Brad S said:As for imf - where are you getting a prime spread to justify chasing it? It's a biological fact that it takes less energy to put a pound of muscle on a critter than a pound of fat. I theorize imf deposition isn't as variable among cattle as people think, but a heavy muscled limmy has more muscle to spread the same amount of fat over. Cab has taught us a lot about feeding cattle. It used to be you wanted to buy condition (thin calves), but if you want to hit the cab grid you simply must avoid the high yg #s. We're learning the calf that did well on his momma, optimized growth - not necessarily a creep bomb - but some neck fat, then a good weaning and feeding period will do better on the grid. It's like the calf is depositing imf while on the cow, so you don't have to do it all in the yard (where you'll get to yg3+).
If you want to know about imf deposition, brethours group at ft hays has it figured out. John passed but their ultrasound work is enlightening.
There is solid gold in that there.
I've been to a number of WSU and OSU deals where they talk about the effect of nutritional plane of grading. The first study was like on 400 pound calves. If you starve 400 pound calves, there is a tremendous difference in the grading on these calves later. They have dialed that clear back to the fetus. If 2 month bred cows lack nutrients, you will see a marked difference in the grading of those calves.
As I remember, it doesn't mean you have to feed super hot feed. You do have to have a good nutritional plane on the cows and the calves to fully express marbling. Yep, you can't starve profit into cattle.
Marbling is hugely genetic as well. I have found I really have to watch my calcium levels on my good marbling cow herd. Marbling and milking are highly correlated.
As far as single trait... Sometimes I think you just want to avoid the bottom half of the breed on a number versus trait benders. When the Zoetis deal came out and had numbers on tenderness, I was pretty excited because of our direct marketing program. When it severely started limiting the bulls I'd use, I paused. We don't get complaints for tough steaks. Hmmmm... I also looked at the MARC research on breed diffeences for tenderness. I am mostly Simangus breeding. Simmentals have a breed advantage with regards to tenderness. So, I decided mostly I want to use tenderness score to keep the worst of the breeds out.
I think that applies to other things as well. Moderate is great. LOL, I have friends who have decided low birth wt may really only mean cattle with shorter gestation periods.