Sometime down the road when feedyards are again shipping green cattle and the Choice/Select spread is six ax handles wide, we’ll remember this spring. We’ll remember the “over-ripe” cattle that went to market, the Choice/Select spread that was often very narrow, the getting paid as well for the carcass’ white as the carcass’ red. And, we’ll remember the innuendoes about breeding programs having gone wrong.
On that thought, I’ll repeat the advice I offered in my January column. Stick with the industry goal of breeding efficient cattle that will reach harvest with respectable marks for yield grade, quality grade and retail percent. This direction has given us many, many cattle that, if fed according to their genetics, will go to harvest with carcasses that are on target.
I have spent some time in the past month looking for evidence that would reinforce this argument. I first developed a model showing what happens to carcasses when animals are fed beyond their logical harvest points (see table). In doing this, I used the mathematical equations used by government graders and breed associations to calculate yield grades and retail yield percentages. I started out with a steer that would feed efficiently and work well on the grid (column one of table) and then added the amounts of fat that would create one yield grade change. Although ribeye area is a factor in the yield grade equation, I didn’t vary it because, generally, ribeye area is bred on, not fed on.
Several things jump right out of this analysis. The prototypic animal profiled in column one would work well for everyone from producer to consumer, and is one that has a high probability of grading Choice in the cooler. Second, it takes a very significant increase in backfat to move a single yield grade. In my example, this amount is over three-tenths inch. Third, the range for fat thickness within YG-2 for the column-one steer is 3.1 tenths, a liberal range that extends from 2.85 tenths to 5.95 tenths. Put another way, this is a pretty big target, which isn’t all that hard to hit.
To look further, I went to a data file I developed on 1,335 steers finished over a six-year period in the OK Feedout, which is conducted annually by the Cooperative Extension Service of Oklahoma State University. This data includes individual records on both feedyard performance and carcass factors. The cattle were managed to optimize both yield and quality grades.
I grouped the results according to breed type (straightbred British, straightbred continentals and crossbreds). None of the types had a backfat average at harvest of more than 4.1-tenths inch. Hardly any of the breed types fell into the YG-4 category — none for straightbred continentals and only 0.2-tenths percent for straightbred British. Quality-wise, 72 percent of the straightbred British types graded Low Choice or better. Fifty-four percent of the British-continental crossbreds graded Low Choice or better.
I also examined end-point projections on a recent 66-head pen of calf feds provided by Dan Dorn, co-manager of supply development for Decatur County Feedyard of Oberlin, Kan. These calves had an average of 2.4-tenths inches of backfat after 124 days on feed and had put on an average of 2.3-tenths inches over this period. These cattle were to be sorted according to logical endpoints, and I don’t know what the backfat was (or will be) at harvest. It isn’t likely, however, it would exceed the amount required to push them out of YG-2 into YG-3.
The point here is there is good evidence that cattle are, generally, being bred to reach harvest as YG-2s and to grade well for quality. This is as it should be. It should be a personal choice if you or a future owner choose to feed animals beyond this point.
To contact Fred Knop, write Drovers or send e-mail to email@example.com.