Colostrum quality halves after the first milking
According to Emer Kennedy, Moorepark, research completed last year at Teagasc Moorepark has shown what factors affect the quality of the colostrum offered to the calf. The quantity of antibodies (immunoglobulins) in colostrum determines quality.
Newborn calves should receive colostrum from the cow’s first milking; the quality of the colostrum halves between the first and the second milking.
Research also show that the quality of colostrum varies greatly amongst cows.
But overall, almost 96% of the samples collected from the Teagasc Moorepark farms were classified as high quality colostrum.
Colostrum from heifers (first lactation animals) is of poorer quality than colostrum obtained from older cows (second lactation upwards).
The highest quality colostrum was obtained from cows in their fifth lactation.
The colostrum collected from cows that had calved more than 15 hours before milking was of poor quality. Results indicate that colostrum quality is maximised when cows are milked within six hours of calving.
This suggests the best practice is to milk the cow as soon as possible after calving.
It is best practice also to feed this colostrum to the calf as soon as possible after it is born, because the older the calf gets, the fewer antibodies it absorbs.
Length of the dry period also has an effect on the quality, which is lowered when the dry period is less than eight weeks, and greater than 16 weeks. Thus, a dry period of between eight and 16 weeks appears to improve quality.
In general, higher yielding cows also tend to have poorer quality colostrum, due to the dilution of immunoglobulins or antibodies.
