There is milk fat and then there is milk fat. Much of the fat we consume through dairy products is determined by what the cows eat; whether it is summer or winter, whether the cows graze or not, and whether the cows are pushed to the highest possible milk yield by feeding them extra fat in the form of palm oil. The image below illustrates the shifts in milk fat composition, and was created based on an analysis of various sources. The main goal was to understand the consequences of feeding palm fat (palmitic acid (PA = C16:0)) on milk fat composition.

Cows can produce PA themselves in their udder (from short-chain grass fats), but they can also transfer PA directly from added palm oil into their own milk fat. A high palmitic acid content in a cow’s diet leads to high milk fat production, with hard milk fat and butter that is difficult to spread. However, palm oil also comes at the expense of tropical rainforests. Palm oil, cheap milk fat and deforestation go hand in hand. Finally, there are shifts in the omega fatty acids that cows excrete in their milk fat. To illustrate the ratio between omega-3 and omega-6 fatty acids, the most important fatty acids (in terms of concentration) were taken below, namely alpha-linolenic acid (ALA n-3) and linoleic acid (LA n-6).

Fig. 1 The relationship between the amount of palmitic acid (C16:0) and the ratio of alpha-linolenic acid (ALA-n3) to linoleic acid (LA-n6) in milk fat. The vertical line (green) represents the difference between summer and winter on the more extensive farms; the horizontal line (red) represents the difference between grass-based milk and milk from maize silage, concentrates and palm fat.

From alpine summer grass to maize rations with palm oil

Data from various studies have been combined in the graph to identify trends (Figs. 1 and 2). The starting point is the most natural milk fat we have, namely that from grass-fed cows in the mountains (alpine grass): soft, yellow and rich in omega-3 fatty acids.

There are two shifts, namely from left to right and from top to bottom. At the top, from left to right, the proportion of palmitic acid increases (from 20 to 35g/100g fat). In terms of quality (ALA/LA ratio), the fat on organic farms remains virtually the same (around 0.8), but the butter produced is harder in winter due to the increase in PA. You see this kind of shift when you move from the mountains to the lowlands or switch from summer grass to winter feed (hay, grass silage).

From top to bottom, the ALA/LA ratio decreases sharply (from 0.8 to 0.3), while the amount of palmitic acid increases even further. This is caused by feeding maize silage, concentrates (soya, grains) and, ultimately, added palm fat. This results in very hard fat (C16:0 can increase further to almost 40 g/100 g fat) of poor quality (ALA/LA drops to a low point of around 0.2).

Figure 2 below illustrates the two types of shifts.

Fig. 2. Shifts in milk fat composition due to a) switching from grass to hay/silage (green arrow) and b) intensification by feeding maize silage and soya, concentrates and ultimately adding palm fat to the ration (red arrows). The circles reflect averages in milk fat from different farming systems. BD = biodynamic; S = summer; W = winter.

When you increasingly squeeze cows and farmers and let the free market determine the end goal in milk production and quality, you end up with poor fat quality, a lot of milk per cow, who live anonymously on very large dairy farms, where there is a lot of imported soya and palm fat from the tropics and the US. Cows no longer graze, but are fed the same winter ration every day in the barn.

If, on the other hand, you start from the integrity of the cow as a ruminant and opt for milk production based on grass and grass products, the milk and butter may be more expensive, but they are of high quality, spreadable, yellow from beta-carotene (in summer) and with a good ratio of omega-3 to omega-6 fatty acids, but also with a high proportion of vitamins A and D in summer, the time to turn-over milk surplus into butter and cheese.

Literature

• Collomb, M., Bütikofer, U., Sieber, R., Jeangros, B., & Bosset, J. O. (2002). Composition of fatty acids in cow’s milk fat produced in the lowlands, mountains and highlands of Switzerland using high-resolution gas chromatography. International dairy journal, 12(8), 649-659.
• Ferlay, A., Agabriel, C., Sibra, C., Journal, C., Martin, B., & Chilliard, Y. (2008). Tanker milk variability in fatty acids according to farm feeding and husbandry practices in a French semi-mountain area. Dairy Science & Technology, 88(2), 193-215.
• Homan, A. N., Ziegler, G., Kaylegian, K. E., & Harvatine, K. J. (2025). The effect of increasing dietary palmitic and stearic acid on melting properties of milk fat from Holstein cows. Journal of Dairy Science.
• Kusche, D., Kuhnt, K., Ruebesam, K., Rohrer, C., Nierop, A. F., Jahreis, G., & Baars, T. (2015). Fatty acid profiles and antioxidants of organic and conventional milk from low‐and high‐input systems during outdoor period. Journal of the Science of Food and Agriculture, 95(3), 529-539.