Colostrum

What is colostrum?

Colostrum is the first secretion from the mammary gland after parturition or birth. It contains immunoglobulins, growth factors, fat and water. Immunoglobulins are proteins which provide the newborn calf with antibodies. This is because the bovine placenta has 6 layers which these proteins are too large to pass through. Therefore, the newborn calf relies on the colostrum to receive immunoglobulins. Growth factors aid in intestinal development of the calf. 

What is passive transfer?

Passive transfer is the term used to define the passing of the immunoglobulins (IgG) to the calf, therefore providing initial immunity. This is measured in grams per liter (g/L) of blood serum IgG content. Successful transfer of passive immunity is defined by the following standards (Lombard et al., 2020). This is typically measured in the laboratory. 

 - Excellent: greater than or equal to 25 g/L

 - Good: 18-24.9 g/L 

 - Fair: 10-17.9 g/L

 - Poor: Less than 10 g/L 

This can be tested calf side using a brix refractometer. A reading of 8% correlates to 5.2 g/DL total protein which further correlates to 10 g/L IgG. 

Why is colostrum necessary?

A calf is born with virtually no immune system as well as low body fat percentage and limited stores for energy. Colostrum provides immunoglobulins for immunity, as well as water, fat and sugar for energy. Failure of passive transfer increases the risk of disease and chance of death for the calf. It can also reduce growth rate (Furman-Fratczak et al., 2011, Faber et al. 2005) and reduce first lactation milk yield (DeNise et al 1989). Colostrum is vital for the health and longevity of the calf. 

How should colostrum be fed?

Colostrum efficacy is dictated by three factors.

1. Quality

This is measured as IgG concentration. Good quality colostrum is defined as a concentration of IgG greater than 50 g/L (NAHMS, 2007) or approximately a 22% Brix reading. 

Quality can be measured in two ways. 

• A colostrometer which uses the correlation between colostrum density and IgG concentration to give a measure. This is when a reading of 50 g/L or better is needed.

• A Brix refractometer is a digital device which measures how much light bends when it passes through the colostrum to give it a score. This is when a 22% or higher reading is needed. 

2.   Management 

Right after birth, two things begin to happen. The first is that the mammary gland stops producing colostrum and turns to producing milk. Colostrum quality and quantity decreases as the time from calving to harvest increases. The second is that the IgG receptors in the small intestine of the calf begin to close, accelerating at 12 hours and ceasing completely at 24 hours of life (Stott et al., 1979). 

Colostrum needs to be harvested as soon as possible after birth and given to the calf within the first few hours of life. It is a race against time. 

3.   Volume 

To accomplish passive transfer, it is recommended to feed 3.8 L or about a gallon of colostrum within the first few hours of life with the possibility of another 2 L at 8 hours of life (Faber et al 2005). 

What if the dam doesn’t produce enough?

Colostrum quality and quantity can be affected by breed, number of lactations and the season. If the dam does not produce enough colostrum, a lacteal based colostrum replacer should be used. These can be purchased and should be fed to the same guidelines. The instructions on the package will outline how it should be made as well as any other recommendations. 

Blood based colostrum replacers should NOT be used. 

References 

• DeNise, S.K., J.D. Robison, G.H. Stott, and D.V. Armstrong. 1989. Effects of passive immunity on subsequent production in dairy heifers. Journal of Dairy Science. 72:552–554. doi:10.3168/jds.s0022-0302(89)79140-2.
• Faber, S.N., N.E. Faber, T.C. Mccauley, and R.L. Ax. 2005. Case study: Effects of colostrum ingestion on lactational performance. The Professional Animal Scientist. 21:420–425. doi:10.15232/s1080-7446(15)31240-7.
• Furman-Fratczak, K., A. Rzasa, and T. Stefaniak. 2011. The influence of colostral immunoglobulin concentration in heifer calves’ serum on their health and growth. Journal of Dairy Science. 94:5536–5543. doi:10.3168/jds.2010-3253.
• Lombard, J., N. Urie, F. Garry, S. Godden, J. Quigley, T. Earleywine, S. McGuirk, D. Moore, M. Branan, M. Chamorro, G. Smith, C. Shivley, D. Catherman, D. Haines, A.J. Heinrichs, R. James, J. Maas, and K. Sterner. 2020a. Consensus recommendations on calf- and herd-level passive immunity in dairy calves in the United States. Journal of Dairy Science. 103:7611–7624. doi:10.3168/jds.2019-17955.
• National Animal Health Monitoring System, United States Department of Agriculture, 2007
• Stott, G.H., D.B. Marx, B.E. Menefee, and G.T. Nightengale. 1979a. Colostral immunoglobulin transfer in Calves II. the rate of absorption. Journal of Dairy Science. 62:1766–1773. doi:10.3168/jds.s0022-0302(79)83495-5. 

Photo Credit

• Lydia Valentine

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