Crop impaction resulting from feather ball formation in caged layers

Abnormal behaviors in commercial poultry, including feather pulling and pica, have been known to occur when birds are exposed to an unfamiliar environment. We report here the development of crop impactions resulting from feather ball formation. Twelve specific-pathogen-free (SPF) chickens were placed in one of three cages housed among a commercial layer flock in three different buildings on a farm site. Three weeks after placement, the birds were removed from the cages and given a physical exam. Chickens were thin, and one bird in each of the three caged groups had a palpable mass at the level of the thoracic inlet. At necropsy, a mass was noted in the crop. Upon further dissection, a wet, foul-smelling mass consisting of feathers and feed debris was recovered. Results from our case indicate that unfamiliar surroundings can cause pica in birds. Hence, avian researchers and veterinarians planning to introduce new birds into a flock, i.e., SPF birds, should consider the birds' previous environmental conditions prior to placement because sudden placement in unfamiliar surroundings can result in pica.     

Matched concurrent case-control study of risk factors for feather pecking in hens on free-range commercial farms in the UK

1. The aim of the study was to compare the management and husbandry of free-range flocks in the UK where feather pecking was either present (case) or absent (control). 2. One hundred flocks were enrolled into a concurrent case-control study: 50 where birds had recently started feather pecking, and 50 matched control flocks where birds of the same age had not started feather pecking. 3. Information was obtained from a detailed interview with the flock manager, and by direct inspection of the flock, house and range. 4. Initial univariate analyses revealed that case flocks were more likely to comprise ISA Brown than Lohmann, were more likely to be restricted from litter areas to prevent floor eggs, and were less likely to use the outside range. 5. Cluster analysis indicated that feather pecking was not associated with any particular husbandry system. 6. The only influential risk factor significant in the multivariable conditional logistic regression analysis was use of the outdoor range. The risk of feather pecking was reduced 9-fold in flocks where more than 20% of birds used the range on sunny days (odds ratio = 0.12). Use of the range was positively associated with the presence of trees and/or hedges on the range.     

Relationships of Body Weight,Feathering, and Footpad Condition with Reproductive and Carcass Morphology of End-of-Season Commercial Broiler Breeder Hens

Reproductive efficiency of broiler breeder hens declines with age. Whereas careful feed management can maximize BW uniformity at housing, there is variability in how rate of lay and flock behavioral dynamics will interact with subsequent growth during the breeder phase. This study characterized differences in carcass and reproductive morphology in end-of-cycle commercial broiler breeder hens based on BW, feather coverage, and footpad condition, and we discuss the potential implications of the findings. At 62 wk of age, 537 hens were studied from an original flock of 3,800. Birds were sorted into subgroups based on BW, feather score, footpad score, and whether they were in laying condition when dissected. The average flock BW was 3.56 kg, with means of 2.86, 3.56, and 4.20 kg for the low (LOW), standard (STD), and high (HIGH) BW groups, respectively. A higher proportion of birds from the STD (85%) and HIGH (81%) groups still had a fully formed reproductive tract compared with birds of the LOW (59%) group. The LOW birds in laying condition had a smaller ovary than the STD or HIGH birds. The ovary condition of birds in laying condition was not related to feather coverage. As feather coverage improved, final hen BW increased, demonstrating a potential role of feather coverage in growth efficiency or of BW in level of mating activity. Birds that received a feather score of 5 (complete back feather coverage) and had a normal reproductive tract made up 14.7% of this flock. It is likely that many of these birds were mating very infrequently or possibly not mating, which has implications for maintenance of flock fertility. Some may also have been returning from a molt. Footpad condition was not related to body size. External traits such as BW, feather score, and footpad score can provide insight into flock reproductive condition and male:female interaction.     

肉仔鸡腿病病因研究报告

1498只出壳A.A.肉仔鸡在同一房宿内分五区网上养育,分别为301,301,297,298和301只。10日龄雏鸡出现腿异常,46日龄腿病死淘鸡总数为248只,占入舍鸡数的16.6％。一经发现病鸡就拣出隔网分开饲养,腿病鸡群称为病鸡组,正常鸡群称为健康组。对不同日龄鸡做病毒性关节炎、滑液囊霉形体、葡萄球菌和大肠杆菌的血清学检查或细菌培养,结果都判定为阴性。从49日龄病鸡组和健康组分别随机抽取15只鸡,分离血清,检测血清总蛋白、碱性磷酸酶、钙、磷和血脂三项,并测定羽毛锰和锌等矿物元素,这些指标在两组之间都呈差异不显著水平(P>0.05)。结合临床剖检结果,认为病鸡没有发生骨质明显病理过程。应用剩余法分析阐明,垫网是这次肉仔鸡腿病的直接病因。连续不间断地光照亦可能与腿病相关。     

Investigations on the pathogenicity of Erysipelothrix rhusiopathiae in laying hens

Erysipelas was diagnosed in 1998 from 34-wk-old laying hens in a free range flock in Germany. Erysipelothrix rhusiopathiae of serotype 1 was cultured from internal organs of the affected birds. This article describes the pathogenicity of the field isolate of E. rhusiopathiae in experimentally infected specific pathogen-free (SPF) laying hens. Three experiments were performed with SPF chickens inoculated at 17, 27, and 37 wk of age by either intramuscular (IM) or oral route. Inoculated birds were observed for 14 days. The highest mortality rates occurred in older birds, with 100% mortality observed in the 37-wk-old birds inoculated IM, 60% mortality reported in the younger 27-wk-old birds, and no mortality in the 17-wk-old age group. In the orally infected 27-wk-old birds, 40% mortality was detected, whereas no mortality was observed in the oldest birds by the same route. The results of the experiments support the contention that older birds are more sensitive to infection than younger birds and that mortality in laying hens is age related and dependent on the route of infection.     

种公鸡日粮营养水平及其对繁殖性能影响的研究

用29～36周龄海赛克斯(褐色)蛋用型父母代种公鸡112只、种母鸡1024只,研究了种公鸡日粮营养水平及其对繁殖性能的影响。上述试鸡,种母鸡饲用同一蛋鸡料,种公鸡则分别给饲下列4种日粮:1.高CP(17.5％),高AA(0.86％L_(Ys),0.63％SAA),高Ca(3.7％)日粮;2.CP(12.5％),低AA(0.55％L_(YS),0.45％SAA),高Ca(3.7％)日粮; 3.低CP(12.5％), 低AA(0.55％ L_(Ys), 0.45％SAA), 低Ca(1.0％)日粮;4,同3,仅更换维生素-微量元素综合预混料。结果:1.采用低CP、低AA、高Ca或低CP、低AA、低Ca日粮时,种公鸡的精液品质、种蛋受精率、孵化率等均无异于用高CP、高AA、高Ca日粮者(P>0.05);2.采用种公鸡专用维生素-微量元素综合预流料,入孵蛋孵化率提高3.35％,日饲用低CP、低AA、低Ca日粮的种公鸡体增重(29～36周龄)大于用高CP、高AA、高Ca日粮者(P<0.05),其36周龄体重较接近于品种标准。     

Enzootic reticuloendotheliosis in the endangered Attwater's and greater prairie chickens

Reticuloendotheliosis (RE) in captive greater prairie chickens (GPC, Tympanuchus cupido pinnatus) and Attwater's prairie chickens (APC, Tympanuchus cupido attwateri) was first reported in 1998. RE is caused by avian reticuloendotheliosis virus (REV), an oncogenic and immunosuppressive retrovirus infecting multiple species of wild and domestic birds. During August 2004 through May 2006 a captive population of prairie chickens was affected simultaneously with a neoplastic condition and also avian pox, the latter being detected in 7.4% (2 of 27) of all birds submitted for histopathology. A survey for REV was conducted in order to examine its possible role in mortality observed primarily in juvenile and adult specimens of prairie chickens. The investigative procedures included postmortem examinations, histopathology, molecular detection, and virus isolation. In total, 57 Attwater's prairie chickens and two greater prairie chickens were included in the study. REV infection was diagnosed using virus isolation or polymerase chain reaction (PCR) or both in 59.5% (28 of 47) of blood samples and/or tumors from suspect birds. Lymphosarcomas were detected in the tissues of 37% (10 of 27) of the birds submitted for histopathology. Such lymphosarcomas suggestive of RE represented the most frequent morphologic diagnosis on histopathology among 27 separate submissions of naturally dead prairie chickens. Overall, REV was detected or RE diagnosed in 34 of 59 prairie chickens (57.62%). The average death age of all birds diagnosed with lymphosarcomas on histopathology was 2.2 yr, ranging from <1 to 4 yr. Although deaths associated with neoplasia occurred in males and females in equal proportions based on submissions, overall more males were diagnosed as REV infected or RE affected (16 males vs. 7 females, and 11 birds of undetermined gender). Reticuloendotheliosis virus was confirmed as a significant cause of mortality in captive prairie chickens.     

Effects of the age of male and female broiler breeders on sexual behaviour, fertility and hatchability of eggs

1. The effects of the age of male and female broiler breeders on fertility, hatchability and sexual behaviour were determined in two 2x2 factorial experiments. In the 1st, male and female birds 27 to 29 and 35 to 37 weeks and in the 2nd at 35 to 37 and 55 to 57 weeks of age were compared. 2. Fertility was not affected by the age of the males or females. 3. Early embryo deaths were higher and hatchability of fertile eggs was lower in eggs from females aged 27 to 29 and 55 to 57 weeks compared with eggs from birds aged 35 to 37 weeks. 4. There were no differences in male display behaviours at any age. The number of observed matings were higher in young males 27 to 29 weeks old compared with males 35 to 37 and 55 to 57 weeks of age. There were no detectable differences in the responses of the females to the males at different ages. 5. Plasma testosterone concentration in males increased from 24 to 30 weeks of age and was relatively constant from 36 to 60 weeks. Plasma oestrogen in females was high at 24 and lowest at 30 weeks of age after which it increased. 6. The results suggest that there may be little difference in the fertility of male and female broiler breeders at different ages when body weight is adequately controlled to at least 60 weeks of age.     

Inheritance of congenital cataracts and microphthalmia in the Miniature Schnauzer

Congenital cataracts and microphthalmia in the Miniature Schnauzer were inherited as an autosomal recessive trait. Eighteen matings of affected X affected Miniature Schnauzers resulted in 87 offspring with congenital cataracts and microphthalmia (49 males/38 females). Two matings of congenital cataractous and microphthalmic Miniature Schnauzers (2 females) X a normal Miniature Schnauzer (1 male) yielded 11 clinically normal Miniature Schnauzers (7 males/4 females). Eighteen matings of congenital cataractous and microphthalmic Miniature Schnauzers (6 males) X carrier Miniature Schnauzers (9 females) produced 81 offspring; 39 exhibited congenital cataracts and microphthalmia (20 males/19 females) and 42 had clinically normal eyes (17 males/25 females).     

Economic effects of clinical chicken anemia agent infection on profitable broiler production.

An outbreak of anemia dermatitis syndrome caused by chicken anemia agent (CAA) occurred in 15 broiler flocks. An average of 29% of chickens in these flocks were derived from a common breeder flock. The breeder flock had no antibody to CAA at 20 weeks of age but had seroconverted by 31 weeks. Diseased broiler flocks were derived from eggs laid by the breeder flock between 25 and 30 weeks of age. CAA infection in the breeder flock was subclinical, with no apparent effects on mortality or performance. A strategic program of therapeutic and/or prophylactic antibiotic therapy was begun in affected broiler flocks as soon as the disease was diagnosed. Nevertheless, when the cost of therapy was taken into account, affected broiler flocks had a net income 17.3% to 19.6% lower than normal flocks. Average bird weights were 3.3% to 3.5% lower in affected flocks than in unaffected flocks, and affected flocks had a significantly greater proportion of lighter birds. Average mortality in affected flocks was 2.0% to 2.3% higher than in normal flocks, with peak mortality occurring in the third week of life. There was no apparent effect on feed-conversion ratio.     

Many quantitative trait loci for feather growth in an F(2) broiler × layer cross collocate with body weight loci

1. A genome-wide scan of 467 F₂ progeny of a broiler x layer cross was conducted to identify quantitative trait loci (QTL) affecting the rate of growth of the tail, wing and back feathers, and the width of the breast feather tract, at three weeks of age.

2. Correlations between the traits ranged from 0·36 to 0·61. Males had longer tail and wing feathers and shorter back feathers than females. Breast feather tract width was greater in females than males.

3. QTL effects were generally additive and accounted for 11 to 45% of sex average feather lengths of the breeds, and 100% of the breast feather tract width. Positive and negative alleles were inherited from both lines, whereas the layer allele was larger than the broiler allele after adjusting for body weight.

4. A total of 4 genome-significant and 4 suggestive QTL were detected. At three or 6 weeks of age, 5 of the QTL were located in similar regions as QTL for body weight.

5. Analysis of a model with body weight at three weeks as a covariate identified 5 genome significant and 6 suggestive QTL, of which only two were coincident with body weight QTL. One QTL for feather length at 148?cM on GGA1 was identified at a similar location in the unadjusted analysis.

6. The results suggest that the rate of feather growth is largely controlled by body weight QTL, and that QTL specific for feather growth also exist.     

Factors related to shell deaths during artificial incubation of ostrich eggs

The ostrich industry experiences a high rate of embryonic mortalities during artificial incubation of eggs. Embryonic deaths were studied from data recorded on 37,740 fertile eggs incubated artificially during the 1998-2005 breeding seasons. Roughly 10,000 eggs that sustained embryonic mortalities were classified according to the stage and nature of death, i.e. before 21 days of incubation, after 21 days of incubation, deaths after pipping and rotten eggs. Although infection may have played a role in approximately 1300 rotten eggs, no detailed knowledge of the pathogens involved was available. The remainder of deaths could not be related to pathogens and the deaths were thus generally referred to as non-infectious. The overall level of embryonic mortality in all the eggs studied was 28.5 %. Overall embryonic mortality was affected by incubator, with higher levels (57.0 %) found in eggs incubated in an African Incubator and also in eggs that were transferred between incubators during incubation (38.1%). Overall embryonic mortality also increased in eggs produced by older females. Eggs produced in the autumn had the highest level of embryonic mortality at 53.6 %, whereas eggs produced in the winter had a marginally higher level of embryonic mortalities of 29.2 % compared with eggs produced during summer (27.4 %). Eggs produced by South African (SA) Black males crossed to Zimbabwean Blue females had high levels of embryonic losses of 45.7 %. The embryonic mortality of eggs produced by SA Blacks or Zimbabwean Blue breeding birds subjected to pure breeding was similar at approximately 33-34 %, but embryonic mortality was improved in eggs produced by Zimbabwean Blue males crossed to SA Black females (27 %). Embryonic mortality was increased in eggs that were set directly (32.0 %) or subjected to longer than 6 days of storage (43.5 %). Embryonic mortality was affected by year. The results that were obtained will assist in determining non-infectious factors that have a negative effect on hatching success. Steps can thus be taken to eliminate such factors that may compromise hatching success.     

Disease Condition of Turkey Poults Characterized by Enlarged and Rounded Hearts

The occurrence of a disease condition in two flocks of young turkey poults characterized by enlarged hearts and marked distension of the right ventricle is described.

Only males were observed to exhibit the condition in the first flock and approximately five per cent of this sex died with the characteristic enlargement. Abnormal hearts were found in progeny from 2-5 sires in each of four strains.

In a second flock at a second location, a small number of females also exhibited the condition. Approximately one per cent of this sex died with enlarged hearts. The incidence in males was similar in both flocks. The second flock was composed of poults from a commercial strain and poults which were a cross of the four laboratory-raised strains with this unrelated commercial strain. The condition was found in both pure and cross strain poults from this flock.

A second type of anomaly which grossly resembled “round-heart disease” of chickens was observed in birds from both flocks over six weeks of age. It was not associated with the death of the birds and was found during examination of injured or sacrificed males and females.

Histological findings have not been consistent, but are being continued. Transmission trials are being conducted.

     

Lethal osteogenesis imperfecta and skin fragility in newborn New Zealand Romney lambs

Osteogenesis imperfecta and skin fragility occurred in about 50 New Zealand Romney lambs born in a flock of 450 ewes. Affected lambs had soft bones and multiple intrauterine bone fractures. Long bones had a thickened diaphysis with almost complete absence of a medullary cavity. Other consistent gross findings were moderate brachynathia inferior, subcutaneous oedema, marked joint laxity, dark blue sclera and small pink teeth. Histopathologic and ultrastructural changes were consistent with a defect in collagen production by fibroblasts. DNA finger-printing was used to identify which of the five rams used in the flock was carrying the genetic defect. The disease was inherited as an autosomal dominant trait and was considered to be a new mutation in the testicular germ cell lines of this ram.     

Influence of rearing and lay risk factors on propensity for feather damage in laying hens

1. Feather pecking is one of the major problems facing the egg industry in non-cage systems and is set to become even more of an issue with the European Union ban on the keeping of laying hens in barren battery cages which comes into force in 2012 and the prospect of a ban on beak-trimming. Reducing feather pecking without resorting to beak treatment is an important goal for the poultry industry. 2. We report here a longitudinal study that included over 335,500 birds from 22 free range and organic laying farms. Accelerated failure time models and proportional hazards models were used to examine the effects of a wide range of factors (management, environment and bird) on development of substantial feather damage in lay. Particular emphasis was placed on risk factors during rear and on practices that could feasibly be changed or implemented. 3. The age at which a flock exhibits substantial feather damage could be predicted both by factors in the environment and by early symptoms in the birds themselves. Factors that were associated with earlier onset of severe feather damage included the presence of chain feeders, raised levels of carbon dioxide and ammonia, higher sound and light levels, particularly in younger birds. Increased feather damage (even very slight) in birds at 17-20 weeks of age was also highly predictive of the time of onset of severe feather damage during lay. Increased feed intake also indicated that a flock was at risk of early severe feather damage. 4. Birds that stayed on the same farm for rearing and lay showed later onset of serious feather damage than those that experienced a change in farm from rearing to lay. However, an increased number of changes between rearing and lay (feeder type, drinker type, light intensity etc) was not associated with earlier onset of serious feather damage. Further research needs to be done on the role of the transition from rearing to lay as a risk factor for FP in lay.     

Testing and management of a specific pathogen free chicken flock with special reference to avian leukosis virus infections.

A specific pathogen free (SPF) chicken flock was reared in isolation under laboratory conditions during five years and continuously tested for presence of specified avian pathogens. The potential occurrence of avian leukosis virus (ALV) was most thoroughly examined. The RIF and neutralization tests were unequivocally negative. Radioimmunoassay was used for detecting the presence of the major protein (gs-a) of the group-specific antigen of avian onoorna viruses. This test seemed to he well suited for checking ALV infections in chicken flocks whereas the COFAL (complement fixation avian leukosis) test was considered unreliable for this purpose. Yolk and serum from SPF chickens were negative for anti-gs-a antibodies measured by the radioimmunoassay; immunized or naturally infected birds showed anti-gs-a amounts correlating with the neutralizing titre. Besides, the flock was regularly tested for presence of seven other contagious avian pathogens. There was no evidence of infection.SPF chicken flock; avian leukosis; laboratory diagnosis of avian leukosis virus infections.     

Influence of mating sex ratio in commercial pheasant flocks on bird health and the production,fertility, and hatchability of eggs

1. The effects of two mating ratios (8:1 and 12:1 females:males) on bird health, egg production and quality, fertility (employing macroscopic and microscopic techniques) and hatchability were examined for pheasants (Phasianus colchinus) on a commercial game farm, to provide a baseline data set for production of pheasants under specific conditions. 2. Mating ratio did not significantly affect mortality or pathology of breeding birds. 3. Egg production was significantly higher for the 8:1 mating ratio over the first 5 weeks of the trial but this difference disappeared during the second half of the trial. 4. Incidence of rejected eggs increased as the season progressed, mainly due to poor shell quality, but it was not significantly affected by mating ratio. 5. Fertility of eggs produced from birds under an 8:1 mating ratio was consistently and significantly 4% higher than fertility of eggs from the 12:1 mating ratio. The incidence of eggs showing no sign of mating (no sperm) was twice as high for the 12:1 pens (13.7% of the sample). There was good agreement between macroscopic and microscopic examination of fertility in eggs. Higher fertility in the 8:1 pens appeared to be related to a higher proportion of the females being recruited and mated. 6. Hatchability was significantly improved by adopting an 8:1 mating ratio, presumably due to the higher fertility of the eggs. Candling of the eggs improved hatchability but only for the 12:1 pens probably because more clear eggs were removed from the tray.     

Isolation of an unidentified,nonfermentative, gram-negative bacterium from turkeys and chickens: 38 cases (1995-2001)

Thirty-eight cases were identified in which a nonfermentative, gram-negative, rod-shaped bacterium was isolated from the respiratory system of turkeys and chickens. Cases were submitted from various parts of the country. Preliminary assessment of phenotypic characteristics indicated this bacterium was different from common pathogenic or opportunistic bacteria isolated from the avian respiratory tract. Most cases reported a history of respiratory distress and/or increased flock mortality. Lesions seen in infected birds included tracheitis and pneumonia, which correlate with the sites of isolation. Sixty-one percent of the isolations were made from the trachea and 25% from the lung. Age of infected birds ranged from 35 to 315 days in turkeys and 53 days to 3 yr in chickens. In most instances (90%), other bacteria were also isolated from affected sites. The significance of this organism in respiratory disease in birds is unknown.     

Antibody prevalence of low-pathogenicity avian influenza and evaluation of management practices in Minnesota backyard poultry flocks

Low‐pathogenicity avian influenza (LPAI) viruses have caused illness in poultry and humans with poultry contact. To determine whether there is evidence of exposure to avian influenza viruses (AIV) among backyard poultry in Minnesota and their human caretakers, 150 flocks of backyard birds were sampled for antibodies to AIV from August 2007 through December 2008. One hundred flocks were tested through routine slaughter surveillance by the Minnesota Board of Animal Health and an additional 50 flocks were contacted and sampled by study investigators. Blood was collected from 10 to 13 birds from each flock and a survey of biosecurity and management practices was administered to the flock owner. Blood samples were tested by agar gel immunodiffusion (AGID) for influenza A antibodies. Tested flocks had a median flock size of 100 birds (range: 12–800 birds), and were most commonly owned for meat for personal use (81% of respondents), fun or hobby (58%) and eggs for personal use (56%). Although 7% of flock owners reported that their birds had shown respiratory signs in the previous 3 months, only 1 of 150 flocks tested positive for influenza by AGID. Antibodies to LPAI H6N1 were detected in the positive flock. The owner of the positive flock did not have antibodies to H6 or other common AIV. Based on the findings of this study, the risk of transmission of LPAI viruses from backyard poultry to owners in Minnesota appears to be low under current conditions and management practices.     

Occurrence of waxy-textured yolk in the egg of the domestic hen (Gallus domesticus)

An unusual yolk material (waxy yolk) was identified in some hard boiled yolks of one strain of domestic hen. Its structure was consistent with it being formed from normal yolk through disruption of the yolk spheres. These are normally stable during even long periods of storage. Formation occurs mainly after ovulation, during passage of the egg down the oviduct; only rarely could it be found in the larger follicles of the ovarian hierarchy. In the flock of birds examined the incidence of eggs with waxy yolk was 75% of all eggs laid over a 7 d period. Of the 173 birds tested, the eggs of only 17 birds were totally unaffected; all eggs of 82 birds contained this material. The results of a hatchability trial indicated this material had no apparent influence on the embryo or hatchability.