Factors affecting microbial dynamics during aerobic deterioration of silages were evaluated in laboratory, pilot-scale and full-scale experiments. Yeasts usually caused the initial deterioration but in some samples with fairly good storage stability (>lo days) the activity was associated with the growth of moulds and bacteria. At a later stage, and especially at higher temperatures (>4OoC), the activity was caused by bacilli. The increase in pH as a result of lactate metabolism permitted the growth of Enterobacteria. Evaluation of storage stability in samples from different levels in a bunker silo indicated low stability in surface samples and fairly good stability in samples from 160cm depth. The surface samples contained higher numbers (10@1000 times) of yeasts but the pH levels were similar.The establishment of yeasts during storage is probably due to diffusion of oxygen by leakage through the plastic cover. Compared with a plastic cover (0.1mm polythene), a rubber seal improved storage stability in laboratory silage (pH 4.0) inoculated with lactic acid bacteria and infected with Candida albicans. An increase in acid content and a reduction in pH (3.7) by means of an efficient inoculant did not seem to increase the storage potential under the conditions described above. The content of adenosine triphosphate has been used as a measure of microbial activity during aerobic deterioration of silages. The main activity was concentrated at the surface (0-5cm). At 20"C, the activity was about ten times higher at the surface than at a depth of 30cm; above 30°C it was about 100 times higher.

The quality of silage from crops fertilized with

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An experiment involving 75 male reindeer calves (mean initial live weight 39.6 kg, SD=3.7) intended for slaughter was undertaken to study the effect of proporrion of barley to silage in the diets on animal performance. The calves were alloted to five groups including one group slaughtered at the start of the experiment in September. The remaining groups were offered diets containing either, 30% (LB), or 60% (HB) rolled barley, based on the dry matter (DM) content, until slaughter in November (LB and HB) or in March (HB). The silage (43% DM) was made from the primary growth of a predominantly grass sward preserved as plastic-wrapped big bales. Small amounts of lichens were mixed with the rations during rhe first two weeks of the experiment and the calves adapted well to the experimental diets. However, health problems and deaths occurred on borh rarions after five weeks of feeding. Since the animals fed the LB diet lost live weight and condition the experimental feeding of these calves were interrupted at the slaughter in November. Calves fed the LB diet had significantly lower daily DM intake (P<0.01). They also had lower live weighr gain (not significant), greater losses of carcass weight and fat in the abdominal cavity relative to those offered the HB diet. During the second period of the study the remaining animals offered the HB diet showed no signs of ill-health and increased live weight, carcass weighr, and fat in the abdominal cavity. The results of the presenr experiment indicate that when silage of the investigated quality is fed to reindeer calves rhe proportion of silage should not exceed 40% of the DM