ALBERT

Notes: The ratios of overtone and fundamental vibrational Einstein coefficients for NO(X 2Π) have been measured by spectrally resolved infrared chemiluminescence near 2.7–3.3 μm and 5.2–6.8 μm. The reactions of N(2D,2P) with O2, in the presence of a small background of He in a cryogenic low-pressure reactor, generated vibrationally excited, rotationally cold (60 K) NO(v), whose emission spectra were recorded with high spectral resolution. Least-squares spectral fitting analysis of the observed overtone and fundamental spectra gave vibrational band intensities, whose ratios at each emitting vibrational level v' yielded the (Δv=2)/(Δv=1) Einstein coefficient ratios for v'=2–13. The results provide comparisons to previous theoretical and experimental data, and reflect the behavior of the dipole moment function for NO(X 2Π). The measured ratios indicate an overtone Einstein coefficient A2,0=0.94±0.11 s−1 for an assumed fundamental value A1,0=13.4 s−1.

Notes: Two experiments investigated (1) the effect of stage of maturity at harvest in the first year on yield and persistency of red clover and lucerne when grown as monocultures and bi-crops, and (2) the effect of ensiling differing ratios of red clover and lucerne on forage quality and degree of proteolysis. Red clover (cv. Milvus) and lucerne (cv. Vertus) were established in triplicate plots at five sowing ratios:1·00 red clover, 0·75 red clover:0·25 lucerne, 0·50 red clover:0·50 lucerne, 0·25 red clover:0·75 lucerne and 1·00 lucerne. In year 1, plots were harvested in three strips, at different stages of plant maturity, either 11 (early), 13 (mid) or 15 (late) weeks after sowing. In years 2 and 3, the whole plot was harvested at each of four harvests taken during the growing season. The DM yield of lucerne in years 2 and 3 was higher than that of red clover, leading to increased yields from bi-crops with increasing proportions of lucerne. Strips harvested at the mid-stage of maturity in the first year on the 0·25 red clover:0·75 lucerne plots produced the highest DM yields overall. Ensiling red clover and lucerne bi-crops was found to combine the improved wilting properties of lucerne and the reduced proteolysis of ensiled red clover.

Notes: Two experiments describe the ensiling potential of whole-crop forage peas (Pisum sativum) and field beans (Vicia faba). In Experiment 1, forage peas (cv. Magnus) and field beans (cv. Mayo) were harvested at 10, 12 and 14 weeks after sowing, and ensiled in 10 kg mini-silos either untreated or treated with an inoculant (Lactobacillus plantarum). In terms of yield and ensiling potential, the optimum growth stage for harvesting forage peas occurred at 12 weeks of growth. In contrast, delaying the harvest of field beans until 14 weeks gave the highest yields of dry matter (DM) and crude protein (CP). Changes in crop maturity had little effect on the chemical composition of the fresh forages, but between-harvest date differences were observed in the DM, ammonia-N, CP, water-soluble carbohydrates (WSC), acid-detergent fibre (ADF), neutral-detergent fibre (NDF), lactic acid and volatile fatty acids (VFA) concentrations and pH of the corresponding silages. Fermentation was improved by applying an inoculant. In Experiment 2, forage peas and field beans were harvested at 14 weeks after sowing and ensiled as round-bale silage, either untreated or treated with an inoculant. The yields of the crops were similar, and the only difference in the chemical composition of the wilted forages was a higher CP concentration in the field beans. However, after the ensiling process was complete, the forage pea silages were found to have significantly higher DM, WSC, starch and butyric acid concentrations compared with the field bean silages, and lower ammonia-N, CP, ADF, acetic acid and lactic acid concentrations. Inoculation was found to increase the lactic acid concentration and reduce the pH and ammonia-N and acetic acid concentrations of the silages. Each of the silages produced in Experiment 2 was offered to six Suffolk crossbred wether lambs, aged 10 months. Voluntary DM intakes were similar on all treatments, despite the apparent digestibility of the forage pea silages being significantly higher than that of the field bean silages. Nitrogen retention was higher for lambs offered forage pea silage. Application of an inoculant was found to have a negative effect on the amount of N retained, indicating the necessity for more detailed investigations into proteolytic activity within these crops during the fermentation process.

Notes: Using new harvesting and ensiling technologies, it is now possible to ensile kale (Brassica oleracea) successfully. However, there is little information available regarding the optimum time for harvest. The aim of this 2-year study was to compare the yield, fermentation characteristics and feeding value of kale harvested at different stages of growth, and ensiled with and without a bacterial inoculant. During Year 1 the crop was harvested after 15, 18 and 20 weeks of growth. The yield at each harvest was similar, but as the crop matured the crude protein (CP) concentration and buffering capacity decreased significantly, and there was a marked increase in the water-soluble carbohydrate (WSC) concentration. During Year 2 the crop was harvested at 14 and 17 weeks of growth. Again, the stage of maturity did not affect yield and, on this occasion, the chemical composition of the crop was unaffected by harvest date. However, the WSC and CP concentrations of the crop were lower in Year 2 than in Year 1, possibly as a result of differences in fertilizer regime. Each of the silages produced in Year 2 was offered to six Suffolk cross wether lambs, aged 10 months, to measure voluntary intake, in vivo digestibility and nitrogen retention. Neither harvesting date nor the use of an inoculant affected voluntary intake or nitrogen retention by the lambs. However, in vivo digestibility was higher in the kale silage harvested after 14 weeks of growth and when an inoculant was applied. The results obtained suggest that harvesting kale after 14 weeks of growth can produce highly digestible silage with a high CP concentration. Although delaying harvest until 18 weeks of growth will probably result in a decrease in the CP concentration of the crop, it should also lead to an increase in the WSC concentration of the crop, ensuring a more reliable fermentation.

Notes: The combined benefits of a high crude protein concentration, and possible protein protection and growth-promoting properties, make forage legumes potentially attractive as a natural means of increasing liveweight gain and time to slaughter of lambs in lamb finishing systems. An experiment was conducted to compare the production performance and meat quality of grazing lambs finished on red clover (Trifolium pratense), lucerne (Medicago sativa) or perennial ryegrass (Lolium perenne) swards. Replicate (n = 2) swards of red clover, lucerne and perennial ryegrass were rotationally grazed by ten ram lambs and ten ewe lambs from weaning until selection for slaughter at UK fat class 3L. Lambs grazing the red clover sward had a significantly higher liveweight gain and required significantly fewer days to slaughter than lambs grazing the lucerne sward (305 g d−1 vs. 243 g d−1; 38 d vs. 50 d), which in turn had a higher liveweight gain and required fewer days to slaughter than lambs grazing the perennial ryegrass sward (184 g d−1; 66 d). Lambs grazing the red clover and lucerne swards had significantly higher herbage intakes than those grazing the perennial ryegrass sward (2·06, 1·72 and 1·16 kg DM d−1 respectively), but in vivo digestibility of herbage was similar. Lambs grazing the red clover and lucerne swards also had significantly higher serum urea concentrations than those grazing ryegrass (12·5, 11·1 and 6·2 mmol L−1 respectively). Killing-out percentage was significantly higher for lambs grazing the red clover sward than for lambs grazing the perennial ryegrass sward (48% vs. 46%). There were no significant effects of finishing system on meat flavour, but meat from lambs finished on the lucerne sward was oxidatively less stable than that from lambs finished on the perennial ryegrass sward. Grazing the forage legume swards significantly increased the proportion of linoleic and linolenic acid in muscle tissue, and therefore the proportion of unsaturated to saturated fatty acids (0·19, 0·16 and 0·12 for the red clover, lucerne and perennial ryegrass swards respectively). However, the n−6/n−3 ratio was significantly lower for the muscle of lambs grazing the perennial ryegrass sward compared with those grazing the forage legume swards (1·13, 1·08 and 0·98 for the red clover, lucerne and perennial ryegrass swards respectively). The results indicate that by grazing lambs on forage legume swards it is possible to increase individual lamb performance without compromising meat quality.

Notes: Low-energy electron-energy-loss spectra of styrene deposited on a thin film of solid argon are measured at a temperature of 15 K. The spectra show vibrationally resolved bands in the region of the lowest valence transitions thus allowing to locate the 0–0 transition to the lowest triplet state at 2.69 eV. The second triplet state of styrene is detected for the first time with a 0–0 transition at 3.98 eV. Semiempirical calculations are performed to characterize the bands observed in the spectrum considering the nomenclature of Platt. They suggest that the lowest triplet state has the same spacial wave function as the second singlet state and is closely related to 3La benzene. The second triplet state which has most likely Ba character cannot directly be related to a specific singlet state because the Ba and Bb states are found to mix strongly in the singlet manifold whereas among the triplets they do not.

Notes: The electric dipole moment function for NO(X 2Π) is determined by nonlinear least-squares analysis of experimental data, including previously reported (Δv=2)/(Δv=1) transition branching ratios for v′≤13. Polynomial fits to the dipole moment function are determined over the range of internuclear separation from 0.97 to 1.50 Å. The fitted dipole moment functions agree well with previous ab initio predictions, but differ somewhat at the larger internuclear separations. The observed dipole moment functions are used to compute rotationless Einstein coefficients for Δv=1–4 vibrational transitions with v′≤20. The absolute Δv=1 and Δv=2 Einstein coefficients are well determined by this analysis, especially for v′≤12. The results provide a firm basis for determinations of vibration-rotation emission intensities of NO(X 2Π) in high-temperature or nonequilibrium chemiexcitation systems. © 1998 American Institute of Physics.