V. Allain

Skin lesions in broiler chickens measured at the slaughterhouse: relationships between lesions and between their prevalence and rearing factors

1. This slaughterhouse-based study was to evaluate correlations between cutaneous lesions which are linked to animal welfare. The relationships between these lesions and various rearing factors were investigated. 2. The percentage of lesions in each flock was determined by observation at the slaughterhouse. Fifty-five flocks slaughtered between May 2005 and May 2006 in 8 slaughterhouses were investigated. 3. Data relating to farm management and housing factors during the rearing period were collected retrospectively from 36 of the 55 flocks scored for lesions. 4. A negative correlation was observed between (i) presence of breast blisters and deep hock burns, (ii) presence of breast blisters and deep footpad dermatitis, and (iii) presence of breast burns and scratches. 5. We proposed an assessment of broiler chicken welfare at the slaughterhouse on the basis of several criteria: (i) footpad dermatitis, hock burns and breast burns, (ii) scratches, and (iii) breast blisters. 6. The presence of contact dermatitis was related to litter quality and several management factors. Only scratches and breast blisters were related to high stocking density. The type of lesion was related to genotype. Genotype A (fast-growing) had fewer breast blisters but deeper footpad lesions than B (slower-growing).

Campylobacter contamination of broiler caeca and carcasses at the slaughterhouse and correlation with Salmonella contamination

In order to estimate the prevalence of Campylobacter spp. and Salmonella spp. on broiler chicken carcasses and the prevalence of Campylobacter spp. in caeca, 58 French slaughterhouses were investigated in 2008. Enumeration of Campylobacter spp. was also performed in order to study the relation between caeca and carcass contamination. A pool of 10 caeca and one carcass were collected from 425 different batches over a 12-month period in 2008. Salmonella was isolated on 32 carcasses leading to a prevalence of 7.5% ([5.0-10.0](95%CI)). The prevalence of Campylobacter was 77.2% ([73.2-81.2](95%CI)) in caeca and 87.5% ([84.4-90.7](95%CI)) on carcasses. No significant correlation was found between Campylobacter and Salmonella. Positive values of Campylobacter were normally distributed and the average level was 8.05 log(10) cfu/g ([7.94-8.16](95%CI)) in caeca and 2.39 cfu/g ([2.30-2.48](95%CI)) on carcasses. A positive correlation (r = 0.59) was found between the mean of Campylobacter in caeca and on carcasses (p < 0.001). Thus, carcasses from batches with Campylobacter-positive caeca had significantly (p < 0.001) higher numbers of Campylobacter per gram than batches with negative caeca. These results show that Campylobacter can be present in both matrices and reduction in caeca could be a possible way to reduce the amount of bacteria on carcasses. Of the 2504 identifications performed, 3 species of Campylobacter (Campylobacter jejuni, Campylobacter coli and Campylobacter lari) were identified. The main species recovered were C. jejuni and C. coli, which were isolated in 55.3% and 44.5% of positive samples, respectively. These two species were equally represented in caeca but C. jejuni was the most frequently isolated on carcasses with 57.1% and 42.5% of positive carcasses for C. jejuni and C. coli, respectively. This study underlines that target a reduction of Campylobacter on final products requires a decrease of contamination in caeca.

Histologically-validated footpad dermatitis scoring system for use in chicken processing plants

1. Footpad dermatitis (FPD) is a recognised welfare problem in broiler chickens. Broiler feet (n = 54) were examined macroscopically and microscopically to determine a reliable correspondence between macroscopic and histological features, and to devise a scoring system that was relevant to bird welfare and easy to use at processing plants. 2. Three types of footpad lesion were defined based on their severity. Type I were mild lesions, visually characterised by scale enlargement and erythema, and histologically by hyperplasia and hyperkeratosis of the epidermis, superficial dermal congestion and oedema. Type II were moderate, superficial lesions, visually characterised by hypertrophic and hyperkeratotic scales covered with yellowish to brownish exudate, and histologically by a prominent pustular and crust-forming dermatitis. Type III lesions were the most pronounced, visually characterised by a thick dark adherent crust, and histologically by extensive ulceration. 3. On the basis of the severity and extent of these three types of lesions, a 5-point scale was devised, i.e. no or type I lesion (score 1), type II lesion (<50% or >50% of footpad, scores 2 and 3 respectively) and type III lesion (<50% or >50% of footpad, scores 4 and 5 respectively). 4. The scoring system has the advantage of making sense in terms of welfare compared with previous schemes. Furthermore, it is histologically validated and easy to use for the routine assessment of broiler welfare in processing plants.

Risk and indicators of condemnation of male turkey broilers in western France, February–July 2006

A field study was conducted to estimate the sanitary condemnation proportion in male turkey broiler flocks, to describe the reasons for condemnation and the related macroscopic lesions, and to investigate whether primary production information would predict the risk of condemnation. Male turkey standard broiler flocks (117) were randomly selected in the 13 slaughterhouses located in Western France, from February to July 2006. The flocks were monitored from their arrival at the slaughterhouse until the results of the post mortem sanitary inspection. Information about rearing conditions, health history, catching and loading conditions, transportation to the slaughterhouse and slaughtering was also collected. Sampling design was considered in the calculations and the condemnation proportion was modelled using a negative binomial regression, accounting for clustering within slaughterhouse. The within-flock weighted average condemnation proportion was 1.8% (95% confidence interval, 1.3-2.3%). Emaciation, arthritis-polyarthritis and congestion were the main reported official reasons for condemnation, representing 76% of the condemned carcases. Three variables were significantly associated with increased risk of condemnation: observed locomotor disorders on the farm, high cumulative mortality 2 weeks before slaughter, and clinical signs observed by the Veterinary Services during the ante mortem inspection at the slaughterhouse. The final model explained 35% of the total variation in condemnation risk. Half of this explained variation could be attributed to locomotor disorders observed during rearing. The sensitivity and specificity of the model to predict a high flock condemnation risk were 80% and 74%, respectively, when using an optimum threshold of 0.95% to define high risk. The results of this study suggested that the variables found to be associated with condemnation proportion were markers of increased risk and could be used as indicators. These risk indicators can easily be retrieved from the pre-existing regulatory document transmitted before flock arrival at the slaughterhouse and could be used to screen flocks before slaughter, according to their expected risk of condemnation.

Prevalence of and risk factors for Campylobacter colonisation in broiler flocks at the end of the rearing period in France

Abstract 1. A study was conducted to estimate the prevalence and quantification by species of Campylobacter infection in broiler flocks at the end of the rearing period and to identify associated risk factors. 2. A questionnaire about the rearing period was completed and caecal samples were collected from 121 broiler flocks in Brittany, France, during 2008. 3. Campylobacter was isolated in 87 out of 121 flocks – a prevalence of 71.9% (95% CI, 63.7–80.1%), including 40.5% of Campylobacter jejuni and 29.8% of Campylobacter coli. 4. The average concentration, in positive flocks, was 7.96 log10 cfu/g and ranged from 3.15 to 10.32 log10 cfu/g. 5. The average concentration by species was: 7.57 log10 cfu/g for C. jejuni and 8.44 log10 cfu/g for C. coli. 6. There was a seasonal effect, with increased risk of Campylobacter colonisation in June, July and August (odds ratio (OR) = 9.59, 95% CI 1.15–79.75). 7. The other factors, associated with lower risk of Campylobacter colonisation, were the acidification of drinking water (OR = 0.33, 95% CI 0.13–0.86), antibiotic treatment at the beginning of the rearing period (OR = 0.20, 95% CI 0.07–0.55) and rodent control around the house (OR = 0.18, 95% CI 0.03–0.95). 8. The results show that hygiene practices and biosecurity measures could lead to a reduction in Campylobacter colonisation.

Risk factors for Listeria monocytogenes contamination in French laying hens and broiler flocks

The objective of this study was to identify potential risk factors for Listeria monocytogenes contamination in French poultry production. Eighty-four flocks of layer hens kept in cages and 142 broiler flocks were included in this study. For each production type, a questionnaire was submitted to farmers and fecal samples were taken to assess the L. monocytogenes status of the flocks during a single visit to the farm. Two logistic regression models (specific to each production) were used to assess the association between management practices and the risk of L. monocytogenes contamination of the flock. The prevalence of L. monocytogenes-positive flocks was 30.9% (95% CI: 21.0; 40.9) and 31.7% (95% CI: 24.0; 39.4) for cage-layers and broiler flocks, respectively. For layer flocks, the risk of L. monocytogenes contamination was increased when pets were present on the production site. When droppings were evacuated by conveyor belt with deep pit storage, the risk of L. monocytogenes contamination decreased significantly. Feed meal was found to be associated with a higher risk of L. monocytogenes contamination than feed crumb. For broiler flocks, the risk of L. monocytogenes contamination was increased when farmers did not respect the principle of two areas (clean and dirty) at the poultry house entrance. A first disinfection by thermal fogging and the absence of pest control of the poultry house before the arrival of the next flock was found to increase the risk of contamination. When litter was not protected during storage and when farm staff also took care of other broiler chicken houses, the risk of L. monocytogenes contamination increased significantly. In the case of the watering system, nipples with cups were found to decrease the risk of contamination.

Prevalence and risk factors for Salmonella spp. contamination in French broiler-chicken flocks at the end of the rearing period.

A nation-wide survey was carried out in 370 randomly chosen French commercial broiler chicken flocks from October 2005 to September 2006 to determine Salmonella spp. prevalence and to identify risk factors for contamination, at the end of the rearing period. The Salmonella status of the flocks was assessed from five faecal samples (litter swabs) analysed by classical bacteriological methods. A flock with at least one contaminated sample was classified as a Salmonella-positive flock. The apparent prevalence of Salmonella was 8.6% (95% CI: 5.7, 11.5%). The most prevalent serovar was S. hadar followed by S. anatum and S. mbandaka. Logistic regression methods were used to analyse the associations between husbandry practices, farm characteristics, general hygiene and the Salmonella status of the sample. The risk for Salmonella contamination of the flock at the end of the rearing period increased when neighbours helped in the placement of day-old chicks. On the contrary, the risk decreased when mobile equipment was dismantled before cleaning and disinfection, when the farm had a specific container for dead-bird disposal and when acetic acid was added to the drinking water.

Prevalence of skin lesions in turkeys at slaughter

1. The aims of this study were (i) to evaluate the prevalence of welfare-related cutaneous lesions in turkeys at the end of the rearing period and (ii) to study the correlations between lesions. 2. The percentage of lesions in each flock was determined by observation at the slaughterhouse. Sixty flocks were investigated in 13 slaughterhouses between April and July 2006. 3. All flocks showed a high proportion of turkeys with footpad lesions, with 40·7% of turkey flocks having severe footpad dermatitis. A significant number of feet had swelling of the footpad and deviated toes (60·0% and 21·4% respectively). Arthritis was observed in 25·4% of the carcases and an average of 30·1% had breast buttons on the keel. 4. Positive correlations were found between evidence of feather pecking and arthritis, toe deviations and swelling of the footpad. Deviated toes, swelling of the feet and feather pecking were negatively linked to the most severe scratches (P < 0·001). 5. A method is proposed to assess turkey welfare at the slaughterhouse based on several criteria: footpad lesions, arthritis, severe scratches, deviated toes, swelling of the footpad and breast buttons.

Rates of and reasons for condemnation of poultry carcases: harmonised methodology at the slaughterhouse

European hygiene regulations require the condemnation of any unsafe food. However, there is little information identifying and quantifying condemnation of poultry carcases at slaughterhouses. We present an in-depth view of rates of and reasons for the condemnation of broiler, turkey, meat and force-feeding duck, guinea fowl carcases in France. The experiment was conducted in 10 slaughterhouses. For one year, all condemnations were recorded on a standard form following a national reference system. The rates of and reasons for condemnation, as well as factors influencing variation were investigated. The global condemnation rates were 1.04 per cent for broilers, 1.85 per cent for turkeys, 1.23 per cent for meat ducks, 1.42 per cent for force-feeding ducks and 1.20 per cent for guinea fowl. Condemnation rates depended on several factors including slaughterhouse, animal gender and season. Reasons for condemnation varied with species, for example, the three main reasons for broilers were cachexia (41.8 per cent of condemned batches), generalised congestion (29.3 per cent) and non-purulent cutaneous lesions (14.2 per cent) versus conformation abnormalities (58.6 per cent), cachexia (14.61 per cent) and ascites (14.56 per cent) for meat ducks. While the condemnation rates can be considered low for all species, the difference between the rates of and reasons for condemnation highlights the need to lead species-specific epidemiological studies to improve the sanitary situation of poultry production.