There is virtually nothing more important to a newborn calf’s long-term health and performance than the timely delivery of high-quality, hygienic colostrum.
In recognition of that fact, researchers continue to study colostrum in search of ways to enhance it and perfect its delivery to calves. One such researcher is Dr. Trent Westhoff, who earned his PhD at Cornell University while investigating the nuances of colostrum.
Westhoff joined Elanco Animal Health in 2025 as a Dairy Technical Consultant. He recently presented a webinar – “Colostrum Management: Factors Influencing Yield, Quality, and Calf Health” -- on behalf of the Dairy Calf and Heifer Association. In it, he shared four recent, research-based findings that may lead to colostrum-management changes in the future:
Dry-period length influences yield and quality – Westhoff acknowledged the seasonal frustration that most dairy producers experience in the fall and winter – a dip in colostrum yield that may result in a colostrum shortage or lowering of quality standards to meet volume needs.
He and other researchers have investigated multiple factors in an effort to boost yields. The one detail that has been recognized so far in making a significant difference is dry-period length. In a study of more than 18,000 cows from 18 commercial U.S. dairies, Westhoff and his colleagues stratified cows into dry-period length of less than 47 days, 47-67 days, and greater than 67 days. They found that colostrum yield increased incrementally with each group. From a commercial production standpoint, he said the data showed managing for a 60-day dry period would yield about 5 pounds more colostrum per cow compared to aiming for a 40-day dry period.
The cows with the longest dry period also had significantly higher Brix %, an indirect assessment of colostrum IgG concentration, than the other two groups, indicating higher quality.
Oxytocin may help boost yield in first-calf heifers – In another study, Dr. Sabine Mann’s team at Cornell University explored whether administering oxytocin 45 seconds before unit attachment during colostrum harvest might help them let down more colostrum. They evaluated 636 cows in one New York herd that were milked in a rotary parlor. They looked at the quantity and quality outcomes of dosing cows intramuscularly with 0, 20, and 40 international units (IU) of oxytocin.
It made a difference in one group – the first-calf heifers that received the highest dose (40 IU) of oxytocin before their first milking. That group produced about 2.9 and 3.5 pounds more colostrum than the 20 IU group and the untreated controls, respectively, without affecting quality. The same response was not observed in second-lactation and older cows.
More is not necessarily better – Westhoff detailed a study (Frederick et al. 2025) of 88 calves that looked at the volume of colostrum delivered relative to subsequent serum IgG concentration and apparent efficiency of absorption (AEA) of immunoglobulin proteins. They examined first-feeding volumes of 6, 8, 10, and 12% of birth bodyweight. For reference, 9% of bodyweight of a 90-pound calf would equate to ~3.7 liters (~1 gallon) of colostrum, which is a standard first feeding for many dairies.
They found that serum IgG concentration increased substantially between 6% and 8% and increased numerically between 8% and 10%, but bumping that volume from 10% to 12% produced no benefit in serum IgG concentration. Meanwhile, AEA went down incrementally with each higher volume of colostrum. Based on these results, Westhoff advised feeding colostrum in the 8-10% of bodyweight range. He noted there is marginal benefit to “mega-dosing” up to 12%, and it could actually cause physical discomfort to calves to feed them that much. “If you want to get more colostrum into them, come back with a second meal,” he advised.
Heat treatment can create bacterial vulnerability – Heat-treating of colostrum can effectively reduce pathogenic bacteria levels. That can be a valuable step, because high bacteria levels have been proven to interfere with antibody absorption. But it comes with a hazard.
Westhoff said heat-treating colostrum to 140°F for 60 minutes has been shown to reduce bacteria count by a median of 93%. But a Cornell study in which he was involved (McKane et al. 2025) that looked at colostrum after heat-treating told another compelling story. They inoculated heat-treated colostrum, colostrum replacer, raw colostrum, and frozen colostrum with fecal E. coli. At 4 hours through 24 hours later, the colostrum replacer and heat-treated colostrum had significantly higher regrowth of bacteria compared to the raw and frozen samples.
The reason: “Colostrum has natural antimicrobial properties,” Westhoff explained. “When we heat-treat colostrum, we remove its ability to naturally manage that bacteria. This underscores the importance of cooling colostrum very quickly after you remove it from the heat-treatment system.”
Looking forward, Westhoff believes researchers will continue to parse the many factors in the complex system that makes up colostrum synthesis and management, with the hope of arriving at practical improvements that can be made on-farm.
As one example, he said in addition to IgG, colostrum contains valuable minerals, vitamins, hormones, immune cells, and antimicrobial peptides. “In the future, it may become possible to quantify colostrum quality with these or other factors, in addition to IgG,” he predicted.
