ALBERT

Notes: A randomized-block experiment was carried out to evaluate a bacterial inoculant, based on a single strain of the organism Lactobacillus plantarum, as a silage additive. The inoculant-treated silage was compared with untreated and formic acid-treated silages. The three silages were harvested from a perennial ryegrass sward on 30 September and 1 October, 1985 using two double-chop forage harvesters. Formic acid (850 g kg−1) was applied at a rate of 31t−1 and the inoculant at a rate of 3 g mixed in 31 water t−1 (1 × 106 colony forming units (g grass)−1). The dry matter and water-soluble carbohydrate contents of the grass at ensiling were 165 g kg−1 and 18·9 g kg−1 respectively. For a period of 84 d, the three silages were offered ad libitum and supplemented with three concentrates in a 3 × 3 factorial design to 63 male cattle which were initially 15 weeks old and 128 kg live weight. The three concentrates were (1) barley (115 g crude protein (CP) (kg DM)−1), (2) barley/soyabean meal (207 g CP (kg DM)−1) and (3) barley/fish meal (200 g CP (kg DM)−1); each was offered at a mean rate of 1·7 kg d−1. For the untreated, formic acid-treated and inoculant-treated silages respectively, ammonia-N concentrations were 162, 91 and 176±60 g (kg total N)−1; pH's were 4·48, 3·89 and 4·45±0·046; butyric acid contents were 12·1, 1·3and 16·6g(kg DM)−1; metabolizable energy contents were 12·4, 12·2 and 1·23±0·29 MJ (kg DM)−1; silage DM intakes were 2·28, 2·49 and 2·44±0·037 kg d−1 and liveweight gains were 0·90, 0·95 and 0·97±0·023 kg d−1. For the barley, barley/soyabean meal and barley/fishmeal supplements respectively, silage DM intakes were 2·29, 2·43 and 2·49 ± 0·037 kg d−1 and liveweight gains were 0·87,0·97 and 0·99 ±0·023 kg d−1. There were no significant interactions between silage type and the supplement offered. It is concluded that silage fermentation and metabolizable energy contents were similar for the untreated and inoculant-treated silages but that silage dry matter intake and liveweight gain were significantly greater for the inoculant-treated than for the untreated silage. Further work is needed to elucidate the mode of action of this type of silage additive.

Notes: Two 2×2 factorial experiments are described in which a bacterial inoculant being developed as a silage additive and containing a strain of Lacto-bacillus plantarum (Ecosyl, ICI plc) was evaluated at two harvests (18 July and 30 September 1985) of two swards (perennial ryegrass and permanent pasture) in difficult ensiling conditions. On each occasion erbage was ensiled with and without inoculant using two 0·5–t capacity steel tower silos per treatment. The contents of the two replicate silos per treatment were combined for feeding to cross-bred wethers in digestibility and metabolizable energy (ME) partition studies.Overall, inoculated herbage declined in pH post-harvest at a faster rate than control herbage (p〈0·001) and three out of the four inoculated silages had lower pH, ammonia-N, acetate and alcohol and higher residual soluble carbohydrate content (p〈0·001) than control. Significantly higher digestibility of nutrients (P〈0·05) was found in three of the inoculant-treated silages and these also had significantly higher ME values than control (P〈0·001), (10·58 and 8·77 MJ kg tol DM−1 for the treated and untreated silages respectively). The use of inoculant on herbage of only moderate ensiling potential therefore, produced significant improvements in fermentation quality and feeding value over control.

Notes: Two 2×3 factorial design experiments were conducted during 1985 to compare the effect of treating grass at ensiling with a silage inoculant (Imperial Chemical Industries plc) or formic acid with an untreated control, on fermentation, in-silo losses, intake and performance of finishing cattle.In experiment 1, three covered concrete-walled silos were each filled with approximately 70 t of primary growth, unwilted herbage at each of two cutting dates, 20–21 May (early harvest) and 3 June 1985 (late harvest). In experiment 2, the above procedure was repeated for second regrowth grass with two cutting dates, 30 September-1 October (early harvest) and 16–21 October 1985 (late harvest). The water-soluble carbohydrate (WSC) contents of the herbage were low in both, being 130–160 and 121–137 g kg−1 DM for the first and second experiments respectively. In both experiments the formic acid-treated silages attained lower temperatures than the inoculant-treated and untreated silages. At both harvests in experiment 1 the pH, ammonia nitrogen (NH3N) and volatile fatty acid (VFA) contents of the inoculant-treated and formic acid-treated silages were significantly lower than those in the untreated silage. However, at the early harvest in experiment 2 the pH and NH3N contents of the inoculant-treated silage were significantly higher than those in the two other silages. At the late harvest in experiment 2 the inoculant-treated and the formic acid-treated silages had significantly lower pH and VFA contents than the untreated silage.After 126 d and 98 d storage periods in experiments 1 and 2 respectively, each of the six silages was offered to twelve 475 kg steers throughout a 70-d period (experiment I) and a 63-d period (experiment 2). In experiment 1 there were no significant effects of additive on silage DM intake, liveweight gain or carcass gain with the mean carcass gains being 0·49, 0·51 and 0·52±0·024 kg d−1 for the untreated, formic acid-treated and inoculant-treated silages respectively. In experiment 2 the mean silage DM intakes were 6·34, 7·33 and 6·60±0·151 kg d−1 and carcass gains were 0·27, 0·35 and 0·26±0·026 kg d−1 for the untreated, formic acid-treated and inoculant-treated silages respectively, formic acid treatment thus gave the most consistent results.

Notes: Eight field-plot experiments were carried out on established grassland swards between 1984 and 1988 to examine the effects of date and rate of application of calcium ammonium nitrate (CAN) on herbage dry matter (DM) yield and apparent efficiency of nitrogen (N) use at first-cut silage.CAN application significantly increased (P 〈0 ·001) the mean yields of herbage and N uptakes by herbage in all experiments. Herbage yields were similar (P 〉 0·05) with N rates of 100 kg ha−1, 125 kg ha−1 or 150 kg ha−1 in five experiments but in the other three there were increases above 100 kg ha−1. Date of N application had a significant effect on DM yield in three experiments; this effect was inconsistent for both single and split dressings. Lower production was associated with reduced uptake of N, a trend that primarily reflected lower DM yields and not wide herbage N content variation.It is concluded that selection of the date on which to apply fertilizer N in early spring to obtain optimum herbage yields at first-cut silage often required little precision. The use of fertilizer N rates 〉100 kg ha−1 should be questioned where there are likely to be appreciable quantities of available N derived from non-fertilizer sources.

Notes: An experiment was carried out during 1986 and 1987 to examine the effects of mid-season slurry injection and fertilizer-nitrogen (N) application on herbage dry matter (DM) yield and N recovery. Cattle and pig slurry were injected at 56 and 112 m3 ha−1 into an established sward. Five rates of fertilizer-N, as calcium ammonium nitrate, ranging from 0 to 120 kg ha−1 in 30-kg increments, were superimposed on these treatments, and in both years DM yield was measured in one cut after 70 d regrowth. Slurry treatments increased herbage DM yields significantly (P 〈 0-001). The efficiency of slurry total N compared with calcium ammonium nitrate-N averaged 53% in 1986 and 86% in 1987. The mean apparent recovery of slurry total N in herbage was 55% in 1986 and 40% in 1987. Fertilizer-N application increased (P 〈 0.001) the mean yields of herbage in both years but when combined with some of the slurry treatments, DM yields over the five N-levels did not differ significantly, giving rise to interactions in 1986 (P 〈 0-001) and 1987 (P 〈 001). It is concluded that mid-season injection of slurry can be an effective means of utilizing slurry-N in terms of herbage DM production and consequent N use.

Notes: An established sward of red clover cv. Hungaropoly sown pure received approx. 30 kg P ha-1 and 200 kg K ha-1 each year for 3 successive years. The P and K were applied either as cattle slurry, inorganic fertilizer or combinations of these. Treatments were applied either in spring or after the first harvest. There were a total of six treatments and these were harvested three times each year. The average yields of total herbage DM over all the treatments in the first, second and third years were 15·2, 14·2 and 14·2 t ha-1 respectively and the various treatments had no significant effect on the overall yields.Treatments had a significnt effect on red clover DM yields and percentage red clover in one harvest in each of the first 2 years and all three in the third year. Yields of red clover were lower and grass higher in treatments receiving cattle slurry only. On this treatment there was a total yield of 23·2 t ha-1 red clover DM in the 3 years compared with 30·2 t ha-1 on the inorganic fertilizer treatments. However, by applying P and K fertilizer in the spring, followed by cattle slurry after the first harvest, it was possible to maintain a high proportion of red clover in the sward and to produce yields of red clover DM similar to those on the inorganic fertilizer treatments.