Farm Table says:
What is the problem?
Bio active fatty acids (FA), such as branched chain fatty acids (BCFA), are an important part of the human diet. The amount produced in milk varies throughout a dairy cows life, and researchers from the University of Vermont and the University of Arizona have investigated the effect that lactation and breed has on the production of these fatty acids.
What did the research involve?
Twenty-two first time calvers, consisting of 7 Holstein, 8 Jersey, and 7 Holstein x Jersey (crosses) were used. All cows had the same feed, using a 70:30 forage to concentrate ratio. Feed ingredients are listed in the article. Measurements of fatty acids were taken at 5 days in milk (DIM), 95 DIM, 185 DIM and 275 DIM.
What were the key findings?
The lowest FA omega 6:3 ratio was observed at 5 DIM, and the highest seen at 185 DIM. At 185 and 275 DIM Jersey cows had the highest total BCFA and odd-numbered carbon chain fatty acids, more that Holsteins and the crosses. Overall, the highest amount of odd and BCFA was seen at 275 DIM. Breed also affected the profiles of the BCFA seen in the milk.
Overall, Holstein and crossed showed a higher level of several bio active FA than jerseys. Across a lactation the greatest content of bio active FA in milk occurred at 5 DIM and odd and BCFA were highest at 275 DIM.