formation, and clot firmness after 30 min) using a Foss
Electric formagraph. The milk coagulating index was
calculated as the clot firmness to clotting time + rate
of clot formation ratio. Milk energy output was calculated
according to the formula of Crovetto and van der
Honing (1984).
For the analysis of milk FA, milk fat was extracted
according to the procedure of Luna et al. (2005) and
transesterification of FA according to ISO-IDF (2002)
procedures. Fatty acid methyl esters were separated and
measured using a gas chromatograph (Agilent 6890N)
equipped with CP-Sil 88 fused-silica capillary column
(100 m × 0.25 mm i.d.; 0.25 μm film thickness). Operating
conditions were as follows: a helium flow-rate of 1
mL/min, a flame ionization detector at 260°C, a splitsplitless
injector at 260°C, and an injection volume of
1 μL with a split ratio 1:50. The temperature program
of the column was set at 100°C and subsequently increased
to 240°C at 3.5°C/min and held for 15 min.
Each peak was identified using standard from Matreya
(Matreya LLC). Fatty acids were reported as g/100 g
of FAME total and saturated FA, monounsaturated
FA, and PUFA were calculated. The desaturase indices
were calculated as described by Kelsey et al. (2003).
Atherogenic and thrombogenic indices were calculated
according to Ulbricht and Southgate (1991).