The atten$ted removal of extraraeous Ketolzic materialsSuch materials causing variation in the conversion factor may possibly be removed if the extract is percolated through activated alumina prior to analysis (after the method of Brown et aZ.12). This technique has been satisfactorily employed in the direct spectrophotometric method of a n a l y~i s .~ Preliminary investigation indicated that deviation between conversion factors for distilled and normal extract was reduced by treatment with alumina to 5%. This work, however, has not been continued since it renders the method cumbersome and shows no great improvement over the normal analysis involving the chromatographic separation of the pyrethrin z,+dinitrophenylhydrazone derivatives. Conclusionsin formulations containing synergists and emulsifying agents. duplicate analyses of the formulation and reagent blank takes from I-I* h.

Two experiments were carried out to examine the nitrogenous changes occurring in herbage during harvesting and ensiling. In the first, ryegrassclover was wilted rapidly in the laboratory (6 h) and in the field under good (48 h) and poor (48 h and 144 h) weather conditions. Protein breakdown and ammonia formation were negligible in herbage wilted rapidly and it was only when the crop was exposed to a prolonged wilt in humid conditions that appreciable proteolysis occurred. In the second experiment ryegrass-clover was ensiled in laboratory silos after treatment with varying levels of formic and sulphuric acids. An additional treatment included herbage inoculated with a mixture of lactic acid bacteria and glucose. The silos were opened after 4 and 50 d and samples were analysed for protein-N, ammonia-N, water-soluble carbohydrates and organic acids. Tliere was a high negative correlation between level of addition of either acid and the degree of proteolysis and deamination. Even at the highest levels of formic acid (7 7 g per kg) and sulphuric acid (4 0 g per kg) additions, however, about 45 % ofthe original herbage protein was degraded after 50 d in the silo. The inoculum treatment was also effective in reducing proteolysis, the effect after 50 d being comparable with formic acid applied at a rate of 41 g per kg.

Three experiments are described. In the iirst, cellulase prepared from Aspergillus niger was added at the rate of 4 g/kg to herbage treated with a variety of silage additives, formic acid, caproic acid, formalin, sodium metabisulphite and zinc bacitracin. The lowest cellulose contents and highest residual water soluble carbohydrate contents were found in the silages treated with formic acid and cellulase. Formic acid was included as a treatment in subsequent experiments. In the second experiment, the enzyme was added td herbage at two levels, 1 .O g/kg fresh grass and 4.0 g/kg fresh grass. Cellulose contents of the silages were significantly lower after 61 days at the higher rate of application of the enzyme. In the third experiment, two enzymes produced from Aspergillus niger were compared with two enzymes derived from Trichoderma viride. Under the conditions of the experiment the cellulase enzymes produced from T. viride were more active.

Formic acid (85 %) was added to wilted perennial ryegrass (36 % dry matter) at the rate of 0.39 %. Changes during ensilage of this material were compared with changes occurring during ensilage of untreated wilted ryegrass and freshly harvested herbage. All silages were well preserved, of low volatile N content and contained only traces of butyric acid. Formic acid restricted fermentation in the wilted grass resulting in silage of high water-soluble carbohydrate content (15.3 %)compared with untreated wilted (4.7%) and fresh (1.2%) silages. Results of microbiological studies indicated that yeasts were more active in the formic acid-treated herbages. Surface waste production and fermentation plus oxidation losses were higher in the acid-treated wilted silages (21 %) than in the untreated wilted materials (14 %).

Lucerne (DM 236 g kg"', WSC 49 g (kg DM)"') was ensiled in test-tube silos with or without either glucose or fructose and with or without one of two commercial inoculanls. The WSC content of the forage as ensiled was too low to obtain a well preserved untreated silage. By day 4 the pH values of the silages with added sugar or inoculant were significantly lower (P < 0001) than the control silage. A satisfactory fermentation was attained only in the silages to which sugar and an inoculant had been added. These silages had a lower pH, more protein-N iP<000[), less ammonia-N (/*<0001), a faster increase in counts of lactic acid bacteria, and decrease in counts of coliforms than the other silages. Homofermentative lactic acid bacteria dominated the fermentation in the inoculated silages while leuconostocs dominated the early stages of fermentation in the control silages-The results indicate that if there is insufficient sugar in the original crop, then the bacteria in an inoculant will not be able to produce enough lactic acid to lower the pH to an acceptable level. This has important implications for the ensilage of lucerne and other highly buffered low sugar crops.