Py. Chouinard et al., FATTY-ACID PROFILE AND PHYSICAL-PROPERTIES OF MILK-FAT FROM COWS FED CALCIUM SALTS OF FATTY-ACIDS WITH VARYING UNSATURATION, Journal of dairy science, 81(2), 1998, pp. 471-481
Holstein cows (n = 24) averaging 42 d in milk were used in a randomize
d complete block design during a 4-wk trial. A control total mixed rat
ion (TMR) was compared with TMR supplemented with Ca salts of fatty ac
ids from canola oil, soybean oil, or linseed oil. The three vegetable
oils were progressively more unsaturated; the dominant fatty acids wer
e, respectively, cis-Delta-9-C-18:1,C- C-18:2,C- and C-18:3. Apparent
total tract digestibility of dry matter, crude protein, ether extract,
and neutral detergent fiber was higher for rations containing Ca salt
s than for the control ration. Milk yield increased linearly as the un
saturation of the dominant fatty acid in the Ca salts increased. Milk
fat percentage was reduced when Ca salts were added to the rations. Th
e addition of Ca salts to the ration decreased the proportions of satu
rated fatty acids that contained C-6 to C-16 and increased the proport
ions of C-18:0, cis-Delta-9-C-18:1, and trans-Delta-11-C-18:1 1 in mil
k fat. Proportions of C-18:2 and C-18:3 increased linearly, and cis-De
lta-9-C-18:1 decreased linearly, as the unsaturation of the dominant f
atty acid in the Ca salts increased. The proportion of fat that was li
quid at 5 degrees C was higher for butter from cows fed diets containi
ng Ca salts, but the proportion of liquid fat at 20 degrees C was not
affected. Calcium salts of unsaturated fatty acids added to the diets
of dairy cows improved the thermal properties of milk fat.