Holstein male sale barn calves evaluated for total serum protein concentrations.

Calves are born with minimal to no immune defense. Colostrum consumption by the calf is critical for transferring immunity from the mother to the newborn calf. Neonatal Holstein male dairy calves are routinely sold off the dairy operation to calf raisers and feedlots for meat production. Recently, recommendations were published for female dairy calves, but no recommendations were given for male dairy calves. A simple method for assessing the transfer of passive immunity is measuring total serum protein (TSP) concentrations within the first days of life. Total serum proteins are routinely measured in our contract research operation studying neonatal calf nutrition. The TSP concentrations for 1,327 Holstein male calves from the past 6 years across 19 separate experiments were measured using an optical with change to digital refractometer in 2021 summer. The mean TSP concentration was 5.40 g/dL with a range from 2.8 to 8.6 g/dL with a CV of 14.2% and SD of 0.77. Mean TSP concentrations increased with year (4.94, 5.40, 5.37, 5.42, 5.58, 5.62 g/dL for 2020, 2021, 2022, 2023, 2024, and 2025, respectively) indicating that dairy producers are improving their colostrum program for newborn Holstein male calves. The latest heifer immunity transfer status recommendations are excellent (>40%), good (>30%), fair (>20%), and poor (>10%), but these data percentages for Holstein male calves were, 14.4, 13.2, 37.0, and 35.5%, respectively for this summary. Thus, a large percentage of the male calves being sold through sale barns are in the poor and fair TSP categories. However, the percentage of poor TSP status has declined with time (60.0, 33.3, 33.2 30.1, 27.7, and 22.3%, for 2020, 2021, 2022, 2023, 2024, and 2025, respectively). Death loss was 4.0% across years and experiments. The death loss within TSP categories was 3.8, 15.1, 35.9, and 45.3% for excellent, good, fair, and poor, respectively. In conclusion, dairy operations are improving the colostrum management of Holstein male calves to minimize failure of passive immunity, but further management improvements are needed to achieve standard recommendations for heifers. A value proposition for calf buyers would be to test Holstein male calves for TSP concentrations at the sale barn before being sold. This would create potential value to both the buyer and seller.