Colostrum More Beneficial To Calves Than Ever
(excerpted from Feedstuffs magazine, 9/4/18)
By: Dr. Al Kurtz, a board-certified, independent dairy nutrition consultant, based out of St. Louis.
While it is known that newborn calves need colostrum because they are born without any immunity as a result of antibody proteins not passing through the placental barrier, there is much more to this picture.
First, there are a number of key factors that determine how much immunity the calves get from being fed colostrum, including that the calf’s ability to absorb antibody proteins, primarily immuoglobulin G (IgG), from colostrum is very time dependent from birth. By four hours after birth, antibody absorption is already decreased by 25% and is virtually gone by 24 hours of age.
Since the objective is to provide a minimum of 100g of IgG, two quarts containing 50g per quart will deliver that amount. However, it is much better to provide 200g, which would require four quarts at 50g of IgG per quart.
This leads to the question of what immunoglobulins are and their functions. Typical immunoglobulin distribution in colostrum is about 85-90% IgG, 5% IgA and 7% IgM. IgG is the main contributor to systemic immunity but also may function within the intestine. IgA has a lesser rolde in intestinal immunity to enteric pathogens, while IgM has a major role in intestinal innunity, primarliy through helping prevent septicemia and in immunity to enteric pathogens. Another key factor is that the sum of all Ig classes function together is more optimal that the puified individual Ig classes alone.
Antibody absorption is reduced by stress, which can occur from varoious sources such as heat, calving difficulty and rough handling and feeding of calves. Another source that decreases antibody absorption is bacterial contamination. So, not only is dirty colstrum a direct problem for the calf, but it also reduces antibody absorption, too.
An enlightening study was done about 20 years ago but was not reported until more recently in which every other heifer calf born in a herd in one year was fed either two or four quarts of colostrum at the first feeding. After that, all heifers were fed and managed the same. Those cavles fed only two quarts had twice the veterinary costs, and at breeding age, those fed four quarts had .5 lb more daily gain.
However, the biggest difference was in the first lactation, when the calves initially fed four quarts of colostrum produced 11% more milk than those fed two quarts of colostrum; this difference in milk production increased by 17% in the second lactation. Why such a difference? Colostrum has been found to have more that 200 bioactive compounds that affect growth, nutrient absorption and bacterial exclusion.
Colostrum has about twice the level of solids present in normal milk. This alone provides twice the level of nutrition of regular milk. The level in colostrum is more than double that of regular or mature milk. A high-quality colostrum shows IgG levels of 81g per liter versus virtually no IgG in regular milk. Lactoferrin, which is antibacterial, is undetectable in milk but present at a high level in colostrum. The balance of components shown in colostrum – six hormones and three metabolic factors – are much higher than in milk. Most of these are known to be anabolic in that they promote growth and nutrient utilization.
To the value of colostrum now add findings from University of Alberta scientist that were presented at the 2017 American Dairy Science Assn. annual meeting. Their finding suggest that feedingdairy calves colostrum immediately after birth can increase the passive transfer of IgG and the colonization of beneficial bacteria in the colon, both of which are hypothesized to assist in protecting the calf from enteric infections during the preweaning period.
Findings from another study indicated that the colonizing microbiome is an essential factor regulating the rapid development of the mucosal immune system during the first week of life.
Not only does colsotrum have value for helping calves with antibody absorption, but its many bioactive compounds have positive effects on growth, nutrient utilization and subsequent milk production. These compounds and nutrient levels would be intermediate in transition milk. So, if possible, also feed calves transition milk in their first three days of life.