Vertical Stratification of Ammonia in a Broiler House

The broiler industry is not immune to the problematic nature of NH₃ production in animal rearing facilities. Though the headlines of today focus on environmental impact considerations, the detrimental effects of the house air quality on farmers and birds remain considerable for industry viability. This research investigated the vertical stratification of in-house NH₃ combined with sampling position down the center of the house and with different NH₃ analysis technologies. The results indicated that reuse of litter and house ventilation correlate to trends in NH₃ concentration at particular measurement heights. When tunnel ventilation was primary, NH₃ concentrations decreased vertically with increasing distance from the litter surface. However, with lower outside temperatures, little ventilation, and a stagnant house atmosphere, no concentration gradient was evident. The work also demonstrated significant variability among professionally calibrated instruments and traditionally used pull tubes. Characterization of interior air quality of broiler houses should consider sampling height to effectively address bird exposure.     

Instrumentation for Evaluating Differences in Ammonia Volatilization from Broiler Litter and Cake

Greater understanding of the mechanisms affecting NH₃ volatilization from reused broiler bedding is needed to determine pathways for mitigating NH₃ emissions. A chamber acid trap (CAT) system was developed to provide an improved laboratory method for determining NH₃ volatilization from litter or cake samples and for assessing treatment technologies to decrease NH₃ losses from poultry litter. The CAT system offers precision control of air flow rate through sample chambers as well as straightforward, precise determination of the amount of N volatilized. This article outlines the basic setup of the CAT system. The system can be utilized and modified for researching specific mechanisms involving physical, chemical, or biological treatments affecting NH₃ volatilization from litter or cake.     

Efficacy of a Litter Amendment to Reduce Pododermatitis in Broiler Chickens

Broiler house environment, especially volatile NH₃ content, has a significant effect on pododermatitis in chickens. The efficacy of NaHSO₄ in reducing pododermatitis in broiler chickens was investigated in this study. A total of 960 straight-run 1-d-old chicks were randomly assigned to 16 environmental chambers with 4 different levels of NaHSO₄ (4 chambers/treatment). The treatments (TRT) comprised of TRT 1 (control), TRT 2 with NaHSO₄ applied at 1 × rate (0.22 kg/m²) on the day of placement of chicks, TRT 3 with NaHSO₄ applied at 2 × rate on the day of placement of chicks, and TRT 4 with NaHSO₄ applied at 1 × rate on the day of placement of chicks and at 1 × rate on 21 d. Birds were raised to 49 d of age on a 4-stage feeding program with diets formulated to contain high protein levels and all-vegetable ingredients. At 35 d of age, the litter was moistened artificially to see the effect of NaHSO₄ on NH₃ volatilization. In addition to assessing live performance, feet were scored on 42 and 49 d of age for incidence and severity of pododermatitis. Ammonia concentration (ppm) in the chambers was measured before placement of chicks and on a weekly basis throughout the experiment. No differences in live performance of the birds were observed throughout the study (P > 0.05). Sex had significant effects on incidence of pododermatitis (P < 0.05), with females showing higher incidence of pododermatitis than males. The NaHSO₄ had a significant effect on NH₃ volatilization in the chambers (P < 0.05). Ammonia concentration was significantly reduced in all TRT except the control (TRT 1). Sodium bisulfate had no significant effect on NH₃ levels after 35 d upon addition of moisture to the litter. Although not significant (P > 0.05), using NaHSO₄ as a litter amendment numerically reduced the incidence of pododermatitis by 10 or more percentage points.     

Efficacy of chlorine dioxide gas in reducing Escherichia coli and Salmonella from broiler house environments

Escherichia coli and Salmonella spp. are considered to be the major pathogens associated with human transmissible infectious diseases in the air of poultry houses. Chlorine dioxide (ClO₂) is an effective biocide against a wide range of microorganisms. Accordingly, this study investigated the efficiency of gaseous ClO₂ application for disinfecting broiler houses by collecting air samples before and after fumigation using a passive method. Fumigation was performed with 125 mL or 250 mL of ClO₂ liquid (containing 2,000 ppm of ClO₂) and 3 trials were conducted for each dose. A total of 27 petri dishes were used for each trial (for each type of bacteria: E. coli or Salmonella) and placed in 3 different locations (front, middle and back) and 3 different positions (top, middle and floor) of the broiler shed. Air samples were collected at 10 min, 1 h, 3 h, 6 h, and 12 h before and after fumigation to evaluate the air quality in terms of the concentration of E. coli and Salmonella. Both levels of ClO₂ were capable of reducing the concentration of E. coli from broiler house air during all measuring periods except 10 min, with highest disinfection rate being observed at 6 h. With the exception of 1 h, the concentration of Salmonella was also reduced after fumigation with ClO₂ in all measuring period; with the highest disinfection rate occurring at 6 h. Fumigation with ClO₂ had no negative effect on birds’ health condition. Taken together, these results suggest that the application of gaseous ClO₂ at the investigated levels can be an effective option for reducing bacterial load from broiler house environments.     

Windrowing poultry litter after a broiler house has been sprinkled with water

In-house windrowing of poultry litter between broiler flocks has been promoted as a management practice to improve the litter condition upon chick placement. Before the onset of the current study, low-pressure sprinklers were used during the grow-out period in a broiler house. Different methods of windrowing were then utilized to determine the effect each had on litter composition. Covered, turned, and static 9 d windrow treatments, and one non-windrowed control were applied to a broiler house containing litter used over multiple flock grow-outs. The house was divided into 16 6 × 6 m plots with each treatment being applied to 4 blocks within the house. Litter from each plot was analyzed for particle size, moisture, N, NH₃, P, K, pH, and temperature over a 20-day period, with d 20 representing 7 d after chick placement. All variables except particle size were statistically different. Of all the treatments, the covered treatment showed the greatest reduction in moisture over the 20-day period. Nitrogen content was lowest in the turned treatment. Ammonia decreased from d 9 to 20. Both the covered and static treatments were able to reach recommended temperatures in both the core and the periphery of the windrows. Conclusively, in-house windrowing after utilizing low-pressure sprinklers did not improve N retention, reduce NH₃ volatilization, or decrease P or K in the litter compared to the control. However, the temperatures obtained in the periphery and core of the covered and static treatments show potential for eliminating pathogens present in the litter.     

Systematic evaluation of in-house broiler litter windrowing effects on production benefits and environmental impact

In-house windrowing of broiler litter between flocks has been adopted by producers to reduce pathogens and improve litter quality before chick placement. In this study, 5 consecutive windrow trials were conducted in commercial broiler houses for their effect on litter bacterial populations, organic matter stabilization, cumulative ammonia emissions, and nutrient transformation and compared with litter conditioning (tilling) in adjacent houses. No significant reduction ofClostridium spp. andEscherichia coli populations was found in windrowed litter from d 0 to 7. No significant difference of 7-d mortality was found between windrow and nonwindrow houses. The windrowed house resulted in better foot quality than the nonwindrowed house from 1 of 3 scored flocks. Water-soluble phosphorus increased in both windrowed and nonwindrowed litter; therefore, appreciable biotic and abiotic activity occurred in litter with both treatments after flocks were removed. Overall, no negative effect of windrow treatments on litter quality for agronomic applications was observed. Both the control and windrow treatments resulted in a decrease in litter moisture content (2 to 5%) likely beneficial to bird health conditions. High ammonia emissions persisted after windrow spreading; therefore, a need may exist for an extended period of ventilation or a litter amendment as crucial before chick placement. Litter amendment at a low dose was effective in lowering ammonia concentrations after windrowing and was more economical comparing to operating fans in winter conditions.     

Presence of fluoroquinolone-resistant coliforms in poultry litter

Litter was collected from four turkey farms (eight houses) with a history of fluoroquinolone (FQ) treatment failure, 10 adult broiler breeder chicken farms (43 houses) with one having a history of FQ treatment, and 30 broiler chicken farms (110 houses) with 24 having a history of FQ treatment. In the turkey litter, the percentage of nalidixic acid-resistant (at 100 microg/ml) coliforms/total number of coliforms ranged from 0.6% to 61.9%. Two of the four farms had houses containing coliforms resistant to the two FQs, enrofloxacin (1 microg/ml) and sarafloxacin (1 microg/ml). There was also multiple resistance to other antimicrobials on all four turkey farms (ampicillin, tetracycline, chloramphenicol, kanamycin). The level of total coliforms from the adult broiler breeder litter was low, and there were no nalidixic acid-resistant isolates from any of the 10 farms. In the broiler chickens, 7 of 91 houses with a history of FQ usage contained coliforms resistant to nalidixic acid; however, 2 of the 19 houses on farms with no history of FQ usage had nalidixic acid-resistant coliforms. All of the broiler farms with nalidixic acid-resistant isolates were also resistant to the FQ sarafloxacin, whereas only 3 of the 24 treatment history farms and 1 of the no-treatment history farms exhibited enrofloxacin-resistant coliforms in the litter.     

Effects of an Aluminum Sulfate and Ferric Chloride Blend on Poultry Litter Characteristics in Vitro

Previous studies have applied various concentrations of aluminum sulfate and ferric chloride separately to poultry litter to reduce environmental pollution and increase chicken productivity. In the present study, we investigated the effect of using a blend of these 2 chemicals under 5 different treatments: control (no addition), 50 + 50, 25 + 50, 50 + 25, and 25 + 25 g/kg of litter, which consisted of fresh chicken manure (1 kg) and sawdust (4 kg) thoroughly mixed in a 70 × 47 × 43 cm box. NH₃ and CO₂ volatilizations, pH, electrical conductivity (EC) and moisture content of the poultry litter were assessed weekly up to 6 wk and in the case of total and water-soluble nutrients they were assessed after 1 and 42 d. The control treatment had higher NH₃ and CO₂ volatilizations than the treated litter throughout the experiment. EC and pH showed an inverse relationship, whereby the control treatment had high pH and low EC values and the treated litter had low pH and high EC values. After 42 d, nitrogen levels were significantly reduced in the control treatment, whereas the 50 + 50 g/kg treatment had the highest content. Conversely, water-soluble phosphorus levels were much lower in the treated poultry litter after 1 and 42 d. A higher ferric chloride concentration (25 + 50 g/kg) in the blend was more effective than a higher aluminum sulfate concentration (50 + 25 g/kg). These findings demonstrate that a combination of aluminum sulfate and ferric chloride may be a useful amendment for reducing NH₃ and CO₂ volatilizations, pH, and moisture content of poultry litter, which will help in improving poultry productivity, pollution control, and poultry litter fertilizer usage.     

Biotin intake and transfer to the egg and chick in broiler breeder hens housed on litter or in cages

1. Biotin concentrations in the plasma of hens and chicks and in egg yolk were measured at different ages in broiler breeder hens housed on litter or in cages and fed restricted amounts of diets containing different concentrations of biotin.

2. In the caged groups, biotin concentrations in these fluids increased with increasing maternal biotin intake over the range of intakes studied.

3. Biotin concentrations in hen plasma and yolk were linearly related and increased with age.

4. Biotin concentration in chick plasma was highly correlated (r = 0·93) with yolk concentration. The poorest biotin status was predicted for chicks from young hens.

5. There was no evidence that ingestion of excreta contributed substantially to the biotin status of hens housed on deep litter.

     

Characterization of Nutrients in Built-up Broiler Litter Using Trench and Random Walk Sampling Methods

Accurate sampling of broiler litter for nutrient analysis is critical for nutrient management and land application. Litter can be applied to agricultural land either fresh or after composting. If applied fresh, sampling should be done before house clean out so that the nutrient analysis results are readily available prior to land application. There are 2 methods that are suitable for obtaining representative litter samples in poultry houses, the trench and the point methods. This study was designed to investigate the effect of sampling methodology on the resultant nutrient content of broiler litter and how nutrient concentrations in broiler litter differ between brooding and nonbrooding areas in the production unit. The sampling methods gave similar results for litter pH, moisture content (MC), total Kjeldahl nitrogen (TKN), and total phosphorus (TP), thus indicating that the random walk method can be used to easily collect representative samples instead of the more time- and labor-intensive trench method for nutrient management purposes. The total ammoniacal nitrogen (TAN) content was significantly higher for the trench method, however, TAN accounted for less than 15% of the litter TKN. Litter MC, TAN, and TP varied significantly in each of the nonbrooding areas and the brooding area. Moisture content was 28.5, 32.0, and 28.0% for the brooding, north, and south nonbrooding areas, respectively. Litter TKN levels were 37.4, 24.9, and 20.5 g/kg for the brooding, north, and south nonbrooding areas, respectively. The TAN concentrations were higher at the north nonbrooding areas. The TP concentrations were 10.4, 8.8, and 8.5 g/kg for north nonbrooding area, brooding area, and south nonbrooding area, respectively. Our results indicate the need for sampling litter in both brooding and nonbrooding areas in broiler houses for the determination of average litter nutrient and MC.     

Evaluation of a Feed-Grade Enzyme in Broiler Diets to Reduce Pododermatitis

Nutritional and management interventions are needed to reduce the incidence of pododermatitis in poultry. In this study, enzyme (Allzyme Vegpro) supplementation of corn-soybean meal-based broiler diets was evaluated in an effort to reduce total N and NH₃ production and its effect on pododermatitis in broiler chickens. A total of 1,600 mixed-sex chicks were raised on floor pens in a design involving 2 × 2 × 2 arrangement of protein level [high or low], protein source [all vegetable (Veg) or vegetable plus animal (Veg + Ani)], and enzyme [with or without enzyme supplementation (0.06%)], on a 4-stage feeding program (4 replicate pens/treatment; 50 birds/pen). In addition to live performance, the feet were scored for incidence of lesions on all birds on 28, 42, and 57 d of age, and the severity was recorded as none, mild, and severe. Pooled gut samples were collected at 57 d of age to determine viscosities of fore- and hindgut contents. Pooled litter samples were analyzed for moisture, total N, and NH₃ production at 14, 28, 42, and 57 d of age. Live performance of birds did not vary among the treatments (P > 0.05). The incidence of pododermatitis was significantly affected by protein source at 42 d (P < 0.05), with birds fed all-vegetable diets showing higher incidence and severity than those fed vegetable plus animal diets. At 57 d of age, birds reared on all-vegetable diets with enzyme supplementation showed a lower incidence of mild footpad lesions compared with other treatments. Enzyme supplementation reduced viscosity of the gut contents irrespective of the protein level or protein source. Higher levels of litter NH₃ were observed with high-protein diets (28 and 42 d), all-vegetable diets (28 d), and with enzyme supplementation (28 and 42 d). In this study, enzyme supplementation had little effect on litter total N and NH₃ production levels, but reduced viscosity of the gut contents and severity of pododermatitis in older birds.     

Studies on Salmonella from Floor Litter of 60 Broiler Chicken Houses in Nova Scotia

Fifteen floor litter samples were collected from each of 60 broiler chicken houses in Nova Scotia. Salmonella was recovered from 270 litter samples (30%) in 33 of 60 (55%) houses. All isolates were serotyped. Salmonella heidelberg and S. infantis were the most common of the 13 serotypes found. Isolates of selected serotypes were phage typed. Most isolates were susceptible to all common antimicrobial agents.     

Concentrations and emission rates of aerial ammonia,nitrous oxide,methane, carbon dioxide,dust and endotoxin in UK broiler and layer houses

1. A survey of the concentration and emission rates of aerial ammonia, nitrous oxide, methane, carbon dioxide, dust and endotoxin was undertaken in 4 examples each of typical UK broiler, cage and perchery houses over 24 h during winter and summer.

2. Overall the air quality within the poultry houses was unsatisfactory as judged by the dual criteria of farmer health and bird performance.

3. Mean concentrations of ammonia ranged from 12.3 to 24.2 ppm while concentrations of methane and nitrous oxide were close to ambient levels. Mass concentrations of aerial dust ranged from 2 to 10 rag/m³ and 0.3 to 1.2 mg/m³ for inspirable and respirable fractions respectively, while endotoxin concentration was typically about 0.1 ^g/m³ (inspirable fraction).

4. Emission rates of gaseous ammonia were rapid (9.2 g (NH₃/h per 500 kg live body weight) and uniform across the three types of building, while emissions of methane and nitrous oxide were slow. Rates of dust emission ranged from 0.86 to 8.24 g/h per 500 kg live body weight in the inspirable size fraction.     

Effect of Various Litter Amendments on Ammonia Volatilization and Nitrogen Content of Poultry Litter

Ammonia volatilization from poultry manure contributes to atmospheric N pollution, negatively affects poultry performance, and decreases the fertilizer value of manure. The objective of this study was to evaluate the effects of alum [Al₂(SO₄)₃·14H₂ O], liquid alum, high acid alum (A7), aluminum chloride (AlCl₃·6H₂ O), fly ash, Poultry Litter Treatment (PLT), and Poultry Guard (PG) litter amendments on NH₃ volatilization and N contents in litter. Two laboratory studies were conducted for 42 d each. The treatments in experiment 1, which were mixed in the upper 1 cm of litter, were 4 g of alum, 8 g of alum, 8.66 g of liquid alum, 17.3 g of liquid alum, 11.2 g of A7, 22.4 g of A7, 4 g of PG, 4 g of PLT, 4 g of fly ash, and 4 g of AlCl₃/100 g of litter. The treatments for experiment 2 were identical to experiment 1, except the fly ash treatment was dropped and an additional 4 g of alum/100 g of litter treatment was added, which was incorporated totally within the litter. The various rates of dry alum, liquid alum, and A7 significantly decreased NH₃ volatilization compared with the controls, with reductions ranging from 77 to 96% for experiment 1 and from 78 to 96% for experiment 2, respectively. Poultry Litter Treatment decreased NH₃ volatilization by 76 and 87% for experiment 1 and 2, respectively. Aluminum chloride decreased NH₃ volatilization by 48 and 92% for experiment 1 and 2, respectively. Litter treated with alum, liquid alum, A7, PLT, and AlCl₃ had a lower pH and a greater N content than the controls in experiment 1 and 2. In contrast, PG and fly ash resulted in a greater pH and were ineffective in decreasing NH₃ volatilization and increasing N contents in experiment 1. However, in experiment 2, PG was effective in reducting NH₃ loss. In this study, the decreased NH₃ volatilization was chiefly associated with reduction in litter pH.     

Fine Particle Measurements Inside and Outside Tunnel-Ventilated Broiler Houses

Emissions from animal feeding operations have become a growing concern. Although many studies describe occupational exposures and exhaust concentrations associated with animal facilities, very little information has been provided about the ambient air around the houses. This study investigates real-time and primarily 24-h time-integrated levels of particulate matter ≤2.5 μm in diameter inside and outside (up to 500 ft from the house) of commercial tunnel-ventilated broiler houses on a farm in northeast Georgia. None of the 24-h particulate matter measures collected when the houses were tunnel ventilated exceeded the Environmental Protection Agency's 24-h National Ambient Air Quality Standard of 65 μg/m³.     

Atmospheric Ammonia Concentration Effects on Broiler Growth and Performance

Atmospheric NH₃ in poultry facilities has been linked to damaged respiratory tract lining, reduced resistance to respiratory diseases, and increased ascites. Therefore, the effects of graded NH₃ concentration (0, 30, 60 ppm) on performance, tracheal lesions, conjuctival lesion, ascites incidence, hematocrit (HCT), blood uric acid (BUR), and blood urea nitrogen (BUN) were investigated using commercial broilers. Final body weight, feed consumption, and body weight gain were not significantly (P > 0.05) affected as NH₃ concentration increased from 0 to 60 ppm. In contrast, gain to feed ratio was depressed (P = 0.05) at 60 ppm NH₃. Right ventricular weight (RV), HCT, tracheal lesions, and pulmonary lesions increased with age (P < 0.05) to 21 d but was not affected by atmospheric NH₃. These data indicate that NH₃ in poultry houses lowers performance and may increase disease susceptibility.     

Performance and Nutrient Utilization of Steers Consuming Broiler Litter with or without Aluminum Sulfate

The objective of this study was to determine the effects of adding alum (aluminum sulfate) to broiler litter on nutrient digestibility and utilization and animal BW gains when fed to steers. To determine nutrient digestibility and utilization, 12 steers were housed in individual metabolism crates and fed one of three diets: 1) 1:1 corn:broiler litter treated with alum (ALUM); 2) 1:1 corn:untreated traditional broiler litter (TRAD); 3) a commercially available diet (CON). Dry matter intake did not differ (P>0.05) among treatments. Digestibility of DM and OM was greater (P<0.05) in steers fed ALUM and TRAD, than in steers fed CON. NDF was most digestible (P<0.05) by animals fed TRAD and least digestible by those fed CON, with those consuming ALUM being intermediate. No differences (P>0.05) were observed in ADF, CP, or energy digestibility. Apparent protein retention was greater (P<0.05) in steers fed ALUM and TRAD than in those fed CON. To determine the effect of broiler litter on steer BW gains, a 28-d grazing trial was conducted with 20 steers randomly allotted to the same two broiler litter dietary treatments (n=10) used in the digestibility trial. Steers receiving ALUM gained faster (P<0.05) than those receiving TRAD. Addition of aluminum sulfate to broiler litter fed to cattle did not inhibit nutrient digestibility or utilization.     

Influence of in-house composting of reused litter on litter quality,ammonia volatilisation and incidence of broiler foot pad dermatitis

1. The objectives of this study were to evaluate the residual effects of two windrow composting methods for reused litter on its quality (pH, moisture, ammonia), ammonia (NH₃) volatilisation and the prevalence (scores 0–4) of foot pad dermatitis (FPD) and hock burn (HB) on d 1, 7, 14 and 21 of age in broilers. Litter was allowed to compost for 8 d within a 14-d interval between flocks.

2. The composting methods studied were with or without a PVC plastic sheet. The same procedures were applied for three consecutive flocks, with litter initially having been used for 12 flocks. Data were analysed with a mixed model of repeated measures of day, with main effects and interactions of day, composting method, litter age (block) and house nested within method.

3. At d 1, litter NH₃ and NH₃ volatilisation were higher in the covered litter method. Litter moisture increased to 45.3% as broilers aged. The incidence of FPD also increased with age. No signs of HB were found in any bird throughout the trials.

4. There was no effect of litter composting methods on the prevalence of FPD or body weight at any age.

5. Litter moisture should be controlled to avoid NH₃ volatilisation reaching critical levels. Windrow composting of litter with a PVC plastic sheet may not be required when considering the broiler housing environment.     

规模化猪场舍内外空气质量变化的研究

为掌握规模化养猪场舍内外环境空气质量的变化,为猪舍空气质量对人、动物健康影响的风险评估和相关控制技术的研究提供理论依据。试验采用环境检测方法对南京市郊某规模化养猪场的哺乳仔猪舍、保育舍和生长育肥舍进行空气质量检测。结果显示,春、夏、秋、冬猪舍内环境空气中平均细菌总数分别为118.77×10³、28.51×10³、102.04×10³、62.71×10³ CFU/m³,NH₃的浓度分别为9.67、10.87、9.95、12.74 mg/m³,H₂S的浓度分别为2.81、1.95、2.68、2.78 mg/m³;猪舍外环境空气中平均细菌总数分别为13.57×10³、13.20×10³、16.70×10³、11.85×10³ CFU/m³,NH₃的浓度分别为1.01、1.44、1.07、0.42 mg/m³,H₂S的浓度分别为0.06、0.08、0.03、0.01 mg/m³。猪舍内环境空气中细菌总数春季＞秋季＞冬季＞夏季(P＜0.05),且猪舍内细菌总数高于舍外(P＜0.05),猪舍内在春、秋、冬季除生长育肥舍外,均超出国家规定的标准,而夏季在规定的标准范围内;环境空气中NH₃、H₂S的浓度在国家规定的标准范围内;猪舍内外环境温度、相对湿度和风速等环境指标均符合国家规定的标准。     

Characteristics of Gas Generation (NH3, CH4, N2O, CO2, H2O) From Horse Manure Added to Different Bedding Materials Used in Deep Litter Bedding Systems

The aim of this study was to analyze the influence of horse manure added to different bedding materials on the generation of gases (ammonia (NH₃), nitrous oxide, carbon dioxide, methane, water vapor) from deep litter bedding under standardized laboratory conditions. Two different types of straw (wheat and rye) and wood shavings were analyzed. The deep litter (substrate) was made of 25 kg of the respective bedding material, 60 kg horse feces, and 60 L ammonium chloride solution (urea), and spread out in identical chambers over 19 days (n = 3). On days 1, 8, 15, and 19, total nitrogen, total carbon, and dry matter content of the substrate, as well as the pH in 500-g samples, were measured along with. At the end of each test period, the nitrite nitrogen, nitrate nitrogen, and ammonium nitrogen contents of the leachate were analyzed. The wheat straw substrate emitted the highest concentration of NH₃ (4.31 mg/m³; P < .0001) and the wood shavings substrate emitted the lowest (1.73 mg/m³; P < .0001); the rye straw substrate generated 3.05 mg/m³. In addition, significant differences occurred during days 1 to 3 with respect to the generation of the gases NH₃, methane, nitrous oxide, carbon dioxide, and water vapor, and after the opening of the chamber on day 15. The nitrogen losses through the leachate occurred mainly in the form of nitrate, where the leachate from the wheat straw substrate had a significantly higher amount of nitrate nitrogen (44.56 mg) as compared with the leachates of the rye straw (14.49 mg; P ≤ .0001) and the wood shaving substrates (22.62 mg; P = .0010).