Milk fat comes from two primary sources: the animal's diet and synthesis within the mammary gland.
The fatty acid composition of milk fat is variable, and the origin of these fats depends on their chain length. Specifically:
- Short-chain fatty acids (4 to 14 carbons): These are primarily synthesized de novo within the mammary gland of the animal (typically a cow). This means the cow creates these fatty acids from simpler building blocks.
- 16-Carbon Fatty Acids: Some of these are also made by the mammary gland, while others are directly derived from the animal's diet.
- Long-chain fatty acids (18 or more carbons): These fats largely originate directly from the animal's diet.
Therefore, the answer is that milk fat originates both from what the animal eats and from synthesis within the mammary gland itself. The relative contribution of each depends on the specific fatty acid composition.
