Milk fat depression and CLA

Milk fat depression is a fall in milk fat content, often sharp, while milk volume and protein are unchanged. It occurs when unsaturated fats are incompletely hydrogenated in the rumen and particular intermediates reach the udder. One of these, the trans-10, cis-12 isomer of conjugated linoleic acid, is a potent inhibitor of fat synthesis.

The usual triggers are a combination of fermentable starch, low effective fibre and unsaturated oil in the ration. Another isomer, cis-9, trans-11 CLA, is the main form found in milk fat.

Written for the 2026 edition of the library.