Four Mediterranean buffaloes (Bubalus bubalis) and
four Nellore zebu cattle (Bos indicus) with average 470 kg
and 446 kg body weight, respectively, were fitted with
rumen cannulae and assigned to two Latin square (LS)
designs (4 × 4), one to each animal species (buffalo and
cattle). Surgery was performed by veterinary personnel to
minimize the animal discomfort. The cannulas were cleaned
daily and sprayed to prevent insect proliferation. All
animal care followed guidelines recommended for use in
animal experiments from the university committee. The
animals were fed around 60% of sugar cane as roughage
(DM basis) with four different concentrate feeds. The
dietary treatments were arranged in a 2 × 2 factorial with
two energy sources (grain corn and citrus pulp), two
nitrogen sources (soybean meal and urea) as follows: COS
(grain corn and soybean meal); COU (grain corn and urea);
PUS (Citrus pulp and soybean meal); PUU (citrus pulp and
urea) (Table 1). The feeds were isoproteic with an average
8.8% crude protein in the total mixed feeds. The sugar cane
was harvested every two days, chopped by machine just
before offering once a day in the morning (8 a.m.). The
concentrate was spread on the sugar cane and the orts
were measured every day.