Pathology of spontaneous colibacillosis in a broiler flock

Forty-eight of 134 chickens collected from a flock on a broiler farm were diagnosed pathologically and microbiologically to have colibacillosis. Both acute septicemia (seven birds, 1 to 36 days old) and subacute serositis (41 birds, 5 to 57 days old) were found. The former consisted of necrosis with fibrinous exudates in the ellipsoids and lymphoid follicles of the spleen, and fibrinous thrombi in sinusoids of the liver with occasional necrosis of hepatic cells. The latter had fibrinopurulent inflammation with granulomatous changes in the serosal tissues--including the epicardium, pericardium, and hepatic peritoneal sac--accompanied by septicemic lesions in the spleen and liver. Respiratory lesions (airsacculitis, pneumonia, and tracheitis) were noted in most chickens affected with acute septicemia and subacute serositis. Degenerative changes also were observed in the bursa of Fabricius.     

A case of aspergillosis in a broiler breeder flock

A case of aspergillosis in a broiler breeder flock having respiratory and nervous system problems caused by Aspergillus fumigatus and Aspergillus niger is documented. Dyspnea, hyperpnea, blindness, torticollis, lack of equilibrium, and stunting were observed clinically. On postmortem examination of the affected birds, white to yellow caseous nodules were observed on lungs, thoracic air sacs, eyes, and cerebellum. Histopathologic examination of lungs and cerebellum revealed classic granulomatous inflammation and cerebellar lesions, necrotic meningoencephalitis, respectively. No lesions were noted in the cerebrum histopathologically. Aspergillus hyphae were observed in stained sections prepared from lesioned organs. Fungal spores and branched septate hyphae were observed in direct microscopy. Aspergillus fumigatus and A. niger were isolated from the inoculations prepared from the suspensions of organs showing lesions.     

Genotype dynamics of Campylobacter jejuni in a broiler flock

We investigated the genotype diversity and dynamics of Campylobacter in a commercial broiler flock during rearing and slaughter. In total, 220 Campylobacter jejuni isolates collected on four sampling occasions during rearing and from routine sampling during slaughter were subtyped by SmaI macrorestriction and pulsed-field gel electrophoresis, PFGE. Eight different SmaI types were found. During rearing, a subsequent addition of genotypes occurred, with two SmaI types found at 2 weeks of age and six types on the day before slaughter. All types that were detected in more than one isolate were also found on all succeeding sampling occasions, including the slaughter sampling. Two new types were found in the slaughter samples. In two-thirds of the individual birds sampled the day before slaughter, more than one SmaI type were found, although there was a clear tendency for dominance of one type in individual birds. Our results show that multiple genotypes of C. jejuni may be present in a commercial broiler flock during rearing and even in gastrointestinal tracts of individual birds. Both recurring environmental exposure and genetic changes within the population may explain the genotype diversity. Although the distribution of genotypes varied between different sampling occasions, we found no indication that any subtype excluded another during the rearing of the broiler flock.     

Comb candidiasis affecting roosters in a broiler breeder flock

A cutaneous mycosis caused by Candida albicans that involved the combs and less frequently the wattles, facial skin, ear lobes, and neck of male broiler breeders is described. Roosters were 35 wk old and housed with hens in two conventional broiler breeder houses on a farm in western North Carolina. Morbidity was approximately 10% in one house and less than 2% in the other house. Mortality and flock fertility were not affected. Three birds from the most affected house were examined. All birds had white adherent material on their combs that presented as crusty patches or lighter diffuse areas. Often, lesions were roughly circular or had a defined margin. Small black scabs were present in a few lesions. Similar but less extensive lesions were located on the wattles, facial skin, ear lobes, and rictus. In one bird, lesions extended down the neck, and they were accompanied by hyperemia and feather loss. Hyperkeratosis with little to no inflammation and intralesional fungi occurring as yeast and pseudohyphae were seen microscopically. High numbers of C. albicans were isolated and identified from the lesions.     

The occurrence of a reovirus variant in a German broiler flock

Broilers deriving from a parent flock, which had been effected in the 6th. month of hatching egg production, show arthritis beginning with the 12th day of life. The tarso-metatarsal joint has been affected. Birds show stunting. Body weights at slaughter and feed conversion of the affected flocks were reduced. The percentage of condemned birds before slaughter was highly increase and came up to 3-5%. Chickens of other breeder flocks, which were reared with the diseased birds, showed viral arthritis at an age of 18-20th day of life. The boilers derived from parent flocks which had been vaccinated twice during the with a 1133 reo live vaccine and before laying with an oil based vaccine of the antigen type WVU. A reovirus has been isolated (isolate K 171/87), which caused viral arthritis in 1133-immune day old chicks after parenteral and oral application. Infection of these chickens with the pathogenic reovirus of the antigen type 1133 didn't cause a disease. Also by serological examinations it was shown, that the reo-isolate K 171/87 possesses a different antigenicity. The kind of occurrence indicates, that this reovirus infection has been transmitted vertically from one parent flock and it spread laterally to chickens of other parent flocks in broiler farms.     

Ophthalmopathy in a broiler breeder flock reared in dark-out housing

Eight 22-week-old broiler breeder replacements were presented from a flock experiencing a mild mortality problem. Approximately 2-3% of the birds were not getting onto the slats to eat or drink. The birds had been reared in dark-out houses under an experimental lighting schedule. Upon examination, several birds appeared blind or partially blind; others exhibited a photophobic response. Two birds lacked a unilateral menace reflex. No other gross abnormalities or lesions were noted. Histopathologic sections of the eyes revealed retinal degeneration and detachment with early degenerative lesions in one lens. The breeder flock came into production normally but peaked below average. Light intensity in the pullet house was measured at 0.3 footcandles (3.2 lux). Although the lighting program under which the pullets were grown is suspect, the etiology of the disorder remains unclear.     

A study of the effects of Marek's disease in a broiler flock

In a flock of 17000 broilers, characteristic Marek's disease (MD) paralysis, accompanied by increased mortality occurred during the fourth week of the flock's life. Cytolytic lesions and atrophy in the bursae of Fabricius, and the severity of lymphocytic infiltration of nerves, livers, proventriculus and brain are suggestive of the involvement of MD virus of greater pathogenicity than has been encountered previously in New Zealand.     

An unusual outbreak of histomonosis in a commercial turkey flock

In the past histomonosis was very well controlled with Dimetridazole as a treatment and/or Nifursol as feed additive. In the European Union both products were banned in 1995 and 2003, respectively. This was followed by the re-emergence of the disease in the recent years. In the present case a farm with two houses was affected by the disease. In each house 2620 hens and 2620 toms were kept, separated by wire mesh. At the 53rd day of age the toms in house 1 showed general clinical symptoms, accompanied by a slightly raised mortality, which sharply increased in the following days. At necropsy all dead birds showed lesions typical for histomonosis in caeca and liver. Histomonosis was diagnosed by histopathology and PCR. Within five days cumulative mortality was 25.1%.The hens kept at the same house didn't show any symptoms. At day 57 two toms, which were kept in house 2, died and showed similar symptoms and lesions. Within the next three days 48 more birds died. Again the hens in house 2 showed neither clinical signs nor mortality. Treatment trials using herbal products and a change of litter directly after the onset of clinical signs did not reduce the mortality. On day 62 the toms of both houses were euthanized by CO2 in closed containers. The hens were kept until they were slaughtered in week 16 and did not show any evidence of histomonosis.     

The cost of Border disease infection in a commercial flock

The performance of a flock of 203 crossbred ewes on a lowland farm was examined. Before lambing the ewes were run in two groups (A and B). Group A (124 ewes) produced significantly fewer marketable lambs as a consequence of neonatal and later losses. The associated clinical features were consistent with Border disease infection and the presence of the virus was demonstrated. These features were not evident in the progeny of group B (79 ewes). The market sale returns of both groups of sheep were compared and the flock performance was contrasted with that of the two previous years. The outbreak of Border disease resulted in a potential reduction of income in excess of 20 per cent. Such a loss supports the necessity for an effective control strategy for Border disease.     

A study of the effects of Marek's disease in a broiler flock

In a flock of 17000 broilers, characteristic Marek's disease (MD) paralysis, accompanied by increased mortality occurred during the fourth week of the flock's life. Cytolytic lesions and atrophy in the bursae of Fabricius, and the severity of lymphocytic infiltration of nerves, livers, proventriculus and brain are suggestive of the involvement of MD virus of greater pathogenicity than has been encountered previously in New Zealand.     

Isolation of a reovirus from a broiler chicken flock with high early mortality

A reovirus was isolated from a flock of 12,000 broiler chickens which experienced a total mortality of 6.3% up to 35 days. The reovirus produced large syncytia in primary chicken kidney cell cultures with eosinophilic intracytoplasmic inclusion body formation. Infected cells reacted with fluorescein conjugated specific anti-reovirus serum. Negatively strained virions had a double shelled appearance with overall diameter of 65 to 70 nm. The nucleic acid had ten discrete segments with electrophoretic mobilities as would be expected for a reovirus.     

Sources of salmonellae in an uninfected commercially-processed broiler flock.

Cultural monitoring was used to study the incidence and sources of salmonellae in a 4160 bird broiler flock during the growing period, transport and processing in a commercial plant. No salmonellae were isolated from any of 132 litter samples of 189 chickens cultured during the seven-week growing period, even though nest litter samples from four of the eight parent flocks yielded salmonellae and Salmonella worthington was isolated from the meat meal component of the grower ration. On arrival at the plant, 2/23 birds sampled carried S. infantis on their feathers, although intestinal cultures failed to yield salmonellae. Three of 18 processed carcasses samples yielded salmonellae (S. infantis, S. heidelberg, S. typhimurium var copenhagen). The most likely source of these salmonellae was the plastic transport crates, since 15/107 sampled before the birds were loaded yielded salmonellae (S. infantis, S. typhimurium). The crate washer at the plant did not reduce the incidence of Salmonella-contaminated crates, since 16/116 sampled after washing yielded salmonellae (S. infantis, S. typhimurium, S. heidelberg, S. schwarzengrund, S. albany).     

Nesting and floor laying by domestic hens in a commercial flock

1. The nesting behaviour of broiler breeders was studied in a commercial flock of nearly 4000 birds kept on deep litter by tagging a sample of 200 hens. Use of nest boxes by tagged birds was recorded on 52 d over 34 weeks.

2. Forty hens were never observed in nest boxes and 33 others were recorded only in ground‐level boxes. These 73 birds were recorded significantly less often in nest boxes and more often apparently laying on the floor than others. Fewer of them perched during observations and they started doing so later than birds which used raised nest boxes.

3. These results suggested that there were consistent floor layers, which had difficulty reaching raised nest boxes, as found previously in experimental conditions. Many or all floor layers may, however, have used ground‐level boxes sometimes.

4. Hens were inconsistent in their use of particular nest boxes, and some even nested in two distinct areas.

5. Most individuals were, however, consistent in their reaction to one or more features of the nest boxes, including height, aspect and area. Individual choices for these features varied, so no boxes were used particularly heavily, with the exception of those at ground level.     

Hock burn: an indicator of broiler flock health

This study aimed to identify risk factors for the prevalence of hock burn, a common disease of broiler chickens that influences the welfare and profitability of affected flocks, using hierarchical logistic regression analysis of routine flock management data. The study identified an association between hock burn and other diseases detected at slaughter and found that the management of flocks around the slaughter period was of particular importance for the control of hock burn, providing a rational basis for intervention.