A 120-day finishing study utilizing 318 heifers (753 lb initial body weight) examined
the effects of ruminally protected choline in diets with no tallow or 2 or 4% of supplemental
tallow. Heifers were fed a finishing diet based on a mix of steam-flaked and dry- rolled
corn; encapsulated choline (20, 40, or
60 g/head/day, supplying 5, 10 or 15 g
choline/head/day) was top-dressed to the diet
or not added. Dry matter intake decreased
linearly with inclusion of fat (P<.05) but was
not affected significantly by addition of choline.
Daily gains also decreased linearly
(P<.05) with fat addition. Choline supplementation
increased gain (linear, P<.1; qua
dratic, P<.05), with the greatest increase
occurring for the first 20 g increment encapsulated
choline/day. Likewise, feed efficiency
improved (P<.1) with supplemental choline.
Again, the greatest response occurred for the
first 20 g/day. Kidney, pelvic, and heart fat
and yield grade both increased linearly (P<.1)
with fat supplementation. The percentage of
carcasses grading USDA Choice decreased
(linear, P<.05; quadratic, P<.1) when choline
was added at 60 g/day. Hot carcass weight,
marbling, dressing percent, and 12th rib fat thickness
were not affected significantly by
either fat or choline. Ruminally protected
choline can improve average daily gain and
feed efficiency of finishing cattle.
