Débora_Santschi_1
ArticleVolume Number April 8, 2019
Débora SantschiPh.D., Agr.

The milk fatty acid profile: what exactly are we going to do with it?

Le profil d’acides gras du lait : on va en faire quoi exactement?
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Everyone is talking about the milk fatty acid profile! It seems really promising! It’s going to answer loads of questions! We can hardly wait for it to be available in Quebec and across Canada!

But, between you and me, how exactly are we going to use it?

First of all, what is the milk fatty acid profile?

Although fat content has been used for years to monitor cow and herd performance, it is really the sum of all the fatty acids (FA) contained in milk, in addition to a few other very minor molecules, such as cholesterol and glycerol, for example. So the FA profile is actually a more detailed analysis of milk fat.

Milk FAs are generally analyzed by gas chromatography GC), a very costly and time-consuming technique ($150 and about 4 h per sample). However, it is now possible to use infrared spectroscopy to quantify the main fatty acids in milk (the same test used for milk recording), so the FA profile can be analyzed at the same time as other milk components, such as fat, protein, lactose and BHB. And it takes all of 6 seconds to do it! Of course, not all of the FAs in milk can be analyzed with this method, but it can at least be used to identify the FA groups that provide valuable information for herd monitoring. The most significant groups are presented below (Figure 1):

Fatty acids groups

  • de novo FAs: short-chain FAs (14 carbons or less) that are synthesized exclusively in the mammary gland from butyrate and acetate, precursors that stem from ruminal fermentation (indicators of rumen health);
  • preformed FAs: long-chain FAs (15, 17 and 18 carbons or more) that come mainly from feed or the mobilization of body fat reserves (indicating weight loss in cows, for example);
  • mixed FAs: 16-carbon FAs that come from both synthesis in the mammary gland and from blood (feed or mobilization of body fat reserves).   

And how can the milk fatty acid profile be used?

FA profiles can be established for both bulk tank milk and for milk from individual cows. Here are some of the practical applications of this new analysis:

In bulk tank milk samples

  • Predict a drop in components

When there is a change in silage or an external factor that affects forage intake or digestibility, it is highly likely that the milk FA profile will reflect that change a few days before milk fat content or milk production is affected. As an indicator, the FA profile will make it possible to react more quickly and thus avoid a drop in components or production, or at least lessen the decline.

  • Evaluate the effect of additives

Some feeds are added to the ration in order to modify ruminal fermentation or to avoid the rumen and influence components. Hence, the FA profile will be used to evaluate this mechanism and cow response to such feeds.

  • Predict methane emissions

Many research teams worldwide have uncovered an interesting correlation between the milk FA profile and herd methane emissions. This may not be the first way the FA profile will be put to use, but it will certainly be a hot topic in years to come.

  • Promote specialty milks

The FA profile of grass-fed cows and cows with access to pasture differs from that of cows fed more corn-based rations. An analysis of the milk FA profile could be used to confirm the application of the specifications for certain types of production and therefore, to promote specialty milks.

In milk recording samples

  • Predict ruminal pH

Far less invasive than traditional methods used to measure ruminal pH, the FA profile will be used to assess rumen health. It will provide valuable information about cows in early lactation to help us optimize our transition management practices and rations.

  • Understand metabolic status

The FA profile can be used to estimate weight loss in cows in early lactation and assess the impact on health and reproductive performance. Coupling this information with BHB to create a new indicator for producers is a promising avenue. Stay tuned!

The FA profile is a topic we’re likely to hear much more about in the coming years. It will provide a better understanding of cow metabolism and make it possible to optimize rations and herd management practices. There’s a good chance as well that milk processors will be interested in identifying FA profiles that generate higher yields and improve processing.

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