Ovariectomized mice fed a diet containing partially hydrogenated safflower oil have increased mammary gland mass. Mice were ovariectomized at 21 days and fed either the control diet (TFA-CON) or that with 5% fat as partially hydrogenated (PH) Linseed oil (PH-LIN), PH-SAF, partially hydrogenated sunflower oil (PH-SUN), or 2.7% conjugated linoleic acid (c9,t11/t10,c12 CLA) from 22 days of age until euthanasia at 42 days of age. Wet organ mass was measured for (a) lymph node-free mammary gland, (b) liver, and (c) uterus. d Body weight (g) was measured at 21, 28, 35, and 42 days of age. Data are mean ± SEM (n = 6–8/diet). a, b, cMeans with different letters are different (P < 0.05). ND no difference