This is a translated article from Le Bulletin. See link at the bottom.
An expert on the issue helps us disentangle the true from the false
The staple diet of cows is forages, but in some circumstances it may be advisable to add fat to the ration. Photo: Marie-Josée Parent
During the past few days, the subject of adding palmitic acid to the diet of dairy cows has caused a stir. For opponents, this is a bad practice that harms the cow, the quality of the milk and the environment. What exactly is it? Professor Rachel Gervais of Université Laval is very familiar with fatty acids in milk and the diet of dairy cows. This is his specialty. We asked him to go over the matter with us. How much fat is added to the diet of dairy cows? Rachel Gervais explains that it is palmitic acid, a saturated fatty acid of type C16: 0. The palmitic acid used in dairy supplements comes from the valorization of the by-products of the extraction of palm oil intended for human consumption. It is therefore waste from palm oil production that is valued. There is a lot of palm oil in the processed and further processed products available in grocery stores. Is there a lot of this fat in cow's milk? Palmitic acid is the fat found in greatest quantity in cow's milk, about a third of all fatty acids, regardless of whether palmitic acid is added to the ration or not. . In fact, it is a fat that the cow can synthesize, but she can also get it through food. “It's a fatty acid that's common,” explains Rachel Gervais. We, as humans, synthesize palmitic acid from it. " If there is no palmitic acid added to the ration, will there still be palmitic acid in the milk? Absolutely because the cow naturally produces palmitic acid. Forages, which cows mainly eat, and grains contain lipids, fats. 50% of the fats contained in milk come from food and 50% from the synthesis carried out by the cow. Is its use widespread on dairy farms? "It is said that there are about 25% of producers who would have it in their supplements and of those, the vast majority do not give it for all their animals in the herd," explains Rachel Gervais. It is an expensive product and therefore, producers do not benefit from using it if the animal does not need it. Can we do without it? “Yes because not all producers use it, but is it wise to do without? asks Rachel Gervais. I would say that is not wise in all cases. " When is palmitic acid most useful in the diet of dairy cows? At the start of lactation, dairy cows are energy deficient, meaning that the energy demands for milk production are great, but their ability to eat is limited because they are starting lactation. Palmitic acid added to the ration at the start of lactation fulfills this high energy requirement. One way would be to add concentrates, but too much corn interferes with the functioning of its rumen. "When the food in the ration does not provide enough energy, the ration is densified by adding lipids because it remains the food which is the richest in energy", summarizes Rachel Gervais. Why not choose other fatty acids? "Since a cow is a cow, she cannot consume any fatty acid, because rumen bacteria don't like unsaturated fatty acids," explains Rachel Gervais. Unsaturated fatty acids are those found in large quantities in plants. "Saturated fatty acids will give the animal energy without messing up the rumen, without affecting the microorganisms which are in the rumen and which digest the forage," adds Rachel Gervais. So adding fat to the ration is good practice? “Targeted, yes, otherwise we wouldn't use them: these are products that cost a fortune,” says the researcher. “It is a practice that is there to support the energy needs of our animals. " Is it true that using this fat in cow feed will increase the fat content of milk? " Yes. What we find in certain situations, when we give these products, we see an increase in the fat content of the milk, she says. So the cow that is not able to produce her fat to her full potential, by giving that product, she succeeds in doing so. But the cow had the potential to do so. Otherwise, she wouldn't have done it. " Does this affect the quality of the butter? “To say that the butter is made hard because of that is a hoax. It's rubbish, says Rachel Gervais. Palm oil by-products have been in use for 40 years and their use has not evolved to such an extent that the fatty acid profile of milk found on the market has changed. " However, she adds that it is known that in an experimental context, by changing the fatty acid profile of milk, it is possible to change the properties of milk. “We know that it increases the hardness of the butter, but the profile has not changed in recent years,” she says. So to say that the butter is harder because the producers gave palmitic acid is wrong. " Is there an impact for the transformation processes? “There is no data on that,” says Rachel Gervais. We have a research project that is funded to explore these questions. Is there an ideal fatty acid profile to make the most profitable cheese for a cheese maker? We do not know. We are going to study it. It is therefore a file to follow, but for the moment, it is impossible to affirm anything.
Original Article in French: