While their cuteness is undisputed, baby animals are also incredibly vulnerable. In the fight to keep any sort of livestock alive, one of the most challenging times is right after birth. The world outside their mothers is full of dangers: predators, birth complications and disease. Anything you can do to help newborns make that transition is a plus, and an incredibly important tool in your arsenal is “first milk” or colostrum. Studies have shown calves that consume enough colostrum are more likely to live past their first birthday, and even some adult problems can be traced to not getting appropriate amounts of colostrum. What is it about this lovely stuff that makes such a difference?
Colostrum is the milk that pretty much all mammalian mothers make the first days after giving birth. It is made up of all sorts of good things. It has extra vitamins, minerals, protein and fats. It’s also lower in lactose than normal milk (making it easier to digest), and the iron content is 10 to 17 times higher. Colostrum also acts as a laxative to help the newborn’s intestines learn to do as nature intended. All of these traits help get a youngster started in the best possible way. For example, lambs are born with low vitamin A, and, to compensate, sheep colostrum is unusually rich in vitamin A.
One of colostrum’s most important functions and the main reason it’s so important for the health of offspring has to do with immunity and fighting disease. An animal’s immune system (as well as yours) creates molecules called “antibodies” to fight disease. Different antibodies are made to combat each disease. Vaccination is all about inducing the creation of these antibodies against a particular disease. A weakened or dead pathogen (such as bacteria or viruses) is introduced (by shot, mouth or inhaler), and the body reacts by creating antibodies, so it’s prepared should it ever come across the live pathogen later in life. A living body creating antibodies for a particular disease is called “Active Immunity.”
Antibodies can also come from an outside source, creating “Passive Immunity.” Colostrum contains many antibodies (also called immunoglobulins or Ig). While babies are new, their intestines are capable of absorbing larger particles, and Ig (a rather large molecule) can enter the bloodstream and act as a line of defense against disease. The baby is protected, though it hasn’t created any new antibodies (which is why this immunity is called passive). However, as young animals’ bodies adjust to the outside world, the cells in their intestines start to change or “close,” and, usually by the time they are 24 hours old, their ability to absorb antibodies into the bloodstream is completely gone. This makes getting newborns enough colostrum during their first day on the ground crucial. (In case you’re wondering, colostrum is more crucial for farm animals than for human babies, because humans are also passively immunized in the womb, while the animals are not.)
A mother can only impart the antibodies that she already has. This creates two situations: because she’s been exposed to more diseases, an older mother will have better colostrum than a young one; and it’s much better to use colostrum from a local mother, because she will have the antibodies needed to fight the pathogens in that environment. People sometimes vaccinate pregnant mothers in order to ensure that the baby will be passively immunized against particular diseases.
Ever wondered about the timing of puppy shots? Before a certain point, the vaccines won’t have the desired affect – the puppies’ passive immunity will kick in, and they won’t create the antibodies for themselves. We want the window of time that they are not immunized to be as small as possible. So, we give them a vaccination at 6 weeks, hoping we’ve hit the earliest point their passive immunity has run out, and then we shoot ’em again later to be sure that we’ve got ’em covered.