There certainly is no shortage of bull pictures. Have you ever wondered just how many bull pictures can be printed in one magazine? A lot, and despite the added color and enhanced graphics, bulls still look like bulls. Yes, there are some subtle differences. To the trained eye, those differences may be notable, but still, there seems to be more similarity than differences in many of the bulls.
We enjoy pictures, but we also should enjoy data. Bulls may be very similar in phenotype, in other words the picture, but their genotype may have no similarity at all. Even the color, although fairly indicative of the DNA on one chromosome, may have no indication of what DNA is on the other chromosome. Because all chromosomes are paired, the calves that the bull produces each will be products of only one of the chromosomes. Therefore, black cattle certainly can sire red calves.
In terms of the many other traits, the variation within the particular lot of bulls can be extreme, even though all the bulls look alike. Some bulls have high-growth DNA, others low-growth DNA. Some bulls will have DNA more likely to produce prime to choice grade calves, while a very similar looking bull may only produce select or low choice grade calves.
Although muscle quantity and expression may be observed in the phenotype or picture of the bull, the ultrasound data indicating rib-eye area, often expressed as rib-eye area per hundred pounds of live weight, certainly will tell the same story.
The point is that true bull selection rests with understanding the data. The action of buying bulls should be a process of sorting through the data first and then looking at the bull. Every single piece of data is directly connected to a strand of DNA somewhere on the chromosome. Positive selection pressure on the correct traits will increase positive DNA within our bull stud. In turn, this DNA will combine with the DNA available in the cow herd to produce the calf crop.
Therefore, the process of buying bulls actually is, or at least should be, fairly methodical. Although data terms may baffle a bull buyer, always check out what the trait abbreviations and the many expected progeny differences (EPDs) values mean. The breed association websites have good glossaries or just ask other breeders.
A personal pet peeve: If there is room for the picture, there should be room for labeling conveniently the various numbers to make the reading of the information more doable. All of these notations lead up to some very important notes. Right up front, a herd should present in the catalog the average EPD values for the various traits the breed evaluates followed by the average EPD values for the bulls and heifers being sold.