Timestamps & Summary Vicki Brisson (01:44)As an introduction, can you explain what de novo fatty acid synthesis is?Dr. Débora SantschiTo me, the fatty acids are basically if we would take that black box of fat, the milk fat test, open it up, and look at what's inside of it. So, if we take, for example, a herd that is at 4% fat, if we open it up, we can see what makes up that 4% fat and see where those fatty acids come from. […]The de novo fatty acids are one of those groups of fatty acids we find in the total fat. It represents, depending on the herds and the cows, roughly between 25-30% of the total fat. And those are the fatty acids that are synthesized in the mammary gland of the cow. […] Vicki Brisson (04:00)What impact does that milk fat composition have on the cow? And what are the periods when the fatty acid profile is more likely to vary?Dr. Débora SantschiI think it's very interesting to look at it from a cow’s side and also from a herd’s side. So, if we take the cow example, a cow in very early lactation, we all know that she's using her body reserves to compensate for that very high demand for milk production. In that case, a big chunk of her fat content will be preformed fatty acids. So, in very early lactation, we see roughly 50, or sometimes even slightly more, as a percentage of her fat being the preformed fatty acids. And in that case, the de novo will be very low and increase slowly over the first 45, 50, and 60 days of lactation. […]If we look at it on a herd level, when we do some ration change, when the forage digestibility changes, but we don't notice too much. All those little effects can also have an impact on the de novo content of the bulk tank sample. In that case, because bulk tank samples are often analyzed very frequently, then we can get a rapid insight into something that we might not have noticed on the farm level. […] Vicki Brisson (05:46)Knowing that the fatty acid profile of milk matters, what can we do to promote the production of de novo fatty acids?Dr. Débora SantschiThe de novo fatty acids are the result of being produced in the mammary gland from rumen volatile fatty acids. So, everything that we can do to maximize rumen volatile fatty acids will have a positive impact. So, we often focus on the ration. So, of course, having a highly digestible ration, well balanced with all the nutrients that are required, is really important, but we need to keep in mind everything around it. […] Vicki Brisson (07:33)Can you expand on specific nutritional solutions that our listeners may want to consider? Dr. Débora SantschiThe way we train our people, and I just want to mention, we have a lot of information that is available directly on the website as well to help understand and find solutions, because it's going to be very herd specific. But when I look at a herd, I look at the fat test, and the protein test, because those are values we know and we handle very well. I look at the MUN value because to me, it's important to look at the overall protein balance as well, and then I go and look at the fatty acid profiles. I always start with the de novo, then look at the mix, then look at the preform. That's my way of addressing a report. […] Vicki Brisson (10:01)Beyond just the amount of de novo fatty acids produced is also the variation in fatty acid levels. So, what are the impacts of that variation in fatty acids and how can we address it?Dr. Débora SantschiVery good question. I think, again, there's some information on the cow level, there's some information on the bulk tank level. I like to work on the bulk tank level first because it's every second day in our case, so it helps to get a very accurate and up-to-date overview. However, the downside is that it's only on a farm level, it's an average, and I have no idea of the distribution of it. […]When there's a lot of variation on the bulk tank, we see it a lot in the inconsistent feeding herds, in the herds that have a lot of changes in the ration, wh