ADG vs F:G

[ROB]

been discussing the effects of selecting bulls with emphasis put on ADG vs. the emphasis put on F:G.

as an example lets say you have two bulls of the same breed, with similar EPD's for BW, WW, CED, CEM, REA, IMF, and FAT. frame score of each bull is 6.0. the only notable difference is that one has an ADG of 3.25 with a F:G ratio of 5.5:1, the other ADG = 4.0 and a F:G ratio of 8:1.

here lies the discussion, if you were to save back replacement heifers from each of the two bulls, which bull would tend to increase the frame size of the resultant cow herd?

ROB

 

[gberry]

I may have missed it, but what is F:G? #Feed:#Gain or something else?

 

[ROB]

dry matter feed to gain ratio

ROB

 

[KNERSIE]

I assume the F:G ratio is the FCR?

Both bulls are the same framesize so I doubt there will too much in it, but I would prefer to use the one with the 5.5:1 FCR. 8:1 is a really p...poor FCR while the 5.5:1 is very good. If the ADG of the second bull was lower you could argue that he is an earlier maturing bull and is already starting to pack fat on hence the poorer FCR. The 4 lbs ADG shows the bull is still growing quite quickly and hasn't started to mature yet so if they are the same frame size I'll take an educated guess that the second bull will be the taller later maturing mature bull and that should also show in the mature FS even though it doesn't show now.

So in my very longwinded way the first bull is less likely to add frame.

 

[ROB]

I assume the F:G ratio is the FCR?

Both bulls are the same framesize so I doubt there will too much in it, but I would prefer to use the one with the 5.5:1 FCR. 8:1 is a really p...poor FCR while the 5.5:1 is very good. If the ADG of the second bull was lower you could argue that he is an earlier maturing bull and is already starting to pack fat on hence the poorer FCR. The 4 lbs ADG shows the bull is still growing quite quickly and hasn't started to mature yet so if they are the same frame size I'll take an educated guess that the second bull will be the taller later maturing mature bull and that should also show in the mature FS even though it doesn't show now.

So in my very longwinded way the first bull is less likely to add frame.

o.k. thats basically my view as well with this scenario. now if you don't mind - could you give me your opinion if we make the scenario a little more "in-general". Lets say we are single trait selecting (which i know you don't do) but for discussion sake... one breeder is looking at high ADG only, and another breeder is looking at improved feed conversions only. which of the two programs will notice an increase in the resultant cow herd frame score if they save back replacement females. thinking in line with 10 to 15 years down the road with the same trait selection of 3 or 4 bulls.

ROB

 

[KNERSIE]

I assume the F:G ratio is the FCR?

Both bulls are the same framesize so I doubt there will too much in it, but I would prefer to use the one with the 5.5:1 FCR. 8:1 is a really p...poor FCR while the 5.5:1 is very good. If the ADG of the second bull was lower you could argue that he is an earlier maturing bull and is already starting to pack fat on hence the poorer FCR. The 4 lbs ADG shows the bull is still growing quite quickly and hasn't started to mature yet so if they are the same frame size I'll take an educated guess that the second bull will be the taller later maturing mature bull and that should also show in the mature FS even though it doesn't show now.

So in my very longwinded way the first bull is less likely to add frame.

o.k. thats basically my view as well with this scenario. now if you don't mind - could you give me your opinion if we make the scenario a little more "in-general". Lets say we are single trait selecting (which i know you don't do) but for discussion sake... one breeder is looking at high ADG only, and another breeder is looking at improved feed conversions only. which of the two programs will notice an increase in the resultant cow herd frame score if they save back replacement females. thinking in line with 10 to 15 years down the road with the same trait selection of 3 or 4 bulls.

ROB

Probably both in a single trait selection scenario, but chasing ADG has been proven to do just that. The timing of the test also play a role, typically bulls that go onto test younger have a better ADG and usually also a better FCR, so make sure you compare bulls that started the test at a very similar age.

 

[Aero]

if you want to add frame, select tall animals.

if you want them to weigh a lot, select high growth, heavy animals.

if you want to be profitable, select efficient animals.

figure out why you want taller animals before you figure out how to get them.

 

[ROB]

if you want to add frame, select tall animals.

if you want them to weigh a lot, select high growth, heavy animals.

if you want to be profitable, select efficient animals.

figure out why you want taller animals before you figure out how to get them.

Aero- not wanting to add frame. quite the opposite. the discussion was whether or not selecting for high ADG would increase frame in replacements over time and if selecting for better feed conversions would increase frame in replacements over time. i know for fact that selecting for higher ADG will increase frame size ...been there done that - seen others do it with the same results. the guy im discussing with doesnt think high ADG bulls will increase frame. He says selecting for better feed converters will increase frame...im not going to disagree, but i do think that shopping around for a better feed converting bull with "adequate or moderate ADG" will not create too many problems.

ROB

 

[Aero]

i havent seen anyone saying conversion ratio was correlated to frame. i do think it might be positively correlated to marbling and waste fat, but i doubt frame unless it takes fewer clories to put on a pound of bone than non-muscle but that's a stretch.

 

[ROB]

i havent seen anyone saying conversion ratio was correlated to frame. i do think it might be positively correlated to marbling and waste fat, but i doubt frame unless it takes fewer clories to put on a pound of bone than non-muscle but that's a stretch.

i can't see it either...and havent found studies where it has been documented.

ROB

 

[novaman]

I don't think anyone can say with any certainty that a high ADG will produce larger framed cows. The frame of the bull will be a better clue as to the results of his matings. I've had many calves that started out at a lower BW but had a high ADG and ended up as a moderately framed animal. On the other hand I've had larger BW calves that had a lower ADG and ended up as a moderately framed animal. Looking at ADG and feed conversion to predict frame is not a dependable method IMO.

 

[Frankie]

I don't think anyone can say with any certainty that a high ADG will produce larger framed cows. The frame of the bull will be a better clue as to the results of his matings. I've had many calves that started out at a lower BW but had a high ADG and ended up as a moderately framed animal. On the other hand I've had larger BW calves that had a lower ADG and ended up as a moderately framed animal. Looking at ADG and feed conversion to predict frame is not a dependable method IMO.

I agree with you. At our bull test station, sons of moderate framed bulls (EXT, Future Direction, Plowman, Freightliner) have topped tests for ADG, as have sons of bigger framed bulls (036, Foreman, Krugerrand). In searching for frame info, I'd pay more attention to their height EPD than their ADG.