Beyond colostrum

Dairy producers understand the importance of feeding high-quality colostrum immediately after birth. We have spent years improving colostrum collection, testing, storage and feeding protocols. However, emerging research suggests we may be overlooking another valuable nutritional resource already available on our farms: transition milk. While the first colostrum feeding is essential for passive transfer of immunity, what calves consume over the following days may also influence intestinal development, immune function and growth.

What makes transition milk different?

Transition milk generally refers to milk produced during the second through sixth milkings after calving. Although antibody concentrations decline rapidly after the first milking, it still contains more immunoglobulins, growth factors, proteins and other biologically active compounds than mature milk. These components may be valuable as the newborn calf’s intestinal lining develops its ability to absorb nutrients and protect against pathogens.

What does the research show?

A 2022 Journal of Dairy Science study compared newborn Holstein calves fed transition milk or milk replacer during the first four days of life. Calves receiving transition milk had intestinal villi that were 63% longer in the duodenum, 96% longer in the proximal jejunum and 76% longer in the middle jejunum. Villi are fingerlike structures that help absorb nutrients. The transition milk group also consumed 13% more milk solids, 30% more metabolizable energy and 29% more protein. Average daily gain was about 1.41 pounds versus 0.75 pounds, although this growth difference was not statistically significant. Because nutrient intake differed, the study cannot isolate the effects of transition milk’s bioactive components from the effects of additional nutrition.

Does transition milk improve calf performance?

A 2025 observational study of 251 dairy and beef-on-dairy calves found that those consuming more than 470 grams of immunoglobulin G through transition milk gained approximately 0.15 pounds more per day than calves receiving less than 260 grams. Higher IgG intake was also associated with lower preweaning mortality, especially in calves with lower initial passive immunity. These associations do not prove cause and effect. Another 2025 study of 50 Holstein calves reported slightly greater preweaning daily gain with transition milk compared with milk replacer, but there was no significant difference in body weight.

What about the newest research?

A September 2026 Journal of Dairy Science study evaluated 81 calves receiving transition milk, whole milk or five days of dam contact. Average daily gains were approximately 1.81, 1.83 and 1.87 pounds, respectively, without statistically significant differences. Body weight and skeletal growth also did not differ significantly. This is an important reminder that differences in intestinal development do not guarantee measurable short-term growth advantages in every management system.

Putting the findings into practice

The first priority remains prompt feeding of an adequate volume of clean, high-quality colostrum. Transition milk complements rather than replaces that first feeding. Farms considering a transition milk program can collect milk from the second through sixth milkings and feed it over the first three to five days. Collect hygienically, cool promptly and store appropriately. Avoid milk from cows with clinical mastitis or other conditions that make it unsuitable. Review pasteurization, Johne’s disease risk and other biosecurity considerations with your veterinarian. Develop consistent collection and labeling procedures, then monitor calf health, growth, treatments and labor to determine whether the program works on your farm.

The bigger picture

Early calf nutrition influences more than immediate weight gain. Transition milk can stimulate intestinal development, and some studies associate greater exposure with improved growth and health. Yet benefits are not consistent across studies, and improved future milk production has not been established. Colostrum remains the foundation of newborn calf health, but the next several feedings deserve attention, too. Transition milk may be an opportunity to support early calf development using a resource already available on the farm.

Portia Seckerson is the owner of Nortnern Valley Livestock Services in Plainview, MN. Their office of six veterinarians cover Minnesota and Wisconsin. She can be reached at pseckerson@nvls.vet