By David Cantrell
As calving season continues in Pittsburg County, let’s re-visit the importance of passive immunity via colostrum (mother’s milk).
Resistance to disease is greatly dependent on antibodies or immunoglobulins and can be either active or passive in origin.
In active immunity, the body produces antibodies in response to infection or vaccination.
Passive immunity gives temporary protection by transfer of certain immune substances from resistant individuals.
An example of passive immunity is passing of antibodies from the dam to calf via the colostrum (first milk after calving).
This transfer only occurs during the first few hours following birth.
New research is indicating that successful transfer of passive immunity enhances disease resistance and performance through the feedlot phase.
Timing of colostrum feeding is important because the absorption of immunoglobulin from colostrum decreases linearly from birth.
“Intestinal closure” occurs when very large molecules are no longer released into the circulation and this occurs before the specialized absorptive cells are sloughed from the gut. In calves, closure is virtually complete 24 hours after birth, although efficiency of absorption declines from birth, particularly after 12 hours.
Feeding may induce earlier closure, but there is little colostral absorption after 24 hours of age even if the calf is starved.
This principle of timing of colostrum feeding holds true whether the colostrum is directly from the first milk of the dam or supplied by hand feeding the baby calf previously obtained colostrum.
Provide high risk baby calves (born to thin first calf heifers or calves that endure prolonged birthing) at least two quarts of fresh or thawed frozen colostrum within the first 6 hours of life and another two quarts within another 12 hours.
This is especially important for those baby calves too weak to nurse naturally.
If at all possible, feed the calf natural colostrums first, before feeding commercial colostrums substitutes.
David Cantrell is the agriculture extension educator for Pittsburg County.
Contact him at 918-423-4120.