When a newborn calf has low serum total protein, the first question is often whether it received enough colostrum. That is an important part of evaluating passive transfer, but Dr. Jeremy Schefers believes another component of the measurement deserves more attention: albumin.
Schefers, technical services veterinarian with Merck Animal Health, has been investigating low albumin concentrations in newborn calves through clinical observations, farm visits and diagnostic testing. He believes the issue may be more common than the industry recognizes and could have implications for calf health beyond passive transfer.
“The albumin fraction of the total protein is often not measured. It’s rarely discussed. But when looking at it and determining whether or not the endogenous serum albumin is adequate in newborn calves, we’re finding a lot of them that are low,” Schefers says.
His findings come from individual farm investigations and clinical experience, not a published or controlled research study. How frequently low albumin occurs in the broader calf population, its potential clinical consequences and the factors contributing to it remain open research questions.
Albumin and IgG Serve Different Roles in Newborn Calves
Serum total protein is made up primarily of albumin and globulins. In newborn calves, globulins include immunoglobulins absorbed from colostrum, particularly immunoglobulin G (IgG). Albumin, meanwhile, is produced by the calf’s own liver.
The two fractions serve different functions. Immunoglobulins provide passive immune protection, while albumin transports substances throughout the body and helps maintain fluid balance.
“Albumin is critically important. It transports nutrients and drugs. It binds toxins. Its most important feature is that it pulls fluid into the blood vessels,” Schefers explains.
Albumin helps maintain oncotic pressure, which keeps fluid within the bloodstream rather than allowing excessive movement into surrounding tissues. When albumin concentrations fall, fluid can accumulate in tissues, a condition known as edema.
Because total protein measures both albumin and globulins together, it does not show how much each fraction contributes to the result. Measuring total protein alone may leave unanswered questions when a calf’s laboratory results or clinical condition do not fit expectations.
Clinical Signs Associated With Low Albumin
Schefers describes seeing calves with clinical signs that do not always fit the typical picture of an infectious disease.
Signs he has observed in calves with low albumin include:
- Puffy joints: Swelling without the heat, redness, pain or lameness typically associated with an infectious joint condition.
- Persistent, nonproductive coughing: Coughing that does not respond as expected to treatment for respiratory disease.
- Generalized weakness: A broader sign that may accompany other clinical changes.
“We’ve seen these calves where producers have complained about them, saying these calves have puffy joints, and they feel like there must be an infection. And when we examine them closer, they don’t have the features of an infection,” he recalls.
These are clinical observations, not a validated checklist for diagnosing hypoalbuminemia. Each sign has multiple possible causes, so veterinarians should investigate the broader clinical picture before attributing symptoms to low albumin.
Farm Investigations Reveal Low Albumin Concentrations
In one farm investigation, Schefers tested 41 calves and found that 33, or approximately 80%, had serum albumin concentrations below 2.5 g/dL. Concentrations ranged from 2.0 to 2.6 g/dL, with an average of 2.3 g/dL. On another farm, 16 of 30 calves had total protein concentrations below 6.0 g/dL. Schefers attributed part of the reduction to lower albumin concentrations.
Schefers uses 2.5 g/dL as the lower limit of the reference range he cites. In one example, a calf had an albumin concentration of 1.9 g/dL and a globulin concentration of 3.5 g/dL, producing a total protein result of 5.4 g/dL. A higher albumin concentration would have increased the total protein result, even with the same globulin level. This illustrates how low albumin can contribute to a reduced total protein measurement independently of the amount of colostrum-derived globulin present.
Maternal Nutrition May Influence Calf Albumin Levels
Schefers’ central hypothesis is that some calves may be born with low albumin concentrations because of conditions during gestation.
Albumin is synthesized by the calf’s liver, a process that requires amino acids supplied through the dam. Schefers suspects maternal nutrition and rumen microbial protein production could influence the amino acid supply available to the developing fetus.
He has observed associations between nutritional challenges in cows and lower albumin concentrations in their calves, although those observations do not establish a direct relationship. He also questions whether dry-period nutritional management could influence the calf’s ability to produce adequate albumin before birth.
“Initially, we would scrutinize colostrum collection, colostrum feeding, everything we’ve ever talked about in colostrum. But in the back of my mind, I’m thinking, well, maybe it’s not a colostrum problem. Maybe these calves aren’t born with enough albumin,” he says.
The theory needs further study. Researchers would need to determine whether maternal dietary protein, amino acid availability, rumen function or specific stages of gestation influence fetal albumin production, and whether those differences affect calf health after birth.
Maternal nutrition is only one potential area of investigation. Low albumin can also result from impaired liver production, intestinal or kidney protein loss, chronic inflammation or infection, and inadequate nutrition.
When to Include Albumin Testing in a Calf Workup
For calves with unexpectedly low total protein or unexplained clinical signs, Schefers recommends considering albumin as part of the diagnostic workup.
“If you’re checking total protein in calves and you feel like they should be higher, dig a little deeper. Take the sample to a diagnostic lab and say, ‘Hey, can you check these samples for albumin?’” he says.
When investigating unexpectedly low total protein, veterinarians can:
- Review passive-transfer management: Revisit colostrum collection, quality, feeding and timing, along with other factors that could affect immunoglobulin absorption.
- Measure albumin directly: Request a serum chemistry panel or ask the diagnostic laboratory about measuring albumin separately.
- Investigate other potential causes: Consider liver function, intestinal or kidney protein loss, chronic infection or inflammation, and nutritional status.
- Interpret results in context: Consider the calf’s age, hydration status, clinical signs and other laboratory findings.
Schefers has cited an albumin reference range of approximately 2.5 to 3.5 g/dL. Veterinarians should confirm the appropriate interval with their diagnostic laboratory, as ranges can vary by laboratory and population. A result below 2.5 g/dL should be interpreted alongside the calf’s clinical condition and other findings, rather than used as a stand-alone diagnosis.
Albumin testing would complement, not replace, routine evaluation of passive transfer. It could provide additional information when total protein results or a calf’s clinical condition raise questions that colostrum management alone does not explain.
The Need for More Research on Calf Albumin
Albumin’s physiological functions are well established, but its concentrations and potential clinical significance in newborn calves have received comparatively little attention.
Schefers believes the industry has focused heavily on total protein, globulins and colostrum while overlooking the albumin fraction.
“I’ve looked and I’ve looked and I’ve looked and I’ve looked and I’ve looked. There’s a mountain of stuff on total protein and calves and globulin and colostrum, and the word albumin never comes up,” he says.
Research is needed to establish normal albumin concentrations in calves at different ages, determine how frequently low concentrations occur, and investigate potential relationships with maternal nutrition, clinical signs and health outcomes.
For now, Schefers encourages veterinarians to consider albumin when evaluating calves that do not fit the expected clinical picture. Measuring the individual protein fractions may reveal information that a total protein result alone cannot provide.
