Evaluation of foot pad health of laying hens in small group housing systems and furnished cages

Foot pad health was examined in a total of 648 Lohmann Selected Leghorn (LSL) in two trials and in 216 Lohmann Brown (LB) laying hens in one trial kept in small group housing systems and furnished cages. The effects of housing system, strain, month of laying period, rearing method, group size and body weight were tested for significance by using analysis of variance. The assessment of foot pads was performed each three months during the laying period. The alterations of foot pads were classified in severity on a scale from 1 (no hyperkeratosis, no epithelial lesions, no swelling of foot pads) to 5 (severe hyperkeratosis and/or deep and large epithelial lesions and/or moderate or high-grade swelling of foot pads). In addition to the macroscopic findings, foot pads were histologically examined. Pathological alterations of foot pads were found in 86.1% of the laying hens, whereas 57.4% of the examined animals showed mild hyperkeratosis (degree 2). Modest hyperkeratosis and/or superficial lesions of the epithelium (degree 3) were detected in 21.0% of the laying hens examined. Severe hyperkeratosis and/or deep epithelial lesions and/or mild swelling of the foot pads (degree 4) as well as very severe hyperkeratosis and/or deep and large epithelial lesions and/or moderate or high-grade swelling of foot pads (degree 5) occurred with frequencies of 5.9% and 1.9% respectively. LB laying hens' food pads were more frequently affected by hyperkeratosis, whereas epithelial lesions were more frequently found in LSL laying hens. The prevalence of pathological alterations in foot pads was significantly influenced by housing system and month of laying period. The results of this study showed that laying hens kept in small group housing systems and furnished cages develop proliferative hyperkeratosis in foot pads due to increased mechanical compression load, caused by the use of perches and staying on wire floor.     

Aviary Systems and Conventional Cages for Laying Hens: Effects on Production,Egg Quality,Health and Bird Location in Three Hybrids

Abstract

In two experiments, a total of 4346 laying hens housed in battery cages, with three hens per cage (C), and in two aviary systems, both with tiered wire floors and litter (Lövsta with two tiers (L) and Marielund with three tiers (M)), were used for studies on production, egg quality, health, plumage and foot condition, bone strength and bird location. Three hybrids were used: Lohmann Selected Leghorn (LSL) were kept in all three systems, Dekalb XL (DK) were kept in both aviaries and Lohmann Brown (LB) in M only. Production and feed conversion in M were inferior but not significantly different from C but significantly better than in L. Proportions of dirty eggs were significantly higher in the avaries. No significant differences were found in interior egg quality traits between keeping systems. LSL showed higher production and better feed conversion than the other hybrids and a tendency for a lower proportion of mislaid eggs. Mortality varied considerably between the aviary pens, reaching 35% in LB mainly owing to cannibalism and salpingitis. Keel bone lesions and bumble foot appeared in the aviaries, while toe pad hyperkeratosis was observed in C. Hens in aviaries had significantly stronger bones (tibia and humerus) and showed more wounds from pecks, inferior plumage condition and dirtier feet than in C. LSL had more bumble foot injuries than LB but better plumage condition than DK. The birds used the different parts in the aviaries well, especially the perches on the resting top tier during the night.     

Effect of furnished small group housing systems and furnished cages on mortality and causes of death in two layer strains

1. Mortality and causes of death were recorded over two trials with 13045 Lohmann Selected Leghorn (LSL, white layer strain) and 4410 Lohmann Brown (LB) laying hens kept in furnished small group housing systems and furnished cages. In trial 1, hens were housed from weeks 19 to 71 (LSL) and 17 to 69 (LB). In trial 2, LSL hens were housed from weeks 18 to 57. 2. The hens were kept in groups of 40 and 60 in the furnished small group housing system Eurovent 625 + a-EU and in groups of 10 and 20 in the furnished cages Aviplus and Eurovent 625A-EU. 3. To investigate the possible effect on mortality of rearing the birds on litter floors or in cages, in trial 2 half of the LSL hens were reared on the floor and half in conventional cages. 4. Mortality was greater in the Eurovent furnished small group housing system (5.2%) than in the furnished cages Aviplus (4.0%) and Eurovent (4.2%). 5. Mortality was also affected by the interactions among housing system and trial, layer strain and rearing. In trial 1, more LB laying hens died in the Aviplus system than in the Eurovent group system. There was no significant difference in mortality of the LSL laying hens between housing systems in trial 1. In trial 2, mortality of the LSL hens was greater in the group housing system (hens reared on litter floors: 10.1%; hens reared in cages: 2.8%) than in the furnished cage Aviplus (hens reared on litter floors: 6.0%; hens reared in cages: 1.5%). 6. Mortality was greater in floor-reared LSL laying hens than in the LSL laying hens reared in conventional cages. 7. Group size within housing system had no significant effect on mortality. 8. The most common findings at autopsy were different types of cannibalism (65.51%), with vent cannibalism (38.57%) the most common.     

Genetic resistance to natural helminth infections in two chicken layer lines

Groups of Lohmann Brown (LB) and Lohmann Selected Leghorn (LSL) hens were reared under helminth-free conditions and kept afterwards together in a free range system. Mortality rate, body weight development, laying performance and faecal egg counts (FEC) were recorded during a 12 month laying period. At the end of the laying period, 246 LSL and 197 LB hens were necropsied and worms counted following the World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) guidelines. In addition adult Heterakis gallinarum and Ascaridia galli were sexed and measured for length. Significant (P<0.01) differences were observed in mortality rates between LSL and LB animals (12.9 vs. 5.7%). LSL hens showed significantly (P<0.05) higher FEC when compared with LB hens at almost all dates of monitoring. Almost all animals became infected with at least one helminth species. The most prevalent species were H. gallinarum, Capillaria spp. and A. galli. LB hens showed a significantly (P<0.05) higher average number of adult H. gallinarum, Capillaria spp. and tapeworms when compared with LSL animals. However, number of adult A. galli was in tendency lower in these animals. In total, LB had a significantly (P<0.05) higher worm burden than LSL (192.3 vs. 94.3). The estimated heritabilities for total worm burden were 0.23 (SE±0.12) in LSL and 0.75 (SE±0.21) in LB, respectively. The number of all different helminth species were positively correlated. The sex ratio of H. gallinarum and A. galli and the average worm lengths were not significantly (P>0.05) different between the genotypes. There was no significant phenotypic correlation between body weight and worm burden in LSL, whereas it was the case in LB (r=0.17, P<0.05). Based on the estimated heritabilities it is possible to select for helminth resistance in both genotypes.     

Occurrence of organic diseases and parasitoses in layer strains Lohmann Selected Leghorn and Lohmann Brown kept in small group housing systems and furnished cages during the laying period

The state of health was examined over two laying periods in a total of 648 Lohmann Selected Leghorn (LSL) and 216 Lohmann Brown (LB) laying hens kept in small group housing systems and furnished cages. In addition, the effect of group size, month of laying, trial, rearing method and body weight was tested. Autopsies of clinically healthy hens were performed every three months during the laying period. Diagnosed fatty livers were classified in three severity codes ranging from moderate to severe alteration. Continuative liver diagnostic was performed by analysing triacylglycerol concentration in serum of every hen. The most common diagnoses at autopsy of clinically healthy laying hens were fatty livers (53.9% in the first trial and 46.3% in the second) and diseases of the reproductive organs. In both trials, there was a significant effect of month of laying and body weight on the occurrence of fatty liver. In the second trial, the occurrence of fatty liver was also significantly affected by the housing system: fatty livers were found significantly most frequently in the Eurovent 625A-EU system. The effect of group size within housing system, layer strain and rearing method regarding the individual trials were found to be not significant.The serodiagnosis showed that laying hens with macroscopically assessed fatty livers had significantly greater triacylglycerol concentrations in serum than the laying hens without fatty livers. Endoparasites did not mean a health problem. In contrast, the red mite of poultry was detected in each examined system.     

Effects of a high oil and fibre diet and supplementary roughage on performance, injurious pecking and foraging activities in two layer hybrids

1. The study investigated the feeding of a high oil and fibre diet containing 260 g/kg organically produced cold pressed sunflower cake or supplemental roughage to aviary-housed Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB) layers between 20 and 74 weeks of age with outdoor access during summer. 2. Feeding roughage was associated with reduced vent injuries, a tendency to improve plumage condition, and was accompanied by improved FCR compared with controls. Feeding the high oil and fibre diet tended to improve FCR compared with the control diet. 3. The dry matter of faeces was reduced in both treatments compared with controls. Foot pad cleanliness and the proportion of dirty eggs were negatively affected by the high oil and fibre diet. Foot health was superior in LB compared to LSL. 4. LB used the outdoor hen-runs more than LSL, but LSL consumed more litter indoors. Fewer LB hens fed on the control feed were recorded in the outdoor hen-runs. Supplemental roughage tended to decrease litter consumption. 5. In conclusion, supplemental roughage reduced vent injuries and was correlated with foraging activities. Feeding 260 g/kg sunflower cake negatively affected hygiene in aviary hens. Sunflower cake is nevertheless a promising alternative feedstuff to fulfil the protein requirement in organic layers.     

Progression of histomonosis in commercial chickens following experimental infection with an in vitro propagated clonal culture of Histomonas meleagridis

Four commercial strains of chickens, namely, ISA brown leghorn (ISA), TETRA-SL brown (TETRA-SL), Lohmann brown (LB), and Lohmann LSL (LSL), were infected with a well-defined clonal culture of Histomonas meleagridis (H. meleagridis/Turkey/Austria/2922-C6/04) to investigate their susceptibility to histomonosis. Each group included 16 chickens, which were housed under the same conditions in separate pens. All chickens were infected with 10(4) histomonads orally and intracloacally at 14 days of age. No mortality or clinical signs were observed during the experiment in all birds. Three birds of each chicken strain were euthanatized on days 4, 7, 10, 14, and 21 postinfection. Incidence of histomonosis on the basis of cecal lesions was found to be 64.00% in TETRA-SL, 62.50% in LB, 53.12% in LSL, and 43.75% in ISA chickens. Fewer lesions were noticed in livers than in ceca, with an incidence of 15.62% in TETRA-SL, 9.37% in LB, and 3.12% in ISA chickens. No liver lesions were found in the LSL chickens. Statistical analysis revealed that there was no significant difference (P > 0.05) in susceptibility to experimental H. meleagridis infection based on cecal and liver involvement. Polymerase chain reaction (PCR) and immunohistochemistry were found to be reliable tools to confirm the presence of histomonads and changes in the ceca. However, some negative PCR results were recorded from the livers despite the presence of macroscopic lesions. Additionally, DNA of H. meleagridis was detected by PCR in a few of the lungs, but immunohistochemistry was negative. Nucleic acid of the protozoan parasite was not detected in samples from kidney, brain, spleen, or bursa of Fabricius. Altogether, the high susceptibility of commercial chicken lines to histomonosis could be demonstrated and characterized by severe lesions in the ceca and insignificant involvement of the liver, approaching a maximum on days 7-14 postinfection.     

Influence of Ascaridia galli infections and anthelmintic treatments on the behaviour and social ranks of laying hens (Gallus gallus domesticus)

In the present study, the effects of an experimental Ascaridia galli infection and anthelmintic treatment on the behaviour and social status of laying hens of two different lines were studied. Sixty white (Lohmann LSL; LSL) and 60 brown (Lohmann Brown; LB) hens were reared under helminth-free conditions. The hens of each line were divided into four groups. The birds in two of the groups were artificially infected with 250 embryonated A. galli eggs at an age of 27 weeks. The other two groups were kept as uninfected controls. One infection and control group was dewormed at 38 weeks of age and slaughtered 4 weeks later, contemporary with the other animals. Individual faecal Ascaridia egg counts (FEC) were performed 11 weeks post-infection (p.i.). Body weights, laying performance and egg weights were recorded regularly. Blood was taken to measure testosterone levels. The worm burdens established in the intestines were counted in the infected not treated group after slaughtering. In addition, 15 behavioural parameters were recorded by focal animal observation (n=10 per group) of one infection (plus anthelmintic treatment) and one control group, according to the time-sampling method throughout the experiment. All agonistic interactions within the groups were recorded simultaneously on an ongoing basis, thereby allowing the calculation of an individual social rank index. The following results were obtained: Mean FEC and worm burden were higher (p < 0.01) in the LSL hens than in the LB hens, but their performances were not different (p > 0.05) from the controls. Infections with A. galli resulted in significant behavioural changes in both lines as the infected birds showed a higher food intake and lower locomotion activity during the prepatent and patent periods. After anthelmintic treatment, food intake decreased and locomotion increased. Behavioural changes were more pervasive in the infected LSL hens, as these hens also showed changes in ground pecking and nesting activity not only during the prepatent and patent periods, but also after anthelmintic treatment. Social rank did not significantly change as a consequence of A. galli infection, but the infection groups of both lines had a tendency to display more agonistic activity than the non-infected controls. Serum testosterone values only increased significantly in the LSL hens during the patent period compared to the controls. No significant correlations were apparent between serum testosterone level, parasitic parameters, social status and/or aggressiveness in any of the groups. This study showed that even sub-clinical A. galli infections and their anthelmintic treatment can have an impact on animal behaviour.     

Welfare of layers housed in small furnished cages on Danish commercial farms: the condition of keel bone,feet, plumage and skin

1. An on-farm assessment of keel bone, feet, plumage and skin damage was conducted in layers in small furnished cages to evaluate welfare implications.

2. Thirteen farms participated, all housing Lohmann LSL layers in systems allowing 8 or 10 hens per cage.

3. Each flock was visited at three different ages: 32, 62 and 77 weeks. During each visit, 100 hens were examined for keel bone fractures and deviations, plumage damage, body wounds, foot pad lesions, bumble feet, missing toes and toe wounds.

4. A deterioration with age of the condition of the plumage and keel bone was found (P < 0.001). At 77 weeks of age, 16% of the birds had poor plumage, and 43% of the birds had keel bone damage. In contrast, foot pad lesions were most prevalent at 32 weeks of age (13%), whereas the other foot injuries and body wounds remained at a relatively low level throughout the three ages examined.

5. Prevention of damage to the keel bone, plumage and foot pads should therefore be considered when aiming to improve welfare of laying hens housed in small furnished cages.     

Behaviour,health and integument of four hybrids of laying hens in modified and conventional cages

1. In 2 trials the health and behaviour of a total of 3552 caged laying hens of 4 hybrids, Dekalb XL, Lohmann Selected Leghorn (LSL) and Shaver 288 in trial 1 and ISA Brown and LSL in trial 2, were studied. The cage designs were Get‐away cages (GA) with 15 hens per cage, a special version of the ‘Edinburgh modified cage’ called ‘Modified and enriched cage’ (ME) with 4 ISA or 5 Leghorn hens per cage, conventional metal cages with 4 hens per cage without (CO) and with a perch (PC) and conventional plastic cages (PL) with three hens per cage. GA and ME included nests, perches and sandbaths.

2. In the first trial two nest models were used, artificial turf and welded wire floor. In the second trial both nest models were used in GA, while all nests in ME were equipped with artificial turf. In the second trial there were 4 sandbath treatments in ME; no sandbath, sandbath (25×50 cm) first opened at 16 weeks of age, sandbath first opened at 26 weeks and double size sandbath (50 × 50 cm) first opened at 16 weeks. Hens in GA were allowed access to the sandbaths from 26 weeks.

3. At 35 and 55 weeks the best plumage condition (feather cover) was found in PL and GA but plumage condition in ME was not significantly inferior than in GA. Hens in GA had the dirtiest plumage and most bumble foot but no toe pad hyperkeratosis. Some toe pad hyperkeratosis occurred in the other systems. Most keel bone lesions were found in systems with perches. The highest mortality was registered in GA. Hens in systems with perches, sandbaths and nests had increased strength of humerus at slaughter.

4. More eggs were laid in nests with artificial turf than in welded wire floor nests. LSL hens laid larger proportions of eggs in the nests (94% and 92% in the two trials) than the other hybrids. Less than 1% of the eggs in ME and 2% in GA were laid in the sandbaths.

5. The use of perches in ME and PC was approximately 30% in the day time. At night the use was 93% in ME and 89% in PC in trial 1 and 96% in ME and 81% in PC in trial 2.

6. Hens in ME with the double sized sandbath both visited the sandbath and performed dust bathing behaviour most, followed by hens in GA, hens in ME with access to the bath from 16 weeks and last, hens in ME with access to the bath from 26 weeks.

7. It is concluded that enrichments of laying cages are used by the hens to a large     

Effect of Perches at Different Positions in Conventional Cages for Laying Hens of Two Different Strains

Production, health and behaviour were studied in 648 White Leghorn hens of two strains, LSL and Shaver 288, housed in three-tier battery cages (four hens per cage, 600 cm2 per hen) with three treatments; two with a perch fitted across the cage, 17 (PB) or 24 cm (PC) from the back of the cage, respectively, and control cages without perch (NP). Introducing a perch did not significantly affect production, but PC gave more dirty eggs, and both PC and PB tended to give more cracked eggs. The perch caused inferior keel bone condition and hygiene of the cage floor and a stronger tibia. LSL hens showed higher production, better feed conversion ratio, fewer cracked eggs, better keel bone health and shorter claws than Shavers. Use of the perch averaged 25 and 90% during day and night, respectively. The perch did not significantly affect other behaviours. There were significant interactions between strain and cage design regarding laying percentage, egg weight, cracked eggs, live weight, foot- and perch hygiene, keel bone condition and toe pad hyperkeratosis.     

Performance of Four Hybrids of Laying Hens in Modified and Conventional Cages

Abstract

In two trials, production, feed consumption, mortality, egg quality and birds' live weight of a total of 2877 caged laying hens of four hybrids, Dekalb XL, Lohmann Selected Leghorn (LSL) and Shaver 288 in Trial 1 and ISA Brown and LSL in Trial 2, were studied during full production cycles. The cage designs were Get-away cages (GA) with 15 hens per cage, a special version of the “Edinburgh modified cage” called “Modified and enriched cage” (ME) with 4 ISA or 5 Leghorn hens per cage, conventional cages of metal (CO) with 4 hens per cage and conventional cages of plastic (PL) with 3 hens per cage. GA and ME included nests, perches and sandbaths. LSL produced significantly better than the other hybrids. Shaver had a significantly lower live weight than Dekalb and LSL, while ISA was significantly heavier than LSL. Production in ME was similar to that in conventional cages and, in Trial 2, birds in ME, CO and PL produced significantly better than those in GA. The highest mortality was registered in GA, where in Trial 2 it was significantly higher than in ME. GA gave a significantly higher and CO a lower proportion of cracked eggs than ME and PL. In both trials ME gave significantly lower proportions of dirty eggs than GA and in Trial 2, the lowest. Few differences between the systems were registered regarding interior egg quality. It was concluded that ME is better for production, mortality and management than GA but similar to conventional cages.     

Ulcerative posthitis in bulls in Uruguay.

Ulcerative posthitis in bulls in Uruguay is described; 1096 bulls in 17 different establishments were examined. The incidence of bulls grazing on improved pasture was 32.9% in those under one year and 80.8% in animals of 18 to 36 months of age. Bulls grazing on natural pasture showed an incidence of 63.5% in adult animals irrespective of age. Histologic characteristics of the preputial lesions were acanthosis, parakeratosis and hyperkeratosis followed by invasion of leukocytes in the epithelium and ulceration. Corynebacterium renale was isolated from 59 of 204 prepuces. Based on the isolation of C. renale, histological lesions and the greater incidence in animals on high planes of nutrition, it is postulated that the lesion is due primarily to production of ammonia following the hydrolization of urea by the organism.     

Effects of group size on performance,health and birds’ use of facilities in furnished cages for laying hens

A total of 1584 Lohmann Selected Leghorn hens were kept in 144 modified cages furnished with—perch, nest and sandbath for 5, 6, 7 or 8 hens per cage or in 162 conventional cages for 4 hens. Cage floor area was 600 cm² per hen excluding nest and sandbath. Doors to nests and sandbaths were time monitored. Production, mortality, exterior egg quality, health, integument and the birds use of facilities were registered from 20 until 80 weeks. No effects of group size or keeping system on production or mortality were detected, but the furnished cage gave more cracked and less dirty eggs than the conventional cage. Hens in the furnished cage had better plumage condition, less toe pad hyperkeratosis, shorter claws, less rear body wounds and stronger humerus, but dirtier feet than hens in the conventional cage. Hens in the larger group sizes had the dirtiest feet. In the furnished cage, on average, 86% of all eggs were laid in the nests and 0.6% in the sandbaths. The rolling out efficiency from nests was best in the larger group sizes. During night less than 0.5% of the hens stayed in the sandbath and less than 2% stayed in the nest. Average use of perches was 28% during the day and 91% at night. Hens in the small group sizes used the sandbath most. Dust‐bathing behaviour also occurred on the wire floor.     

Genetic differences of Ascaridia galli egg output in laying hens following a single dose infection.

Groups of 20-week-old white (Lohmann LSL) and brown (Lohmann Brown) hens were reared under helminth-free conditions and both divided into two subgroups. One subgroup was artificially infected with 250 embryonated Ascaridia galli eggs, the other subgroup were kept as uninfected controls. During the following 12-month laying period individual faecal Ascaridia egg counts (FEC) were performed and bodyweight measured at monthly intervals. Laying performance and egg weights were determined daily. The mean FEC were significantly (P < 0.01) higher in infected white hens than in infected brown hens. The growth rate of the white hens was significantly (P < 0.05) higher in the control group, whereas in brown hens no significant group difference was observed. The laying performances and egg weights did not differ significantly (P > 0.05) between control and infected animals for either line. The estimated repeatabilities for mean log(10) FEC of different samples were reasonably high (0.16-0.54). Heritabilities for mean log(10) FEC were between 0.13 and 0.19 for white hens and between 0.0 and 0.10 for brown hens. Thus, it should be possible to select for A. galli resistance in chickens, which will be of importance for birds kept in alternative and organic farming systems.     

Evaluation of bone strength,keel bone status,plumage condition and egg quality of two layer lines kept in small group housing systems

1. The aim of the present study was to determine the influence of large (54 or 60) and small (36 or 40) group sizes and tiers of the small group housing system “Eurovent German” on tibia and humerus bone breaking strength, keel bone status, plumage condition and egg quality for two commercial layer lines, Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB), at the same stocking density (890 or 830 cm²/bird).

2. In 4 consecutive trials, 4752 hens were recorded for keel bone status. Evaluation of plumage condition was made for 1440 hens and bone breaking strength was recorded for 1200 hens. A total of 4962 eggs were analysed for internal and external egg quality traits. Analyses involved 30 small group compartments per trial.

3. The layer line had a much more pronounced influence on humerus breaking strength than on tibia breaking strength.

4. Plumage condition, particularly on the neck, was positively correlated with humerus breaking strength in both layer lines.

5. An average of 34% of LB and 23% of LSL hens showed keel bone deformities, with higher proportions of slight deformities.

6. Slight keel bone deformities, rather than moderate to severe, increased significantly during the laying period.

7. Stocking density had no influence on bone breaking strength, keel bone status and egg quality traits.

8. LB layers had a 1.4-fold higher humerus, but only a 1.06-fold higher tibia breaking strength compared to LSL layers.

9. Tibia breaking strength was significantly affected by the interaction of group size and layer line. LSL layers in small groups had lower tibia breaking strengths than those of the large groups.     

Oral leukoplakia and costochondral hyperplasia induced by diethylnitrosamine in hamsters exposed to cigarette smoke with or without dietary vitamin C

Male Syrian golden hamsters receiving 12 weekly subcutaneous injections of diethylnitrosamine (DEN) were subjected to cigarette smoke-inhalation and fed a diet or without 1% vitamin C supplement for a period of 58 weeks. Another group was a sham-smoked control and was not fed vitamin C. Tissues of the oral cavity and costal cartilage were examined by light and/or scanning electron microscopy. Oral leukoplakia and costochondral hyperplasia occurred with high frequency in all groups treated with DEN. Leukoplakic lesions were found in the palate, tongue, and pharynx; the early change was focal erosion with mild epithelial hyperplasia and inflammatory cell infiltration. Advanced lesions had marked mucosal thickening due to acanthosis, parakeratosis, hyperkeratosis, and submucosal infiltration of lymphocytes and plasma cells. Precancerous lesions were noted in tongue and pharynx. Scanning electron microscopy of tongues revealed destruction of filiform papillae. The incidence of leukoplakic lesions were higher in smoke-exposed hamsters than in controls, but the incidence in vitamin C-supplemented hamsters was low when compared with the smoke-exposed hamsters without vitamin C. Costochondral hyperplasia was initiated by thickening of the perichondrium followed by proliferation of chondrocytes. Costochondral hyperplasia appeared earlier, and the incidence was higher in the vitamin C-supplemented hamsters. It could not be determined whether costochondral hyperplasia was the primary lesion induced by DEN or secondary change.     

An outbreak of teat papillomatosis in cattle caused by bovine papilloma virus (BPV) type 6 and unclassified BPVs

Out of 700 heifers at a local farm in Hokkaido, the Northern island of Japan, 560 (80%) were found to have benign teat tumors. All of the analyzed tumors were macroscopically of the flat-and-round type, and no other types such as rice-grain or frond epithelial type were found. The lesions were characterized by epithelial hyperplasia, acanthosis and hyperkeratosis. Unlike in typical fibropapilloma, fibroplasia of the underlying dermis was not observed. Bovine papilloma virus (BPV) capsid antigen and virus particles were found in basophilic intranuclear inclusions of the stratum granulosum of the epidermis by immunohistochemistry and electron microscopy, respectively. BPV-specific DNA was also detected in the lesions. By means of the polymerase chain reaction (PCR) and DNA sequencing of the PCR products, the viruses causing this outbreak were identified mainly as BPV-6 (64%), partly as unclassified BPVs (14%) and their co-infections (21%). Our findings suggest that this outbreak of benign teat tumors was associated with several BPV types.     

Degree of synchronous feeding behavior of two types of laying hybrid hens in battery cages with a feeder space of 12 cm per hen

There is a considerable lack of scientific evidence on the necessary feeder space with respect to the legal requirement that all hens of one battery cage must be able to feed simultaneously. Moreover it is likely that hens from different lines, differing in weight and width, have different space needs at the feeding trough. In order to ascertain the degree of simultaneous feeding in two types of laying hybrids with different weights, feeding activity was recorded in 29 cages, populated with four hens each with a feeder space of 12 cm per hen. Recordings took place over 6 days at seven feeding times under ad libitum feeding conditions. In all cages, the lighter and apparently slimmer LSL-hens (Lohmann Selected Leghorn, white) were able to feed simultaneously. However, for the somewhat heavier and apparently broader LT-hens (Lohmann Tradition, brown) this could not be observed in two of 16 cages. Nevertheless, was the average proportion of cages higher in LT-hens in which synchronous feeding of all hens could be noted at least once within each 30 minutes observation period. These were 35% of cages (LT) compared to 18% in LSL-hens (p < 0.001). Therefore, not only the physical space needs, but also possible differences in social and feeding behaviour may affect synchrony in different lines. In general, the proportion of observation time with simultaneous feeding was low (3.3% in LT, 1.7% in LSL, n.s.). As there are no comparable figures available for different feeder space allowances from the literature, an assessment of the presented data is not possible. Investigations on the synchrony of feeding behaviour in small groups of laying hens under varying environmental conditions and in different layer lines should be continued.     

Plasma cell pododermatitis in a cat

Plasma cell pododermatitis, an uncommon disease of unknown etiology, is described in a six year old male domestic short-haired cat. The cat was referred with a history of lameness associated with swelling, softness and ulceration of the foot pads. The history suggested a seasonal occurrence of the condition. The dermis and subcutis of the foot pads were infiltrated by inflammatory cells which were mainly plasma cells. The large number of plasma cells present in the lesions suggests an immunological basis for the condition.