Life cycle assessment of pasture-based suckler steer weanling-to-beef production systems: Effect of breed and slaughter age.

Demand for beef produced from pasture-based diets is rising as it is perceived to be healthier, animal friendly and good for the environment. Animals reared on a solely grass forage diet, however, have a lower growth rate than cereal-fed animals and consequently are slaughtered at an older age. This study focused on the former by conducting life cycle assessments of beef production systems offering only fresh or conserved grass, and comparing them to a conventional pasture-based beef production system offering concentrate feeding during housing. The four suckler weanling-to-beef production systems simulated were: (i) Steers produced to slaughter entirely on a grass forage diet at 20 months (GO-20); (ii) Steers produced to slaughter entirely on a grass forage diet at 24 months (GO-24); (iii) Steers produced to slaughter on a grass forage diet with concentrate supplementation during housing (GC-24), and (iv) Steers produced to slaughter entirely on a grass forage diet at 28 months (GO-28). Two breed types were evaluated: early-maturing and late-maturing (LM). The environmental impacts assessed were global warming potential (GWP), non-renewable energy (NRE), acidification potential (AP), eutrophication potential (marine (MEP) and freshwater) were expressed per animal, per kg live weight gain (LWG), kg carcass weight gain, and kg meat weight gain (MWG). The GO-20 production system had the lowest environmental impact across all categories and functional units for both breeds. Extending age at slaughter increased environmental impact across all categories per animal. The LWG response of EM steers to concentrate feed supplementation in GC-24 was greater than the increase in total environmental impact resulting in GC-24 having a lower environmental impact across categories per kg product than GO-24. Concentrate feed supplementation had a similar effect on LM steers with the exception of NRE and AP. The increase in daily LWG in the third grazing season in comparison to the second grazing and housing resulted in GO-28 having lower GWP, NRE, AP, and MEP per kg product than GO-24. Early-maturing steers had lower environmental impact than LM when expressed per kg LWG. However the opposite occurred when impacts were expressed per kg MWG, despite LM steers producing the least LWG. The LM steers compensated for poor LWG performance by having superior carcass traits, which caused the breed to have the lowest environmental impact per kg MWG. The results reaffirms the importance of functional unit and suggests reducing the environmental impact of LWG does not always translate into improvements in the environmental performance of meat.

Water footprinting of pasture-based farms; beef and sheep.

In the context of water use for agricultural production, water footprints (WFs) have become an important sustainability indicator. To understand better the water demand for beef and sheep meat produced on pasture-based systems, a WF of individual farms is required. The main objective of this study was to determine the primary contributors to freshwater consumption up to the farm gate expressed as a volumetric WF and associated impacts for the production of 1 kg of beef and 1 kg of sheep meat from a selection of pasture-based farms for 2 consecutive years, 2014 and 2015. The WF included green water, from the consumption of soil moisture due to evapotranspiration, and blue water, from the consumption of ground and surface waters. The impact of freshwater consumption on global water stress from the production of beef and sheep meat in Ireland was also computed. The average WF of the beef farms was 8391 l/kg carcass weight (CW) of which 8222 l/kg CW was green water and 169 l/kg CW was blue water; water for the production of pasture (including silage and grass) contributed 88% to the WF, concentrate production - 10% and on-farm water use - 1%. The average stress-weighted WF of beef was 91 l H2O eq/kg CW, implying that each kg of beef produced in Ireland contributed to freshwater scarcity equivalent to the consumption of 91 l of freshwater by an average world citizen. The average WF of the sheep farms was 7672 l/kg CW of which 7635 l/kg CW was green water and 37 l/kg CW was blue water; water for the production of pasture contributed 87% to the WF, concentrate production - 12% and on-farm water use - 1%. The average stress-weighted WF was 2 l H2O eq/kg CW for sheep. This study also evaluated the sustainability of recent intensification initiatives in Ireland and found that increases in productivity were supported through an increase in green water use and higher grass yields per hectare on both beef and sheep farms.

Hydrogen sulfide gas emissions during disturbance and removal of stored spent mushroom compost.

Spent mushroom compost (SMC) is a by-product of the mushroom industry that is used as an agricultural fertilizer. In Europe, SMC storage and use are governed by EU Nitrates Directive 91/676/EEC to protect waterways against pollution by nitrates. A health and safety risk was identified during the removal of stored SMC for land application, as the stored SMC released high levels of toxic H2S gas into the atmosphere when disturbed. In this study, emissions of H2S were monitored at two outdoor and two indoor locations where stored SMC was being removed for land application. A repeating peak-trough pattern of H2S emissions was detected at all sites, with peaks corresponding to periods of active disturbance of SMC. The highest H2S concentrations (10 s average) detected at the SMC face were, respectively, 680 and 2083 ppm at outdoor sites 1 and 2, and 687 and 89 ppm at indoor sites 3 and 4. Higher concentrations of H2S were released from older SMC compared to newer material. Indoor-stored SMC had lower moisture content (53% to 65%) compared to outdoor-stored material (66% to 72%), while the temperature of indoor-stored SMC was higher (33 degrees C to 51 degrees C) compared to outdoor-stored material (24 degrees C to 36 degreees C). The current short-term exposure limit (STEL) of 10 ppm was exceeded at all sites except site 4, which was smaller than the other sites, indicating a significant health and safety risk associated with working in the vicinity of stored SMC when it is being actively disturbed. Results suggest that SMC stored under cover in small heaps (600 m3) emits less H2S during disturbance and removal compared to SMC stored outdoors in large heaps (> 1500 m3). This should be taken into consideration in the design, construction, and management of SMC storage facilities. Health and safety protocols should be in place at SMC storage facilities to cover the risks of exposure to toxic H2S gas during disturbance of stored SMC.

Hydrogen sulfide gas emissions in the human-occupied zone during disturbance and removal of stored spent mushroom compost.

Hydrogen sulfide (H2S) gas levels were monitored in the human-occupied zone at four spent mushroom compost (SMC) storage sites during removal of SMC for application on agricultural land. During SMC removal operations, H2S gas monitors were mounted on the outside of the tractor positioned at the SMC periphery, and worn by individual tractor drivers. The highest H2S concentrations (10 s average) detected outside the tractor, at the SMC periphery, and for the tractor driver were, respectively, 454, 249, and 100 ppm for the outdoor sites and 214, 75, and 51 ppm for the indoor sites. The highest short-term exposure values (STEV over a 15 min period) outside the tractor at the SMC periphery, and for the tractor driver were 147, 55, and 86 ppm for the outdoor sites and 19, 9, and 10 ppm for the indoor sites. The values exceeded the current maximum permissible concentration limit of 10 ppm for all the sites except for the SMC periphery and tractor driver at the indoor sites. Results suggest that H2S levels detected at indoor storage sites during SMC removal are lower compared to outdoor storage sites. Results indicate that there is a substantial health and safety risk associated with working in the vicinity of stored SMC when it is being disturbed and removed for land application, and that the risk is great for the tractor driver. This article discusses possible control measures and lists recommendations to reduce the risks.

Evaluation of the odour reduction potential of alternative cover materials at a commercial landfill.

The availability of virgin soils and traditional landfill covers are not only costly and increasingly becoming scarce, but they also reduce the storage capacity of landfill. The problem can be overcome by the utilisation of certain suitable waste streams as alternative landfill covers. The objective of this study was to assess the suitability of Construction & Demolition fines (C&D), Commercial & Industrial fines (C&I) and woodchip (WC) as potential landfill cover materials in terms of odour control. Background odour analysis was conducted to determine if any residual odour was emitted from the cover types. It was deemed negligible for the three materials. The odour reduction performance of each of the materials was also examined on an area of an active landfill site. A range of intermediate cover compositions were also studied to assess their performance. Odour emissions were sampled using a Jiang hood and analysed. Results indicate that the 200 mm deep combination layer of C&D and wood chip used on-site is adequate for odour abatement. The application of daily cover was found to result in effective reduction allowing for the background odour of woodchip.

The effect of cereal type and enzyme addition on pig performance, intestinal microflora, and ammonia and odour emissions.

Two 2 × 2 factorial experiments were conducted to investigate the interaction between cereal type (wheat v. barley) and exogenous enzyme supplementation (with or without) on odour and ammonia emissions (experiment 1) and growth performance (experiment 2) in grower-finisher pigs. The enzyme supplement used contained endo-1, 3 (4) - ß- glucanase (EC 3.2.1.6) and endo-1, 4 - ß-xylanase (E.C 3.2.1.8). The diets were formulated to contain similar levels of net energy (9.8 MJ/kg) and lysine (10.0 g/kg). The experimental treatments were as follows: (1) wheat-based diet, (2) wheat-based diet containing a ß-glucanase and ß-xylanase mixed enzyme supplement, (3) barley-based diet and (4) barley-based diet containing a ß-glucanase and ß-xylanase mixed enzyme supplement. In experiment 1, the diets were offered to the pigs for 23 days in sealed pens (eight pigs per pen) and this was repeated four times (n = 4). Odour and ammonia emissions were measured on days 9, 11, 14, 16, 21 and 23 of each replicate period. Odour samples were collected in 20-l Nalophan bags and analysed for odour concentration using an ECOMA Yes/No Olfactometer. Ammonia concentrations in the ventilation air were measured using Dräger tubes. In experiment 2, 220 pigs were group fed in mixed sex pens using single-space feeders (11 pigs per feeder, six boars and five gilts) (n = 5). There was a cereal × enzyme interaction in odour emission rates, ammonia emissions and selected microbial populations in the caecum and colon (P < 0.05). The addition of an enzyme supplement to the barley-based diet increased both odour and ammonia emission, however the addition of an enzyme to the wheat-based diet decreased ammonia emission rates and had no effect on odour emission. Pigs offered the unsupplemented barley-based diet had a significantly (P < 0.05) lower population of Enterobacteriaceae spp. and a higher population of Bifidobacteria spp. compared with enzyme-supplemented barley diets. However, there was no effect of enzyme supplementation in wheat-based diets. In the performance experiment, neither cereal type nor enzyme inclusion had an effect on pig performance or carcass characteristics. In conclusion, the inclusion of an enzyme mix to barley-based diets increased odour and ammonia emissions, while the addition of an enzyme mix to wheat-based diets decreased ammonia emissions.

Odour and ammonia emissions from intensive poultry units in Ireland.

Odour and ammonia emissions were measured from three broiler, two layer and two turkey houses in Ireland. The broiler units gave a large range of odour and ammonia emission rates depending on the age of the birds and the season. A considerable variation between the odour and ammonia emission rates was evident for the two layer units which may have been due to the different manure handling systems utilised in the houses. There was relatively little difference in the odour and ammonia emissions from the two turkey houses. As a precautionary principle, odour emission rates utilised in atmospheric dispersion models should use the maximum values for broilers and turkeys (1.22 and 10.5 ou(E) s(-1) bird(-1) respectively) and the mean value for the layers depending on the manure handling system used (0.47 or 1.35 ou(E) s(-1) bird(-1)).

Odour and ammonia emissions from intensive pig units in Ireland.

Odour and ammonia emissions were measured at four intensive pig units in Ireland. Odour samples were collected on-site and analysed for odour concentration using an olfactometer. Ammonia concentrations in the exhaust ventilation air were measured using a portable sensor. The geomean odour emission rates over the four pig units were 17.2, 44.4, 4.3, 9.9 and 16.8 ou(E) s(-1) animal(-1) for dry sows, farrowing sows, first stage weaners, second stage weaners and finishers, respectively. The mean ammonia emission rates, measured at two of the units, were 12.1, 17.1, 1.4, 2.9 and 10.0 g d(-1) animal(-1) for dry sows, farrowing sows, first stage weaners, second stage weaners and finishers, respectively. In general, the odour and ammonia emission rates were comparable to those reported in literature, although some odour emission rate figures were noticeably lower for finishing pigs in this study. The variability in the data highlights the need for individual site assessment.

A dispersion modelling approach to determine the odour impact of intensive poultry production units in Ireland.

The use of atmospheric dispersion modelling has become more common for the determination of odour impacts from existing poultry production facilities and the assessment of setback distances for new facilities. Setback distances for broiler, layer and turkey units were determined using the atmospheric dispersion model ISCST3 and the Environmental Protection Agency (EPA, Ireland) recommended criterion (C(98,1-h)6.0 ou(E) m(-3)) and a new odour annoyance criterion (C(98,1-h) 9.7 ou(E) m(-3)) developed in this study. For a typical size unit in Ireland, maximum setback distances of 660, 665 and 1035 m were calculated for 40,000 broilers, 40,000 layers and 10,000 turkeys respectively at the current limit (C(98,1-h) 6.0 ou(E) m(-3)). However, if the suggested odour impact criterion (C(98,1-h) 9.7 ou(E) m(-3)) is implemented, the maximum setback distances decrease to 460, 500 and 785 m for broilers, layers and turkeys, respectively.

The influence of diet crude protein level on odour and ammonia emissions from finishing pig houses.

Feed trials were carried out to assess the influence of crude protein content in finishing pig diets on odour and ammonia emissions. Eight pigs (4 boars and 4 gilts), average initial weight 70.8 kg (s.e. 3.167) were housed in two pens that were isolated from the rest of a pig house at University College Dublin Research Farm, Newcastle, Dublin, Ireland. Four diets containing 130, 160, 190 and 220 g x kg(-1) crude protein were fed during six four-week feeding periods (one treatment per room). The first week of the feeding periods served to allow odour build up in the pens and as a dietary adjustment period. The pens had partially slatted floors that were cleaned and had all the manure removed after each four-week period. Odour and ammonia concentrations were measured on days 9, 14, 16, 21 and 23 of each trial period. Odour samples were collected in Nalophan bags and analysed for odour concentration using an ECOMA Yes/No olfactometer. The odour threshold concentration was calculated according to the response of the olfactometry panel members and was displayed in Ou(E)m(-3), which referred to the physiological response from the panel equivalent to that elicited by 40 ppbv(-1) n-butanol evaporated in 1 m(3) of neutral gas. Ammonia concentrations in the ventilation air were measured using Dräger tubes. The odour emission rates per animal for the 130, 160, 190 and 220 g x kg(-1) crude protein diets were 12.1, 13.2, 19.6 and 17.6 Ou(E)s(-1)animal(-1), respectively (P<0.01). The odour emission rate per livestock unit (500 kg) for the 130, 160, 190 and 220 g x kg(-1) crude protein diets were 77.6, 80.0, 115.8 and 102.9 Ou(E)s(-1)LU(-1), respectively (P<0.01). The ammonia emission rates per animal for the 130, 160, 190 and 220 g x kg(-1) crude protein diets were 3.11, 3.89, 5.89 and 8.27 g x d(-1)animal(-1), respectively (P0.05). Manipulation of dietary crude protein levels would appear to offer a low cost alternative, in relation to end-of-pipe treatments, for the abatement of odour and ammonia emissions from finishing pig houses.

A dispersion modelling approach to determining the odour impact of intensive pig production units in Ireland.

It is becoming more common now to use atmospheric dispersion models to predict where odour nuisance is likely to occur near pig units. An odour threshold concentration of 1 OuE m(-3) is the level at which an odour is detectable by 50% of screened panellists. A new odour annoyance criterion (C(98,1-h) (98%-ile, 1-h average odour concentration) < or = 4.3 OuE m(-3)) was developed in this study and compared to the Environmental Protection Agency (EPA) (Ireland) recommendation (C(98,1-h)< or = 6 OuE m(-3)) using the ISCST3 model with data from three meteorological stations. Abatement techniques such as exhaust vent modification, feed manipulation, and biofiltration were assessed. Based on current limits (C(98,1-h)< or = 6 OuE m(-3)) for existing facilities, predicted setback distances can be up to 780 m for a 1000-sow unit, depending on which meteorological data set is used. However, if using the suggested odour impact criterion in this research (C(98,1-h)< or = 4.3 OuE m(-3)), setback distances could reach a maximum of 1000 m. Biofilters on second stage weaning and finishing pig buildings offer the greatest single reduction (up to 650 m) in odour impact. When combined with feed manipulation and increased exhaust air velocity, the figure can be as high as 920 m. Due to the critical requirement for local meteorological data, it is recommended that a meteorological station be installed on large pig units to facilitate more accurate predictions. Site measurements of odour emissions should be made in each case because emissions are influenced by a range of local factors including feed, manure management, building design and operation.

Biofiltration of n-butyric acid for the control of odour.

Odour control from pig production facilities is a significant concern due to increased public awareness and the development of more stringent legislation to control production. Although many technologies exist, biofiltration is still the most attractive due to its low maintenance and operating costs. One of the key odour components, n-butyric acid, was selected for a laboratory scale biofilter study. It was examined as a sole carbon substrate in order to investigate the effectiveness of biofiltration in reducing n-butyric acid concentration under different operating conditions using a moist enriched woodchip medium. Three superficial gas velocities; 38.2, 76.4, and 114.6 m x h(-1) were tested for n-butyric acid concentrations ranging from 0.13 to 3.1 g [n-butyric acid] m(-3) [air]. For superficial gas velocities 38.2, 76.4, and 114.6 m x h(-1), maximum elimination capacities (100% removal) of 148, 113 and 34.4 g x m(3) x h(-1), respectively, were achieved. Upon investigation of effective bed height, true elimination capacities (100% removal) of 230, 233 and 103 g x m(-3) x h(-1), respectively, were achieved at these superficial gas velocities. Averaged pressure drops for superficial gas velocities 38.2, 76.4, and 114.6 m x h(-1) were 30, 78 and 120 Pa, respectively. It was concluded that biofiltration is a viable technology for the removal of n-butyric acid from waste exhaust air, but near 100% removal efficiency is required due to the low odour detection threshold for this gaseous compound.

Assessment of the influence of media particle size on the biofiltration of odorous exhaust ventilation air from a piggery facility.

Two pilot scale biofiltration systems were constructed and installed at the University College Dublin Research Farm, Lyons Estate. Experimental units consisting of two pens in a 12 pen pig house were sealed off from other pens. Air from each pen was extracted and treated separately in two biofiltration systems. Wood chips larger than 20 mm were selected as the medium for biofiltration system 1, whereas chips of between 10 and 16 mm were used in biofiltration system 2. The moisture content of the media was maintained at 69+/-4% (w.w.b.) using a load cell method. The volumetric loading rates ranged from 769 to 1847 m3 [gas] m(-1) [medium] h(-1) over a 63-day experimental period. Both biofilters reduced odour between 88% and 95%. Ammonia removal efficiencies ranged from 64% to 92% and 69% to 93%, for biofiltration systems 1 and 2, respectively. Sulphur-containing compounds were reduced between 9-66%, and -147-51% across biofiltration systems 1 and 2. The pH of the biofilters' leachate remained between 6 and 8. Pressure drop for biofilter 2 was 16 Pa greater than that of biofilter I at the maximum volumetric loading rate of 1847 m3 [gas] m(-3) [medium] h(-1). It is recommended that a wood chip media particle size greater than 20 mm be used for large scale operation of a biofiltration system on intensive pig production facilities to reduce the development of anaerobic zones and to minimize pressure drop on the system fans.

A short synthesis of bicyclic dipeptides corresponding to Xxx-L-Pro Xxx-D-Pro having constrained trans-proline amides.

[formula: see text] A short synthesis that generates two isomeric bicyclic dipeptides having constrained, trans-proline amide bonds has been developed. One of these bicyclic dipeptides corresponds to an Xxx-L-Pro dipeptide (4), while the other isomer corresponds to an Xxx-D-Pro dipeptide (5). The two isomers are readily distinguished by their 1H NMR spectra.

Modulation of the activity of angiogenin by mutagenesis at Asp-116.

Substitution of Asn, Ala or His for Asp-116 in angiogenin increases its ribonucleolytic activity towards tRNA and, at least in the case of His, its ability to induce blood-vessel formation (Harper, J.W. and Vallee, B.L. (1988) Proc. Natl. Acad. Sci. USA 85, 7139-7143). Six additional Asp-116 mutants have been examined to further probe the basis for this phenomenon. Substitution of Val, Lys, Glu, or Ser increases activity towards tRNA 2-, 4-, 9- and 16-fold, respectively, whereas substitution of Trp and Pro leads to 2- and 10-fold decreases, respectively. Similar changes are seen in activity towards rRNA. Studies of base-cleavage specificity towards dinucleotide substrates (NpN') reveal a change in preference for G vs. A at the N' position when Ser replaces Asp-116 and a diminished preference for C vs. U at the N position. The Pro, Lys and Glu mutants have essentially unchanged angiogenic activity. The results demonstrate that the principal effect of replacing Asp-116 in angiogenin is to modulate enzymatic activity, possibly through an effect on His-114, and suggest that Asp-116 plays a role in controlling specificity.

Alteration of the enzymatic specificity of human angiogenin by site-directed mutagenesis.

The molecular basis for the enzymatic specificity of human angiogenin has been investigated by site-directed mutagenesis of Thr-44, Glu-108, and Ser-118--residues corresponding to those thought to be involved in substrate base recognition in the homologous protein, RNase A. Mutations of Thr-44 to Ala, His, and Asp affect both activity and specificity dramatically. The Ala and His replacements decrease activity toward tRNA by factors of 25 and 40, respectively, and reduce cleavage of cytidylyl more than uridylyl dinucleotides. Substitution by Asp does not influence the rate of tRNA and rRNA degradation but alters specificity even more markedly than the other mutations: T44D-angiogenin has 17-40-fold decreased activity toward CpN' dinucleotides and 1.3-1.9-fold increased activity toward UpN', resulting in an inverted order of preference (U > C) compared to native angiogenin. Mutations of Glu-108 to Lys and Gln change activity toward RNA and dinucleotides by no more than 50% and produce slight increases in preference for adenosine vs guanosine at position N' of NpN' substrates. Mutations of Ser-118 to Asp and Arg have a larger effect, decreasing activity by factors of approximately 2 and 4, respectively, toward all substrates examined. These results indicate that: (i) Thr-44 is important for recognition of the pyrimidine moiety at position N, (ii) Glu-108 may make a small contribution to binding the N'-nucleotide, and (iii) Ser-118 has a minor functional role, which appears to involve catalysis rather than nucleotide binding.(ABSTRACT TRUNCATED AT 250 WORDS)