There are several factors to consider when selecting a bull to sire replacement females. The bull makes a lasting contribution to the herd (good or bad). The quickest way to change genetics of a herd is through sire selection. You want that contribution to be beneficial, moving the herd in the best direction to meet your goals.
If you raise your own replacements, maternal qualities in a bull are as important as weaning weight, yearling weight or carcass traits. Some of the most important maternal qualities cannot be measured very accurately (or at all) with EPDs — things such as conformation, disposition, udder shape and teat size, for instance.
Many ranchers look at every bull they purchase as having potential for keeping his daughters. If possible, look at the bull’s mother to make sure she has features such as good feet, good udder and good disposition.
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Also inspect his EPDs and make sure the data is acceptable for your goals. If your herd is already producing adequate milk, you don’t want a bull with high-milk EPDs or his daughters may produce too much milk, to the detriment of their own body condition and ability to rebreed on time.
Look for maternal qualities, stay-ability (longevity) and calving ease data — both direct calving ease and maternal calving ease. Most ranchers want a bull to be in the upper 50 per cent of the breed for these. Breeding is always a compromise. If you select for extreme in one trait, it will usually hurt you someplace else. You want a balanced package.
Some breeders try to evaluate at least three generations in the bull’s pedigree. His ancestors need to be the kind of cattle you want to get consistency in his calves. Check the female side of his pedigree in those three generations as well make sure they’re the right kind of cows. Even though you can look at paper records, it’s best if you can actually see the individuals (ancestors and offspring and half siblings,
Udders are very important. If you don’t want to have to help a newborn calf suckle, be very selective on udder quality. You want cows that still have a good udder (tight and not saggy, and with small, short teats rather than long or ballooned) when they are 12 years old. Many cows have nice, correct udders — and good udder scores — when they are two and three- year-olds, but break down later as they get older. If you are buying a bull that was out of a 12-year-old cow, her udder score is more accurate than that of a two or three-year-old dam.
The sire tends to pass on characteristics from its dam and this has a big influence on his daughters’ udders. The daughters will look a lot like their paternal grandmother.
Look at birthweights
Many ranchers look for moderate birthweight and maternal calving ease (not just direct calving ease) when choosing a sire, even when that bull will be bred to mature cows. If a sire has a big birthweight, his daughters will have big calves and might have trouble calving. The heifer inherits her own birthweight from her sire and dam. If she comes from family lines with heavy birthweights, she may have trouble calving, even if you breed her to an easy-calving bull.
Size at birth is influenced just as much by the female side as by the easy-calving bull you bred her to. Many ranchers who use light birthweight bulls on heifers still have calving problems if the heifers were produced from heavy birthweight sires. A light-to-moderate birthweight sire is best for producing daughters that calve easily.
It also pays to select for moderate frame size. Big cattle have higher maintenance requirements. It takes too much feed for that kind of cow. This goes hand in hand with milking ability. You can end up with big, heavy-milking cows that can’t produce very well unless they get extra feed. Milk is something many ranchers today select against, since longevity is important.
You don’t want poor udder attachments or the udder will break down. Even if a cow raises a good calf, if she can’t breed back, or her udder goes bad, she won’t last long in your herd. Some cows can milk well and still have a good udder in their old age, while others sag and the udder becomes a problem.
Disposition is also very important. You want cows that are easy to handle. Calm, mellow cattle are also more profitable and gain better in the feedlot than wild ones.
Indexes also spell out economics
Expected Progeny Differences or EPDs have been a great selection tool for bull buyers, but now we have another tool that can be even more beneficial. Indexes are composites of some of the EPDs that each breed association calculates. Economic weightings are placed on the various EPDs to create the indexes.
Potential profit is the primary goal, when selecting bulls. If you have a dozen EPDs to compare, it’s a challenge, especially when sitting at a bull sale trying to make a decision. The indexes, by contrast, answer the question about how much profit a certain bull might make compared to another.
Many breeds have terminal sire indexes to predict profit potential of offspring in terms of feedlot performance and carcass qualities. Some now have maternal indexes as well. The maternally oriented indexes are designed to combine genetic factors that impact productivity and profitability of cows in a herd that retains its own replacements and to help producers select bulls that will sire good females to retain in the herd and produce calves that can be marketed profitably.
When using bulls to sire replacement females, some of the maternal indexes will simplify selection. These indexes take into consideration calving ease, longevity, growth performance, how much calf you’ll have at weaning to sell — all the things that go into low-cost, long-lived, productive females. It simplifies putting together the information you’d need.
It takes away a lot of the guesswork and mathematical calculations, especially when trying to balance traits that can negatively impact one another such as milk (bigger calves) and longevity, or going too far on calving ease and reducing performance, or feed-efficient cattle that don’t grow enough. Putting too much emphasis on any one trait or facet of production will affect other parts of the profit equation. The index puts all of these important factors into good balance.
