Can You Spot Your Best Milk Cow at Eight Weeks Old? What the Research Says

Every dairy producer has done it.

Walk through your calf facilities, and it's easy to pick favorites.

There's always one calf that's taller, heavier, or seems to grow faster than the rest. It's natural to wonder: Is that future high-producing cow already standing in front of me?

Research offers an interesting perspective on that question.

While no one can predict with certainty which calf will become the highest-producing cow in the herd, research suggests that what happens during a calf's first eight weeks of life can have a lasting impact on her future performance. The key isn't simply raising bigger calves. It's supporting healthy, consistent growth during one of the most important developmental stages in a dairy animal's life.

More Than Just Getting Calves to Weaning

For decades, successful calf programs were often measured by one simple outcome: getting calves through the preweaning period alive and healthy.

While calf health has always been a priority, today's research suggests the preweaning period also plays an important role in shaping future productivity.

Researchers now recognize that the first weeks of life represent a critical window of development. Scientists refer to this as developmental programming, the idea that early nutrition and management may influence how an animal develops and, ultimately, performs throughout adulthood.

What Does the Research Say?

The connection between early growth and future milk production has been studied for more than two decades.

One of the most influential papers on the topic came from researchers at Cornell University. In a 2013 meta-analysis, Fernando Soberon and Michael Van Amburgh analyzed data from multiple calf nutrition studies and found that greater preweaning nutrient intake was consistently associated with higher milk production during the first lactation. Their analysis estimated that for every additional kilogram of preweaning average daily gain (ADG), first-lactation milk yield increased by approximately 1,550 kilograms (3,417 pounds).

More recently, a 2025 meta-analysis published in the Journal of Dairy Science reviewed data from 18 studies and reached a similar conclusion. Researchers found that calves with greater preweaning ADG generally produced higher yields of milk, fat, and protein during their first lactation, reinforcing the importance of healthy early growth rather than simply achieving a larger body size.

Healthy growth reflects more than body weight alone. It can indicate that calves received adequate nutrition, remained relatively free of disease, and were raised under good management. In that sense, preweaning growth may serve as an indicator that multiple aspects of calf care were working together successfully.

That doesn't mean the largest calf in the pen will automatically become the highest-producing cow. Instead, the research suggests that investing in healthy growth early in life can produce benefits that extend well beyond weaning.

Growth Matters More Than Size

It's easy to assume that bigger calves make better cows, but research suggests healthy, consistent growth matters most.

Birth weight is largely determined by genetics and gestation. What happens after birth, however, is shaped by management. A large calf that experiences illness, inconsistent nutrition, or environmental stress may never reach her potential, while an average-sized calf that grows steadily and stays healthy may ultimately outperform her larger herdmates.

The goal isn't simply producing heavier calves. It's supporting efficient growth through good colostrum management, balanced nutrition, clean water, comfortable housing, proper ventilation, sanitation, and careful daily observation. These management practices help calves convert nutrients into growth rather than diverting energy toward disease or stress.

Building the Foundation for Future Performance

The preweaning period is one of the fastest phases of growth in a dairy animal's life. During these first weeks, organs continue developing, the immune system matures, and mammary tissue undergoes critical stages of growth.

Researchers believe this period represents an important window of developmental programming, during which nutrition and management may influence future performance. Although the biological mechanisms are still being studied, evidence suggests early-life nutrition affects more than short-term growth.

Because so much development occurs during this brief period, disease, poor nutrition, or chronic stress can have lasting consequences. Healthy calves that experience steady growth are better positioned to express their genetic potential, making calf raising an investment in the future productivity of the herd.

Looking Beyond the Scale

While weight gain remains an important benchmark, it shouldn't be the only measure of success. Healthy calves are typically alert, curious, eager to drink, and recover quickly from routine management events. Changes in behavior often appear before more obvious signs of illness, making daily observation an important part of calf management. Combined with objective measurements like average daily gain, these observations provide a more complete picture of calf health and development.

No Crystal Ball, But Better Odds

No producer can walk through the calf facilities and accurately identify which eight-week-old calf will become the herd's next record-breaking milk producer.

Too many variables remain. Genetics, reproductive success, transition management, nutrition after weaning, and countless other factors all influence lifetime performance.

However, research continues to reinforce one important message: the decisions made during a calf's first weeks matter.

Every effort to support healthy growth, including excellent colostrum management, proper nutrition, clean housing, fresh air, and disease prevention, helps create the conditions necessary for calves to reach their full genetic potential.

So, can you spot your best milk cow at eight weeks old?

Probably not.

But by focusing on healthy, consistent growth instead of simply raising bigger calves, you can improve the odds that every calf has the opportunity to become one.

By Maggie Faulkner

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References

Jiang, W., He, J., Gelsinger, S. L., & Hanigan, M. D. (2025). Effects of preweaning calf daily gain and feed intake on first-lactation milk yield and composition: A meta-analysis. Journal of Dairy Science, 108(4), 4787-4804.

Lohakare, J. D., & Kim, Y. H. (2012). Nutrition-induced changes of growth from birth to first calving and their impact on mammary development and first-lactation milk yield in dairy heifers: A review. Asian-Australasian Journal of Animal Sciences, 25(9), 1338-1350.

Soberon, F., & Van Amburgh, M. E. (2013). The effect of nutrient intake from milk or milk replacer of preweaned dairy calves on lactation milk yield as adults: A meta-analysis of current data. Journal of Animal Science, 91(2), 706-712.