October 6, 2021
One of the many benefits of colostrum is that, when fed shortly after birth, it provides a source of internal warmth for the newborn calf.
But a team of Brazilian researchers recently conducted a study on the longer-term impact of colostrum on calves’ ability to tolerate cold and regulate their body temperatures.
The first-of-its kind trial was conducted at the Experimental Calf Facility of the “Luiz de Queiroz” College of Agriculture, University of Sao Paulo, Brazil. The research team studied the impact of various levels of colostrum feeding on thermoregulatory response, along with a host of other health and performance measures.
In total, 30 newborn Holstein calves were fed high-quality colostrum at 2 and 8 hours after birth. Three feeding rates were evaluated – 10% (low), 15% (medium), and 20% (high) of bodyweight. At 24 hours post-birth, each calf was placed in a cold chamber at 50°F for 150 minutes, representing a cold challenge.
Skin and rectal temperature; heart and respiratory rate; and shivering were measured every 15 minutes. Blood samples were taken every 30 minutes. After the cold challenge, calves were housed in an environment at approximately 80°F with free access to water and starter grain, and fed 6 L of milk replacer per day.
Feed intake, fecal score, and rectal temperatures were taken daily, until weaning at 56 days of age. Blood samples, body weight and body frame measurements were taken weekly.
Highlights of the results included:
Fecal score at 24 hours of life were significantly lower for the calves in the low colostrum group. No other significant differences in fecal scores were observed among the three groups over the course of the entire preweaning period.
Heart girth was significantly greater at the end of the preweaning period for calves in the medium and high colostrum groups compared to the low group.
Colostrum feeding volume resulted in lower starter grain intake for calves in the low group at week 4, and significantly higher intake for calves in the medium group at week 5.
Blood concentrations of beta-hydroxybutyrate (BHB) were higher in the preweaning period for calves in the medium and high groups.
During the cold challenge, prescapular temperature and total serum protein were greater for the middle and high colostrum groups.
Calves fed a higher volume of colostrum (20% of birth weight) presented increased leukocyte count suggesting improved immune responses during the preweaning phase.
Ultimately, colostrum feeding rate did not influence calf performance in the preweaning phase. However, the researchers concluded that feeding more colostrum had a positive effect on newborn calves’ thermoregulatory responses during the cold challenge. Calves fed the highest volume of colostrum also showed improved immune responses during the preweaning phase.
The researchers attribute these results to the beneficial ingredients in natural colostrum. They said colostrum supplies lactose, amino acids, and triglycerides, which collectively provide an excellent energy source for internal heat production.