Risk factors for foot-pad dermatitis in chicken and turkey broilers in France.

A prospective cohort study was conducted in the Brittany region to identify the risk factors related to foot-pad dermatitis (considered an indicator of animal well-being) in chicken and turkey broilers reared under commercial conditions. Factors related to the shed, equipment, litter management and stocking density were recorded; the dependent variable was the prevalence of lesions observed on the slaughterhouse chain. Lesions were scored from 0 (no lesion) to 3 (severe lesion). Our survey lasted from May 1999 to October 2000. Fifty flocks of chicken broilers (15 farms), 27 flocks of female turkey broilers (21 farms) and 41 flocks of male turkey broilers (27 farms) were surveyed. In chicken broilers, 10% of flocks were of high quality (80% of birds with score 0) and this was related to the use of concrete floors with a thin layer of wood shavings. In turkey broilers, 48% of female and 46% of male flocks were of bad quality (>10% of birds with score 3). A poor fan ventilation system (<150m(3)/h/kg) was a significant risk factor. Turkey flocks of high quality were not observed. Stocking density had no influence on the prevalence of foot-pad dermatitis. We concluded that it is possible under high commercial stocking densities to have flocks with a low prevalence of foot-pad dermatitis in chicken broilers, whereas it is not in turkey broilers. Hence in chicken broilers, implementing a monitoring system based on the observation of foot-pad dermatitis prevalence at slaughter appears to be more appropriate than to legislate stocking density. In turkey broilers, it would probably be necessary either to reduce the stocking density drastically or to investigate new systems of floor drainage.

Influence of environmental enrichment on injurious pecking and perching behaviour in young turkeys.

1. In order to reduce injurious pecking, the influence of environmental enrichment on pecking and perching behaviour was studied in young male and female turkeys. 2. Two different types of enrichment and a control treatment (TO) were tested: T1, metal objects and straw; T2, similar to T1 + wood perches. Birds were housed in 36 m2 pens at a light intensity of 5 lux with 4 replicates per treatment in a 2x3 factorial design. 3. Pecking at objects and perching behaviour were observed weekly. Behaviour was video recorded at weeks 5 and 10. Birds were examined daily for the occurrence of injuries. At the end of the rearing period, an ACTH challenge was performed and H/L ratio was measured. 4. Objects were regularly pecked at. Perching was more common in females, peaked at week 5 (10% to 13% of birds perched) and declined to 0% by week 10. Aggressive pecking was more frequently observed in males in T0 than in T1 or T2 at week 10. Wing (in males and females), tail and head (in males) injuries were more common in T0 than in T1 or T2. T1 and T2 were similar Response to ACTH challenge and H/L ratio were not consistently influenced by treatments. 5. It is concluded that metal objects and straw reduced injurious pecking in young female and male turkeys by redirecting, pecking activity.

Influence of stocking density, artificial dusk and group size on the perching behaviour of broilers.

1. Perching behaviour of Ross broiler chickens was studied in order to increase the available space at the floor level. Pens (36 m2) were equipped with wooden perches mounted 20 and 33 cm above the litter (5 cm perch length per bird). 2. The influences of stocking density (22 vs 11 birds/m2, experiment 1) and of a 10 min artificial dusk (17 birds/m2, experiment 2) were tested in a 2x2 factorial design (n=4 by treatment) including control pens without perches. In experiment 3, perching behaviour between 2 different group sizes (1020 vs 4590 birds, 17 birds/m2, no replicates) was compared. 3. The percentage of perching birds (PPB) was assessed by scan sampling observations during the 20 to 22 h light period (8 observations per d, 5 d a week, from week 3). In experiment 2, infra-red video recording was performed at the time lights were dimmed and during the dark period. In experiment 1, carcase lesions were noted. In experiment 2, tibia breaking strength of frequently perching birds was compared with controls. Birds were weighed before slaughter and food conversion was calculated. 4. PPB increased with age and density (P<0.01) and was highest at the 22 birds/m2 density during week 6 (mean=10.6%, maximum=13.5%). PPB was not influenced by a 10-min artificial dusk. In experiment 3, PPB was slightly lower during weeks 5 and 6 in the large group size compared to the small group size (6.8% vs 7.9% respectively in week 6). 5. Prevalence of carcase lesions and tibia breaking strengths were unrelated to perch usage. Final body-weights were not influenced by the presence of perches except at the 22 birds/m2 density where males were slightly heavier in the control pens compared with males in pens equipped with perches (2096 g vs 2051 g, P=0.015). Food conversion was independent of the presence of perches.

Influence of stocking density on behavioural, health and productivity traits of turkeys in large flocks.

1. The effect of stocking density on welfare traits of turkeys was studied in 2 experiments. In each experiment 2,633 sexed BUT turkey poults were assigned to 3 rooms, 135 m2 with 1 treatment per room. Because of the large flock size (675,878 and 1080 birds in T1, T2 and T3 respectively) treatments were not replicated 2. Floor space allowances varied according to treatment; for the males: 24 dm2, 18.5 dm2 and 15 dm2 until week 12 and 40 dm2, 31 dm2 and 25 dm2 from week 12; for the females: 16 dm2, 12.3 dm2 and 10 dm2. 2. The scan sampling method in experiment 1 and the focal sampling method in experiment 2 were used to record behaviour at week 6, 9, 12 (males and females), and 16 (males). Birds' ethogram was divided into 7 mutually exclusive behaviours: standing/walking, resting, feeding, drinking, pecking at the environment, pecking at another bird, and preening. Position changes in the pen and the frequency of disturbances of resting birds by other birds were recorded in experiment 2. 3. Gait was assessed at week 12 (females) and week 16 (males). Prevalence of lesions, breast (males), hip and foot (males and females), were recorded at slaughter. Birds were weighed at week 12 (males and females) and week 16 (males). 4. Stocking density had little influence on behaviour except on the frequency of disturbances of resting birds by other birds, which tended to be more frequent at the highest density. 5. Gait deteriorated as stocking density increased. Hip and foot lesions were more frequent at the highest density. Bodyweight decreased significantly with decreasing floor space. 6. The results suggest that turkey welfare was poorer at the highest density than at the 2 lower stocking densities.

Influence of stocking density on some behavioural, physiological and productivity traits of broilers.

In order to investigate the influence of stocking density on broiler welfare, 17,616 Ross chickens were assigned to three different treatments: T1, T2 and T3 with a final stocking density of 27, 35 and 43 kg/m2, respectively (corresponding to an initial density of 12, 16 and 20 birds/m2). Animal welfare was assessed by measuring behavioural, physiological and productivity traits. Behavioural observations included the disturbance frequency of resting birds by other birds, the duration of the lying bouts and the standing/lying ratio. The heterophil/lymphocyte ratios were assessed from blood collected before departure to the slaughterhouse. Main productivity traits were the final live weight and carcass degradation due to foot and pad dermatitis and breast blisters. Most of the observed parameters were adversely affected by the highest density (P < 0.05). Between T1 and T2, some traits tended to demonstrate that a better degree of bird welfare existed in T1 (higher standing/lying postures ratio and final live weight, lower frequency of pododermatitis and hock lesions; P < 0.05) whereas other traits showed no differences (frequency of disturbances by other birds during resting, heterophil/lymphocyte ratio). In conclusion, a stocking density of 43 kg/m2 seemed to induce poor bird welfare whereas it was not clearly demonstrated that 27 kg/m2 was better than 35 kg/m2.

[Use of the B19 strain in the prevention of bovine brucellosis in northern Cameroon. Study of effect of the dose on seroconversion rate and duration in female zebu]. / Utilisation de la souche B19 dans la prophylaxie médicale de la brucellose bovine au Nord-Cameroun. Etude de l'effet de la dose sur le taux et la durée de séroconversion chez des femelles zébus.

Four herds of zebus from northern Cameroon totalling 136 animals were vaccinated subcutaneously with the following doses of Brucella abortus strain 19: 5 x 10(9) colony-forming units (CFU), 10(9) CFU, 5 x 10(8) CFU and 10(7) CFU. Twenty-eight days after vaccination, the following seroconversion rates were observed respectively: 97.4, 96.2 84.2 and 73.3%. Of the 52 animals which could be tested subsequently including 39 over one year old on the vaccination day, only one showed antibodies 6 months after vaccination. The cost price of the strain 19 vaccine produced at the Boklé National Veterinary Laboratory was estimated to be 65 F CFA at the 10(9) CFU dose and 1,740 F CFA at the 5 x 10(10) CFU dose usually recommended. The use of the Buck 19 strain in the medical prophylaxis of bovine brucellosis in northern Cameroon is discussed.

[Main infectious agents involved in the etiology of lung diseases of small ruminants in northern Cameroon]. / Etude des principaux agents infectieux intervenant dans l'étiologie des pneumopathies des petits ruminants au Nord-Cameroun.

Between 1990 and 1992, 91 necropsies of small ruminants affected with pulmonary illness led to the isolation of the following strains of Mycoplasma (M.): M. mycoides subsp. mycoides LC, M. ovipneumoniae, M. agalactiae, M. sp. type D2 and M. arginini. Eleven Pasteurella multocida strains (serotypes A1, A3, A5, A7 and D2) and 11 Pasteurella haemolytica strains (serotypes 1, 2, 3, 6, 7, 8 and 9) were isolated. Corynebacterium pseudotuberculosis, Actinomyces pyogenes, Staphylococcus sp., Streptococcus sp., Bacillus sp. and Mycobacterium sp. were also isolated. Thirty-two antibiograms were performed on Pasteurella, Corynebacterium pseudotuberculosis and Actinomyces pyogenes strains. Eighty eight p. cent were sensitive to penicillin G and oxytetracycline, and 84% to chloramphenicol; 50% were not sensitive to spiramycin and 47% to streptomycin. One Capripoxvirus strain was isolated on sheep. Pest of small ruminants (PPR) virus was detected by immunocapture ELISA test performed on some lung samples. Two serological surveys, one for contagious caprine pleuropneumonia (898 goats), between 1991 and 1993, and one for PPR (902 sheep and goats) in 1993, were conducted in the North and Far North provinces. No antibody against contagious caprine pleuropneumonia was detected. Among the animals in the sample, PPR prevalence was 64 +/- 7% in the Far North province and 14 +/- 3% in the North province. Concerning control measures, a vaccination campaign against small ruminant pasteurellosis appears to be hardly feasible because of the antigenic diversity of the isolated Pasteurella strains. PPR is endemic especially in the Far North province. The efficiency of a vaccination campaign against PPR must be estimated with a field survey.

[First case of an outbreak of hemorrhagic septicemia caused by Pasteurella multocida serotype B6 in northern Cameroon]. / Première observation d'une épidémie de septicémie hémorragique due à Pasteurella multocida sérotype B6 au Nord-Cameroun.

For the first time in Cameroon, a strain of Pasteurella multocida serotype B6 was isolated from a haemorrhagic septicaemia outbreak in Zebu cattle in the area of Maga (Far Northern Province). Through the mouse protection test, evidence was given that there was no cross protection between this strain and the strain of Pasteurella multocida serotype E6 which is used as an inactivated vaccine in Cameroon. Hence, it is recommended to use a combined vaccine including both serotypes for the Central and West African countries.

[Epidemiology of digestive parasitic diseases of young cattle in northern Cameroon]. / Epidémiologie des parasitoses digestives des jeunes bovins dans le Nord-Cameroun.

Studies of gastro-intestinal parasites of zebu calves were carried out in traditional herds in Northern Cameroon through monthly faecal analysis in 17 herds for a period of two years. Toxocarosis appeared to be the most important parasitic infection in the North province where its prevalence reached 58% in calves aged 0-6 months; 60% of the infested calves passed large numbers of eggs at least once. Samples revealing high egg counts were more frequent in the dry season. Deworming calves aged one month with a cheap anthelmintic against Toxocara is likely to be economically profitable in the North. Seventy-five and a half per cent of the calves 0-12 months old were infested with Strongyloides; high counts of Strongyloides eggs were registered at least once for 31% of these calves. As for toxocarosis, calves seemed to be more often and more heavily infested with Strongyloides in the North than in the Far North province. Strongyloidosis was apparently of low clinical importance, with the rare clinical manifestations accompanied by toxocarosis. The importance of digestive tract strongylosis was difficult to evaluate. Every steer was affected at one stage of its life in a similar manner in the two provinces; 6.8% of samples showed high egg counts and 35% of the steers aged over six months passed large numbers of eggs at least once. These results did not permit a priori recommendation of a systematic deworming programme against strongyles; instead, several less intensive deworming programmes have to be tested in order to determine their economic profitability. Coccidia were found in 77.4% of calves aged 0-12 months, with heavier and more frequent infections in the North. However, infections of high intensity were generally rare. Trichuris, Moniezia, Fasciola and paramphistomes were rarely found. Concerning nematodosis, curative treatments and cost-profit studies of deworming programmes should be aimed at toxocarosis in calves aged 0-3 months in the North, and strongylosis in steers aged 6-12 months, in both provinces.

[Experimental infection of the Guyanese zebu with Trypanosoma vivax]. / Infection expérimentale de zébus guyanais avec Trypanosoma vivax.

The Guyanese strain of Trypanosoma vivax is pathogenic for the local Brahman zebu; the experimental infection of 19 one-year old cattle was followed by a moderate and transitory fever, a drop in packed cell volume (PCV) and a quick and marked weight loss of 10 to 17 kg one month after as compared to the 16 non-infected animals. Other symptoms were associated with the parasitaemia: diarrhoea, swollen haematic glands on the neck and the flank, lachrymation, weakness. Despite a trypanocidal treatment injected one month post-infection, one animal died and the weight losses of others were not compensated for three months later. The particular susceptibility of weaning animals is discussed as well as its implications in the control of trypanosomosis.