Florida Agricultural Experiment Station


crude protein above the calculated requirements. Preliminary
periods were 10 days in length, and the experimental periods
consisted of four successive 5-day periods, except in the trials
with Napier grass silage which were only three 5-day periods.
 Individual feedings for an entire trial were weighed into
 separate paper bags on a solution balance, and samples were
 taken before the beginning of the trial, except in the case of
 the silages. The silages were weighed before the evening feed-
 ing, and a one-kilo sample was taken each day. These were
 dried and 5-day composite samples prepared.
 Four steers (three Jerseys and one grade Hereford) ranging
 in weight from 450 to 700 pounds were used in all trials. The
 feed was given in two equal portions at 6:00 a.m. and 6:00 p.m.
 The steers were held in a dry lot for the first nine days of the
 preliminary periods and then stanchioned in a barn. Water
 was provided in buckets. Salt was offered in small boxes. Each
 animal was brushed vigorously for one hour daily as a substitute
 for exercise.
 Feces were collected manually, and placed in covered galvan-
 ized iron cans. The daily collections of feces were weighed,
 mixed, and sampled separately at 9:00 a.m. each day. Twentieth
 aliquots of each daily collection were taken in pyrex dishes, dried,
 and used in the preparation of 5-day composite samples, for the
 determination of the constituents other than nitrogen. Tripli-
 cate five to 10 gram samples of the fresh feces were taken in
 weighing bottles for daily determination of nitrogen, thus mini-
 mizing nitrogen losses through the volatilization of ammonia.
 Proximate analyses were made by methods of the Association
of Official Agricultural Chemists (1). Calcium, magnesium,
and phosphorus were determined by the method of Morris, Nel-
son, and Palmer (7).
 Indirect calculations were made of the digestibility of the
nutrients. Coefficients of digestibility for cottonseed meal, as
compiled by Henry and Morrison (4), were used for that feed.
Coefficients for the alfalfa hay were calculated from the trial
on the basal ration of cottonseed meal and alfalfa hay, and were
used in the calculations with the Napier grass silage, C. inter-
media silage and Natal grass hay. The crude protein, as deter-
mined in the fresh feces, was used in all calculations to avoid
any error due to the volatilization of ammonia in the drying
process.