In this paper, composites based on unsaturated polyester resin reinforced with short Alfa fibers are studied in detail. Alfa fibers have been previously treated with various concentrations NaOH (1, 3, 5, 7%) during 24 h. The influence of alkali treatment on fiber morphology is analyzed. Analysis by FTIR and X-ray diffraction showed physico-chemical changes in Alfa fiber treated surfaces. SEM observations also helped to highlight these changes. The results of static tests on composites showed improvements in tensile and flexural strengths of composites reinforced with the treated fibers, particularly the composite with treated fibers at 7% NaOH. These improvements were about 30% and 50%, respectively, compared to untreated fiber reinforced composite.

Three dominant morphological fractions (i.e. leaf blade (LB), leaf sheath (LS) and stem) were analysed for chemical composition and ruminal degradability in three rice straw varieties. In one variety treated with alkali, cell wall features were also characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy. The highest concentrations of cell wall carbohydrates (hemicellulose and cellulose) were observed in LS, whereas the highest concentrations of non-fibre (silica, phenolic compounds and CP) and lignin were recorded for LB. The stem had the lowest silica and hemicellulose contents but intermediate levels of other components. In terms of ruminal degradability, stem ranked higher than LB, which was followed by LS. Hemicellulose was found to be less degradable than either dry matter or cellulose in all the three fractions investigated. FTIR results indicated that the highest levels of hydrogen bonding, esterification and crystallinity within the cell wall components belonged to LS. In the alkaline treatment, these indices decreased to a larger extent for leaf fractions and a greater improvement was achieved in the degradability of LB and LS compared with that of stem. In the 24-h ruminal incubation, the silicified layer of epidermis and the underlying cell walls showed a rigid structure in the control fractions, whereas the treatment with NaOH resulted in crimping of the silicified cuticle layer and the loss of integrity in cell structure. Despite the highest silica and lignin contents observed in LB, LS showed the lowest degradability, which might be due to its high level of hydrogen bonding, crystallinity and esterification within its cell wall components as well as its high hemicellulose content.

A study was conducted to examine the effect of fine grinding or sodium hydroxide treatment of wheat, and increasing concentrate food level, on milk production. Two concentrates based either on ground wheat (450 g/kg, GW) or sodium hydroxide treated wheat (500 g/kg, SW) were offered at four concentrate levels of 2·5, 5·0, 7·5 and 10·0 kg dry matter (DM) per day to 24 dairy cows in a three-period, change-over design experiment. On average, across all concentrate food levels, silage DM intake was significantly (P < 0·01) higher with the SW concentrates, reflecting a significantly lower silage substitution rate with SW relative to GW concentrates (P < 0·01). Milk yield was also significantly higher with the SW concentrates (P < 0·05), although marginal responses to increased concentrate food level were similar (P > 0·05). Milk protein concentration increased linearly with increasing concentrate food level (P < 0·001), with a significantly greater response with the GW relative to the SW concentrate (0·59 v. 0·24 g/kg (P < 0·05) increase per kg additional concentrate). However, milk protein concentration was also significantly lower with the GW concentrate at low food levels (P < 0·05). Milk fat concentrations were similar with the two concentrate types with significant reductions in milk fat concentration with increasing concentrate food level (P < 0·05). Blood urea (P < 0·001) and β-hydroxybutyrate (P < 0·05) concentrations were significantly lower in animals offered the SW concentrate. Apparent digestibility coefficients were unaffected by either concentrate type or concentrate food level (P > 0·05), although modified acid-detergent fibre apparent digestibility was significantly reduced with increasing concentrate food level (P < 0·001). Results indicate that, at similar levels of concentrate feeding, silage intake and milk yield were significantly greater with SW compared with GW concentrates (P < 0·05 or greater). Increases in milk protein concentration with increasing concentrate food level were significantly greater with GW than with SW concentrates (P < 0·05).

The mineral balance of male calves given neutralized (with HC1) and unneutralized 35 g NaOH per kg treated wheat straw (WS), was determined in a digestibility trial in which WS was offered at inclusion levels of 300, 500 and 700 g/kg diet. The ratio of apparently retained sodium (Na) and potassium (K) increased with increasing proportion of straw in the diet and was lower on neutralized straw diets.

The effect of supplementation with 3 and 6 g K per kg diet dry matter in a diet comprising approximately 500 g/kg of 35 g NaOH per kg treated WS, on performance, mineral status and acidbase balance was examined in a growth trial with 56 Israeli-Friesian male calves. The animals on the untreated WS diet had significantly (P < 0·05) less fat in the large depots and lower fat trim of carcass than did animals on the treated WS diets. No other differences in performance were significant. Ammonia concentration in rumen liquor and urea in blood were lower in the animals given alkali-treated WS. The concentrations of Na, K and chlorine in blood serum of the experimental animals were not affected by the treatment. The data on Na, K and magnesium (Mg) in muscle show depletion of Na and K and a trend towards a decrease in Mg concentration. K supplementation reduced the extent of depletion of Na and K. In bone, only Na was affected by the feeding of alkali-treated WS, the pattern being the same as in the muscle. The blood acid-base balance of the experimental animals was not significantly affected by treatments. The values of pH, actual bicarbonate and pCO2 of the animals given 35 g/kg alkali-treated WS indicate mild alkalosis in those animals. This alkalotic state did not affect performance. It appears that there is no Na loading problem which might interfere with growth.

Three trials were conducted to evaluate the effects of treating soya-bean straw with various alkalis plus ensiling on digestibility of various nutrients and on nitrogen retention in ruminants. Soya-bean straw was treated with sodium hydroxide, calcium hydroxide or ammonium hydroxide and ensiled at 650 g/kg moisture. In trial 1, the effects of level and type of alkali on in vitro digestibility of ensiled soya-bean straw were evaluated. Concentrations of alkalis used were 0 (control), 20, 30, 40 and 50 g/kg dry matter. Both in vitro digestibilities of dry matter and organic matter of soya-bean straw were significantly (P < 0·05) increased with alkali treatment at all levels plus ensiling compared with untreated or treated unensiled straw. The 40 g/kg alkali concentration level in combination with ensiling appeared to be the most effective overall. In trial 2, the effects of type of alkali on nutrient digestibility and nitrogen retention in wether lambs were evaluated. Sixteen wether Suffolk lambs were given untreated or alkali-treated (40 g/kg) ensiled soya-bean straw. Treatments were: (1) water-treated straw; (2) NaOH-treated straw: (3) Ca(OH)1-treated straw; and (4) NH4OH-treated straw. Lambs given NH4OH-treated ensiled straw digested the dry matter, organic matter, and crude protein better than those given water-treated ensiled straw (P < 0·05). NH4OH improved nitrogen intake by proportionately 0·181 but not nitrogen retention. For trial 3, eight Angus steers were used. Chopped soya-bean straw was treated with NH4OH and ensiled in Silopress bags. Treatments were: (1) untreated dry straw; (2) water-treated straw; (3) 30 g/kg NH4OH-treated straw; and (4) 40 g/kg NH4OH-treated straw. The trial consisted of a 7-day collection period which was replicated once. Apparent digestibilities of dry matter, crude protein and various fibre constituents were increased by ensiling or ensiling and NH4 OH treatment combinations (P < 0·05). Alkali treatments in combination with ensiling appeared to improve digestibility of soya-bean straw, but ammoniation did not improve nitrogen utilization. Ensiling appeared to have a more significant effect than alkali treatments per se on the degradability of soya-bean straw.