Levels of foot pad dermatitis in broiler chickens reared in 5 different systems

1. The prevalence and severity of foot pad dermatitis (FPD) was examined in 359 flocks of broiler chickens comprising about 3.93 million birds produced on 91 farms and reared under 5 types of system: standard intensive, free-range, organic, systems complying with the RSPCA Freedom Food scheme, and corn-fed. 2. The mean prevalence of FPD in standard systems was 14.8%. Flocks that had access to the outside (free-range and organic systems) showed higher prevalence of FPD than those kept entirely indoors (standard, corn-fed and Freedom Food systems). The lowest prevalence of FPD (9.6%) and severity of the lesions occurred in Freedom Food systems, and the highest prevalence (98.1%) and severity in organic systems. 3. The implication from the results is that there are large variations in the prevalence and severity of FPD in birds reared under different systems and this needs to be taken into account when assessing the overall welfare associated with each type of system.     

Footpad dermatitis in broiler chickens in Japan

The prevalence of footpad dermatitis (FPD) in broiler chickens in Japan was investigated. In the first examination at slaughterhouses, lesions were commonly observed on the footpads of a total of 8,985 broiler chickens from 45 flocks on 36 farms. In 3 flocks, all the birds examined had lesions. In the other 42 flocks, the incidence of FPD ranged from 31.9% (81/254) to 99.5% (1/222). The footpad lesions were classified into 4 categories according to the severity of dermatitis as follows; score 0, 1,181 birds (13.1%); score 1, 2,992 birds (33.3%); score 2, 3,000 birds (33.4%); and score 3, 1,812 birds (20.2%). The mean scores of the flocks varied widely from 0.31 to 2.69. Males had higher mean scores than females. No significant differences were found between the mean scores of birds reared in windowless houses and those in open-sided houses. On 4 farms, the investigation was carried out in different seasons, and 3 of them showed higher mean scores in winter than in summer. Next, observation of 2,255 birds from 15 flocks on 5 farms during a 4-week rearing period revealed that FPD was already produced at 7 days of age and worsened with age.     

Practical assessment and management of foot pad dermatitis in commercial broiler chickens: A Field Study

Foot pad dermatitis (FPD) is a welfare concern in broiler chickens characterized by ulcerated lesions on the pad of the foot, which results from prolonged contact of foot pads with wet litter. During Canadian prairie winters, barn moisture levels tend to increase due to reduced ventilation as a means of conserving heat and minimizing costs. However, there are no published benchmarks regarding the prevalence of foot pad dermatitis in broilers reared in western Canadian provinces such as Alberta, Canada. As such the objectives of the current study were to evaluate practical means of assessing FPD in Alberta broilers as well as on-farm management practices which correlate with higher prevalence of foot pad dermatitis. A management-practices survey and 3 foot pad assessment methods were used to benchmark foot pad dermatitis in 32 broiler flocks throughout the province of Alberta. Four flocks per farm were sampled from a total of 8 commercial broiler farms. Per flock, 200 birds were assessed on-farm, 3 processor-line scores were taken at the processing plant, and 600 foot pad samples were assessed post-processing. The prevalence of foot pad dermatitis by assessment method was benchmarked on a per-flock basis at 28.65% on-farm, 26.17% on the processing line (processor-line), and 31.83% for samples taken off the processing line (processor-sampled). On-farm and processor-sampled assessment results were highly correlated (r = 0.90) compared with processor-line and on-farm (r = 0.77) and processor-line and processor-sampled results (r = 0.72; P < 0.001). Specifically, processor-line assessments were not found to be reliable when repeated (P > 0.10). On farm, wheat straw was used by the majority of Alberta’s producers (62.5%) and was associated with a higher prevalence of foot pad dermatitis per flock (40.6%). In contrast, pine shavings was associated with lower FPD prevalence (6.4%; P < 0.001), but was used by only 21.9% of producers in Alberta. Primary results from this field study support the use of on-farm FPD assessments rather than processor-line-based assessments, and a shift away from wheat straw as a broiler litter substrate.     

Economic effects of subclinical chicken anemia agent infection in broiler chickens

To evaluate the economic effects of subclinical chicken anemia agent (CAA) infection on broiler performance, clinically normal broiler flocks were grouped into two categories: A) flocks in which none of 10 birds sampled at slaughter had antibody to CAA, and B) flocks in which six or more of 10 similarly sampled birds had CAA antibody. Production and performance parameters of 25 flocks in each category were compared. No statistically significant differences were found between category A and category B flocks in major production parameters such as sex, feed manufacturer, type of litter, stocking density, and age at slaughter. However, category A flocks achieved 13% (P less than 0.05) greater net income per 1000 birds, 2.0% better feed-conversion ratio (P less than 0.05), and 2.5% (P less than 0.05) greater average weight per bird than category B flocks. No significant differences in hockburn bonus per 1000 birds (a bonus payable to growers whose broilers have the lowest prevalence of contact dermatitis lesions on the hocks) and mortality were found between category A and category B flocks. These results show that subclinical CAA infection has a substantial, statistically significant effect on commercial broiler performance and profitability.     

Foot pad dermatitis develops at an early age in commercial turkeys

1. A field experiment was conducted to identify the macroscopic and histological changes associated with the development of foot pad dermatitis (FPD) in growing turkeys. Two affected and two unaffected turkeys were sampled weekly from 1 to 8 and at 10 and 21 weeks of age. 2. At one week old, birds with external signs of FPD (surface skin discolouration) showed abnormal cellular changes of the foot pad integument. As the flock aged the reactions intensified, with one sample exhibiting a fully developed macroscopic lesion at 3 weeks. 3. Major pathological changes had occurred by 6 weeks and all turkeys with external signs of lesions had fully developed microscopic inflammatory cellular lesions. From 6 weeks of age onwards lesions were increasingly numerous and became more overtly necrotic. 4. Externally normal foot pads showed microscopic evidence of lesions after the turkeys reached 4 weeks. 5. We conclude that FPD lesions become severe over a short period of time and at a very early age.     

Effects of litter quality (moisture, ammonia, uric acid) on development and severity of foot pad dermatitis in growing turkeys

High dietary protein is thought to increase the incidence of foot pad dermatitis (FPD) as a result of increased uric acid and secondary ammonia production in the excreta or litter. This study was conducted on female turkeys over a period of 3 wk to test the effects of water alone, and also of these end products of protein metabolism, independent of the presence of excreta, on the development and severity of FPD. The animals were allocated into four groups, with 20 birds in each, and housed in floor pens on dry, clean wood shavings (changed daily) throughout the experiment. The control group was housed continuously in its pen, whereas the other groups were additionally exposed daily (for 8 hr) to experimentally treated wood shavings, in adjacent separate boxes, enriched with water alone or water with NH4Cl or uric acid. NH4Cl and uric acid were added via water to the litter to achieve the concentrations of ammonia and uric acid in the litter as found in the excreta of turkeys (about 0.50 g ammonia and 20 g uric acid/kg). The wet litter was kept clean by removing the excreta twice daily and by changing the litter twice a week. The foot pads of all birds were examined on days 0, 7, 14, and 21 and scored externally (macroscopically). Three birds were selected from each group on days 0, 7, and 14, while the remaining 11 birds/group were sacrificed on day 21 for histopathologic assessment of foot pads. The severity of FPD was found to be markedly higher (about 3 times) on wet than on dry litter. There were no negative effects of ammonia and uric acid on foot pad lesions. The results indicate that high litter moisture is the most likely factor causing FPD in turkeys. A focus on nitrogenous irritants in the litter was not substantiated. Exposure of birds to wet litter (in the absence of excreta) for only 8 hr/day was sufficient to develop foot pad lesions. The present results suggest that a focus on the protein content of the diet as a cause of FPD may be misplaced, but all dietary factors which increase excreta or litter moisture, or both, should be considered. The prevalence and severity of FPD can be reduced by maintaining dry litter.     

Seroprevalence of Histomonas meleagridis in pullets and laying hens determined by ELISA

Serum samples from 1120 layers from 56 flocks and 400 pullets from 20 flocks were tested by an indirect sandwich ELISA to investigate the prevalence of antibodies to Histomonas meleagridis in chickens kept in alternative husbandry systems. The overall prevalence of antibodies to H meleagridis in layers was 37.3 per cent, and positive birds were identified in 50 flocks. This was significantly higher than in pullets, where only 8.3 per cent of the birds tested positive. Optical density (OD) values obtained from pullet sera were much lower than the OD values from layers; however, positive birds were detected in half of the pullet flocks. In particular, all birds from an organic pullet flock were found to be positive, with high OD values. Overall, the highest prevalence of positive sera was obtained from birds kept in free-range flocks. Attempts to reisolate live histomonads from birds in 18 layer flocks were unsuccessful.     

Incidence of histomonosis in turkeys in France since the bans of dimetridazole and nifursol

Between April 2003 and March 2005, 113 outbreaks of histomonosis were recorded in standard turkey farms in France, and 15 cases were recorded in turkey breeding centres. Most of the cases were in north-west France, the principal farming area for turkeys. The majority of the cases occurred during the hottest months, from April to September. Large numbers of cases occurred among birds from four to eight weeks of age, but there were some cases in three-week-old birds and some in birds up to 17 weeks of age. In most of the standard turkey flocks the mortality was less than 10 per cent, but it was above 30 per cent in nearly 20 per cent of the outbreaks. In the breeding flocks, the average mortality was 60.2 per cent. The size of the flocks, the sex of the birds and the age at which the first clinical signs appeared did not seem to influence the mortality.     

Influences of increased levels of biotin, zinc or mannan-oligosaccharides in the diet on foot pad dermatitis in growing turkeys housed on dry and wet litter

Foot pad dermatitis (FPD) is very common in turkeys and it is an animal health and welfare issue affecting not only performance and walking ability but also the carcass quality. Thus, there is a great need to find out the preventive measures against this problem. The potential roles of extra dietary biotin, Zn and mannan-oligosaccharides (MOS) in preventing the development of FPD were assessed in this study which was conducted on 2-week-old female turkeys over a period of 4 weeks. The birds were allotted to four groups, with 29 each, and housed on dry wood shavings in floor pens. The turkeys were fed a control (300 μg biotin and 50 mg Zn/kg), high biotin (2000 μg/kg), high Zn (150 mg/kg) or MOS (1%) diet. Half of the turkeys in each group were additionally exposed to wet litter (27% DM) for 8 h daily in adjacent separate boxes. Foot pads of the birds were examined on days 0, 7, 14, 21 and 28 and assessed macroscopically and histopathologically for foot pad lesions. High dietary levels of biotin or Zn significantly reduced the severity of FPD on dry litter (score 1 vs. 2 in control) but not on wet litter. However, MOS did not affect the severity of foot pad lesions either on dry or wet litter. In addition, the severity was overall substantially higher on wet (approximately three times) than on dry litter. The present results suggest that adding high levels of biotin or Zn to the diet could reduce the development and severity of FPD on dry litter but without having any preventive effects on wet litter. Finally, the high litter moisture appears to be the major factor resulting in FPD. Therefore, the litter should be maintained dry to minimize the prevalence and severity of FPD in turkeys.     

Risk factors associated with the prevalence of footrot in sheep from 1999 to 2000

A postal survey of the techniques being used for the treatment and control of footrot in sheep flocks between November 1999 and October 2000 was conducted in England and Wales in November 2000. Of the 392 questionnaires circulated, 251 (64 per cent) were returned, and 209 of these were usable. Negative binomial regression analysis indicated that the isolation of bought-in sheep, and the separation and individual treatment of diseased sheep with parenteral antibiotics, foot trimming and topical foot sprays were associated with a significantly lower prevalence of footrot in a flock. In contrast, ewe flocks which were routinely foot trimmed more than once a year had a significantly higher prevalence of footrot. No evidence was found that footbathing a flock reduced the level of footrot, except on the 14 per cent of farms where the penning and race facilities for footbathing were reported by the farmer to be excellent. Vaccination had no significant beneficial effect on the level of footrot in a flock     

Postmortem condemnations of processed broiler chickens in western France

A total of 404 broiler chicken flocks processed in 15 slaughterhouses in western France were studied to estimate the condemnation prevalence and describe the official reasons for condemnation and the main macroscopic lesions observed in a sample of the condemned carcases. The condemnation rate was 87 per 10,000 birds slaughtered (95 per cent confidence interval 79 to 95 per 10,000) but differed significantly according to the type of poultry produced (standard, light, heavy or certified). The main reasons for condemnation were emaciation and congestion, with rates of 30 and 22 per 10,000 birds slaughtered, respectively. Congestion was significantly associated with arthritis and ascites, whereas infected skin lesions were associated with bruises and abnormalities of colour, odour or conformation.     

Foot lesions in finishing pigs and their associations with the type of floor.

The associations between individual foot lesions and different types of floor were investigated in 4038 finishing pigs on 21 units. The overall prevalence of foot lesions was 93.8 per cent and the prevalence ranged from 79.4 per cent to 100 per cent on different units. Analysis showed that pigs kept on bedded floors, with either sparse or deep straw, had a lower prevalence of sole erosions, heel erosions and heel flaps and a higher prevalence of white line lesions, false sand cracks, wall separations and toe erosions than pigs kept on bare solid concrete floors. Partially slatted floors were associated with an increased prevalence of heel erosions, heel flaps, white line lesions, wall separations and false sand cracks, and totally slatted floors were associated with an increased prevalence of sole erosions and heel flaps.     

A census of the prevalence of vaginal prolapse in sheep flocks in the Borders region of Scotland

A postal census of vaginal prolapse in sheep flocks in the Borders region of Scotland yielded 540 replies from 963 owners (56 per cent). There were 262,250 ewes in 976 flocks and 2573 vaginal prolapses were reported. Analysis of the data revealed that 390 (40 per cent) of the flocks had no vaginal prolapses and in 237 (24.3 per cent) the reported prevalence was between 0.1 per cent and 1.0 per cent. Only 63 (6.5 per cent) of flocks had a greater than 5 per cent prevalence of vaginal prolapses. The greatest number of prolapses occurred in an upland flock of greyface ewes mated with Suffolk tups with 50 cases among 700 ewes (7.1 per cent) and the highest prevalence was in an upland Scottish blackface flock of ewes bred with Suffolk tups with 15.2 per cent (35 cases among 230 ewes). There were marked breed differences; very few hill breeds were affected and most cases occurred in greyface ewes mated with Suffolk tups.     

Effect of aflatoxin B1 on the efficacy of turkey herpesvirus vaccine against Marek's disease

The effect of feeding aflatoxin B1 (AFB1) (0.5 ppm) was studied in young chicks. The frequency and the severity of gross and microscopic lesions of Marek's disease were significantly higher in those birds which had been vaccinated with turkey herpesvirus (HVI) and birds challenged with Marek's disease virus which had been given AFB1 in the feed than in those given normal feed. The protective efficacy of HVT vaccine, as judged on the basis of gross and histopathological lesions, was 86.1 and 77.3 per cent in normally fed birds in comparison to 37.6 and 8 per cent in AFB1 fed birds.     

Rearing conditions and foot-pad dermatitis in Swedish broiler chickens

A method of classification of broiler foot-health status was developed to estimate the prevalence of foot-pad dermatitis in Swedish broilers. Data on foot health were collected from 101 commercial broiler flocks at slaughter. The producers were asked to fill in a questionnaire on rearing conditions and equipment for every flock.

Lesions were commonly observed; only 62% of the birds were classified as being without lesions, 32% had mild lesions only (discoloration, erosions) and 6% had severe lesions (ulcers). Flocks reared in houses equipped with small water cups had significantly (P < 0.05) higher prevalences of foot-pad dermatitis than flocks reared with water nipples. Thick layers of litter, regardless of litter material, also resulted in significantly (P < 0.05) higher prevalences of foot-pad dermatitis than litter layers thinner than 5 cm.     

Pestiviral infections in sheep and pigs in Northern Ireland

Serological surveys were carried out to determine the prevalence of pestiviral infections in sheep and pigs in Northern Ireland. Sera from 918 ewes in 92 flocks from 10 regions were tested by ELISA for antibodies to border disease virus and positive results were obtained from 49 ewes (5.3 per cent) in 28 flocks (30.4 per cent). There were highly significant geographical variations in its flock prevalence ranging from 0 per cent in the Enniskillen region to 70 per cent in the Coleraine region. There was no significant association between the proportion of seropositive flocks and the presence of cattle on the farm (P = 0.583). In the positive flocks, the average rate of seroprevalence was 17.5 per cent, and the highest was 40 per cent. Comparative neutralisation studies on 14 positive sera with bovine viral diarrhoea virus type I (BVDV I) and border disease virus revealed higher titres (> or = four-fold) to BVDV I in all cases. Only one positive result was obtained when fluids from 186 aborted ovine fetuses were tested for border disease virus by ELISA. Serum samples from 680 pigs in 46 herds were tested for virus neutralising antibodies to border disease virus. Twenty sera (2.9 per cent) were cytotoxic, and only one of the remaining 660 sera gave a positive result. This sample tested negative for classical swine fever by ELISA, and comparative neutralisation studies showed that it had a four-fold higher titre to BVDV I than to border disease virus.     

Survey of prevalence and control of ectoparasites in caged poultry in China

To investigate the prevalence and control of ectoparasites in China, 1200 questionnaires were delivered to caged commercial layer or parent hen keepers. Of the 860 respondents, 785 (91.3 per cent) claimed they found suspected ectoparasites in their birds and 833 samples were received. Ectoparasites of the species Dermanyssus gallinae, Ornithonyssus sylviarum or Menacanthuss stramineus were found in 736 (88.4 per cent) samples. For caged commercial layers, D gallinae was the most common ectoparasite (64.1 per cent). For caged parent hens, O sylviarum was the most common ectoparasite (46.9 per cent). Most bird keepers (95.0 per cent of commercial layer keepers and 74.9 per cent of parent hen keepers) used pyrethroids, organophosphates or other insecticides or acaricides to control ectoparasites. However, 34.6 per cent of layer keepers and 25.7 per cent of parent hen keepers did not re-treat their birds with insecticides or acaricides within two weeks after the first treatment. Sanitation procedures, including cleaning, washing and disinfection, were conducted in empty houses between flocks and on most commercial layer farms and parent hen farms. However, insecticides or acaricides were used in empty houses between flocks only in 24.8 per cent of commercial layer farms and in 36.1 per cent of parent hen farms.     

Prevalence of haematozoa in birds of prey in Catalonia, north-east Spain.

Blood samples from birds of prey, 95 Strigiformes and 190 Falconiformes, were examined for the presence of haematozoan parasites. The birds had been admitted to a raptor recovery centre in Catalonia, north-east Spain. Parasites were counted in positive smears. A second blood sample was obtained from 99 birds at least seven days after their arrival at the centre. Haematozoa were detected in all seven species of Strigiformes and in nine of 19 species of Falconiformes. The overall prevalences in the two groups were significantly different, 30.5 per cent and 46.3 per cent in the nocturnal and diurnal raptors, respectively. Eleven species of haematozoan parasites were identified. The genus most commonly detected in members of the nocturnal Strigiformes was Leucocytozoon, followed by Haemoproteus, Plasmodium and Trypanosoma. In the diurnal Falconiformes only Leucocytozoon and Haemoproteus were detected. The highest infection rates were found in Accipiter nisus (sparrow hawks), Accipiter gentilis (goshawks) and Athene noctua (little owls). Relapses were detected in 9 per cent of the birds sampled twice. The highest intensity of infection (6.2 per cent) was observed in a Buteo buteo (buzzard) infected with Haemoproteus.     

Preliminary study to examine the utility of using foot burn or hock burn to assess aspects of housing conditions for broiler chicken

1. Eleven broiler chicken farms, representing 4 production system types, were visited during the last 5 d of the flock cycle: bird and flock details were recorded. Litter friability was assessed at 9 sites within the house, atmospheric ammonia was measured at three sites and bird cleanliness was assessed on a numerical rating scale. 2. For these flocks, hock burn, foot burn and breast burn were measured at the processing plant by standardised assessors. 3. Significant correlations were identified between the percentage of birds with foot burn and average litter score, average house ammonia concentrations and feather score. 4. No correlation was found between the percentage of birds with hock burn or breast burn and average litter scores, average ammonia concentrations or feather score. 5. No correlation was found between stocking density and foot burn, hock burn or breast burn.6. If confirmed, these findings may have implications for the draft EU Broiler Directive, for which it is proposed that permitted stocking density on farm may be determined by the incidence and severity of contact dermatitis measured on plant.     

Isolation of Escherichia coli from cellulitis and other lesions of the same bird in broilers at slaughter.

Cellulitis results in substantial losses to the broiler industry due to condemnations at slaughter. This study was conducted to clarify the association between Escherichia coli isolated from cellulitis and other lesions caused by E. coli in individual birds. Fourteen flocks were sampled and 118 birds with cellulitis were examined. Escherichia coli was isolated from all but 2 of the cellulitis lesions, and serogroups O78, O1, and O2 predominated. Thirty-six birds had at least 1 other lesion in addition to the cellulitis lesion. Isolation of E. coli from cellulitis and other lesions occurred in 7 of the 14 flocks. Escherichia coli of the same serogroup were isolated from cellulitis and other lesions in some birds, suggesting that a single E. coli may sometimes be responsible for both types of lesions.