In-silo Losses Research Articles

Effect of invasive slug populations (Arion vulgaris) on grass silage: I. Fermentation quality, in-silo losses and aerobic stability

This study aimed to explore how invasive slug populations of Arion vulgaris influence fermentation quality, in-silo losses and aerobic stability of grass silage, and the efficiency of silage additives and wilting to improve the quality of silages from slug contaminated crops. The effect of four levels, including control, of a slug contaminated grass crop, was evaluated in laboratory scale. The crop used was wilted to two dry matter (DM) levels: low (253g DM/kg) and high (372g DM/kg). Adult slugs were applied to the low DM crop corresponding to 5 (low level), 10 (medium) and 20 (high level) 7-g sized A. vulgaris per m2 in an assumed harvested regrowth yield of 2.5ton DM per ha. For the high DM crop, the applied slug levels corresponded to 6 (low level), 12 (medium) and 24 (high level) slugs per m2.At low DM level, the effect of four additive treatments, control (C), inoculation with Lactobacillus plantarum (LP), a formic, propionic and benzoic acid mixture (ACID) and a chemical additive containing benzoic acid, NaNO2, hexamethylenetetramine and propionic acid (CHEM) were tested. Increasing slug contamination gave increasing quality reductions both in silages containing 253 and 372g DM/kg. Compared with untreated silage, LP-treatment did not improve silage fermentation quality of contaminated crops. Treatment with ACID and CHEM, however, considerably improved the quality of heavily contaminated silages. The much higher crude protein concentration in slugs compared to grass crop made slugs a more “difficult-to-ensile” material. Wilting of the harvested crop to 372g DM/kg was not sufficient to control silage fermentation of slug contaminated crop. With contamination levels from 138 to 553g fresh slug weight/kg crop DM, efficient silage additives were able to ensure acceptable fermentation quality of grass silages.

The Effect of In-Silo Effluent Absorbents on Effluent Production and Silage Quality

Experimental data on the effects of absorbent inclusion in the silo on effluent production and silage quality is reviewed. The absorbent materials used in various studies include straw, hay, paper, bentonite, polymers, cereals, dried sugarbeet pulp, various by-products and compound feeds formulated to reduce effluent and enhance silage quality. Most studies have shown absorbent inclusion (20–80 kg/t) to reduce total effluent production by 20–85%. The amount of effluent retained per unit of absorbent varied widely for different absorbents and for the same absorbent in different experiments. This variation cannot be attributed simply to differences in experimental procedures and implies that crop characteristics such as proportion of stem, amount of surface water, etc. influence the effectiveness of absorbents. Highly lignified materials (hay, straw, newspaper) and absorptive minerals (bentonite), though highly absorptive, adversely affect nutritive quality and are unlikely to find application in current conservation systems. The inclusion of cereals in the silo has generally improved fermentation and nutritive quality but their effectiveness as absorbents is questioned in several experiments. Inclusion of dried sugarbeet pulp has almost invariably reduced effluent production although the amount retained has varied widely between experiments. Sugarbeet inclusion improved fermentation and reduced losses when the untreated grass was poorly fermented. Silage quality was improved by sugarbeet inclusion; the overall efficiency of inclusion, compared to supplementary feeding, appears to depend on the extent to which sugarbeet inclusion influences in-silo losses and silage intake. The results repeated for proprietary absorbents have been generally similar to those for sugarbeet. The evidence available suggests that incorporation of sugarbeet or proprietary absorbents in the silo would be beneficial, particularly if the untreated crop is likely to be poorly fermented. The main factors mitigating against these or other absorbents is the unpredictability of effluent retention and the additional labour, resources and silo space required at harvest time.

Effect of incorporating rolled barley in autumn-cut ryegrass silage on effluent production, silage fermentation and cattle performance

SUMMARYDirect-cut silage was made in mid-October 1985 from established swards of predominantly hybrid ryegrass (Lolium perenne x Lolium multiflorum). The crop contained 161 g dry matter/kg and 94 g soluble carbohydrate/kg and was ensiled in bunker silos with (i) no additive (control), (ii), formic acid (5 litres/t) or (iii) addition of 45 kg rolled barley per tonne of grass in silo.The inclusion of barley reduced effluent production to 27 litres/t of ensiled grass compared with 51 litres for the control and 60 litres for the formic acid treatment. Losses of DM in effluent were small but total in-silo DM loss was reduced from 25 % for the control to 11% by formic acid and to 13% by inclusion of barley.DM content of the silage containing barley was 30 g/kg higher than that of the other silages. Silage treated with formic acid contained least ammonia-N, 6% of the total N, compared with 9% in the barley-added silage and 11% in the control. In vivo assessment in sheep gave metabolizable energy values of 98, 10·9 and 11middot;2 MJ/kg for the control, formic and barley silages, respectively; N retention was higher in the formic acid and barley-added silages.The silages were fed ad libitum to beef cattle for 8 weeks, with a daily feed supplement to the control and formic acid groups to equate barley intakes. Silage DM intake was higher for the barley silage, daily live weight gain per animal was similar for the barley-added and formic acid silages (c. 1 kg), both being higher than the control (0·8 kg).It was concluded that barley inclusion achieved similar improvements in silage quality, in-silo losses and cattle performance to formic acid treatment but with the additional benefit of markedly reducing effluent production.

The effect of system of harvesting grass for silage on the output of silage and milk per hectare

SummaryFour systems of harvesting grass for silage were evaluated in terms of in-field losses, in-silo losses and milk output per hectare. The systems were: single-chop flail harvester direct cutting (SCD); doublechop flail harvester direct cutting (DCD); mown with a rotary mower and picked up with a precisionchop harvester either immediately (PCU) or after wilting until the dry-matter concentration had increased by approximately 100 g/kg (PCW). The in-field and in-silo losses were measured at each of three consecutive harvests during 1984 and during the following winter the resulting silages were evaluated through eight British Friesian cows in a balanced change-over design experiment using four periods each of 5 weeks duration.There was a greater quantity of herbage ensiled with the two direct cutting systems (SCD and DCD) than with the systems involving pre-mowing and picking up with the ensiled yields, being 12·4, 11·8, 10·8 and 10·8t OM/ha for the SCD, DCD, PCU and PCW systems respectively. These differences were only partly reflected in greater mechanical in-field losses with the pre-mown systems.Losses during the in-silo period tended to be greater with the wilted than the unwilted silages being 98, 76, 83 and 132 g/kg OM with the SCD, DCD, PCU, and PCW systems, respectively.Animals offered the PCW silage tended to have a higher silage organic-matter intake and had a significantly higher milk yield than those offered the other silages with fat corrected milk yields being 25·1, 24·5, 24·5 and 25·9 kg/day for the SCD, DCD, PCU and PCW systems, respectively. Milk outputs per hectare, at 30·3, 27·8, 25·7 and 240 for the SCD, PCD, PCU and PCW systems respectively, was lowest for the PCW treatment.

The effect of system of harvesting grass for silage on in-field and in-silo losses and milk output per hectare

There has been considerable research into individual components of harvesting systems in terms of their effects on nutritive value and animal performance. However few studies have examined total harvesting systems, involving in-field and in-silo losses, nutritive value of the product and the effects on animal output per hectare. The present study was set up to examine these effects.Four systems of harvesting grass for silage were compared over each of 3 harvests during 1984. The systems were: single chop flail harvester direct cutting (SCD); double chop flail harvester direct cutting (DCD); mown with a rotary mower and picked up with a precision chop harvester either immediately (PCD) or after wilting until the dry matter concentration had increased by approximately 100 g kg-1 (PCW). The field wilting periods for PCW were 48, 48 and 24 hrs for the 1st, 2nd and 3rd harvests respectively.