Methane emissions of differently fed dairy cows and corresponding methane and nitrogen emissions from their manure during storage

This study investigated the effects of supplementing 40 g lauric acid (C₁₂) kg^-1 dry matter (DM) in feed on methane emissions from early-lactating dairy cows and the associated effects on methane, nitrous oxide and ammonia release from the manure during storage. Stearic acid (C₁₈), a fatty acid without assumed methane-suppressing potential in the digestive tract of ruminants, was added at 40 g kg^-1 DM to a control diet. The complete feed consisted of forage and concentrate in a ratio of 1.5:1 (DM basis). The manure was stored for 14 weeks either as complete slurry or, separately, as urine-rich slurry and farmyard manure representing two common storage systems. Methane release of the cows, as measured in respiratory chambers, was lower with C₁₂ by about 20%, but this was mostly resulting from a reduced feed intake and, partly, from a lower rate of fibre digestion. As milk yield declined less than feed intake, methane emission per kg of milk was significantly lower with C₁₂ (11.4 g) than with C₁₈ (14.0 g). Faeces of C₁₂-fed cows had a higher proportion of undigested fibre and accordingly methane release from their manure was higher compared with the manure obtained from the C₁₈-fed cows. Overall, manure-derived methane accounted for8.2% and 15.4% of total methane after 7 and 14 weeks of storage, respectively. The evolution of methane widely differed between manure types and dietary treatments, with a retarded onset of release in complete slurry particularly in the C₁₂ treatment. Emissions of nitrous oxide were lower in the manures from the C₁₂ treatment. This partially compensated for the higher methane release from the C₁₂ manure with respect to the greenhouse gas potential. The total greenhouse gas potential (cow and manure together) accounted for 8.7 and 10.5 kg equivalents of CO₂ cow^-1 d^-1with C₁₂ and C₁₈, respectively. At unaffected urine-N proportion ammonia and total nitrogen losses from stored manure were lower with C₁₂ than with C₁₈ corresponding to the differences in feed and nitrogen intake. The present results suggest that manure storage significantly contributes to total methane emission from dairy husbandry, and that the identification of effective dietary mitigation strategies has to consider both the digestive tract of the animals and the corresponding manure.     

Nitrogen turnover on organic and conventional mixed farms

Separate focus on crop fertilization or feeding practices inadequately describes nitrogen (N) loss from mixed dairy farms because of (1) interaction between animal and crop production and between the production system and the manager, and (2) uncertainties of herd N production and crop N utilization. Therefore a systems approach was used to study N turnover and N efficiency on 16 conventional and 14 organic private Danish farms with mixed animal (dairy) and crop production. There were significant differences in N surplus at the farm level (242 kg. N/ha. vs. 124 kg. N/ha. on conventional and organic dairy farms respectively) with a correlation between stocking rate and N surplus. N efficiency was calculated as the output of N in animal products divided by the net N import in fodder, manure and fertilizer. N turnover in herd and individual crops calculated on selected farms showed differences in organic and conventional crop N utilization. This is explained via a discussion of the rationality behind the current way of planning the optimum fertilizer application in conventional agriculture. The concept of marginal N efficiency is insufficient for correcting problems of N loss from dairy farms. Substantial reductions in N loss from conventional mixed dairy farms is probably unlikely without lower production intensity. The concept of mean farm unit N efficiency might be a way to describe the relation between production and N loss to facilitate regulation. This concept is linked to differing goals of agricultural development—i.e. intensification and separation vs. extensification and integration. It is discussed how studies in private farms—using organic farms as selected critical cases—can demonstrate possibilities for balancing production and environmental concern.     

Methane emissions during storage of different treatments from cattle manure in Tianjin

Many studies on methane emissions from animal manure have revealed that animal manure is a major source of methane emissions to the atmosphere that can have negative consequences for people,animals and environment.In general,the release of methane can be influenced by the type of feed taken by animals,temperature,manure characteristics and so on.This study aimed at quantifying and comparing methane release from dairy manure with different piling treatments.Four treatments were designed including manure piling height 30,45,60 cm and adding 6 cm manure every day until the piling height was 60 cm.Static chamber method and gas chromatography were adopted to measure the methane emissions from April to June in 2009.Methane emission rates of all four manure treatments were low in the first week and then increased sharply until reaching the peak values.Subsequently,all the methane emission rates decreased and fluctuated within the steady range till the end of the experiment.Wilcoxon nonparametric tests analysis indicated that methane emission rate was greatly influenced by manure piling height and manner.There were no significant relationships between methane emission rates and the temperatures of ambience and heap.However,regression analysis showed that the quadratic equations were found between emission rates of all treatments and the gas temperature in the barrels.     

Holy Cows: A Look at the Influence of Religious Beliefs on Dairy Animal Welfare on Kibbutzim in Israel

The influence of religious beliefs on people's attitudes andactions in the area of animal welfare was examined by interviewing dairyworkers on kibbutzim (communal agricultural settlements) in Israel.Workers on religiously observant kibbutzim were no more consistent intheir attitudes toward and treatment of dairy cows than workers onnon-observant and selectively observant kibbutzim.     

新西兰氮排放配额与交易制度对中国的启示——以奶牛养殖业为例

近年来,排污权有偿使用与交易制度在中国部分省份开展了试点工作,许多大型的规模化畜禽养殖场也进行了排污许可证的申领。针对新西兰奶牛养殖业的污染治理措施进行了研究,梳理其开展污染防治工作的措施体系,以陶泊湖周边施行的氮排放配额与交易为主要对象,阐述了新西兰在养殖业排放配额与交易制度方面的工作实践,其配额基准核定方法、"资源许可证"申领制度、配额交易体系、相关支撑措施在一定程度上具备优势和先进性,对中国的畜禽养殖污染减排工作具有借鉴意义。     

Thermochemical characteristics of dairy manure and its derived biochars from a fixed-bed pyrolysis

Based on the data on the thermogravimetric analysis (TGA), oven-dried dairy manure was performed at moderate temperatures (673–1,073 K) with proper residence time of 60 min by a vertical fixed-bed pyrolyzer. The thermochemical properties of the dairy manure and its biochar products, such as elemental analysis and calorific value (higher heating value), were investigated to evaluate their potential use as biomass fuel. Furthermore, the true densities of the manure-derived biochars were also obtained to relate the property with their thermochemical properties. It showed that the calorific value of the dairy manure-derived biochar (denoted as DMBC) was on increasing trend with temperature, while its maximal increase occurred at around 873 K. This result was in high agreement with the data on the yields and carbon contents of DMBC products. By contrast, their contents of H, N, and O decreased slightly due to the devolatilization because of thermal decomposition reactions like depolymerization and carbonization. The optimal manure-derived biochar revealed an excellent characterization with high content of carbon (60 wt%) and calorific value (22.3 MJ/kg), low contents of nitrogen (0.5 wt%), and no traces of sulfur and heavy metals, suggesting that DMBC can be used as a solid fuel for energy use.     

The efficiency of electrocoagulation in treating wastewater from a dairy industry,Part I: Iron electrodes

Iron electrodes were used for electrocoagulation (EC) treatment of wastewater from a dairy plant. Electrolysis time, pH, current density and distance between electrodes were considered to assess the removal efficiency of chemical oxygen demand (COD), total solids (TS) and their fractions and turbidity. Samples were collected from the effluent of a dairy plant using a sampling methodology proportional to the flow. The treatments were applied according to design factorial of half fraction with two levels of treatments and three repetitions at the central point. The optimization of parameters for treating dairy industry effluent by electrocoagulation using iron electrodes showed that electric current application for 15 minutes, an initial sample pH close to neutral (pH 7.0) and a current density of 50 A ^{. m?2} resulted in a significant reduction in COD by 58 %; removal of turbidity, suspended solids and volatile suspended solids by 95 %; and a final treated effluent pH of approximately 9.5. Negative consequences of the type of electrode used were the emergence of an undesirable color and an increase in the proportion of dissolved solids in the treated effluent.     

Health and Welfare in Danish Dairy Cattle in the Transition to Organic Production: Problems, Priorities and Perspectives

During the past few years,organic dairy farming has grown dramatically inDenmark. Consequently, an increasing number ofpeople are encountering this method ofproduction for the first time. Amongst these,many veterinarians have suddenly had to dealwith organic herds in their home district, and,meeting examples of poor animal welfare, theyhave recently started to express some concerns.Against this background, a so-called``Synthesis of Knowledge' project was initiatedto examine the health and welfare of dairycattle and the use of medication in thetransition to organic production. The aim ofthe project was to investigate associatedproblems from the point of view of the dairyherd. Based on qualitative research interviewswith vets and agricultural advisors, as well asfocus group interviews with farmers who hadrecently converted from conventional to organicfarming, an expert panel attempted to identifyproblem areas and possible solutions. Theproblems related to (a) the adjustment to newand unknown practices, (b) poor management ingeneral, and (c) inappropriate legislation fororganic farming.One problem area was the rearing of dairycalves, particularly with regard to theestablishment of post partumrelationships between cow and calf, grouphousing, and the grazing of young animals. A``natural life' was identified as beingfundamental to organic animal husbandry. Interms of animal welfare, this concept can beunderstood as a way of living in which the calfis allowed to express its natural behavior andsatisfy its natural needs. Essentially, theconditions needed for good calf welfare requirethe compatibility and interplay of elementsfrom ``nature' (the natural life; includingopportunities to satisfy natural needs) and``culture' (farmer management skills; exerciseof care). These elements should be balanced toensure animal welfare in organic herds.     

Veterinary drugs in groundwater in a dairy region of central Argentina and risk assessment for human health

Veterinary drugs used in dairy production are potential contaminants of surface or groundwater sources, being able to affect human and environmental health. It is known that chronic exposure to antibiotics in low concentrations present in water can generate microbial resistance. This study aimed to evaluate the presence of veterinary drugs in 53 groundwater samples used for animal and human consumption, collected in dairy milking parlors, in an important milk-producing area of central Argentina, and to assess the risk to human health when they are used as drinking water. In 75% of the total samples analyzed, at least one veterinary drug was detected. The most frequently found drugs in water samples were the antibiotics tetracycline in 58.5% and oxytetracycline in 56.6%, and an anti-inflammatory, flunixin in 39.6%. In the water samples, the tetracycline and oxytetracycline concentrations were between 0.1 and 5.3 μg/L and flunixin concentrations were between 0.01 and 2.1 μg/L. The frequency of appearance and the concentration levels of the substances found in the water samples were evaluated according to the productivity, size, and production system (confined or pasture) of the dairy farms. Higher concentrations and proportions of water samples containing antibiotics were observed when the number of animals per dairy farm was >182 and when the productivity was high (>25 liters per animal per day). In the case of flunixin, the percentage of detection was similar in all evaluated categories. The risk assessment for children and adults, considering the intake of drinking water containing residues of these drugs, did not indicate a significant health risk. It would be advisable to evaluate other sources of drinking water, both surface and underground, in other regions of the country, to provide data to assess the impact of these substances and the other contaminants on environmental and human health.     

Preliminary studies on occurrence of monensin antibiotic in Bosque River Watershed

Water quality impact due to excessive nutrients has been extensively studied. In recent years, however, micro-pollutants such as pharmaceuticals and hormonal products used in animal agriculture have added an additional impact to overall water quality. Pharmaceuticals used in the poultry, swine, beef, and dairy industries have been detected in various environmental matrices such as, soil, groundwater and surface water. In this study, 26 surface water samples were collected throughout the Bosque River Watershed (BRW) with samples representing a range of land use conditions and locations of major dairy operations. Samples were analyzed using commercially available Enzyme-Linked Immunosorbent Assay test. Of the 26 samples, three samples consistently tested positive for monensin antibiotic with concentration ranging from 0.30 to 3.41 μg/L. These three samples were collected from sites that received varying amount of agriculture wastes (11.7% to 31.3%) and located downstream from sites associated with moderate levels of animal agriculture. The preliminary results suggest that there is a potential for monensin occurrence in the BRW, although initial findings indicate only very low levels.