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Forty layer farms from 2 states participated in a study to examine the risk factors and incidence of Salmonella Enteritidis from multiple samples, including environmental drag swabs from the bird areas, feed, water, flies, rodents, live rodent traps, and environmental swabs from areas occupied by other livestock. Twenty-four of these farms had between 3,000 and 31,000 bird flocks (medium-sized flocks) and 16 had less than 3,000 birds (small-sized flocks). All were housed in cage-free production systems. Twenty-two farms included outside pasture areas for the birds. Most of the participants had just come under the FDA Egg Rule and had not yet tested their flocks (flocks under 3,000 birds are exempt) for Salmonella Enteritidis. Many, however, obtained their pullets from commercial Salmonella Enteritidis-clean breeder sources hatched in National Poultry Improvement Plan hatcheries. Vaccination against Salmonella Enteritidis was performed on 21 of the 40 farms (combination of live and killed vaccines). Salmonella Enteritidis was detected on 7 out of the 40 farms, primarily in rodents, their feces, or from swabs taken inside live traps. Of these 7 Salmonella Enteritidis-positive farms, 3 farms that had vaccinated their pullets with live Salmonella Typhimurium vaccine and killed-Salmonella Enteritidis vaccine; no Salmonella Enteritidis was isolated from the environmental drag swabs taken from the bird area or from the eggs on these farms. However, on the farms that had not vaccinated for Salmonella Enteritidis, the organism was isolated from 4 environmental drag swabs and 3 egg pools. The last 4 farms had flocks under 3,000 birds. No Salmonella Enteritidis was isolated from any of the samples of feed, flies, water, or swabs taken from other livestock areas. Based on the initial findings in this study, we suggest the 2 most important risk factors for Salmonella Enteritidis contamination inside the bird area and in the eggs in these small- and medium-sized flocks are the presence of infected rodents and the absence of an Salmonella Enteritidis vaccination program.

In this field observational study, 3 types of laying-hen houses, namely, high-rise (HR), manure-belt (MB), and cage-free floor-raised (FR), were monitored for air temperature, RH, CO2, and atmospheric NH3 under winter and summer conditions in Iowa. Under winter conditions, the HR and MB houses had more comfortable temperature and NH3 levels (mean 24.6 and 20.6°C, and maximum 9 to 24 ppm of NH3, respectively) than the FR houses (mean 15.5°C and maximum 85 to 89 ppm of NH3, respectively), and house temperature varied more with outside conditions. Under summer conditions, house temperature showed the least increase above ambient in the FR houses (mean 0.3°C vs. 4.7 and 1.2°C for the MB and HR houses, respectively), and NH3 levels were similar for all housing types (mean 3 to 9 ppm). Examination of the hen health status revealed differences in pathogen prevalence between housing systems for winter and summer, but not conclusively in favor of one system over another. Results of this study indicate that the benefits of each system were season dependent. Further monitoring of the environment, bird health, and production performance over an extended period (e.g., 1 yr) to quantify the benefits and limitations of each system is warranted. Information of this nature will aid in optimizing hen housing systems for enhanced bird welfare and sustained production efficiency for the egg industry.

Dietary spray-dried plasma protein (SDPP) is effective in improving growth performance of pigs raised in unsanitary conditions. However, little is known about the efficacy of SDPP in improving growth performance and carcass characteristics of broiler chickens. In the present study, graded levels of bovine SDPP (0 to 2% of the diet) were fed to male broiler chickens (Ross 308) from 1 to 42 d of age. The study was divided into 2 experiments, each with 480 chickens, with identical experimental designs. Broilers in the second experiment were raised on the soiled litter from the first experiment, thereby creating 2 environments with different levels of sanitation. Broilers fed the control diet in experiment 2 had higher mortality, lower rate of body weight gain, and were less uniform than broilers fed the control diet in experiment 1, suggesting that reusing the soiled litter in experiment 2 resulted in a relatively more unsanitary environment. Dietary bovine SDPP did not affect growth performance or carcass characteristics in the first experiment, but improved growth rate, feed conversion, breast-meat yield (as a percentage of carcass weight), and flock uniformity of the broilers in the second, more unsanitary, experiment. In conclusion, dietary SDPP, fed throughout the growth period, improved growth performance and breast-meat yield of broilers raised in an unsanitary environment.