Experiments were conducted to find out the effect of energy content of the feed on power output
of medium size bullocks in summer season at a draft load of 10% of their body weight. The bodyweight
of the bullock pair was 610 kg. Three types of feeds were formulated having metabolizable energy
values of 7.25, 8.43 and 9.57 Mcal, which were referred as Feed-I, Feed-II and Feed-III, respectively.
Each feed was given to the bullocks for twenty-one days and then they were put to draftability tests.
The results indicated that the bullocks got fatigue after 4th hour of work in Feed-I and were on the
threshold fatigue limit of 20 in Feed-II. The bullocks sustained the draft load in Feed-III through out
the working hours. The average power output was 0.437, 0.444 and 0.449 kW in case of Feed-I,
Feed-II and Feed-III respectively. The power out put of the bullocks was increased by 1.6 and 2.75 %
respectively in Feed-II and III over that of Feed-I (farmers’ practice). Feed-III with metabolizable
energy content of 9.57 Mcal may be recommended for the medium size bullocks to work sustainably
in summer season.