"Experimental design
Diets.
The horses were offered a forage-only diet (F) consisting
of early-cut haylage (timothy, meadow fescue mixture;
Table 1) and a mixed diet (FC) consisting of late-cut haylage
(timothy, meadow fescue mixture) supplemented with concentrate
(50 : 50 DM basis) in a 29-day change-over design
experiment. Feed allowance was based on individual BW and
was 13 to 17.4 kg haylage and 180 to 240 g sugar (only
to ensure complete intake of the salt, mineral and vitamin
supplements) for diet F and 6.3 to 8.4 kg haylage, 5.3 to 7.1 kg
oats, 0.9 to 1.2kg soy bean meal, 0.18 to 0.24kg wheat bran
and 90 to 120 g sugar for diet FC. The diets were estimated to
be iso-caloric and iso-nitrogenous, and provided energy and
nutrients according to requirements specified by National
Research Council (NRC, 1989). Horses on both diets were
offered a mineral and vitamin supplement (5162g/day,
Miner Ro¨ d, Krafft, Falkenberg, Sweden), NaCl (3661g/day),
and those on diet FC were offered ground chalk (calcium carbonate,
3461 g/day) in order to meet mineral and vitamin
requirements specified by NRC (1989). Water was provided
ad libitum from graded buckets. The forage allowance was fed
in the afternoon and the concentrate and mineral and vitamin
supplement (diet FC) at 1500, 2300 and 0600 h. With diet F,
the mineral and vitamin supplement was fed at 2300 and
0600 h. Diet FC was introduced gradually during the experimental
period (on days 1 and 2, horses were fed 50% of the
F diet and 50% of the FC diet, and then the FC diet was
increased by 10% per day until the full ration was reached on
day 7). Diet F was introduced abruptly on day 1."