Jk. Drackley et al., COMPARISON OF 3 METHODS FOR INCORPORATION OF LIQUID FAT INTO DIETS FOR LACTATING DAIRY-COWS, Journal of dairy science, 77(5), 1994, pp. 1386-1398
Two experiments were conducted to determine whether method of incorpor
ation of tallow (iodine value = 57.7) into a TMR for lactating dairy c
ows affected DMI, milk production or composition, ruminal characterist
ics, or nutrient digestibilities. In Experiment 1, 8 Holstein and 8 Je
rsey cows were fed diets containing 1) control, no fat; 2) fat (5% of
DM) added first to the concentrate; 3) fat added first to the haylage;
and 4) fat added as the last ingredient in the TMR. The DMI was lower
when fat was added last to the TMR; DMI was decreased for Jerseys, bu
t not Holsteins, when fat was added first to the concentrate. Milk pro
duction was increased, and milk fat percentage decreased, by fat suppl
ementation, but neither differed among application methods. Milk prote
in percentage was decreased by fat supplementation but was decreased l
ess when fat was added last to the TMR. Production of milk CP, true pr
otein, and casein protein was greater when fat was first mixed with ha
ylage or added last to the TMR. In Experiment 2, four Holstein cows wi
th ruminal cannulas were fed the same diets. Ruminal fermentation char
acteristics and apparent total tract digestibilities of DM, OM, CP, ND
F, ADF, and ash were not different among diets. Digestibility of total
fatty acids was decreased when fat was added first to haylage or last
to the TMR. Incorporation method had relatively minor effects on vari
ables.