Built-up Litter Research Articles

Effects of Feed-Through Sulfur on Growth Performance, Atmospheric Ammonia Levels, and Footpad Lesions in Broilers Raised Beginning with Built-Up Litter.

Simple SummaryDuring commercial farming of chickens, accumulation of feces and moisture in the litter on the floor of the chicken house can lead to ammonia production by natural bacteria in the litter that ingest the chicken feces. Excessive ammonia levels can lead to health problems for the chickens, which can inhibit their growth and cause sores on their breasts and paws. To mitigate this animal welfare issue, this experiment tested the use of sulfur as a feed additive (feed-through sulfur) to acidify chicken feces and prevent ammonia from being formed from bacterial action. In this experiment, feed-through sulfur was tested on three different flocks of chickens. The combination of feed-through sulfur with a traditional litter acidifier, sodium bisulfate, showed improved ammonia control over sodium bisulfate alone in one flock. For the other two flocks, ammonia control was similar between feed-through sulfur with sodium bisulfate and sodium bisulfate alone. In addition, litter acidification was best with the combination of feed-through sulfur and sodium bisulfate in 2 out of 3 flocks. These results indicate the possibility that adding sulfur to feed while also using sodium bisulfate litter treatment may work together to better control ammonia in the chicken house.To the poultry industry, ammonia accumulation within poultry houses can be a costly issue, as this can lead to problems with bird performance, damage to economically important parts such as paws, and customer disapproval due to animal welfare concerns. Common management practices for ammonia control can be quite effective; however, these methods are used variably from farm to farm, which necessitates ammonia control measures that poultry companies can more uniformly implement across all contract growers. One possible measure is ammonia control through feed additives, which would allow poultry companies more direct control over the treatment. This project explored the efficacy of elemental sulfur added directly to the feed (feed-through sulfur) in controlling litter ammonia levels, live performance, and paw quality of broilers raised on built-up litter over three successive flocks. Feed-through sulfur on its own showed inconsistent effects on performance or footpad lesions after 38 days of production compared to sodium bisulfate or control treatments. However, combination of feed-through sulfur and sodium bisulfate showed a potential synergistic effect on ammonia levels and litter pH, although there were few differences between treatments and controls; therefore, additional research must be explored to confirm these observations.

Assessing Biosecurity Compliance in Poultry Farms: A Survey in a Densely Populated Poultry Area in North East Italy.

Simple SummaryIn intensive animal farming, biosecurity represents a crucial point to guarantee animal welfare and health. Therefore, it is necessary that proper biosecurity measures are complied with and implemented. To date, several tools to assess biosecurity compliance in poultry farms are available with the general purpose of providing an evaluation of the implemented biosecurity measures. With this study, we aimed to assess the level of compliance with biosecurity measures in poultry farms located in the most densely populated Italian poultry area. Standardized biosecurity checklists according to national legislation were used to collect information. The main findings of our study show an overall good level of biosecurity implementation with some measures still requiring improvement. Our study may help to highlight the importance of biosecurity compliance in poultry farms by identifying the main achievements/challenges in a context in which measures are to be implemented by law and poultry production is vertically integrated.Biosecurity in poultry farms represents the first line of defense against the entry and spread of pathogens that may have animal health, food safety, and economic consequences. The aim of this study was to assess biosecurity compliance in poultry farms located in a densely populated poultry area in North East Italy. A total of 259 poultry farms (i.e., broilers, turkeys, and layers) were surveyed between 2018 and 2019 using standardized checklists, and differences in biosecurity compliance between the poultry sectors and years (only for turkey farms) were tested for significance. Among the three sectors, turkey farms showed the highest compliance. Farm hygiene, infrastructure condition, cleaning and disinfection tools, and procedures were the biosecurity measures most complied with. Some deficiencies were observed in the cleanliness of the farm hygiene lock in broiler farms, as well as the presence of the house hygiene lock in broiler and layer farms and an adequate coverage of built-up litter in turkey and broiler farms. In conclusion, this study highlighted a generally high level of biosecurity in the visited poultry farms (probably due to the stringent national regulation and the integration of the poultry industry) and identified some measures that still need to be improved.

Effectiveness of Sodium bisulfate and Calcium carbonate litter amendments on the Microbial load of Broiler Built-up Litter

In the poultry industry, litter treatment is an effective tool used to control microbial growth, public health risk, and the environmental impact of built-up litter. Our study aimed to compare the efficacy of the two commercial litter amendments, Calcium carbonate and Sodium bisulfate, to reduce the total aerobic (TAC) and total fungal counts (TFC) of dry and wet-caked built-up broiler litters. Litter samples were obtained from 21 and 35 days two broiler houses, then each sample was divided into three sub-groups (500 g/group): control untreated groups, desiccant treated groups (40g Calcium carbonate), and acidifier treated groups (40 g Sodium bisulfate). TAC and TFC and log reduction were determined at zero, 2, and 14 days post-application. Calcium carbonate was highly efficient when applied on the wet litter and achieved a 4.76 log reduction of TAC after 48 h of application. Sodium bisulfate was effective on both litter conditions, with a 3.4 log reduction of total aerobic count in wet litter samples, higher than 2.47 in the dry litter samples after 48 hrs. Both litter amendments showed low efficacy after two weeks of application, as log reduction ranged from 0.50 to 1.86. The efficiency of calcium carbonate and sodium bisulfate on total fungal count was negligible and ranged from 0.00 to 0.10 log reduction. In conclusion, calcium carbonate and sodium bisulfate are efficient litter amendments that can be used as a preventive measure for minimizing bacterial growth in broiler built-up litter with periodical reapplication to maintain good litter quality.

Effect of sodium bisulfate amendments on bacterial populations in broiler litter

The accumulation of ammonia in poultry houses is of concern to bird and human health. Acidification of the litter by application of acidifying amendments such as sodium bisulfate (SBS) retains ammonia generated by microbial degradation of uric acid as harmless ammonium in the litter. Although some studies on the effects of litter amendments on specific bacteria and groups of bacteria have been carried out previously, wide gaps in knowledge remain. In the present study, 2 types of samples were prepared and either left unamended or amended with 2.5 or 10% SBS. One set of samples consisted of a 1:1 mixture of built-up litter and fresh poultry manure (L/M); the other of fresh wood shavings and fresh poultry manure (S/M). The samples were kept in the laboratory at room temperature for 35 d. The pH of unamended mixtures increased to 7.3 and 6.9 for L/M and S/M, respectively. A pH of 6.7 and 3.9 on day 35 was observed for L/M and SM with 2.5% SBS, respectively. The corresponding values for LM and SM amended with 10% SBS were 3.5 and 2.5, respectively. Plating data indicated that coliforms became less numerous in the unamended samples than the SBS-amended samples. This difference was also seen in data obtained by high-throughput sequencing of 16S rDNA. The sequencing data also indicated that sequences from the genus Oceanisphaera accounted for as much as 80% of the sequences from L/M and about 40% of those from S/M samples early on. Sequences from members of the order Clostridiales were enriched in L/M and S/M amended with 10% SBS as were sequences from the genus Turicibacter. Weisella species sequences were more prevalent in SBS-amended samples than in unamended ones. Sequences from the genus Corynebacterium, Brachybacterium, and Arthrobacter were more common in L/M samples than in S/M samples regardless of the SBS content. The data indicate that litter amendments affect some bacteria populations and not others. Further studies are required to determine if the observed population changes such as increased survival of coliforms warrant actions to improve the microbial quality of litter to be reused.

Effects of Environment, Feed Form, and Caloric Density on Energy Partitioning, Subsequent Performance and immune response

SUMMARY Past literature lacks studies that compare diets containing an improved feed form vs. an increased energy. The objective of the study was to assess the effect of variations of feed form and dietary caloric density on broilers reared on clean shavings and built-up litter. Treatments were arranged in a 2 × 2 factorial randomized block design within a split plot. Whole plot treatments considered one room (11 × 7.32 m) of either clean shavings or built-up litter; divided into 16 treatment replications of either standard (30%) or improved (80% feed form), and 16 replications of either commercial or increased (+110 kcal/kg) dietary caloric density comprising the 2 × 2 factorial arrangement. Broilers consuming an improved feed form demonstrated an improved feed intake, live weight gain, feed conversion ratio, breast weight and breast yield (P 0.05) compared to broilers provided standard feed form at increased energy regardless of environment. These data suggest feed form improvements may partition energy towards growth more than feeding an increased energy diet.

A simple mathematical method to estimate ammonia emission from in-house windrowing of poultry litter

ABSTRACTIn-house windrowing between flocks is an emerging sanitary management practice to partially disinfect the built-up litter in broiler houses. However, this practice may also increase ammonia (NH3) emission from the litter due to the increase in litter temperature. The objectives of this study were to develop mathematical models to estimate NH3 emission rates from broiler houses practicing in-house windrowing between flocks. Equations to estimate mass-transfer areas form different shapes windrowed litter (triangular, rectangular, and semi-cylindrical prisms) were developed. Using these equations, the heights of windrows yielding the smallest mass-transfer area were estimated. Smaller mass-transfer area is preferred as it reduces both emission rates and heat loss. The heights yielding the minimum mass-transfer area were 0.8 and 0.5 m for triangular and rectangular windrows, respectively. Only one height (0.6 m) was theoretically possible for semi-cylindrical windrows because the base and the height were not independent. Mass-transfer areas were integrated with published process-based mathematical models to estimate the total house NH3 emission rates during in-house windrowing of poultry litter. The NH3 emission rate change calculated from the integrated model compared well with the observed values except for the very high NH3 initial emission rate from mechanically disturbing the litter to form the windrows. This approach can be used to conveniently estimate broiler house NH3 emission rates during in-house windrowing between flocks by simply measuring litter temperatures.

A Review of Ammonia and Particulate Matter Control Strategies for Poultry Housing

Abstract. Poultry production has the potential to be a large contributor of ammonia and particulate matter emissions to the atmospheric environment. To understand how to mitigate the emissions of ammonia and particulate matter, it is necessary to conduct a science-based review of the control strategies that are available to poultry producers or are currently being developed. Strategies considered in this article are ventilation, electrostatic precipitators and space charge systems, filtration and biofiltration, litter and manure amendments, management of built-up litter, manure cleanout, litter moisture management, selection of bedding material, oil and water spraying, dietary manipulation, and immunization. Currently, no single strategy can provide high emission reduction and/or control of both ammonia and particulate matter. The reduction and/or control efficiencies summarized here can be used by regional air quality modelers as a first step in determining the effects of reduced emissions on ambient air quality by widespread adoption of the various strategies considered.

Can Bacteriotherapy Using Commercially Available Probiotics, Prebiotics, and Organic Acids Ameliorate the Symptoms Associated With Runting-Stunting Syndrome in Broiler Chickens?

Runting-stunting syndrome (RSS) in poultry has been known for more than 40 years, but the precise etiology remains unknown and a licensed vaccine is consequently not currently available. In order to mitigate the symptoms associated with RSS, a series of experiments was performed to investigate whether a combined bacteriotherapeutic treatment consisting of probiotics, prebiotics, and organic acids could influence the outcome of this disease. Initially two groups of commercial broiler chickens were either left uninoculated or inoculated with filtrate from homogenized intestines of RSS-affected broiler chickens. One group from each of these two challenge groups was treated, with a bacteriotherapeutic regimen. After 12 days chickens were euthanatized, the body weight was measured, and duodenal lesions were enumerated. Five consecutive broiler chicken flocks were then raised either on litter from RSS-affected birds or on fresh wood shavings. Treatment had no beneficial effect on the number and severity of intestinal lesions. There appeared to be a significant build-up of RSS agent(s) in poultry litter, with each consecutive flock placement, independent of bacteriotherapeutic treatment, as more individuals exhibited intestinal lesions on built-up litter in RSS-affected houses (28.9% vs. 44%). While treatment did not appear to consistently reduce intestinal lesions, it did significantly improve the mean body weights (P<0.05) and uniformity of 12-day-old chickens placed on reused litter in houses in which RSS-infected birds were previously raised. A combination of litter management and bacteriotherapy may be needed to ameliorate the adverse effects of RSS on intestinal health and body weight in broiler chickens.

Effects of direct-fed microbial supplementation on broiler performance, intestinal nutrient transport and integrity under experimental conditions with increased microbial challenge

1. The effects of Aspergillus oryzae- and Bacillus subtilis-based direct-fed microbials (DFM) were investigated on the performance, ileal nutrient transport and intestinal integrity of broiler chickens, raised under experimental conditions, with increased intestinal microbial challenge.2. The first study was a 3 × 2 factorial experiment, with 3 dietary treatments (control (CON), CON + DFM and CON + antibiotic growth promoter) with and without challenge. Chicks were fed experimental diets from 1 to 28 d, while the challenge was provided by vaccinating with 10 times the normal dose of commercial coccidial vaccine on d 9. In a second experiment, two groups of 1 d-old broilers, housed on built-up litter (uncleaned from two previous flocks), were fed the same CON and CON + DFM diets from 1 to 21 d.3. The challenge in the first experiment reduced performance, but no differences were observed among dietary treatments from 8 to 28 d. The challenge reduced the ileal epithelial flux for D-glucose, L-lysine, DL-methionine and phosphorus on d 21. Epithelial flux for D-glucose, L-lysine and DL-methionine were increased by DFM. Ileal trans-epithelial electrical resistance (TER) was increased in challenged broilers fed DFM, although this was not observed in unchallenged birds as indicated by a significant interaction.4. Ileal mucin mRNA expression and colon TER were increased, and colon endotoxin permeability was reduced by DFM on d 21 in the second experiment.5. It was concluded that the addition of DFM in the diet improved the intestinal integrity of broiler chickens raised under experimental conditions designed to provide increased intestinal microbial challenge.

Quantification of nitrogen balance components in a commercial broiler barn

Characterizing the respective nitrogen (N) use efficiency requires understanding the N flow of inputs and outputs from a commercial broiler barn. In this study, an N mass balance was performed for one entire growing cycle. The objectives were to quantify, sample, and analyze all N components entering and leaving the barn. The N from feed, chickens, and bedding material was considered as inputs, the outputs included the N accretion in mature broilers, the total N emissions (N&lt;sub&gt;TNE&lt;/sub&gt;), the N accumulation in litter, and the N of mortality. Of particular relevance was the determination of an appropriate method to mirror the heterogenic texture of the litter. Litter samples were collected weekly according to a defined procedure. The major N input was feed N, accounting for 99% of the total N input. After the 36-day growing cycle, the N outputs were portioned as follows: 59% (1741.3 kg N) in mature broilers, 37% (1121.3 kg N) accumulated in litter, and 4% in NTNE (114.3 kg N). The N accumulations in broiler tissue and litter agree well with other studies. The measured emissions were consistently lower compared to other references, due to the fact that these references were mainly based on studies where broilers were raised on built-up litter. In contrast to in situ quantified N emissions in this study, other published values were assumed to be the difference of N between inputs and outputs. This study illustrates that extensive sampling of litter is a prerequisite for calculating litter masses. The accurate specification of the litter texture proved to be crucial within the mass balance approach. With this information, the feasible improvements within management practices can be identified.

In-house windrowing of a commercial broiler farm during early spring and its effect on litter composition

SUMMARY The use of in-house windrowing of broiler litter between flocks has been used as a litter management procedure to reduce pathogen content and improve the quality of the house environment for newly placed chicks. A trial was conducted to determine what effects different methods of in-house windrowing would have on litter composition during the early spring months of March and April. Using 2 commercial broiler houses, 3 in-house windrowing treatments were applied to built-up litter from multiple flock grow-out cycles and compared with traditional decaked, nonwindrowed litter management. Each windrowing treatment consisted of a 6-d windrow, composed of either decaked litter, caked litter incorporated into windrows, or decaked litter covered with a nonbreathable tarp. Each commercial broiler house was divided into sixteen 6.1 × 6.1-m plots with each treatment being replicated using 4 plots per house. Litter samples from each treatment plot were collected and analyzed for percent moisture, pH, and bacteria levels on d 0, 7, and 14 of the trial. Broiler chicks were placed in each house on d 7. Ammonia volatilization was assessed from each plot on d 7 and 14. Litter moisture decreased over time for all treatments and was not significantly different between treatments. Litter pH in all treatments decreased from d 7 to 14 with no differences between d 0 and 7. Temperatures for the decaked and cake-in treatments exceeded the temperature (50°C) necessary to eliminate pathogenic bacteria, but the control and covered treatments did not. Ammonia volatilization was significantly less on d 14 compared with d 7, but was not different among the treatments. Aerobic, anaerobic, and coliform litter counts decreased from d 0 to 7 with no difference between d 7 and 14 and no treatment effect. In conclusion, no differences were found between the decaked control and windrowing treatments during the spring layout period studied.

Comparison of performance and intestinal morphology of broilers using step-down supplementation with a mannan-rich fraction versus bacitracin methylene disalicylate

SummaryTwo experiments were conducted to compare effects of utilising step-down dosing of a mannan-rich fraction (MRF) of yeast cell wall or the antimicrobial growth promoter (AGP) bacitracin methylene disalicylate (BMD) when chicks were raised on built-up litter. Chicks were randomly assigned to one of three treatment groups (12 pen replicates; 50 birds per pen): basal diet (control) or basal diet plus MRF (Actigen™; Alltech Inc., Nicholasville, KY) or BMD (Alpharma Inc., Fort Lee, NJ). In experiment two, intestinal morphology and litter scores were determined on d 42. In experiment one, MRF and BMD increased BW gain at d 21 and d 42 compared with control (P ≤ 0.05) and d 42 BW was greater in BMD birds than controls (P ≤ 0.05). Adjusted FCRs were lower in MRF and BMD birds from d 0 to d 42 (P = 0.06). In experiment two, there was no effect of treatment on d 21 BW, but MRF and BMD improved adjusted FCR (P = 0.02) compared with control. By d 35, both MRF and BMD birds had greater BWs than controls (P = 0.04). At d 42, MRF-supplemented birds had greater BW than controls (P ≤ 0.05). D 35 and d 42 FCR improved with MRF or BMD compared with control (P ≤ 0.01). Litter conditions improved (P ≤ 0.05) when birds were fed diets with BMD and MRF compared with control-fed birds. Jejunal morphology, including villi height (P ≤ 0.05), villi height: crypt depth ratio (P ≤ 0.05), and goblet cell numbers (P ≤ 0.05) improved with MRF and BMD compared with control. Both MRF and BMD improved broiler performance, potentially related to the improvements observed in intestinal morphology. In conclusion, step-down supplementation with MRF may offer a potential alternative to AGP to improve performance in broilers raised in commercial settings.

Dose-depend response of plasma ghrelin concentration to ovine ghrelin in sheep

The use of in-house windrowing of broiler litter between flocks has been used as a litter management procedure to reduce pathogen content and improve the quality of the house environment for newly placed chicks. A trial was conducted to determine what effects different methods of in-house windrowing would have on litter composition during the early spring months of March and April. Using 2 commercial broiler houses, 3 in-house windrowing treatments were applied to built-up litter from multiple flock grow-out cycles and compared with traditional decaked, nonwindrowed litter management. Each windrowing treatment consisted of a 6-d windrow, composed of either decaked litter, caked litter incorporated into windrows, or decaked litter covered with a nonbreathable tarp. Each commercial broiler house was divided into sixteen 6.1 × 6.1-m plots with each treatment being replicated using 4 plots per house. Litter samples from each treatment plot were collected and analyzed for percent moisture, pH, and bacteria levels on d 0, 7, and 14 of the trial. Broiler chicks were placed in each house on d 7. Ammonia volatilization was assessed from each plot on d 7 and 14. Litter moisture decreased over time for all treatments and was not significantly different between treatments. Litter pH in all treatments decreased from d 7 to 14 with no differences between d 0 and 7. Temperatures for the decaked and cake-in treatments exceeded the temperature (50°C) necessary to eliminate pathogenic bacteria, but the control and covered treatments did not. Ammonia volatilization was significantly less on d 14 compared with d 7, but was not different among the treatments. Aerobic, anaerobic, and coliform litter counts decreased from d 0 to 7 with no difference between d 7 and 14 and no treatment effect. In conclusion, no differences were found between the decaked control and windrowing treatments during the spring layout period studied.

Impact of feeding lower levels of chelated trace minerals versus industry levels of inorganic trace minerals on broiler performance, yield, footpad health, and litter mineral concentration

SUMMARY Two 54-d grow-out trials were conducted in a commercial broiler facility to determine the effect on performance, carcass yield, footpad lesions, and litter trace mineral concentrations when feeding broiler chicks diets containing reduced levels of chelated Zn-(HMTBA)2 [where HMTBA is 2-hydroxy-4-(methylthio)butanoic acid; trials 1 and 2], Cu-(HMTBA)2 (trial 2), and Mn-(HMTBA)2 (trial 2) in comparison with industry levels of the respective inorganic trace minerals (ITM). A total of 122,400 Ross 708 straight-run chicks were distributed into 8 houses with approximately 15,300 chicks per house for trials 1 and 2, with 4 replicate houses per treatment. Treatments in trial 1 consisted of 30 ppm of Zn as chelated Zn-(HMTBA)2 and 100 ppm of Zn as ZnSO4 (ITM). In trial 2, treatments consisted of 32, 8, and 32 ppm from Zn-, Cu-, and Mn-(HMTBA)2, respectively, and 100, 125, and 90 ppm of Zn, Cu, and Mn, respectively, as sulfates (ITM). Trial 1 was carried out on built-up litter, and trial 2 was on fresh litter. In trials 1 and 2, no differences (P > 0.05) were observed in performance, carcass yield, or tibia Zn over the 54-d period between treatments. On d 54 (trial 1), chicks fed diets supplemented with Zn-(HMTBA)2 had 27.3% more grade 1 and 2 paws than those fed ITM (P < 0.01). On d 54 (trial 2), the chicks fed Zn-, Cu-, and Mn-(HMTBA)2 had 23.3% more grade 1 and 2 paws than those fed ITM (P = 0.07). For trial 2, litter Zn, Cu, and Mn from birds fed Zn-, Cu-, and Mn-(HMTBA)2 were reduced by 40, 74, and 35%, respectively, compared with birds fed the respective ITM. In summary, based on the present data, commercial levels of ITM can effectively be replaced with reduced levels of Zn-, Cu-, and Mn-(HMTBA)2 without compromising bird performance while achieving a significant improvement in footpad health and a reduction in trace mineral concentrations in the litter.

Dose-Responses of Broiler Chicks, Given Live Coccidia Vaccine on Day of Hatch, to Diets Supplemented with Various Levels of Farmatan® (Sweet Chestnut Wood Tannins) or BMD®/Stafac® in a 42-Day Pen Trial on Built-Up Litter

Dose-Responses of Broiler Chicks, Given Live Coccidia Vaccine on Day of Hatch, to Diets Supplemented with Various Levels of Farmatan® (Sweet Chestnut Wood Tannins) or BMD®/Stafac® in a 42-Day Pen Trial on Built-Up Litter

Effects of Dietary Antibiotics, Actigen&lt;sup&gt;®&lt;/sup&gt; Yeast Cell Wall Derivative, or Both on Broiler Chicken Live Performance in a Fifty-Two Day Pen Trial on Built-up Litter

Effects of Dietary Antibiotics, Actigen&lt;sup&gt;®&lt;/sup&gt; Yeast Cell Wall Derivative, or Both on Broiler Chicken Live Performance in a Fifty-Two Day Pen Trial on Built-up Litter

Ammonia emissions in tunnel-ventilated broiler houses

Gas production in broiler houses and their emissions are closely related to the microclimate established inside the house according to air temperature, humidity, and velocity. Therefore, the internal house environment is influenced by building typology and ventilation system. The objective of the present study was to evaluate ammonia emission rates in broiler houses equipped with different ventilation systems (negative or positive pressure) and litter conditions (new or built-up). The environment of six commercial broiler houses was evaluated internal and external NH3 concentrations. Ventilation rates were recorded to estimate ammonia emission rates. The efficiency of circulation and exhaust fans was assessed, and higher ventilation rates were determined in negative-pressure houses due to the higher flow of the fans. Houses with new litter increased ammonia emission rates along the rearing period, indicating the relationship between gas emissions, bird age and ventilation rates, and presented a typical curve of NH3 emission increase. Negative-pressure houses with built-up litter presented higher emission rates during the first rearing week due to the high NH3 concentration during the brooding period, when the ventilation rates required to maintain chick thermal comfort are low. Although the results of the present study indicate an advantage of the positive-pressure systems as to gas emissions, further research is needed reduce gas emissions in broiler houses with negative-pressure systems.

The use of metam-sodium to reduce bacteria in poultry litter

SUMMARY The use of built-up litter is currently standard practice in the US poultry industry. However, there is the potential for pathogens to accumulate in built-up litter. One significant pathogen associated with a variety of diseases in poultry is Clostridium perfringens. This particular bacterium is relatively hardy and can survive even some of the more rigorous litter treatments commonly used by the poultry industry. It was the purpose of this research to determine the efficacy of a common soil fumigant, metam-sodium, in reducing C. perfringens numbers in the litter. In addition to C. perfringens, total aerobic and anaerobic bacterial numbers were measured after the product was applied at 1, 3, and 5 gal/ton (4.17, 12.52, and 20.86 mL/kg). This product had only a minor effect in reducing C. perfringens numbers. Conversely, aerobic bacteria were significantly reduced at all application levels, and anaerobic bacteria were significantly reduced at levels of 3 and 5 gal/ton. Because of the inability of this product to influence ammonia, pH, or litter moisture levels, we concluded that it is best used in conjunction with one of the currently available litter treatments for reducing overall bacterial numbers.

Susceptibility of Poultry Red Mites to Entomopathogens

The killing efficacy of the entomopathogenic fungi Beauveria bassiana and Trichoderma album as well as the bacteria Bacillus nigateria israelensis against the poultry red mite, Dermanyssus gallinae De Geer, 1778 were experimentally evaluated. In spite of Dermanyssus gallinae is a major pest in the poultry production, no information is available on the susceptibility of these mite to entomopathogens. Therefore, infection experiments with two fungi and one bacterial species were carried out in the laboratory. Beauveria bassiana and Trichoderma album were tested in assays in which the mites were exposed to high doses of conidia. Beauveria bassiana and Trichoderma album caused high mortalities within the first 5 and 10 days of exposure as well as the bacteria Bacillus nigateria israelensi. Trichoderma album and Bacillus nigateria israelensi proved to be fatal against the poultry red mite D. gallinae, to our knowledge, this is the first record. Trichoderma album and Beauveria bassiana mixture in built-up litter were highly fatal to poultry red mite.

Use of CO2 Concentration Difference or CO2 Balance to Assess Ventilation Rate of Broiler Houses

Ventilation rate (VR) is one of the two key elements for quantifying aerial emissions from animal production facilities. Direct, continuous measurement of building VR can be challenging and impractical under certain circumstances, e.g., naturally ventilated animal housing or a large number of ventilation fans in the building. This study examined the suitability of estimating VR of broiler houses with built-up litter (mixture of manure and bedding), when supplemental heating was not in use, through either carbon dioxide (CO 2 ) balance or the relationship of VR to CO 2 concentration difference between exhaust and inlet air. The reference VR was based on direct measurement by continuously monitoring operation of the in-situ calibrated exhaust fans. The comparative analysis of the direct method vs. each indirect method was conducted for a measurement integration time (MIT) of 10, 30, 60, or 120 min. The analyses revealed that MIT of 30 min or greater resulted in non-significant differences in VR between the indirect and direct methods. The broiler building VR (m 3 s -1 ) may be related to the exhaust-inlet CO 2 concentration difference (ΔCO 2 , ppm) as VR (±3.0) = 4456 (±41) ΔCO 2 -0.786 (±0.019) at 30 min MIT. The VR may also be determined by the CO 2 balance method (including litter CO 2 generation) with a correction factor of 0.97 at MIT of 30 to 120 min. If litter CO 2 generation is omitted from the total building CO 2 production, the actual VR may be estimated by applying a correction factor of 1.077 to the bird respiration CO 2 balance VR. Hence, the CO 2 balance or concentration difference method offers a viable alternative or supplemental check for quantifying building VR under certain conditions where direct, continuous VR measurement is not feasible.