digestibility, energy concentration, and pro-
tein contents. In the first part of this study (ETTALA et al. 1975), good quality silage was obtained with the silage additives investigated (AIV 1, AIV 2, formic acid and Viher solutions). The nutritive characteris-tics of these silages are presented in this paper. Feeding experiments (5) were perform-
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designated by the same symbols (1-5 b) as the corresponding experiments in part I of this study.
ed with dairy cows and digestibility and nitrogen balance experiments (5) were conducted with sheep. The experiments are
Materials and methods Experimental aninzals and feeding
Ayrshire cows (96 in ali) weighing 400-500 kg were used. They received silage ad libitum in individually weighed portions. Each animal was also offered 2 kg hay a day, a kilogram being given at each feeding time. Barley was given as the only concentrate, at the rate of 1/3, 2/3 or 3/3 of the energy required for milk production exceeding 10 kg (4 %), except in the case of one group in experiment 4, which did not receive any supplemental concentrate. The barley ration was determined on the basis of the milk production of the preceding 5 days. The energy requirement was taken as 0.4 f.u./kg 4 % milk (1 feed unit = 0.7 kg starch equivalent).
The mineral supplementation of the rations was adjusted to meet the mineral requirements of the cows according to the mineral contents of the feeds of previous experiments. In experiment 1, the cows were given sodium carbonate to satisfy their sodium require-ment; in the other experiments they received a mineral mixture containing sodium as chloride or phosphate. In most of the experiments the mineral mixtures contained the necessary vitamin D supplement, but in some vitamin D preparations were given separately.
In the feeding experiments there was a preliminary period of 20 days, during which the cows all received the same feeding, consisting predominantly of silage. This was followed by a transition to the experi-mental diet. The experiexperi-mental period ranged from 80 to 160 days. A Latin square design (4 x 4) was used in the first experiment, the rations being used for 30 days. Since
the aim was to examine the long-term effect of the feeds, the other trials were conducted as factorial experiments (experi-ments 3, 4 and 5) or as a group feeding experiment (experiment 2). In the factorial experiments the silage additive was used as one of the factors and the level of the concentrate (experiments 3 and 4) or the botanical composition of the silage (experi-ment 5) as the other.
The cows were divided into groups, which were as uniform as possible in respect of the milk production and silage intake during the preliminary period, and the liveweight and time elapsed since calving. The average time elapsed between calving and the group-ing of the cows ranged from 70 to 104 days (Table 4). The experimental period was divided into 5-day stretches, which were used as the temporal unit throughout the experiments.
The milk yields of the cows were weighed individually at each milking time. The milk was analysed for fat at 5-day intervals and for protein and lactose at 10-day intervals, the determinations being made on combined samples for 2 days. The cows were weighed at the beginning of the preliminary period, the transitional period and the experimental period, and also at 30-day intervals during the experimental period and at its end.
Weighing was- performed on two successive days before the afternoon feed.
Digestibility and nitrogen balance trials were performed with the silages of experi-ments 3, 4 and 5. The silages used in the digestibility experiments were preserved frozen in plastic sacks. Two successive digestibility experiments, conducted as Latin 305
squares (2 x 2, with two replicates), were performed with the silage of experiment 4, so that digestibility and nitrogen balance values could be obtained separately for the two silages — the first consisting predom-inantly of timothy grass cut in early summer at an early stage of growth, the second consisting of clover cut at the flowering stage in late summer (cf. part I, p. 288). The other digestibility experiments were con-ducted as 4 x 4 Latin squares. The diges-tibility experiments lasted 21 days, compris-ing a 7-10 day preliminary period and a 7-10 day collection period. The sheep were offered silage only, either ad libitum or, during the collection period, at the rate of 1 kg dry mattel= per animal per day (experiment 5). Water and minerals were offered ad libitum.
Digestibility experiments could not be performed with ali the silages, and values obtained in earlier studies for the same kind of silages were taken in some cases. The values for the silage of experiment I were obtained from POUTIAINEN and HUIDA (1970), and those for experiment 2 from POUTIAINEN
and RINNE (1971). The values for the digestibility of the hay and the barley were taken from the feed table published for the Nordic countries (N JF, Fodermiddeltabel 1969).
Sampling
In the feeding experiment with the cows, samples representing two weeks' feeding were taken from the towers (part I, p. 287).
Hay and barley samples were collected daily and composite samples representing one month's feeding were taken for analysis.
Silage samples for the digestibility exper-iments were taken for each experimental period when the silage was thawed out.
When necessary, samples were also taken from the feed residues. Faeces and urine were weighed daily and pooled, the samples made up for analysis representing each sheep and each experimental period. A complete feed analysis was made on the feed and the dried faeces (cf. part I, p. 290) and total nitrogen was determined on the urine and the fresh faeces.
The fat content of the milk was determined with a Milko-Tester II apparatus or by the method of Gerber. Its protein content was either measured with a Pro-Milk apparatus (experiment 1) or determined together with lactose contents with an Infra Red Milk Analyser (experiments 2-5).
Statistical methods
The statistical analysis was performed with an IBM 1130 computer. The significance of the differences between the treatments was determined with the least-squares anal-ysis of variance (HARVEY 1966). To eliminate the effect of differences between the animals, the following parameters were taken as linear regression variables: weight, milk production, milk composition and voluntary intake of silage in the preliminary period, and time elapsed since calving. The regression variables were changed, depending on the object of the analysis. In experiment 1, which was designed as a Latin square, corres-ponding regression variables were obtain-ed from the results of the first 10 days of the experiment and the results of the follow-ing 20 days were used for the calculations and analyses. The differences between the feeds were examined with the analysis of variance, and Tukey's test (STEEL and TORRIE 1960) was applied to the differences between the means.
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