The number of calves in North America that fail to receive adequate colostrum ranges from 11%-31%. This article will review key points on colostrum management to ensure calves are set up for success from the beginning of life.
Why do calves need colostrum?
The placenta is unique in the bovine because it stops maternal and fetal blood supplies from mixing. This separation prevents immunoglobulins from being transferred to the fetus prior to birth. Immunoglobulins are a class of proteins that act as antibodies to protect the immune system from disease. Without the transfer of protective antibodies from the dam to the calf, the calf is at risk for preweaning morbidity and mortality. Failure of passive transfer has also been shown to have a negative effect on weaning weights and average daily gain in the feed yard.
What exactly is colostrum?
Colostrum is the first milk produced by the dam. It contains immunoglobulins, specifically IgG which is derived from the dam’s blood serum. This process begins several weeks before calving and peaks around 1-3 days before birth. In addition to IgG, colostrum also contains white blood cells, such as neutrophils and leukocytes, that help further protect the calf from pathogens while also providing the necessary energy and protein required for neonatal nutrition and vigor. Colostral vitamins A and E play a vital role in immune stimulation and antioxidant properties.
How much colostrum does a newborn calf need?
Previous studies have shown that calves require at least 150 g of IgG for immune protection, with recent research suggesting 200-300g as ideal. Several factors can influence the quality of colostrum, including dam nutrition, body condition score, and age of the dam. Older cows usually have higher quality and quantity of colostrum than heifers. Researchers have shown calves born to heifers with a body condition score of 5-6 stood faster and had higher levels of IgG than calves born to BCS 3-4 heifers. As reference, a healthy beef cow with at least BCS 5 should produce approximately 95 g of IgG per liter of colostrum.
Timing is everything.
The cells lining the small intestine are primed to readily absorb IgG at birth, but the timing window decreases significantly after 12 hours of life. Peak absorption happens in the first four hours post-calving and complete gut closure is observed at 24 hours of life. Temperature can affect gut absorption as well as metabolic acidosis, which occurs in calves that experienced difficult births. If you assisted in the birth of the calf, it is a good idea to ensure colostrum intake by milking the cow and offering it to the calf. Studies have shown minimal difference in IgG absorption when comparing nipple feeding versus esophageal tube feeding, therefore either method is correct. Tubing is usually required in calves born under distress because they lack the vigor to nurse.
Not all is created equal.
The best source of colostrum for a newborn calf is the mother. If that is not an option, the next option would be a donor cow from the same herd. Usually the older the cow, the better antibodies she can provide. Healthy cows with a solid vaccine history are ideal. Colostrum can be stored in quart bags in the freezer for up to one year. It is important to remember that heat from the microwave can denature the IgG antibodies. A water bath with temperatures below 140° F is the best environment to thaw colostrum.
There are several choices for freeze dried colostrum options. Always remember to read the labels! Colostrum supplements are intended to only supplement a calf that already received some colostrum. Most of the time these contain low levels of IgG and will not provide adequate protection alone. A true colostrum replacement needs to contain at least 150 g of bovine IgG as well as protein and fat for nutritional requirements. Double check to see how to mix the product to ensure proper absorption.
Being prepared is key. Maintaining a good relationship with your veterinarian throughout the year will provide added value to your operation during calving season.
Interviews with the authors of BeefWatch newsletter articles become available throughout the month of publication and are accessible at https://go.unl.edu/podcast.
Dr. Lindsay Waechter-Mead, DVM, Nebraska Extension Beef Educator