Color Coded Calf Rearing- Colostrum is Key

Colostrum is a secretion of the mammary gland. It is produced in the final stage of pregnancy and in the first days after calving. Colostrum is a superfood designed to provide the calf with necessary nutrients, biologically active ingredients, and immune enhancing properties. 

You may have heard how important IgG from colostrum are to calves, and they are!  Unlike humans, calves do not receive placental passage of immunoglobulins, and must receive them in their colostrum. Although important, colostrum is much more than just IgG. Let’s take a look at some of the components in colostrum that give it such super powers!

• Excretion of meconium: the first meal of colostrum stimulates the digestive system to eliminate and pass the first stool, meconium.
• Nutrition: colostrum is rich in protein, fat, carbohydrates, macronutrients, vitamins and minerals.
• Immunoglobulins: proteins used by the immune system to fight bacteria and pathogens. Those present in bovine colostrum include IgG, IgM, and IgA. 
  • IgGI and IgG2 work together to provide passive immunity to the calf. This provides immune protection until the immune system of the calf is fully functioning.
  •  IgM conditions antibody-mediated immunity.
  •  IgA protects mucosal epithelia.
• Growth Factors: hormones that stimulate animal growth and growth of intestinal cells.
• Enzymes:  include those that aid in the digestion, and impact immune status of the animal.
• Amino Acids: guarantee enzyme activity, activate cell metabolism, and growth.
• Lactoferrin: regulates absorption of iron, protects against bacterial infection, enhances growth and differentiation of intestinal cells.
• Lysozyme: works synergistically with IgA and lactoferrin to protect against bacterial infections.
• Lactoperoxidase: catalyst to oxidize thiocynates, the reaction produces intermediate compounds with a wide range of antimicrobial properties.
• b-lactoglobulin: combats pathogens.

Colostrum’s composition changes over time, decreasing its biological and nurturing value with the onset of milk production (see table below). Calves benefit from receiving colostrum early and from multiple feedings of colostrum or transition milk before transitioning to mature milk or milk replacer.

Dr. Michael Steele and his team of researchers at the University of Guelph recently conducted a study comparing length of intestinal villi and gut surface area of calves.  Calves fed colostrum for only one day and then abruptly transitioned to whole milk showed depressed length of intestinal villi compared to calves fed colostrum or transition milk for 5 additional feedings prior to transitioning to whole milk.

The transition from colostrum to milk feeding is an important one that should not be overlooked. This transition is an cruical for gut development, and for setting the calf up for success in lifetime growth, health, and milk production.

                                                                                                                                                                                                                       Connelly et. al, 2014

Although, IgG are not the only important component of colostrum, we can measure the success of our colostrum protocol by measuring serum blood proteins. This value correlates with the amount of IgG in the blood stream, and can help us have a good idea of how well bioactive and immune enhancing components in our colostrum are being absorbed. Our goal would be to have 40% of our calves with Serum IgG levels of >25 g/L.

Much is known about colostrum, but many of the components are still not entirely understood.  There is still much to learn and lots of exciting new research coming!

Written by: Mariah Gull, M.S.