ebv debate

[neilo]

Ideal weight to market lambs for me would be 44kg, most will be slaughtered between 42 and 44kg, ( typicaly R3L's) which is a higher weight than it was 10 years ago and about 6kg heavier than 20 years ago, but with growth have come the male lambs that need to grow to 48kg+ before laying down cover.

That would be down to the increasing mature weight that often comes with higher growth rates. The resultant lambs are still growing than attaining a level of maturity where they lay down fat (finish). It is not purely a result of recording, but of breeding bigger mature weight sheep, as demanded by the show & sale ring (recorded or not).

There is a bit of tinkering going on with weightings for fat level ebvs, which I think is a complete red herring as regards finished lamb weights, without addressing late maturing sheep. Mature weight ebv is totally inaccurate in terminal sire breeds, as nobody is actually weighing their adults. If they were, most would be looking to use it to increase mature weights to breed a bigger shearling for sale/show.

The only answer to it, is to use a ram breeder that isn't chasing ever increasing size and actually has some experience of finished lamb production in a commercial scenario. Unfortunately there aren't many, in any breed, recorded or not.

On your in-lamb ewe purchase, what did that ewe produce the next year? I have never had anything any good come out of a pedigree ewe bought in-lamb. They are coming onto a new farm, with different bugs and a different feeding regime, at just the worst stage in their pregnancy. They have usually been fed (& not necessarily concs) well for quite a while, knowing there was a sale coming up, so their feed level was too high in early pregnancy leading to poor placental development, small lambs and poor colostrum. I've only ever had any decent lambs from those purchases the following year, after they've settled into the system, and not always then.

 

[ford4000]

That would be down to the increasing mature weight that often comes with higher growth rates. The resultant lambs are still growing than attaining a level of maturity where they lay down fat (finish). It is not purely a result of recording, but of breeding bigger mature weight sheep, as demanded by the show & sale ring (recorded or not).

There is a bit of tinkering going on with weightings for fat level ebvs, which I think is a complete red herring as regards finished lamb weights, without addressing late maturing sheep. Mature weight ebv is totally inaccurate in terminal sire breeds, as nobody is actually weighing their adults. If they were, most would be looking to use it to increase mature weights to breed a bigger shearling for sale/show.

The only answer to it, is to use a ram breeder that isn't chasing ever increasing size and actually has some experience of finished lamb production in a commercial scenario. Unfortunately there aren't many, in any breed, recorded or not.

On your in-lamb ewe purchase, what did that ewe produce the next year? I have never had anything any good come out of a pedigree ewe bought in-lamb. They are coming onto a new farm, with different bugs and a different feeding regime, at just the worst stage in their pregnancy. They have usually been fed (& not necessarily concs) well for quite a while, knowing there was a sale coming up, so their feed level was too high in early pregnancy leading to poor placental development, small lambs and poor colostrum. I've only ever had any decent lambs from those purchases the following year, after they've settled into the system, and not always then.

I actually bought 2 , but 1 gave birth to twins , both of whom couldn't breathe and died (lot of fluid came out of lungs after death! ! ) , the following September I couldn't even get a sponge in her as she had "sealed up" !....she went in the freezer !!
The other one never had any lambs worth keeping, they never did as well as my home bred texels ,which are run with the commercial ewes and lambs.Rightly or wrongly this makes me a bit sceptical about EBV'S in the real world!


And no, I wouldn't buy a inlamb ewe again either ! Lol

 

[dogandstick]

What does the accuracy value mean in real terms?

For instance, if a sheep's EBV's have a 50% accuracy value, does it mean that it's performance (all things being equal) might lie 50% either side of the "estimate", whilst the variation of one with 90% accuracy might be 10% either side? If not, is there not a better way of estimating the estimate?

 

[NZDan]

That would be down to the increasing mature weight that often comes with higher growth rates. The resultant lambs are still growing than attaining a level of maturity where they lay down fat (finish). It is not purely a result of recording, but of breeding bigger mature weight sheep, as demanded by the show & sale ring (recorded or not).

There is a bit of tinkering going on with weightings for fat level ebvs, which I think is a complete red herring as regards finished lamb weights, without addressing late maturing sheep. Mature weight ebv is totally inaccurate in terminal sire breeds, as nobody is actually weighing their adults. If they were, most would be looking to use it to increase mature weights to breed a bigger shearling for sale/show.

The only answer to it, is to use a ram breeder that isn't chasing ever increasing size and actually has some experience of finished lamb production in a commercial scenario. Unfortunately there aren't many, in any breed, recorded or not.

On your in-lamb ewe purchase, what did that ewe produce the next year? I have never had anything any good come out of a pedigree ewe bought in-lamb. They are coming onto a new farm, with different bugs and a different feeding regime, at just the worst stage in their pregnancy. They have usually been fed (& not necessarily concs) well for quite a while, knowing there was a sale coming up, so their feed level was too high in early pregnancy leading to poor placental development, small lambs and poor colostrum. I've only ever had any decent lambs from those purchases the following year, after they've settled into the system, and not always then.

But my understanding was that higher growth and higher fat levels were strongly correlated? And the issue was caused by strong selection for low fat levels but the measurement for fat being done at high weights? Ideal weight to do ema and fat scanning is slaughter weight. I realize that high adult size and growth rate are also strongly correlated.

 

[neilo]

But my understanding was that higher growth and higher fat levels were strongly correlated? And the issue was caused by strong selection for low fat levels but the measurement for fat being done at high weights? Ideal weight to do ema and fat scanning is slaughter weight. I realize that high adult size and weight at maturity are also strongly correlated.

I have used very lean rams with low mature weights where the lambs have been finished and full of flesh at slaughter weights (40-45kg) and also high positive fat ebv rams with high mature weights, were the lambs have been practically unsaleable due to lack of finish at those same slaughter weights, they've still been growing at a daft rate of knots. Needless to say I took the hit and got rid of most of them, as no good for breeding fat lambs.

I don't think many have been selecting for low fat levels in the UK for quite some time, and the extreme lean ones are getting penalised heavily by the Signet system. Signet will still tell you that there is a problem with prime lambs being too fat, so rams need to be leaner, but that's too simplistic an approach and done from behind a desk.

I have noticed a distinct correlation between high muscle and low fat levels, with fat, muscular animals being a job to find. I'm looking for 'curve benders', that grow fast then tail off. They aren't popular rams though, as they won't make monster shearlings.

 

[dogandstick]

But my understanding was that higher growth and higher fat levels were strongly correlated? And the issue was caused by strong selection for low fat levels but the measurement for fat being done at high weights? Ideal weight to do ema and fat scanning is slaughter weight. I realize that high adult size and weight at maturity are also strongly correlated.

Doesn't look like anyone's got an answer for this one!

 

[NZDan]

But my understanding was that higher growth and higher fat levels were strongly correlated? And the issue was caused by strong selection for low fat levels but the measurement for fat being done at high weights? Ideal weight to do ema and fat scanning is slaughter weight. I realize that high adult size and growth rate are also strongly correlated.

Doesn't look like anyone's got an answer for this one!

Right.
High mature weight is correlated to high growth.
High Growth is correlated higher fat (Fat weights more than Muscle)
But a high mature weight animal is leaner an any given weight (Fat is linked to stage of maturity not size).
One of NZs big breeding company have there index set so that carcass fat stays about constant, doing this restricts there growth gains to about 50% of what is possible if they ignored fat, but about half of that 50% would be fat anyway. They are also increasing carcass value by increasing the amount of meat in the carcass at any given weight.

 

[neilo]

Doesn't look like anyone's got an answer for this one!

Sorry, thought we had, sort of... Also posted further back about several large flocks canning March lambs at slaughter weights, and ebv' standing up OK.

Right.
High mature weight is correlated to high growth.
High Growth is correlated higher fat (Fat weights more than Muscle)
But a high mature weight animal is leaner an any given weight (Fat is linked to stage of maturity not size).
One of NZs big breeding company have there index set so that carcass fat stays about constant, doing this restricts there growth gains to about 50% of what is possible if they ignored fat, but about half of that 50% would be fat anyway. They are also increasing carcass value by increasing the amount of meat in the carcass at any given weight.

I'm not convinced there is any correlation between high growth rates and high fat ebvs. Looking through our (Charollais) Signet report at the moment and I can't see that at all. There are a range of fat ebvs at a similarly wide range of scan wt ebvs. There are fat animals with high growth and also lean animals with similar growth, and similarly with lower growth animals.

The Charollais index used to be weighted so as to aim to maintain fat levels (not giving undue credit to very lean or very fat animals) until it was changed last year. Now more weighting is given to higher fat wt and higher growth animals, consequently the later maturing, high growth types have moved up the rankings at the expense of slower growing, leaner, higher muscle types. Most definitely a backward step IMO, and given several of the largest recording stalwarts some serious 'wobbles' about whether to carry on with it. It again emphasises the need to drill down beyond the overall index and look at trait ebvs. I am still absolutely furious about the new index weighting, but the principle of recording and ebvs is right IME, so giving it a couple more years to see if it sorts itself out. It's just a shame when breed politics have to get involved.

 

[NZDan]

Sorry, thought we had, sort of... Also posted further back about several large flocks canning March lambs at slaughter weights, and ebv' standing up OK.



I'm not convinced there is any correlation between high growth rates and high fat ebvs. Looking through our (Charollais) Signet report at the moment and I can't see that at all. There are a range of fat ebvs at a similarly wide range of scan wt ebvs. There are fat animals with high growth and also lean animals with similar growth, and similarly with lower growth animals.

The Charollais index used to be weighted so as to aim to maintain fat levels (not giving undue credit to very lean or very fat animals) until it was changed last year. Now more weighting is given to higher fat wt and higher growth animals, consequently the later maturing, high growth types have moved up the rankings at the expense of slower growing, leaner, higher muscle types. Most definitely a backward step IMO, and given several of the largest recording stalwarts some serious 'wobbles' about whether to carry on with it. It again emphasises the need to drill down beyond the overall index and look at trait ebvs. I am still absolutely furious about the new index weighting, but the principle of recording and ebvs is right IME, so giving it a couple more years to see if it sorts itself out. It's just a shame when breed politics have to get involved.

I think that an increase in growth is botth fat and lean increasing. So they restrict it to no change in fat and only a lean increase.

 

[ford4000]

Would it be possible to have a days to slaughter ebv since that's what lamb producers really want?

 

[cowboysupper]

Sorry, thought we had, sort of... Also posted further back about several large flocks canning March lambs at slaughter weights, and ebv' standing up OK.



I'm not convinced there is any correlation between high growth rates and high fat ebvs. Looking through our (Charollais) Signet report at the moment and I can't see that at all. There are a range of fat ebvs at a similarly wide range of scan wt ebvs. There are fat animals with high growth and also lean animals with similar growth, and similarly with lower growth animals.

The Charollais index used to be weighted so as to aim to maintain fat levels (not giving undue credit to very lean or very fat animals) until it was changed last year. Now more weighting is given to higher fat wt and higher growth animals, consequently the later maturing, high growth types have moved up the rankings at the expense of slower growing, leaner, higher muscle types. Most definitely a backward step IMO, and given several of the largest recording stalwarts some serious 'wobbles' about whether to carry on with it. It again emphasises the need to drill down beyond the overall index and look at trait ebvs. I am still absolutely furious about the new index weighting, but the principle of recording and ebvs is right IME, so giving it a couple more years to see if it sorts itself out. It's just a shame when breed politics have to get involved.

What range in fat EBVs are you targeting with your rams?

 

[Ysgythan]

See NZ Charolais are recording at 50 days and weaning and prioritising the differential.

 

[NZDan]

Would it be possible to have a days to slaughter ebv since that's what lamb producers really want?

That is what a growth rate (wwt) BV is.

 

[neilo]

What range in fat EBVs are you targeting with your rams?

Personally, I am not particularly concerned as long as they aren't extreme positive (fat) or extreme negative (lean). However, those extremes also have a place within a pedigree flock, to use over females at the other end of the scale. As an example, one lamb I've used this year has a fat ebv of -0.90, which is so extreme that he is losing points off his index because of it. However, he would give any Beltie a run for their money for gigots and certainly hasn't ever had a problem with finish as he's always been one of the best fleshed lambs in the field. A bit more growth and length wouldn't go amiss, but he has a place.

 

[neilo]

See NZ Charolais are recording at 50 days and weaning and prioritising the differential.

So at 8 weeks and 16 weeks? They are reared on grass only and selection is being made on the maternal traits too IIRC. It would certainly be interesting to see how they compared with current UK genetics on a similar system.

 

[NZDan]

Personally, I am not particularly concerned as long as they aren't extreme positive (fat) or extreme negative (lean). However, those extremes also have a place within a pedigree flock, to use over females at the other end of the scale. As an example, one lamb I've used this year has a fat ebv of -0.90, which is so extreme that he is losing points off his index because of it. However, he would give any Beltie a run for their money for gigots and certainly hasn't ever had a problem with finish as he's always been one of the best fleshed lambs in the field. A bit more growth and length wouldn't go amiss, but he has a place.

Maybe the fat figure is a red herring when it comes to lambs that aren't finishing and in fact its animals that while they can grow fast they lack the ability to 'flesh'. I know in my flock when research was being done on BCS, my best BCS sire was also my leanest, even though in general BCS and leanness were correlated.

 

[NZDan]

What range in fat EBVs are you targeting with your rams?

So at 8 weeks and 16 weeks? They are reared on grass only and selection is being made on the maternal traits too IIRC. It would certainly be interesting to see how they compared with current UK genetics on a similar system.

@Global ovine

 

[Ysgythan]

You wean at 16 weeks? Oh...

 

[NZDan]

You wean at 16 weeks? Oh...

12-14 weeks here.

 

[andybk]

Right.
High mature weight is correlated to high growth.
High Growth is correlated higher fat (Fat weights more than Muscle)
But a high mature weight animal is leaner an any given weight (Fat is linked to stage of maturity not size).
One of NZs big breeding company have there index set so that carcass fat stays about constant, doing this restricts there growth gains to about 50% of what is possible if they ignored fat, but about half of that 50% would be fat anyway. They are also increasing carcass value by increasing the amount of meat in the carcass at any given weight.

High mature weight means a longer growth curve , not nessesarily high growth rates , we have rams here that grow well to 50kg then slow quickly but not stopping giving a fast long weight finish
Fat is laid down as growth slows its why ewe lambs are easier to finish , you can have good growth rates without excessive fat

spot on
neils assumption on high fat , high muscle is pretty near the mark assuming the right weight regard the best rams to use imo , and they wont be those hulking great showstoppers either .
its pretty much what we have found , and i think signets early purge on fat may have lost some very good genetics (can you go back ? )