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L aying hens are increasingly being kept in backyard flocks, and there is also a growing consumer demand for improved welfare practices in commercial operations. 1 , 2 Poor bone quality is a major welfare concern because it places laying hens at

Open access
in American Journal of Veterinary Research

Inadvertent or intentional administration of pesticides to food animals such as egg-laying hens (layers) and broilers often leads veterinarians to contact FARAD to inquire about withdrawal intervals. Unfortunately, US law permitting ELDU does not

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To assess the effects of electromagnetic (EM) field modification by use of Nufield EM field modification (NEFM) units on egg-laying hens in commercial flocks as indicated by production measures, including hen-day mortality rate (HDMR) and eggs per hen housed (EHH).

Animals—16 commercial flocks of egg-laying hens.

Procedure—5 caged commercial table egg layer flocks (Single Comb White Leghorns) successively housed at the same location during a 6-year period were exposed to NEFM. There were 7 hens/cage (317 cm2 of floor space/bird). At the same site, 11 concurrent non–NEFM-exposed flocks (4 genetically different strains) were sequentially housed. All 16 flocks underwent the same feed and management practices. For each NEFM- and non–NEFM-exposed flock, HDMR and EHH were compared with their respective national breeder goals (BG), defined as the reasonable genetic potential expressed under optimal management and environmental conditions. Furthermore, the HDMRs and EHHs of the NEFM- and non–NEFM-exposed flocks were compared.

Results—Mean HDMR and EHH of the NEFMexposed flocks was 36.9% less and 4.96% greater than the relevant BG, respectively. Mean HDMR and EHH of the non–NEFM-exposed flocks was 12.6% and 0.49% greater than the relevant BG, respectively. Compared with the 11 non–NEFM-exposed flocks, the NEFM-exposed flocks collectively had a 47.6% decrease in HDMR and 1.33% increase in EHH.

Conclusions and Clinical Relevance—Results strongly suggest that application of NEFM in commercial egg-layer flocks improves production measures, which has important welfare implications as well as gross economic advantage. (Am J Vet Res 2005;66:1425–1429)

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in American Journal of Veterinary Research

over various time intervals in poultry particularly in laying hens. As early events in the process of inflammation are the most critical for the immune system to effectively combat microbial infections, 12 the focus of this study was on the early

Open access
in American Journal of Veterinary Research

Leghorns is 250 mg/hen/d (dependent on performance and bone strength), 2 most commercial diets for laying hens are formulated with high concentrations of phosphorus (0.34% to 0.45% NPP; 450 mg/hen/d) to avoid phosphorus deficiency. 3,4 Results of multiple

Full access
in American Journal of Veterinary Research

12 days after surgery, and the cause of death was determined to be sepsis resulting from severe air sacculitis. Data regarding this bird's ovariectomy were included in the analyses. Figure 1 Representative photographs of 2 domestic laying hens

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in American Journal of Veterinary Research

Abstract

Objective

To investigate prevalence of Salmonella enteritidis-positive eggs, excretion of the organism in fecal droppings, and infection of internal organs after oral inoculation of White Leghorn hens with S enteritidis phage type 8.

Animals

30 White Leghorn laying hens.

Procedure

At 25 weeks of age, hens were each inoculated orally with 1010 colony-forming units of S enteritidis, then were observed for 8 weeks.

Results

Salmonella enteritidis Y-8P2 did not cause any clinical signs of disease or decrease in egg production. However, at 1 week after inoculation, 63.9% of the eggs collected from inoculated hens were culture positive for S enteritidis. The organism was isolated from the shell washings, egg shells, yolk, and albumen. A total of 592 eggs from S enteritidis-inoculated hens were examined. Of these eggs, 157 (26.5%) were positive for S enteritidis on external shell washings alone, 17 (2.9%) were positive for S enteritidis internally, and 44 (7.4%) were positive for S enteritidis externally and internally. The percentage of culture-positive eggs gradually decreased between postinoculation weeks 2 and 5, then gradually increased to a high of 76% at week 8. At 3, 7, and 10 days after S enteritidis inoculation, cloacal swab specimens from 3 hens were positive for S enteritidis. Salmonella enteritidis was recovered from ovary, oviduct, liver, and cecal junction from S enteritidis-inoculated hens.

Conclusions

Our results indicated that birds infected with this isolate produced S enteritidis-positive eggs at high frequencies initially, that decreased over time. When S enteritidis antibody began to decrease, reaching geometric mean titer ≤ 40, the frequency of S enteritidis-positive eggs increased. (Am J Vet Res 1996;57:489–495)

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in American Journal of Veterinary Research

In the report “Egg residue considerations for treatment of backyard poultry” ( J Am Vet Med Assoc 247;12:1388–1395), chlortetracycline products approved for use in laying hens were inadvertently omitted from Table 2 . Table 2 should be as

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in Journal of the American Veterinary Medical Association

poultry flocks. There are a limited number of drugs approved for use in laying hens in the United States, and the few drugs that are approved were designed for administration to birds in large commercial operations, which makes their administration to

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in Journal of the American Veterinary Medical Association

, all systems have the potential to provide satisfactory welfare for laying hens.” 4,5 LayWel concluded that “conventional cages do not allow hens to fulfill behavior priorities, preferences and needs for nesting, perching, foraging and dustbathing

Full access
in Journal of the American Veterinary Medical Association