Probiotics are an alternative to increase broiler productivity and flock health. For this reason, the objective of the first study was to evaluate commercially available Bacillus spp. based probiotic products on their ability to reduce Salmonella Heidelberg, in vitro. Results showed that most products reduced the lower concentrations of S. Heidelberg and maintained a reduction for up to 8 h. The second study was conducted to determine if bacterial colonization occurred in a broiler chick after in ovo injection. Using bioluminescence, it was demonstrated that bacteria could migrate and colonize the embryo within 2 h after in ovo injection into the amniotic fluid. The results of these studies demonstrated that probiotics could reduce pathogenic microorganisms and can potentially have a positive impact on the chick before it even hatches and is placed in a broiler house.

The objective of this dissertation was to (1) determine which grow-out and processing sampling points best predicts and causes Campylobacter later in production (2) identify risk factors within the hatchery that influenced Campylobacter prevalence later in production (3) identify biosecurity risk factors that were associated with Campylobacter presence during production and processing (4) identify farm and production characteristics that were associated with Campylobacter presence later in production, and (5) to estimate the proportion of variance and the intraclass correlation coefficients within the hierarchical levels (complex, farm, bird) of the data. The best predictors of post-chill Campylobacter carcass status were the exterior whole carcass sample in the grow-out environment and the crop upon arrival at the processing plant. The best post-chill causal model contained the grow-out whole carcass. Variables associated with the increased odds of a Campylobacter positive sample included controlling the humidity in the hatchery chick room, 2-4 people handling the chicks at the hatchery, washing the setter twice yearly, 2 or more breeder farms providing eggs for the sampled flock, using low water pressure when washing the hatch trays, having more walk-in doors on the boiler house, the farmer removing the litter from the farm, concrete at most used door of the broiler house, the number of workers that work with the birds during grow-out, having more houses on the farm, standing water on the farm day 1, wood interior walls, a vegetation surface next the house footing, and 6 or less flocks on the litter. Protective factors included the use of footbaths and dedicated shoes, greater frequency of entering the house during brooding, disinfectant added to the drinker lines, having concrete outside the most used door, the cleanliness of the workroom, and harvesting birds at 56-63 days of age. The highest percent of variance occurred at the farm level meaning intervention efforts should focus on factors at the broiler farm level i.e. factors that are different among farms within a broiler complex.

The effects of dietary antimicrobial removal and Bacillus subtilis supplementation on the growth and intestinal health of male broilers were investigated. Birds were fed either a control, antimicrobial, or a B. subtilis probiotic diet at different feeding phases. Birds were challenged with a 10 × dose of a coccidiosis vaccine. Supplementation of B. subtilis in for antimicrobials in the late grower and early finisher phases improved growth similar to birds fed antimicrobials until withdrawal, while antimicrobial removal without B. subtilis supplementation in those periods hindered growth. The improved growth suggests that the probiotic was able to alleviate the stress of the challenge compared to antimicrobial removal. Processing yields were improved with antimicrobial removal and B. subtilis supplementation in late grower and early finisher phase. Intestinal health was improved with lower intestinal lesions when antimicrobial were removed and B. subtilis supplemented suggesting the reduction of Eimeria species from colonizing the intestine.

In-house windrow composting of broiler litter has been studied to reduce microbial populations between flocks. Published time-temperature goals are used to determine the success of the composting process for microbial reductions. Spatial and temporal density of temperature measurement can influence the ability to determine what portion of a windrow pile has achieved specified time-temperature goals. Based on this motivation, an investigation of the heating profile in windrowed litter and the identification of the effects of spatial and temporal sampling densities on the prediction of the heating profile in windrowed broiler litter were executed. Likewise, an investigation of the effects of moisture content on heat generation during composting of broiler litter was conducted. Ultimately, the research projects were designed with the goal of determining the efficacy of windrow composting as a treatment method for reducing microbial populations in broiler litter and to produce recommendations for the implementation of future windrow temperature monitoring investigations. While past investigations have reported success of windrow composting for microbial population reductions, a lack of intense spatial and temporal temperature monitoring has likely mis-represented the pile heating profile and resultant effects on microbial populations.

Campylobacter is the leading cause of bacterial gastroenteritis in the United States. The objective of this study was to investigate the prevalence of Campylobacter in newly constructed broiler houses and compare three microaerophilic gas delivery methods used to culture Campylobacter in the laboratory. Of 2,300 litter, 900 fecal, and 45 water samples, only 5, 6 and 1 of the samples, respectively, were confirmed positive. style='mso-spacerun:yes'> Results indicated litter moisture content was different across day, location and house. An interaction was detected for litter pH between day, location and flock. Temperatures averaged 26.8°C inside and 27.6°C outside. style='mso-spacerun:yes'> No difference in colony counts were detected among the gas delivery methods. In conclusion, the newly constructed houses showed no significant prevalence of Campylobacter. style='mso-spacerun:yes'> High litter pH, low temperatures, and other onarm management strategies may have suppressed Campylobacter’s ability to colonize the litter. When selecting a gas delivery method price and space should be considered.

Loss of ammonia from broiler litter degrades air quality, decreases litter fertilizer value, and can have negative health consequences for birds and their caretakers. Rates of NH3 emission from broiler houses are complicated by interrelated management and environmental factors such as air temperature, humidity, house style, ventilation rate,bird age, litter conditions, litter characteristics, and cleanout schedule. Wide variations inemission rates necessitate further investigation of litter characteristics and abatement techniques. The research was designed to clarify the impact of moisture effects that are critical to emissions for poultry litter, in conjunction with bedding type and temperature. Experiments were conducted on litter samples in the laboratory using anacid trap method for determining NH3 losses. Statistical models were developed for predicting release from each bedding material and within the range of litter moistureand temperatures found in commercial broiler houses. This allowed development of relationships that describe the effects of bedding, moisture, time, and temperature on litter generation that have not been published previously. First, type of bedding material was investigated within a limited scope of moisture contents. The results indicated that increasing moisture increases generation from litter. Literature supports the phenomenon that greater litter moisture content up to apoint elicits greater release. At the original moisture content, sand and vermiculite litters generated the most, whereas wood shavings, commercial, and rice hull. Second, an extended range of litter moisture contents (20 – 55%) was investigated while including temperature (18.3 – 40.6 °C) effects. Experiments were conducted using built-up commercial broiler litter from multiple flocks. Response surfaces were parabolic cylinders, indicating maximum production was between 37.4 and 51.5% litter moisture depending on temperature. Comparing the temperature extremes, the maximum up to 7 times greater at 40.6 vs. 18.3 °C. This research defines intermediate critical moisture levels in broiler litter where NH3 is maximized, providing target areasfor researchers and the poultry industry to develop management scenarios to reduce from litter.

Effects of gender and strain cross on carcass characteristics, meat quality and sensory acceptability were studied. Strains consisted of a commercially available strain (Strain A), and a strain genetically selected to maximize breast yield currently in the test phase (Strain B). Broilers varying in gender and strain cross had similar compositional characteristics; all treatments yielded high quality breast and thigh meat and did not differ in sensory acceptability. Effect of salt concentrations on yields, instrumental quality, and sensory acceptability of broiler breast meat was determined. Breast fillets were vacuum-tumbled with different concentrations (0, 0.25, 0.50, 0.75, 1.00, 1.25 and 1.50%) of NaCl and 0.35% sodium tripolyphosphate (STP). Marination showed improvent in CIE L*, shear force, and cooking loss. Marinated samples were highly acceptable to the majority of consumers. Results indicate that 0.5-1.0 % NaCl could be used to effectively marinate broiler breast meat depending on product application and desired attributes.

A preliminary test was conducted evaluating the effect of digestible lysine (dLys) on broiler breeder (BB) male semen quality from forty-one to forty-nine wk of age. Five dietary treatments: corn-soybean meal diet with 1,000 mg dLys/rooser/day (Soy1,000), distillers dried grains with solubles diet with 1,000 (DDGS1,000), 850 (DDGS850), 700 (DDGS700), and 550 (DDGS550) mg dLys/rooster/day. Semen quality was similar except percentage dead sperm which was higher in DDGS550. A second trail was conducted using the same dietary treatments as the preliminary test during twenty to thirty-nine wk of age. Semen quality was similar except percentage dead sperm which was higher in Soy1,000. Soy1,000 exhibited higher body weight (BW), breast weight, and plasma testosterone. In conclusion dLys levels from 1,000 to 700 mg/rooster/day will not adversely affect semen quality of BB males. Attention should be given to BW in BB as it could lead to an increased percentage dead sperm.

The effect of decreasing digestible lysine (dLys) intake by broiler breeder (BB) hens from 35 to 45 wk of age on their reproductive performance and performance of their progeny was evaluated. Two types of diets were fed: a diet from commercially available ingredients consisting of dLys intakes of 1,200 (IDL) and 1,010 mg/hen/day (ID) and a semi-purified diet with dLys intakes of 1,010 (SPL) and 600 mg/hen/day (SP). Hens fed the SPL and SP diets had lower hen-day egg production compared to BB hens fed the IDL and ID diets. Fertility and hatchability of eggs set were lowest (P <0.05) for hens fed the SPL diets. Chick weight at hatch was lower (P<0.05) for those that came from the SP and SPLed hens, but 42 and 56 day body weights (BW) were similar for all treatments. Marginal improvements (P<0.10) in FCR were seen at 42 and 56 days for chicks from IDed hens compared to IDL hens. A decrease in daily intake of dLys appeared to improve BB reproductive performance when hens were fed a semi-purified diet and the same response was not observed in hens fed a diet from commercially available ingredients. Furthermore, the progeny study revealed marginal improvements in some live performance parameters. In a second study, a diet based from corn-soybean meal and formulated to a dLys intake of 1,000 mg/hen/day (CS) and three diets composed primarily of corn, soybean meal, and DDGS with 1,000 (DDGS-1,000), 800 (DDGS-800), and 600 (DDGS-600) mg of dLys/hen/day were fed to evaluate the reproductive performance of BB hens from 24 to 42 wk of age. Feeding diets composed of commercially available ingredients with dLys intake levels below 1,000 mg/hen/day did not impact BB reproductive performance. Reduced BW, carcass and breast weight, and higher (P<0.05) back half weight at 42 days of age was observed from broilers that came from 26 wk old BB hens fed the DDGS-600 diet. Reducing dLys intake in later BB hen ages did not impact progeny performance or carcass characteristics. This suggests that Lys may be in dietary surplus concentrations for commercial breeders under current practical conditions.

Cover crops and composted broiler litter (CBL) are two organic methods used to improve soils and organic vegetable production. The objectives of this study included determining the extent summer cover crops and CBL alter nutrient availability in soil, determining how summer cover crops and CBL influence fall vegetable crops in organic production systems and identifying which cover crops/ CBL combinations improve fall vegetable crop production best. Four cover crops were tested: sunn hemp (Crotalaria juncea), sesame (Sesamum indicum), sorghum sudan grass (Sorghum X drummondii) and a sunn hemp + sesame blend, in combination with four composted broiler litter rates: 0, 2,800, 5,600, 11,200 kg.ha-1 for two years. Few differences were seen among cover crop treatments except for the sorghum sudan grass treatment, which had negative effects on fall broccoli production unless combined with CBL. The CBL increased nutrient availability, percent organic matter, pH and broccoli yield as the rate increased.