, now 14 has a milk EBV of +12 this year.
Whilst not a particularly well muscled cow herself, I would call her moderate, her calves seem to get better and better. This years being no exception, and an improvement on the last two. She has consistently weaned the top or near to best calf each year. Her milk EBV has an accuracy of 69% (It is +15 this year, was +16 last year!) and her birth weight EBV is +1.4kg, breed standard +2.5kgs accuracy 79%. Her breeding interval after 8 calves is 369 days!

I realise this breeding game is very much a lottery and you never know just what will happen, but at least with EBV's and dna testing we can be slightly more confident in the outcome!
Her Genestar results are 8/8 tenderness 7/8 feed efficiency and 0/8 marbling. Now theres an interesting link ;-)

By the way said cow has only had two heifers, the first is black , and calved at 17 months-a forward wee girl whilst still unweaned-but she is now on her second calf and has done them both well.

Now I know most of you guys with Limo or Charolais blood will say this guy isn't that well muscled-but for a grass fed Murray Grey at 5 months I think he is developing nicely.
His first day tied up, alongside his dam, in preparation for our local show in 3 weeks time.

That's quite a calf!

 

[KNERSIE]

I would be more inclined to think that the "well-muscled cow with low BW and very high Milk EPD" is manifesting phenotype traits, and not necessarily legitimate reproducible Genotype characteristics. It will NEVER show 100% of the resulting expectations that you would like to see! Another justification for not selecting for one trait only! Don't put all of your 'eggs' in one basket! I would not bet on a 'freak' of genetics resulting in the perfect answer for your breeding bull. His EPD's might be as mixed up as a bowl of Jello, but you wouldn't really know until he was bred to a 'bunch' of cows - and you wouldn't really KNOW even then!

and "keep an eye on her inter calving period"

Many thanks DOC and Knersie for your words of wisdom.

The cow in question is a '98 born on her eighth lactation. She has been a consistent performer since first calving at 22 months. That bull calf went to another stud and performed creditably for 4 seasons, ranked highly for producing low birth weight calves suitable for dairy heifer mating. We kept her second calf to use over a few heifers before selling him and one of his daughters is still in our herd. The cows mother, now 14 has a milk EBV of +12 this year.
Whilst not a particularly well muscled cow herself, I would call her moderate, her calves seem to get better and better. This years being no exception, and an improvement on the last two. She has consistently weaned the top or near to best calf each year. Her milk EBV has an accuracy of 69% (It is +15 this year, was +16 last year!) and her birth weight EBV is +1.4kg, breed standard +2.5kgs accuracy 79%. Her breeding interval after 8 calves is 369 days!

I realise this breeding game is very much a lottery and you never know just what will happen, but at least with EBV's and dna testing we can be slightly more confident in the outcome!
Her Genestar results are 8/8 tenderness 7/8 feed efficiency and 0/8 marbling. Now theres an interesting link ;-)

By the way said cow has only had two heifers, the first is black , and calved at 17 months-a forward wee girl whilst still unweaned-but she is now on her second calf and has done them both well.

Now I know most of you guys with Limo or Charolais blood will say this guy isn't that well muscled-but for a grass fed Murray Grey at 5 months I think he is developing nicely.
His first day tied up, alongside his dam, in preparation for our local show in 3 weeks time.

That's quite a calf!

I agree the calf doesn't lack much, he is muscled enough for a british breed calf at 5 months.