VanC":26pqx3f7 said:
Alan":26pqx3f7 said:
I read this from a statement Doc made on another thread and once again my hat is in my hand asking for an education. :oops:
Doc's Quote:
But, in increasing the Milk EPD's, it has resulted in loss of muscling (funnelbutts) and loss of Scrotal Circumference
Because explain to me how increasing Milk EPD's effects hind end muscling and scrtal circumference. Thanks, now for the second question.
but I have noticed a disparity between High Rib eye and very LOW IMF. IMF and Milk seem to go hoof in hoof, but RibEye and IMF are far apart, unless the phenotype is beef type. Then they are both fairly high - lately. Look at the IMF and Ribeye EPD's on your Ohlde cattle. They should be fairly close! Right?
I have asked this question a few times and haven't ever recieved an answer to complete my question. I don't think there is even too many Herefords with the REA and IMF close, it seems to me that would be a no brainer to try to breed both of those carcuss quailities into your herd. Why are they so far apart?
Thanks to all,
Alan
On question #1, my guess is Doc is referring to single trait selection. Any time you go overboard selecting for one trait, such as milk, others are going to suffer. In most cases, animals with balanced EPDs are better in the long run than ones that are outstanding in one or two traits.
On question #2, REA and IMF have always been considered antagonistic traits. If you go after one, the other suffers. There are animals out there that are good in both but very few that are outstanding in both. If you're going to retain ownership through slaughter, both are important. In that case, more money can be made through crossbreeding, IMO.
-Alan and VanC-
Alan hit the answers square on the head on both questions! "Single trait selection" in seedstock or production breeding is a formula for failure - in my opinion! Erase your blackboards, and think of it this way: if a breeder decides that he must improve his Weaning Weights to increase his income ( which it certainly will do!), and concentrates his mating selections on THAT CHARACTERISTIC
ONLY for several breeding seasons and retains the heifers which will help him achieve that goal - that WILL happen! Absolutely! Like Begets Like! After 12 or 15 years (figure out the time it will take) he will have great weaning weights if he has selected that Single Trait judiciously in his breeding stock. In the same period of time, along with increased WW, he has probably DECREASED his Calving Ease Direct EPD, INCREASED his Birth Weight EPD, (not good) INCREASED his Yearling weight EPD (...and here we arrive at a dichotomy - - or a division of objectives - - which are sharply opposed!) For feedlot production - it is fine! On the other hand, for retaining heifers for the breeding herd from the SAME matings it is terrible because they are too big, requiring more feed - year round for the breeding cow herd - and getting larger every retained heifer crop! Of course, this is assuming that you continue to select your herd bulls with High Weaning Weight EPD's, as per our original protocol example.
Continuing with this same procedure of explanation, single trait selection for WW ONLY, probably would result in increased Yearling Height (more feed requirements), more calving problems, and a lower $EN (Cow Energy Value) meaning higher feed energy expenses. The $W (Weaned Calf Value) might be higher at first glance, but includes both revenues and cost adjustments associated with differences in birth weight, weaning direct growth, maternal milk, and mature cow size - which continues to get larger and larger with the higher WW EPD selection choices.
VanC is absolutely "Right On!" with his comment ". . .more money can be made through crossbreeding." Lee Leachman has proved that crossbreeding adds $100+/- per cow per year to your bottom line. And he does this by advocating 1150 - 1350 pound brood cows with 5.5 body score.
It should be easy to see from these examples that Single Trait Selection (ANY single trait) is not the most optimal choice for expected profit in a beef cattle breeding operation.
Insofar as the REA and Marbling traits are concerned, they ARE antagonistic to each other - and perform as an automobile would if you pressed on the accelerator with your right foot and the brake pedal with the left foot at the same time! It would cost you nothing but money - burned out brakes and high fuel costs! Read the beef cattle sale catalogs and note the differences in MOST of the REA and Marbling scores. One is high - one is low. Not always, but usually.
The same principle applies to the discussion regarding HIGH Milk/Lower Birth Weight EPD's and loss of Muscle Definition (Funnel Butt). Not always, you understand, but usually! And, as usual, I recommend Moderation In Everything - and single trait selection is NOT moderation. It is Radical.
These are just two more justifications for UNDERSTANDING the correct function and employment of Expected Progeny Differences in
conjunction with Phenotype and your own good eyesight! One is Hamstrung without the other. Successful breeders use both.
DOC HARRIS
