Determination of apparent digestibility of organic nutrients was asses
sed in 196 fattened bulls of the Czech Pied breed from the Research In
stitute of Animal Nutrition at Pohorelice. The average weight of bulls
was 379.69 kg (S(x) = 98.09), average daily weight gain was 1.137 kg
(S(x) = 0.198). The feed ration contained com silage and supplementary
mix in 168 bulls, and beet-top silage and supplementary mix in 28 bul
ls. The average content of gross energy (GE) of the feed ration made 1
7.55 MJ/kg dry matter (S(x) = 0.86), average value of metabolizable en
ergy (ME) was 9.28 MJ/kg dry matter (S(x), 0. 69) and average content
of net energy (NE) amounted to 5.34 MJ/kg (S(x) = 0.58). The above-nie
ntioned concentrations of energy indicate the bulk type of feed ration
s used in the trials. This equation was calculated by means of regress
ion analysis from the data on individual NE uptake: NE uptake = -1.84
+ 0.076 x weight + 13.59 x weight gain (R = 0.798).The calculated valu
es were compared with literary data (Van Es, 1978; INRA 1988). The sha
pe of the equation proposed for practical conditions: NE requirement =
-9.39 + 0.095 x weight + 17.40 x weight gain.