Egg Production Farm Research Articles

Particulate Matter in the Vicinity of an Egg Production Facility: Concentrations, Statistical Distributions, and Upwind and Downwind Comparison

Animal feeding operations (AFOs) satisfy the demand for meat, dairy, and eggs; however, they may negatively impact air quality. In this study, the concentrations of PM2.5 and PM10 were simultaneously monitored at four ambient locations in the vicinity of a commercial egg production farm for over two years. Overall, concentrations and temporal patterns were similar to other rural sites in the southeast U.S. Concentrations near the farm property line did not exceed the 24 h National Ambient Air Quality Standards (NAAQS) for PM2.5 (35 g m-3) or PM10 (150 g m-3). Daily average ambient PM concentrations were best described by a lognormal distribution. Downwind concentrations were statistically significantly higher than upwind concentrations, but differences were <1.0 g m-3 for PM2.5 and <5.0 g m-3 for PM10. Relationships between ambient PM concentrations and rates of PM emission from the poultry houses were statistically significant; however, the strength of the linear relationships (Pearson correlation) was relatively weak (r = 0.15 for PM10 and r = 0.33 for PM2.5). On a diurnal time scale, variability was consistent with expected patterns of mobile source emissions, with observed higher concentrations of PM10 on weekdays attributed to on-farm vehicle activity. The observation of higher ambient PM concentrations during summer months was attributed primarily to seasonal variability in non-local primary PM emissions, as well as regional secondary PM precursor emissions and formation mechanisms. Results of this study provide helpful information for understanding the influence of emissions from egg laying facilities on local PM concentrations.

Biosecurity on a Multiple-Age Egg Production Complex: A 15-Year Experience

A multiple-age egg production farm was conceived, designed, constructed, and managed with the goal of blocking the introduction of preventable poultry diseases and infestations. Fifteen years after conception and 13 years after housing the first hens, the 4 million-hen farm remains free of Mycoplasma gallisepticum, infectious laryngotracheitis, and Ornithonyssus sylviarum. Annual savings in vaccine use exceed the estimated annual costs of the biosecurity program. The cumulative design, construction, and operation of this farm are a successful demonstration of practical, effective biosecurity on a commercial poultry farm.

A flock-tailored early warning system for low pathogenic avian influenza (LPAI) in commercial egg laying flocks

The aim of this study was to develop and evaluate an early warning system (EWS) for commercial egg laying flocks to detect the subtle mortality and egg production changes that characterize low pathogenic avian influenza virus (LPAIV) infections. An EWS will create an alert when the recommended ‘trigger point’ is reached or exceeded. Previously used EWSs are based on fixed alert levels, while the proposed EWS customizes the alert level to each flock. While a fixed approach may be valid for highly pathogenic diseases, it results in a lower detection probability for low pathogenic diseases. The EWS was based on daily data collected from flocks affected by the 2000–2004 H6N2 LPAI epidemic in California. Three EWSs were evaluated: (1) EWS1, which is triggered when the observed mortality increase or production decrease exceeds more than “ x” times the expected daily value (2.75–3.50 times the expected mortality), (2) EWS2, which is triggered when the observed mortality increase or production decrease exceeds more than “ y” times during each of 2 consecutive days the expected daily values (1.75–2.15 times the expected mortality), and (3) a combination of the two. The EWSs were evaluated according to three parameters: detection delay (days) of a LPAI outbreak, false alerts (%) and outbreaks missed (%). Results showed that an egg production-based EWS added no benefit to a mortality-based system, mainly because H6N2 LPAI-related egg production decrease always occurred after increase in mortality. Combining the two EWSs resulted in a reduced detection delay and no missed outbreaks, but at the expense of a slight increase in the number of false alerts triggered. The system presented in this study also outperformed fixed EWSs in all three evaluated parameters. The proposed EWS, if used as part of a poultry cooperative program and combined with a rapid laboratory diagnosis, could be a useful tool in the detection and control of LPAI outbreaks and other poultry diseases. Built in a spreadsheet, the system could be inexpensively, easily and quickly incorporated into a commercial egg production farm decision support system. In addition, the proposed system could be quickly adjusted to changing epidemic situations, and easily customized to individual flocks.

Sustained Mass Release of Pupal Parasitoids (Hymenoptera: Pteromalidae) for Control of Hydrotaea aenescens and Musca domestica (Diptera: Muscidae) in Broiler-Breeder Poultry Houses in Arkansas

Abstract Muscidifurax zaraptor Kogan and Legner, M. raptorellus Kogan and Legner, and Spalangia cameroni Perkins were released bi-weekly in two facilities at a broiler-breeder egg production farm in Arkansas during 2003 and 2004. Of the recovered house fly, Musca domestica L., sentinel pupae, 18.8% were parasitized in 2003, with M. zaraptor being the dominant species (66.8%) and M. raptorellus contributing 6.9% of the parasitism. The release of M. raptorellus did not result in substantial parasitism in sentinel house fly pupae until the second year of study when M. raptorellus was the most dominant species, contributing approximately 61.9% parasitism. At the non-release farm, 13.9% of the sentinel house fly pupae were parasitized, with S. cameroni and M. zaraptor dominating in 2003. Parasitism at the control farm decreased to 3.4% in 2004. It appeared that sustained releases of parasitoids at the release farm over two years provided a significant increase in house fly pupal parasitism when compared to the...

Lessons Learned from a Salmonella Enteritidis Phage Type 4 Outbreak in Austria, 2005

An outbreak of gastroenteritis due to Salmonella Enteritidis phage type 4 occurred in people who attended a traditional hunting festivity in a small village in western Austria 6 through 11 November 2005. Of approximately 250 attendees, 227 had consumed dishes offered at the festival, and of these consumers 35 persons fulfilled the outbreak case definition (attack rate of 15.4%). Spätzle (traditional pastalike side dish) was most likely the contaminated part of the incriminated main course (relative risk of 18.9, 95% confidence interval of 4.6 to 76.7; P < 0.001). Thirteen eggs that remained from the preparation of the spätzle were negative for Salmonella when tested individually without shell disinfection, as were 1,200 eggs collected at the egg production plant and examined with shell disinfection. The back-traced egg production farm had been initially certified as Salmonella free by a voluntary quality control program. However, an intensified environmental investigation of the incriminated egg production farm performed in the first quarter of 2006 and based on an appropriate method of sampling revealed Salmonella Enteritidis phage type 4 in 4 of 13 flocks. Although a combination of epidemiological and microbiological investigations allowed elucidation of the mode of spread, no restrictions were placed on the incriminated flocks of laying hens. These flocks were kept in production until they were stalled out due to age in August 2006. In June 2006, a cluster of 23 cases of Salmonella Enteritidis phage type 6 infection was again associated with this egg production farm. Evidence provided by epidemiological analyses is often disregarded by decision makers. However, negative results from microbiological testing of food involved in an outbreak are often weighted as strong evidence against a causal association between that food and the outbreak.

Effects of Different Molting Procedures on Incidence of Salmonella Infection in Flocks of Naturally Contaminated Laying Hens in a Commercial Egg-Producing Farm by Detection of Yolk Antibodies to Salmonella in Eggs

Indirect enzyme-linked immunosorbent assays (ELISAs) have been applied to detect immunoglobulin Y antibodies to different serotypes of Salmonella in the yolks of chicken eggs with heat-extracted antigens of Salmonella enterica serotypes Agona (SA), Cerro (SC), Enteritidis (SE), Montevideo (SM), and Putten (SP). The egg yolk samples examined were classified as positive if their ELISA absorbance values exceeded the value for eggs from specific-pathogen-free flocks by more than two standard deviations. Of 30 egg yolk samples from three flocks vaccinated with a killed SE vaccine, 29 were antibody positive by the ELISA assay for the SE antigen. Four to 29 of the 29 yolk samples showed positive results for the other serovars, although the absorbance values for SE were higher than those obtained for the other serotypes in each of the yolk samples. All 30 yolks from three flocks that were not administered any SE vaccines were found to be antibody negative for SE, and two samples were determined to be positive for SC. Thirty-nine or 40 eggs were obtained from each of four layer flocks in a commercial egg production farm where the laying houses were naturally contaminated with SA, SC, SM, SP, Salmonella serovar Infantis (SI), and untypeable strains. The ELISA absorbance values for SM in the egg yolks obtained from the two flocks molted through feed withdrawal when the birds restarted laying were significantly (P < 0.05) higher than those observed in the yolks obtained before the molt. In egg yolks from the two other flocks that were molted through a wheat bran diet, there was no significant difference between the absorbance values before and after the molt. The observations in the present study provide further evidence to suggest that a molt initiated through the administration of a wheat bran diet can reduce the risk for Salmonella problems in a commercial egg-producing setting.

Persistence of Immunity in Commercial Egg-Laying Hens Following Vaccination with a Killed H6N2 Avian Influenza Vaccine

The California poultry industry experienced an outbreak of H6N2 avian influenza beginning in February 2000. The initial infections were detected in three commercial egg-laying flocks and a single noncommercial backyard flock but later spread to new premises. The vaccination of pullet flocks with a commercially prepared, killed autogenous vaccine prior to their placements on farms with infected or previously infected flocks was used as a part of the eradication programs for some multiage, commercial egg production farms. The purpose of this study was to follow three vaccinated flocks on two commercial farms to track the immune responses to vaccination. The antibody-mediated responses of the three flocks followed in this study were markedly different. One flock achieved 100% seroconversion at 12.5 wk of age, but by 32 wk of age, all of the hens were seronegative by agar gel immunodiffusion (AGID). In contrast, at 32 wk of age, flocks from the other farm (flocks 2A and 2B) were 95% and 72% seropositive by AGID, respectively. Of the differences that were identified between the vaccination protocols on the two farms, the distinction that could explain the level of disparity between responses is the delivery of the second dose of vaccine with a bacterin on the first farm, which may have interfered with the persistence of immunity in this flock. Hens from flocks 2A and 2B were experimentally challenged at 25 wk of age with H6N2 avian influenza virus. Hens from flock 2A did not transmit virus to naive contact-exposed hens, but hens from flock 2B did. At 34 wk of age, hens from flock 2A were again challenged and naive contact-exposed hens were infected in this second trial. These challenge experiments served to demonstrate that despite detectable antibody responses in flocks 2A and 2B, the birds were protected from infection for less than 21 wk after the second vaccination.

Antimicrobial Susceptibilities of Salmonella Isolates Obtained from Layer Chicken Houses on a Commercial Egg-Producing Farm in Japan, 1997 to 2002

Susceptibility to antimicrobial agents was examined for 325 isolates of Salmonella enterica serotypes Cerro, Infantis, Livingstone, and Montevideo isolated from layer houses on a commercial egg-production farm in the western region of Japan between 1997 and 2002. No antimicrobials were used for therapeutic purposes on the farm during this period. From 1.8 to 3.1% of the isolates were resistant to ampicillin, chloramphenicol, and tetracycline. Resistance to streptomycin and sulfisoxazole was found in 52.9 and 65.5%, respectively, of Salmonella Montevideo isolates and in 0 to 13.2% of the isolates of the other serotypes. All the streptomycin-resistant isolates of Salmonella Montevideo also exhibited resistance to sulfisoxazole. Salmonella Montevideo isolates were first isolated in 1998, and 80.0% of the isolates obtained in this year were resistant to streptomycin and sulfisoxazole. The results suggest that Salmonella Montevideo isolates that had already acquired resistance may have been introduced into the layer houses, although the route and vehicle of transmission were uncertain. The proportion of Salmonella Montevideo isolates resistant to streptomycin and sulfisoxazole significantly decreased (P < 0.01) from 79.5% for 1998 through 1999 to 37.3% for 2000 through 2002. This decrease probably was due to the fact that no antimicrobials were used on the farm. Among 10 isolates from different serotypes obtained from 1997 to 2002 that were resistant to ampicillin, two and five isolates harbored 42- and 63-kb R plasmids and identical DraI restriction enzyme digest patterns, respectively, and carried the blaTEM gene. The results suggest that the ampicillin resistance determinants were transferred among different serotypes of Salmonella in the layer houses.

Effects of sex composition on fear measured as tonic immobility and vigilance behaviour in large flocks of laying hens

Fear can be a damaging stressor, resulting in impaired animal welfare and poor production economy. Often fear reactions are elicited in situations that are in some way related to predator defence. As males have a guarding role, mixing the sexes might be a way of reducing fear in large groups of laying hens. Tonic immobility (TI) and vigilance are anti-predator behaviours shown by poultry. They have been used in several studies to measure the level of fear or stress. The influence of males on duration of TI, vigilance and total number of behaviour transitions in female laying hens was studied on an egg production farm. Eight groups of 1200 white LSL layers each were used and 25 focal birds in each group were studied. In half of the groups one male per 100 females was added. The presence of males had a significant effect on TI-duration and frequency and duration of vigilant behaviour (P<0.001); females in the mixed-sex groups had shorter TI-duration and showed less and shorter vigilance than females in the all-female groups. There was no significant effect on observed agonistic behaviour or the total number of behaviour transitions. However, significantly fewer females in the mixed groups had peck wounds on the comb. These results indicate that female laying hens show less signs of fear if the flock also contains males.

Risk factors for Marek’s disease and mortality in White Leghorns in Norway

A prospective longitudinal field study was conducted in the period from January 1994 to January 1996 to analyse the relationship between some selected risk factors in the growing and laying periods and (1) the flock-level occurrence of Marek’s disease (MD) during the period from 16 to 32 weeks of age and (2) the cumulative mortality during the same period. A total of 171 layer flocks in 102 egg-production farms were included in the statistical analyses. A logistic regression (with strain of layer and vaccination program against MD as fixed effects) of flock-level MD-status during the first 16 weeks of the laying period was conducted. Of the risk factors investigated, “multi-age management” and “housing system” were significantly associated at the rearing farm, and “number of hens in each cage” at the egg-production farm. Flocks kept in single-age facilities had a lower risk of MD than flocks housed in farms with multi-age management. The odds of MD were larger for flocks housed on a litter floor in the rearing farms compared to flocks housed in battery cages. At the egg-production stage, flocks kept in battery cages housing more than three hens were at greater risk of MD than those held in cages for three hens or less. A weighted least-squares regression (with strain of layer and flock-level MD-status as fixed effects) of cumulative mortality during the period from 16 to 32 weeks of age was also run. The same risk factors (with the same directions of effects) and “size of the rearing farm” were included in the final model of mortality. Chicks reared in medium-sized farms were at higher risk of dying than those coming from either small or large rearing farms. Our results confirm the importance of preventing chicks from being exposed to MD-virus during the rearing period, to reduce the risk of MD-outbreaks (and thereby, mortality losses) during the early stage of the egg-laying period.

Performance of Laying Hens Provided Water from Two Sources

The effect of drinking water source (well vs. city water) on laying hen performance was evaluated using 48 commercial layers (64 wk of age) housed in an environmentally controlled facility at a density of two birds per cage (12″ × 18″). After a 10-day adjustment period, four replicate groups (six hens each) were provided water from a commercial egg production farm (drilled well) and the other four groups were provided city water for 4 wk of egg production.The results indicated that water quality differed between the two water sources. A water analysis revealed that the farm well water had sodium and chloride concentrations of 190 and 210 ppm, respectively, compared to sodium and chloride concentrations of 29 and 80 ppm, respectively, for the city water. Average water consumption for the 4-wk experiment was significantly lower for hens consuming well water. Hen-day egg production and egg yield was also lower for hens consuming the well water. Egg weight, feed consumption, feed efficiency, egg specific gravity, and manure moisture were not affected by water source. These results indicate that the quality of drinking water may affect layer performance.

A longitudinal field study of mortality and Marek's disease in Norwegian and imported White Leghorns

High mortality during the first part of the laying period was observed in Norwegian White Leghorns during the period 1988–1992. A longitudinal field study with repeated measurement of cumulative mortality was undertaken in the period from January 1994 to January 1996 to investigate (1) the mortality and susceptibility to Marek's disease (MD) in the Norwegian strain (NB41) compared to two imported layers, (2) the effect of MD on the total cumulative mortality in the period from 16 to 32 weeks of age in White Leghorn flocks, and (3) the effect of MD as judged by repeated measurement of cumulative mortality in the same period. All five layer hatcheries and 67% of the pullet-rearing farms in Norway participated in the field study. The egg-production farms were sampled by convenience. Recordings for the whole period were completed for 169 flocks in 101 farms. The statistical analyses were performed using both a general fixed-effects linear model and a mixed model with repeated measurements, with total flock-level cumulative mortality and flock-level cumulative mortality in four-week intervals as outcome variables, respectively. The overall cumulative flock-level incidence of MD was 12% (24% and 8% in NB41 and Lohmann White, respectively). MD was not recorded in any of the Shaver White flocks. A significant difference ( p < 0.001) was found in (1) total cumulative mortality: 8.2% in the NB41 and 5.0% in the imported layers, and (2) `interval-specific' cumulative mortality: 0.36% in the NB41 and 0.15% in the imported birds. A strong relationship was also demonstrated between MD and repeated measurements of `interval-specific' cumulative mortality ( p < 0.001) but not when cumulative mortality was used as an overall measure for the whole laying period ( p = 0.11). The results from the repeated-measures analysis also indicated a stronger effect of MD on flock-level `interval-specific' cumulative mortality in the NB41 than in the imported hens. The different cumulative mortality and susceptibility to MD observed in the NB41, compared to the imported hens, shows that the farmers will be able to reduce their losses by replacing the NB41 strain with one of the imported strains.

An Association of Hardness of Water with Incidence of Fatty Liver Syndrome in Laying Hens

Twenty-one samples of water were collected from commercial egg production farms in Georgia with or without a history of fatty liver syndrome. These samples plus a sample of water from the University of Georgia Poultry Farm were analyzed for various mineral elements by atomic absorption, direct reading emission spectroscopy and by neutron activation. Water samples from farms with a history of fatty liver syndrome had significantly more calcium, magnesium, strontium, sodium, iron and barium than water samples from farms reporting no significant problem with fatty liver syndrome. Levels of manganese, boron, copper, zinc and aluminum were not significantly different.Although the results do not prove that water quality is the cause of the disease, they do demonstrate an association of hardness of water with fatty liver syndrome that should be further investigated.

An Assessment of Some Public Health Problems Resulting from Feeding Poultry Litter to Animals.: Microbiological and Chemical Parameters

INTRODUCTIONTHE rapid development of large-scale broiler and egg production farms in recent years has made the disposal of poultry litter a major problem for producers. Studies by Belasco (1954) and Jurtshuk et al. (1955) showed that rumen microorganisms can utilize the uric acid of poultry litter as a nitrogen source. Feeding studies on the utilization of poultry litter as a feed additive for ruminants demonstrated satisfactory animal nutrition when litter was fed as 20–30% of the ration of growing cattle (Southwell et al., 1958), 10–15% of the ration for lactating ewes (Noland et al., 1955), and 15–25% of the ration of breeder swine (Camp, 1959). Thus, poultry and shell egg producers were provided with a profitable means of litter disposal, and livestock producers were afforded an attractive source of cheap feed with a value on an equivalent basis with grain of fifteen dollars a ton.As…