Despite the droughts of 2011 and 2012, cattle producers are interested in improving the genetics of their herds by inserting new heifers. Kansas State University cow-calf specialist Bob Weaber says there are number of things to consider when replacing or adding new cows to the herd.
“If you have an opportunity to pick replacement heifers from cows that have been in your environment and under your management for a period of time, that makes some sense. We think of fertility as a lowly inheritable trait, which it is, but that doesn’t mean it has a heritability of zero. In light of many commercial operations that don’t have EPDs for fertility traits, selecting those heifers from cows that have been successful reproductively in your program makes a lot of sense. It says those cows fit your environment and management, so keeping heifers out of that group, I think, makes a lot of intuitive sense.”
Dr. Weaber says avoiding extremes is also a wise strategy to employ when selecting replacement heifers to avoid high maintenance costs.
“Heifers, maybe, that are extremely fleshy relative to their peers or very thin relative to their peers are likely ones you may not want to keep. I say that because the very fleshy ones may be evidence of a cow that’s very high lactation potential cow in your operation. Temperament or docility is one, I think, is always one producers need to keep an eye on. It really helps when the animals are more docile to start with. So, keeping an eye on temperaments of females as you make a selection decision could be really key.”
To lower forage and feed grain costs, it is important to select heifers with a moderate growth and performance level. Weaber says to pick “heifers that are sort of from the middle of your calf crop in terms of growth potential. We have a tendency to pick the biggest, fleshiest, nicest looking set of heifers in the pen. The problem with that is, over time, that contributes to making much larger cows.
“If your goal is to start minimizing or decreasing supplemental feedstuffs to your cows, thinking about picking heifers from sort of more moderate levels of growth and performance to fit that environment makes a lot of sense.
“The best way to pick those females, then, is to actually collect weaning weights on each of those individual replacement heifers. And, then, if you have birth date data available on those heifers, actually go back and compute adjusted 205-day weights. What we know is if a producer, say, has the 90-day calving season, there can easily be 200 pounds of difference in the weights of heifer calves born in that operation just due to age and being born at the beginning or the end of the calving season. So, correcting that bias out of the decision is really important.”