Casey W. Ritz

Isolation and characterisation of Salmonella in a turkey production facility

1. A comprehensive ecological survey was conducted from April 1997 to June 1999 on 4 turkey flocks (F1 to F4) to identify key pre-harvest sources/vectors of Salmonella colonisation. 2. Turkey caecal and crop content, litter, drinker, air, feed, feeder and environmental swab samples were collected. Conventional microbiological and serological procedures were used to isolate, identify, and confirm the presence or absence of Salmonella. 3. Salmonella was isolated from 13% of litter, 11% of turkey caeca, 10% of drinker, 5% of environmental swab, 3% of feed and 1% of feeder samples. Salmonella heidelberg (65%), S. senftenberg (19%), S. muenster (10%), S. anatum (3%), and S. worthington (3%) were identified. 4. Identifying environmental sources associated with Salmonella colonisation and characterising serotypes would assist in designing pre-harvest controls for this poultry-borne pathogen. Integrators and poultry producers may be able to design hazard analysis and critical control point (HACCP) protocols to reduce the incidence of Salmonella arriving at the processing plant.

Successional changes in the chicken cecal microbiome during 42 days of growth are independent of organic acid feed additives

BackgroundPoultry remains a major source of foodborne bacterial infections. A variety of additives with presumed anti-microbial and/or growth-promoting effects are commonly added to poultry feed during commercial grow-out, yet the effects of these additives on the gastrointestinal microbial community (the GI microbiome) as the bird matures remain largely unknown. Here we compared temporal changes in the cecal microbiome to the effects of formic acid, propionic acid, and medium-chain fatty acids (MCFA) added to feed and/or drinking water.ResultsCecal bacterial communities at day of hatch (n = 5 birds), 7d (n = 32), 21d (n = 27), and 42d (n = 36) post-hatch were surveyed using direct 454 sequencing of 16S rRNA gene amplicons from each bird in combination with cultivation-based recovery of a Salmonella Typhimurium marker strain and quantitative-PCR targeting Clostridium perfringens. Treatment effects on specific pathogens were generally non-significant. S. Typhimurium introduced by oral gavage at day of hatch was recovered by cultivation from nearly all birds sampled across treatments at 7d and 21d, but by 42d, S. Typhimurium was only recovered from ca. 25% of birds, regardless of treatment. Sequencing data also revealed non-significant treatment effects on genera containing known pathogens and on the cecal microbiome as a whole. In contrast, temporal changes in the cecal microbiome were dramatic, highly significant, and consistent across treatments. At 7d, the cecal community was dominated by three genera (Flavonifractor, Pseudoflavonifractor, and a Lachnospiracea sequence type) that accounted for more than half of sequences. By 21d post-hatch, a single genus (Faecalibacterium) accounted for 23-55% of sequences, and the number of Clostridium 16S rRNA gene copies detected by quantitative-PCR reached a maximum.ConclusionsOver the 42 d experiment, the cecal bacterial community changed significantly as measured by a variety of ecological metrics and increases in the complexity of co-occurrence networks. Management of poultry to improve animal health, nutrition, or food safety may need to consider the interactive effects of any treatments with the dramatic temporal shifts in the taxonomic composition of the cecal microbiome as described here.

Ammonia emissions from broiler litter: response to bedding materials and acidifiers

1. In a pen study, NH3 flux estimates were performed when clean wheat straw or wood shavings were used as bedding materials in combination with two NH3 control amendments: sodium bisulphate and a commercial premix of phosphoric + hydrochloric + citric acids. 2. Ammonia emissions from wood shavings were 19% greater than from wheat straw around waterers, but statistically similar around feeders. These results could be due to the greater caking observed when wheat straw was used. 3. Sodium bisulphate reduced NH3 emissions significantly only in the first half of the rearing period; the loss of efficacy in the second half resulted in total NH3 volatilisation not statistically different from the untreated control. The treatment containing phosphoric + hydrochloric + citric acids did not have a significant effect in decreasing NH3 emissions. 4. Bird mortality was not affected by the treatments, but broiler weight gain when wheat straw was used was significantly lower than with wood shavings, which could have been caused by the greater caking observed with wheat straw.

Growth, livability, feed consumption, and carcass composition of the Athens Canadian Random Bred 1955 meat-type chicken versus the 2012 high-yielding Cobb 500 broiler

A flock of the Athens Canadian Random Bred (ACRB), a 1955 meat-type chicken control strain, was raised alongside a flock of 2012 Cobb 500 fast feathering high-yielding broilers to determine selection changes over the past 57 yr. All birds were reared under management practices appropriate for the Cobb 500. Birds were weighed weekly and processed at 6, 8, and 10 wk. Whole carcass, carcass parts, and organs were weighed. Modern broilers outweighed ACRB at every age, ranging from 3.7 to 4.7 times the size of the ACRB. All parts and organs were compared as a percentage of live fasted BW. The ACRB had significantly heavier feet, wings, internal organs, and feathers. The modern Cobb broiler had double the breast and larger leg muscles and had a significantly greater fat pad. Despite the larger muscle mass, the supply organs, the heart and lungs, were significantly smaller in the Cobb broiler than the ACRB as a percentage of BW. Relative size of supply and other vital organs should be given consideration for genetic selection of the future broiler. Comparisons of ACRB weights and organ percentages with past published data indicates that the ACRB remains a consistent control strain.

Tenacity of low-pathogenic avian influenza viruses in different types of poultry litter

To determine the risk of infection associated with exposure to low-pathogenic avian influenza (AI) virus-contaminated poultry litter, the tenacity of low pathogenic A/Ck/CA/431/00(H6N2), A/Mallard/MN/355779/00(H5N2), and A/turkey/Ohio/313053/04(H3N2) was evaluated. Viral stocks were incubated with poultry litter from commercial flocks at 25°C. Three types of poultry litter, wood shavings, shavings plus gypsum, and shavings plus peanut hulls, from commercial broiler flocks were used. The 3 low-pathogenic avian influenza viruses retained infectivity for one day in wood shavings and shavings plus peanut hulls litter types, whereas in wood shavings plus gypsum, litter viruses remained infective for up to 3 d. In contrast to the survivability in litter, all the viruses maintained infectivity in water for 4 d at titers of log(10)4.5. The infectivity of A/Ck/CA/431/00(H6N2) shed by experimentally infected layers, broilers, and turkeys was retained for one day, independently of the type of litter. In commercial production where a high density of birds are housed, the viral load shed by an infected flock will be significantly higher than the viral load shed 3 d postinfection obtained under the experimental conditions used in this study. Therefore proper management and disposal of poultry by products, such as windrow composting of litter and the composting of carcasses during an AI outbreak should be implemented.

Electrostatic Space Charge System for Air Quality Improvement in Broiler Production Houses

Reducing airborne dust in enclosed animal housing has been shown to result in corresponding reductions in airborne bacteria, ammonia and odor. Technologies that have been shown to be effective for reducing airborne dust in animal areas include misting with an oil spray, water mists, extra ventilation, and electrostatic space charge systems. Increasing pressure from environmental groups to reduce PM-10 and ammonia emissions from animal housing has led to considerable interest by the poultry and swine industries for practical systems to reduce these air pollutants. This presentation will describe an electrostatic space charge system (ESCS) that was designed to reduce airborne dust and ammonia emissions from a commercial broiler production house. The ESCS for this application was based on patented technology that was developed over a period of several years to reduce airborne dust and pathogens and proven in numerous research trials in poultry hatchers and growout areas. A recently completed study in a small broiler breeder house showed the ESCS reduced airborne dust by an average of 60%, ammonia by 56%, total bacteria by 76%, and it reduced the number of Salmonella infected broilers produced from eggs gathered in the study. Preliminary results of the present study in a broiler production house during the cool months of November through April indicate the ESCS reduced airborne dust by an average of 55% and ammonia by an average of 8% in a house with built-up litter. Later studies will include litter that is fresh or not over a few months old which is expected to improve the effectiveness of the ESCS for ammonia removal since a higher percentage of the ammonia produced would be on the dust that is removed.

Supplementation of nitrocompounds in broiler diets: Effects on bird performance, ammonia volatilization and nitrogen retention in broiler manure

ABSTRACT A study was conducted to evaluate the effects of dietary nitrocompounds on bird performance, ammonia volatilization, and changes in manure nitrogen (N). A total of 200 one-day-old male chicks (Cobb 500) were used for this study. The chicks were raised in electrically heated battery brooders for 18 days. On day 1, birds were allocated into five treatment groups with four replicated pens: (T1) control, a corn and soybean meal diet (3,100 kcal kg−1 metabolizable energy (ME) and 21% Crude Protein (CP)); (T2) 16.7 mg kg−1 nitroethanol (NEL); (T3) 33.3 mg kg−1 NEL; (T4) 16.7 mg kg−1 nitropropanol (NPL); and (T5) 33.3 mg kg−1 NPL. The body weight gain, feed intake and feed efficiency were measured on days 7, 14 and 18. Volatized ammonia (VA) and other N forms were measured at collection and following 2 weeks of incubation at 30°C. Broiler growth was not adversely affected by the nitrocompounds at concentrations up to 33.3 mg kg−1. The results show that initial manure pH was reduced by adding nitroethanol (NEL) and nitropropanol (NPL) to the diet by 0.2 and 0.5 pH units, respectively. Total VA after 2 weeks was unaffected by dietary treatment. The amounts of uric acid decomposed and ammonia produced were closely balanced in the control sample. However, this balance was significantly different among the manures produced by birds receiving nitrocompound treatments. The inclusion of NEL and NPL resulted in the presence of measurable amounts of Xanthine not found in the control group. This study indicates that supplementation of nitroethanol or nitropropanol into broiler diets up to 33.3 mg kg−1 influences uric acid degradation and ammonia production in broiler manure while maintaining optimal growth performance.

Ammonia and Fine Particulates Inside and Outside Tunnel Ventilated Broiler Houses – A First Look

Air emissions from animal feeding operations have become a growing concern. Much work has been done to study occupational exposures and the exhaust concentrations associated with animal facilities, however little information has been provided about air quality around the houses. This study investigates ammonia and PM2.5 (particulate matter = 2.5 um in diameter) inside and outside (up to 152 m from the house) of commercial tunnel-ventilated broiler houses on a farm (6 houses 11 x 130 m) in northeast Georgia. PM2.5 was measured in real time using aerosol monitors and on a time-integrated basis using cyclone samplers. Ammonia was measured using electrochemical sensors. None of the 24-h PM2.5 measures collected when the houses were in tunnel ventilation exceeded the U.S. EPA 24-h National Ambient Air Quality Standard (NAAQS) of 65 ug/m3. Ammonia levels outside the house appeared to be considerably less than 1 ppm, but wind direction at the site was not recorded and wind at a remote weather station was contrary to the direction of the sensors on the days that ammonia data were taken. Additional study is needed to confirm these results.

Effects of Heavy Application of Litter Amendment on Broiler House Ammonia Concentration

Litter amendments for ammonia control have been used extensively by the poultry industry. They are applied prior to chick arrival and are critical in maintaining proper air quality during the brooding period when ventilation rates are the lowest. While effective, these amendments generally are depleted by the time the birds are 10-14 days of age. The objective of this study was to examine whether litter amendment effectiveness can be extended by increasing application rates to reduce overall broiler house ammonia emissions and whether the effect is additive as multiple applications are applied to built-up litter. The study was conducted on a 6-house commercial broiler farm. At the beginning of the study all litter was removed from the houses and clean shavings were applied. A commercial litter amendment (PLT) a product with sodium bisulfate as the active ingredient was applied at the rates of 50, 100, and 150 lbs per 1000 ft2. House temperature, relative humidity and ventilation rates were monitored by the house controller and a computer placed on the farm. Ammonia concentrations were measured with GasTech Dosi-Tubes, Rae draw tubes, and Draeger electrochemical sensors. Litter samples were taken at the end of each flock for mineral analysis. Results indicate that the duration of reduced ammonia production appears to be positively correlated with the amount of sodium bisulfate applied to the house. Litter in the higher treatments retained more N in the form of ammonium than the control indicating that less N had been volatilized as ammonia The addition of increased amounts of litter treatment at the beginning of the flock may reduce ammonia production for an additional week, but additional applications or other solutions will be necessary to control ammonia during the last weeks of production.

Signal processing for animal behavior detection

Researchers at the Georgia Tech Research Institute and the University of Georgia recently concluded an experiment studying animal reaction to robotic systems. The purpose of this study was to determine if the operation of robots in a poultry grow-out house environment is feasible from an animal behavior perspective. To determine this, an experiment was conducted operating both an aerial and a ground robot in a small-scale grow-out house housing broiler chickens for a typical growth cycle (6 weeks). Humans also interacted with the flock daily. The environment and robots were equipped with cameras and other sensors to record data for the entire duration of the experiment. The research team established a set of measurable metrics with which to quantitatively assess the impact of operating the robots. These metrics included average avoidance distance, average speed when avoiding, and average recovery time. A software program was developed to assist in the analysis of these metrics. Analysis shows that there are statistical differences in the average avoidance distance metric but there is no significant difference between the average speeds, or with the recovery time metric, indicating that operating robots in the environment is no more stressful to the chicken than the presence of a human.