Nutritional and environmental effects on ammonia emissions from dairy cattle housing: A meta-analysis

Nitrogen (N) excreted in urine by dairy cows can be potentially transformed to ammonia (NH3) and emitted to the atmosphere. Dairy production contributes to NH3 emission, which can create human respiratory problems and odor issues, reduces manure quality, and is an indirect source of nitrous oxide (N2O). The objective of this study was to (i) investigate environmental factors and measurement method that influence NH3 from dairy housing, and (ii) identify key explanatory variables in the prediction of NH3 emissions from dairy barns using a meta-analytical approach. Data from 25 studies were used for the preliminary analysis and data from 10 studies reporting 87 treatment means were used for the meta-analysis. Season, flooring type, manure handling and housing type and system significantly affected NH3 emission rates as well as the measurement method used to quantify the NH3 emission. Ammonia emissions rates from open-lot and scrape systems were considerably greater and those from deep pit systems lower compared to U.S. Environmental Protection Agency (USEPA) estimates used in national inventory calculations. For nutritional effect analysis, the between-study variability (heterogeneity) of the mean emission was estimated using random-effect models and had a significant effect (P < 0.01). Therefore, random-effect models were extended to mixed-effect models to explain heterogeneity. Available dietary and animal variables were included as fixed effects in the mixed-effect models. The final mixed-effect model included dietary crude protein, milk yield and dry matter intake, explaining 45.5% of the heterogeneity in NH3 emissions. A unit increase in milk yield (kg/d) resulted in 4.9 g cow/d reduction in NH3 emissions, and a unit increase in diet crude protein content (%) and dry matter intake (kg/d) resulted in 10.2 and 16.3 g cow/d increase in NH3 emissions, respectively. Ammonia emissions from dairy barns are driven by several factors including housing system, season and diet. Crude protein content of the diet, dry matter intake and milk production are important animal related factors that significantly affect ammonia emission from dairy facilities

Study of animal housing technologies and trends of development

Darbe analizuoti gyvulių laikymo technologijų pastarųjų metų tyrimų rezultatai ir raidos tendencijos Europos Sąjungos valstybėse. Surinkti duomenys apie pastaraisiais metais Lietuvoje pastatytų bei modernizuotų būdingų karvidžių ir penimių kiaulidžių techninius, technologinius rodiklius. Tirta karvių ir kiaulių būdingų laikymo technologijų ir aplinkosaugos reikalavimų atitiktis gamybos sąlygomis matuojant amoniako koncentraciją ir emisijos intensyvumą. Per 220 d. tvartinį laikotarpį iš karvės vietos išgaruoja apie 3,7 kg amoniako neapšiltintoje karvidėje (vidutinė patalpos oro temperatūra 3°C), o apšiltintoje (10°C) - apie 6,4 kg. Tai mažiau negu Vakarų valstybių standartas (8,8 kg per 190 d.). Mažiausia amoniako emisija (2,1 kg per metus iš penimos kiaulės vietos) buvo laikant kiaules ant kas savaitę keičiamo kraiko (per parą kiaulei teko 2,0 kg šiaudų); didesnė (2,5 kg) - laikant kiaules ant ištisinių grotelinių grindų ir didžiausia (2,8 kg) - laikant kiaules ant vientisų lygaus betono nekreikiamų grindų. Visais atvejais amoniako emisija neviršijo Vakarų valstybių standarto - 3 kg per metus iš penimos kiaulės vietosThis study analysed the tendency of animal housing technologies development in State of the EU and collected some basic information about technological data on cows and pigs housing technology that has been introduced in Lithuania intrecent yers. Under productions conditions ammonia emission was studied in there types of cowsheeds: in an insulated cowshed of tied cows, in an uninsulated cowshed with lying boxes and open manure tracks, and in a cowshed with the insulated roof, boxes and partly slatted floor. Ammonia emission during a 220-d housing period from animal place in an uninsulated cowshed is 3,7 kg, and in an insulated one - 6,4 kg. The influence of pigs housing system on ammonia rate was investigated in the -production process. The lowest emission (2,0 kg a pig per year) was achieved while keeping pigs on abundant straw litter, which was changed every week (approx 2kg of litter for a pig per day). At the application of slatted floor system ammonia emission rate was 2,2 kg a pig per year, and in the case of concrete floor system -2,8 kgVytauto Didžiojo universitetasŽemės ūkio akademij

Development of a simulation model of temperature regime of milking parlor

Sudarytas paprastu metodu sprendžiamas patalpos oro temperatūros dinamikos panašumo (matematinis) modelis, kuris įvertina atitvarų šilumos akumuliaciją, periodinį šildytuvų bei gyvulių šilumos srautą. Modelio parametrai parinkti išanalizavus tipiškų melžyklų technologinius ir techninius duomenis. Kai lauke 20°C šalčio ir norima, kad melžimo metu patalpos oro temperatūra pakiltų iki 15°C, sprendžiant modelį nustatyta: du kartus per parą po 3 val. turi būti įjungtas šildytuvas, kurio galia 1,5 kW/melžimo vietai. Tarp melžimo patalpos oro temperatūra sumažėja iki 6° CThe objective of this study is to develop a simulation model of temperature regime of typical milking parlor. The fundamentals of construction termophysics were applied while developing simulation model. The parameters of named model were expressed by total heat flow of animals, choosing milking place to be adequate to 1 kW of total heat of animals. Model developed initially had differential equation form. When the latter is integrated, the model is received, according which calculation is simple. The model evaluates the heat accumulation of external barrier and heat accumulation of equimpment, as well as changing heat flow of heating heat and heat of animals. After analysing technological and technical solutions of typical milking parlors, there were receiwed the following values of initial and model parameters: coefficient of the heat transmission of the walls - 0,5 W/m²K and roof - 0,25 W/m²K; specific area of external barrier that accumulate heat - 18,5 m²/kW total heat flow of animal; specific heat losses through the external barriers of the milkign parlor and losses with ventilation (heat losses for 1 kW flow of the total heat of cattle, when temperature difference between inside and outside air is 1 K) - 0,022-0,039 1/K. While working out the model, the following results were receiwed: when outside temperature is -20°C and required air temperature in milking parlor is 15° C twice a day for 3 hours, the heater, of 1,5 kW for one milking unit, must be turn on. Between milking inside temperature decreases to 6° CVytauto Didžiojo universitetasŽemės ūkio akademij

Model symulacyjny warunkow temperaturowych pracy dojarni

Mathematical model of the dynamic resemblance of the inside air temperature that could be solved by the simple method has been made. The heat accumulation of the partitions, periodical heaters and the flow the animal heat been estimated with the help of this model. The model parameters have been chosen after analysis of the technological and technical data of the typical milking parlors. When the outside temperature is 20°C below zero and the inside temperature during milking time should be 15°C, then the heater has to be used twice a day for 3 hours and its power should be 1,5 kW/ for every milking place. This has been calculated with the use of this mathematical model. The inside temperature fell down to 6°C between the milking periodsVytauto Didžiojo universitetasŽemės ūkio akademij