Making the Most out of Colostrum

28 March 2012

Colostrum is the milk produced at the first milking post-calving and contains a host of vital immunological and nutritional substances that are crucial to ensure the health of the newborn calf. The most important of these are the immunoglobulins, cells of the immune system that protect the newborn calf from the environmental pathogens it will encounter as soon as it is born. The bovine placenta does not allow the transfer of immunoglobulins from the mother to the calf while the calf is in utero so the calf is born with no circulating immunoglobulins, and depends entirely on colostrum to provide it with immunological protection.

“Without adequate immunological protection, the newborn calf is more vulnerable to infection, more likely to develop disease and die in the pre- and post-weaning periods, has a slower growth rate and even reduced milk production during the first and second lactation,” explains Dr Emer Kennedy, Teagasc Animal and Grassland Research & Innovation Centre.

Researchers at Teagasc Moorepark, analysed the concentration of immunoglobulin G (IgG) in colostrum of 642 spring-calving dairy cows using an ELISA method. “The concentration of immunoglobulin G (IgG) in the colostrum determines its quality; the higher the IgG concentration, the better the quality,” explains Dr Kennedy.
The researchers found that the quality of colostrum was high (greater than 50mg/ml) in 96% of the samples.

The study found that older parity cows produced colostrum with a higher IgG concentration at the first milking. The highest quality colostrum was obtained from cows in their fifth lactation. For all parities, IgG concentration in milk declined rapidly with each successive milking post-calving: the concentration at least halved between first and second milking. Only the colostrum from the first milking had an IgG concentration above the threshold of 50mg/ml IgG.

“This study highlights the importance of using only the colostrum obtained at the first milking as a source of colostrum for newborn calves regardless of which parity the cow is,” concludes Dr Kennedy.

The article ‘Making the most of colostrum’ is featured in the spring 2012 issue of TResearch, Teagasc’s research and innovation magazine available online at: http://www.teagasc.ie/publications/tresearch/index.asp