By Kourtni Curry
It is known that colostrum contains elevated concentrations of immunoglobulins, nutrients, and bioactive compounds, such as IGF-1, insulin, and growth hormone. Therefore, feeding colostrum to calves provides an array of health benefits, such as passive immunity, increased cell regeneration after inflammatory damage, and stimulated growth of the gastrointestinal tract (GIT). Much like colostrum, transition milk (TM), which are the 2nd to 6th milkings after calving (Godden, 2008), contains increased levels of nutrients and bioactive components that are not found in whole milk or milk replacers (MR). Although the nutrient levels of TM are lower than that of colostrum, a study conducted by researchers at Michigan State University (J. Dairy Sci. 105:7011-7022) observed that feeding neonatal Holstein calves TM following colostrum further promotes intestinal development.
This study consisted of 23 neonatal Holstein bull calves. Every weekend, 4 calves that were born within the previous 12 hours were selected and given 2.84 L of stored colostrum, which was from the same dam, within 20 minutes of birth. Calves were blocked by bodyweight (BW) to 2 blocks per weekend and randomly assigned to the TM or MR treatment diet. The TM used during this study was collected from the same 16 cows for the entirety of the study. All calves were bottle-fed 1.89 L of their assigned treatment diet 3 times a day at the same times per day for 4 days before being euthanized for tissue sampling on day 5.
The calves fed the TM consumed 13% more solids, 30% more metabolizable energy (ME), and 20% more protein than those fed MR. In comparison to the MR fed group, the TM fed group gained twice as much BW over the course of the study and tended to increase gain in heart girth and hip height. With the increased maturation of the GIT of calves fed the TM, it is suggested that feeding TM over MR increases the ability of the calves to absorb more of their diet sooner and grow more efficiently. Based on calf growth prediction of the NRC (2001), most, if not all, increases in calf growth could be attributed to the increased ME contributed by the TM.
Compared to calves fed MR, calves fed TM had increased villus length and mucosa thickness in several sections of the small intestines. The villi of the intestines play a significant role in nutrient absorption, and the increased size of villi further increases the surface area available to do so. Having thick intestinal mucosa also plays a large role in increasing surface area for nutrient absorption. Due to the increased size of the villi and thickness of the mucosa in the TM calves, the quantity of immune cells and nutrients absorbed from the TM increased.
Overall, the calves fed TM had improved health scores. In the first 4 days after colostrum, calves fed TM had a 46% reduction in fecal scores, a 95% reduction in nasal scores, a 62% reduction in cough scores, and a 60% reduction of ear scores when compared to the calves fed MR. The increased immune cells in TM, such as T cells, may have helped TM calves defend against illness at the level of the GIT.
When analyzing blood measurements for days 2 to 5 before feeding time, in comparison to MR, TM increased the average concentrations of serum IgG by 20%, and serum total protein by 11% within the blood. TM tended to increase the average pre-feeding concentration of non-esterified (unsaturated) fatty acids (NEFA) by 16%. This is an indication of how beneficial TM is and its ability to passively transfer immune cells from cow to calf. Even though calves fed TM consumed less lactose on day 5, this group showed an increase in glucose and plasma insulin blood concentrations. This may be due to the TM’s influence on the greater glycogen reserves, increased function of the digestive tract, and more adaptable systems that used the available nutrients most efficiently. On the other hand, calves fed TM had decreased lipopolysaccharide binding protein (LBP) and haptoglobin concentrations, indicating a more effective functioning of the intestinal barrier.
When implementing this practice onto a farm, the milk from cows that are 2 to 4 days in milk can be collected and given to neonatal Holstein calves to drink during their first 2 to 4 days of life after receiving colostrum immediately after birth. As demonstrated from this study, feeding TM to a neonatal calf during the first 2 to 4 days of its life can prove to be very beneficial in the most critical first 3 weeks of its life. Overall, feeding TM versus MR increases most measures of intestinal development by at least 50%. Feeding TM has also shown to increase health, growth, and nutrient digestibility.
Kourtni Curry is a recent graduate from North Carolina State University where she received a Bachelor of Science degree in Animal Science with a concentration in Veterinary Bioscience. Kourtni is currently a Dairy Research Intern at the William H. Miner Agricultural Research Institute. In the future, she desires to become a large animal veterinarian, contribute to farm animal research, and serve in rural communities that are lacking accessible and reliable veterinary services.
References
Godden, S. (2008). Colostrum management for dairy calves. Veterinary Clinics of North America: Food Animal Practice, 24(1), 19-39. https://doi.org/10.1016/ j.cvfa.2007.10.005
National Research Council. (2001). Nutrient requirements of dairy cattle: 2001. National Academies Press.
Van Soest, B., Weber Nielsen, M., Moeser, A. J., Abuelo, A., & VandeHaar, M. J. (2022). Transition milk stimulates intestinal development of neonatal Holstein calves. Journal of Dairy Science, 105(8), 7011–7022. https://doi.org/10.3168/jds.2021-21723
