Parent Flocks Research Articles

Breeder line and age affects the occurrence of developmental defects, the number of culled one-day old broiler chicks and their body mass

The objective of this work was to study the reasons for culling one-day old broiler chicks and to examine the relationship between the age and line of the hens and the culled chick’s body mass. Hatching eggs and day-old chicks were collected from a commercial flock of the Cobb 500 and Ross 308 broiler lines. The eggs were collected when the hens were 32, 42 and 52 weeks old. The reasons for culling the chicks were assessed immediately after the chicks had been removed from the hatcheries. The four main groups of defects were distinguished, depending on the part of the chick’s body. A fifth group covered general developmental defects. Within each group, the structural defects were identified in detail. The statistical analysis was performed in the R project. Amongst 57 600 chicks evaluated, 1042 malformations disqualifying them from further rearing were found in 666. The most frequent developmental defects were associated with the structure of the abdominal wall and umbilical cord: these were found in 155 chicks from the Ross 308 line and in 107 from the Cobb 500 line. In turn, umbilical defects occurred in 95 and 104 chicks from the Ross 308 and Cobb 500 lines, respectively. Abdominal defects were the most common in 107 chicks from the 42-week-old layers and in 89 chicks from the 52-week-old layers. There were also correlations between the age of the parent flock and the following defects: glued down, lack of down on the wings, contorted hips, wry neck and spine, and lack of a wake-up reflex. The average body weights of the Ross 308 and Cobb 500 chicks were 44.00 g and 43.13 g, respectively, but these differences were not statistically significant. However, the age of the broiler breeders (42 or 52 weeks) did affect the chick’s body weight (P ≤ 0.05). The lightest chicks (40.75 g) came from the Ross 308 line (age 42 weeks) and were nearly 4 g lighter than all the other groups. Most relationships between the lines of the layer hens at a particular age and the occurrence of malformations in the chicks were found in the hens aged 32 weeks, which may indicate the need for changes in the management of the eggs from the youngest layers belonging to the different lines.

FOOD HABITS OF NORTHERN DEER, CONDUCING THEIR INVASIATION BY HELMINTHS

Reindeer, in contrary to the notion of him as a ruminant animal, moreover, is able to develop strategies against ectoparasites and has a specific eating habits, increasing its chances of helminths invasion. Thus, there are reports of the reindeer eating snow soaked in human urine, brackish soil, horns of both reindeer and elks, chicks, bird eggs and excrement, as well as lemmings. Using the method of a passive experiment (observation), reindeer have been investigated in a recreational farm in the Leningrad Region (60°8′32′′N, 30°19′35′′E60.142207, 30.326466) starting from February 2018. The animals of the parent flock were brought there from the Murmansk region, and in May-June 2018 females calved. Animals are kept in a fenced area in conditions close to natural. During the growing season, they eat grass (with the addition of concentrates), in the winter they are fed with lichen. Fresh water is always available in drinkers. Photo registration of animals was carried out using a 5D Mark II (Canon) SLR camera and Xperia XA2 smartphone (SONY) camera. In addition to typical ruminant eating behavior (grazing, rumination), synchronized drinking and urination/defecation were recorded. This illustrates the route of invasion of reindeer with elafostrongylosis (previously diagnosed in these animals) – namely, through the absorption of freshwater mollusks, which, along with land gastropods, are intermediate hosts of Elaphostrongulys rangiferi. Thus, it was discovered that reindeer not only tend to avoid water consumption from reservoirs polluted with feces and urine in the presence of an alternative, but also intentionally prefer this method to compensate for the loss of minerals.

Longitudinal Study on Causes of Mortality in Danish Broiler Breeders.

Broiler production is highly dependent on good health in the parent flocks. The so-called normal mortality in these flocks remains to be addressed to further reduce mortality of the breeders and to improve the quality of broilers. The aim of the present study, therefore, was to investigate the etiology of this breeder mortality to map out possible critical periods during production in relation to possible risks of importance to the offspring. Dead birds from four flocks were subjected to postmortem and bacteriologic examination from onset of lay until slaughter (20-60 weeks). Causes of mortality were divided into noninfectious and infectious etiology. The infectious group could be subdivided into suppurative salpingitis/peritonitis caused by Escherichia coli and other infections (e.g., sepsis, endocarditis, and arthritis) mainly caused by Gram-positive cocci. Data analysis showed that 41% of the birds died from noninfectious causes, while 55% died from infectious causes, and 4% had no known cause of death. The prevalence of noninfectious mortality was highest in the youngest birds and lowest in the oldest birds. In contrast, the infectious mortality was lowest in the young birds and highest at the end of production. Within each age group, the prevalence of salpingitis/ peritonitis was 26% in young birds (20-29 weeks) and progressed throughout production to 41% in the oldest birds (≥50 weeks of age). Mortality due to other infections was low at onset of production (12%), peaking at 40-49 weeks of age (25%). Consequently, 40-49 weeks of age is identified as a critical period with regard to causes of mortality, possible vertical transmission of E. coli to the offspring, and increased risk of Gram-positive coccal infections.

Hematological parameters and incubation quality of eggs for different levels of tryptophan in the diet of geese of the parent flock

The aim of the work was comparative study of the effect of various amounts of tryptophan in the diet of the herds geese on changes in the parameters of protein metabolism in the blood, their eggs laying capacity and the incubation quality of the eggs, as well as the elimination of herbs and their preservation. The research was carried out during the 4-month reproductive period (December-March) on the gray Obroshino breed group of geese in the research enterprise (SE). The experimental farm (Myklashiv) of the Myklashiv Institute of Agriculture of the Carpathian region of NAAS (Myklashiv village, Pustomytiv district, Lviv region). For this purpose, 4 groups of geese-analogues by age and live weight were selected. The control group did not receive synthetic tryptophan supplements for feed additives. The level of this amino acid in this group amounted to 0.16 g per 100 g of mixed fodder. To the diet of the geese of 2-, 3-, 4-th experimental group additionally injected, respectively, 0.04; 0.09 and 0.14 grams of synthetic tryptophan per 100 g of mixed fodder. The conducted studies have shown that increasing the level of tryptophan in mixed fodders of geese with respect to the norms in force in Ukraine from 0.16 to 0.25 g due to its synthetic analogue per 100 g of mixed fodder during the oviposition period increases the hemoglobin level in the blood by 0.6 g %, white blood cells – by 10.2%, ammonium nitrogen – by 10.5%, stimulates fertility and improves the quality of incubation eggs. While analyzing productivity indices of geese, it should be noted that they were the highest in the 3rd experimental group receiving an additive of 0.09 grams of synthetic tryptophan per 100 grams of mixed fodder. The isolation of the caterpillars was the highest in the 3rd group and amounted to 79.3%. An important indicator, as the egg mass was the largest in the 3rd experimental group and was 172.7 grams or 3.1 g more than in the 1st control geese group. The analysis, namely width and length, shows that the most optimal egg shape index was found in the 3rd experimental group (1.8% higher than in the control group). The thickness of the shell of eggs in the experimental and control groups did not change significantly. It has been experimentally proved that the optimization of tryptophan levels in the feed grain of the gray Obroshin genera of geese in the reproductive period has a significant effect on the hematological parameters and the incubation quality of the eggs.

ПОКАЗАТЕЛИ ИСПОЛЬЗОВАНИЯ МИНЕРАЛЬНЫХ ВЕЩЕСТВ КУРАМИ-НЕСУШКАМИ ПРИ ВВЕДЕНИИ В РАЦИОН КОРМЛЕНИЯ ЗЕРНА СОРГО КАМЫШЕНСКОЕ-75

The aim of the study is to increase the production efficiency of the hatching eggs by using the Kamyshenskoye-75 sorghum grain in the layer diet. For research, four groups of laying hens were formed from parent stock of 60 ones each (control, experimental-1, experimental-2, experimental-3). The duration of the scientific and economic study was 52 weeks. The layer diet of the control group was provided by the pedigree producer JV «Svetly». In Layer di-et, grain maize was replaced by sorghum: the first group content – 25.0%; the second group – 50.0%; the third group – 100.0%. The conditions of keeping and feeding of laying hens met the requirements of the parent flock of Hisex Brown. On the basis of the conducted studies, it was established that the balance of nitrogen utilization de-pends on the dose of sorghum grain for experimental layer diet. With sorghum grain in a volume of 50.0% in the layer diet, the balance of nitrogen use was 53.14%, which is more than when using grain sorghum 25.0 and 100.0%, and also exceeds the indicator of the control group by 2.06%. The balance of use of calcium by the control group of laying hens is 0.17% less than in the group with 100% grain maize substitution for sorghum in mixed feed. 50.0% sorghum grain use in mixed feed increases phosphorus performance efficiency by 2.36%, lysine amino ac-ids and methionine compared with the control. Grain maize substitution in mixed feed for the layer hen diet for grain sorghum cultivar Kamyshinsky-75 in the amount of 50.0% increases the nutritional value of mineral and availability of amino acids lysine and methionine.

Lupine in diets for broiler parental flock and broiler chicks

Lupine in diets for broiler parental flock and broiler chicks

Assessing the Ability of Maternal Antibodies to Protect Broiler Chicks Against Colonization by Salmonella Heidelberg.

Vaccine regimes and maternal antibody protection are important in ensuring the health of poultry and critically important in decreasing contamination of poultry products with foodborne pathogens that threaten human health. Here, we assessed the role of passive immunity on the resistance of progeny to early colonization when challenged with Salmonella Heidelberg. Two broiler breeder hen flocks which had received a Salmonella vaccine regime consisting of two live attenuated and two killed vaccines during rearing were selected for study. ELISA titers were used to assess antibody levels in the parent flocks, with one low- and one high- titer flock selected for study. Progeny chicks (1 day of age) were taken from each flock and challenged with Salmonella Heidelberg at low (103) or high doses (105) at 3 days of age. At 14 days postinoculation, all birds were euthanatized and their liver, spleen, and ceca collected for culture. ELISA analysis found Flock A (30-wk flock) demonstrated higher Salmonella antibody titers in the parents as well as yolk titers in the progeny, resulting in greater early protection from colonization by Salmonella Heidelberg while Salmonella colonization rates were higher in the progeny of the older parent Flock (B) that demonstrated lower antibody titers in the parents and the yolks of the progeny. These results suggest that as the breeder hens' protective antibodies wane with age; the maternal antibody protection in their progeny also becomes less effective in preventing cecal colonization by Salmonella early in life, which has the potential for affecting the health of the bird and contamination of meat products destined for the consumer.

Sequential DNA immunization of chickens with bivalent heterologous vaccines induce highly reactive and cross-specific antibodies against influenza hemagglutinin

Vaccines against avian influenza are mostly based on hemagglutinin (HA), which is the main antigen of this virus and a target for neutralizing antibodies. Traditional vaccines are known to be poorly efficient against newly emerging strains, which is an increasing worldwide problem for human health and for the poultry industry. As demonstrated by research and clinical data, sequential exposure to divergent influenza HAs can boost induction of universal antibodies which recognize conserved epitopes. In this work, we have performed sequential immunization of laying hens using monovalent or bivalent compositions of DNA vaccines encoding HAs from distant groups 1 and 2 (H5, H1, and H3 subtypes, respectively). This strategy gave promising results, as it led to induction of polyclonal antibodies against HAs from both groups. These polyclonal antibodies showed cross-reactivity between different HA strains in ELISA, especially when bivalent formulations were used for immunization of birds. However, cross-reactivity of antibodies induced against H3 and H5 HA subtypes was rather limited against each other after homologous immunization. Using a cocktail of HA sequences and/or sequential DNA vaccination with different strains presents a good strategy to overcome the limited effectiveness of vaccines and induce broader immunity against avian influenza. Such a strategy could be adapted for vaccinating laying hens or parental flocks of different groups of poultry.

Биологически активные добавки из лиственницы даурской в рационах кур родительского стада кросса «Хайсекс коричневый»

Биологически активные добавки из лиственницы даурской в рационах кур родительского стада кросса «Хайсекс коричневый»

The most important dilemmas regarding the welfare of farm animals

In this review paper, contradictions in modern livestock production as dilemmas of farm animal welfare are considered. The main dilemma concerns the question of whether extensive production in small farms is generally better than intensive production in large farms. The next dilemma relates to an intensive selection of animals and its impact on the emergence of welfare problems. Another dilemma is related to the two main interconnected problems of pig welfare in individual farrowing pens: the piglet death by crushing and the sows? movement restriction. Similarly, welfare dilemma is the paradox of parent flocks of broiler line breeding that could not be solved until the pressure for genetic advancement in production is required due to the economic efficiency. The next example of the dilemma is the widespread practice of tail docking in piglets in order to reduce the risk of tail biting. Although the tail docking is painful and may cause death, anaesthesia is usually not applied on farms. A similar example of the dilemma is debeaking in the laying hens and the occurrence of feather pecking in free rearing systems. It is important to notice the difference between the described dilemmas, where one premise opposes the other, which is essentially a conflict between the animal welfare goals and other values, such as economic, ethical and moral issues. Finally, there are also some dilemmas about the consumers? willingness to pay a higher price of products that originate from welfare friendly rearing conditions.

Characterization of Escherichia coli Isolated from Day-old Chicken Fluff in Taiwanese Hatcheries.

Avian colibacillosis resulting from avian pathogenic Escherichia coli (APEC) seriously disrupts poultry production. Hatcheries are the main source of chickens for commercial farms. To characterize the potential pathogenicity of E. coli strains isolated from hatcheries, 2344 fluff samples from 1-day-old chickens were collected from hatching incubators between October 2016 and November 2017. Among the hatcheries, the incidence of E. coli varied from 0% to 16.9%, with an overall incidence of 2.0%. High incidences reflected inadequate sanitation in some hatcheries. We also compared 20 clinically isolated APEC strains with fluff-originated E. coli in terms of existence of 10 virulence-associated genes (VAGs) and antimicrobial-resistance genes, and antimicrobial resistance using minimum inhibitory concentration (MIC) values. Our results showed that APEC more-frequently possessed most of the assessed VAGs (papC, astA, cvaC, hlyF, fyuA, iroN, iutA, iss, and ompT), suggesting that fluff-originated E. coli is less likely to cause avian colibacillosis. However, fluff-originated E. coli more-frequently expressed the adhesion gene fimC, which could confer higher upper respiratory tract adhesion. Both APEC and fluff-originated E. coli demonstrated multidrug resistance including 100% resistance to ampicillin, amoxicillin, cephalexin, florfenicol, and trimethoprim-sulfamethoxazole. Based on median MIC values, fluff-originated E. coli was more susceptible to antibiotics. However, resistance-gene existence did not significantly differ between groups, suggesting that fluff-originated E. coli should still be a public health concern. Molecular subtyping with XbaI-digested pulsed-field gel electrophoresis revealed that only a few strains showed identical patterns, indicating that a variety of contamination sources were present within individual hatcheries. Identical strains within the same hatchery may indicate vertical transmission from parent flocks. Overall, this is the first study to characterize fluff-originated E. coli. Our results suggest that it has lower pathogenicity than APEC and that thorough sanitation should be performed to reduce the occurrence of fluff-originated E. coli in hatcheries.

ESBL-Producing Klebsiella pneumoniae in the Broiler Production Chain and the First Description of ST3128.

ESBL-producing Klebsiella pneumoniae (K. pneumoniae) represent an increasing problem both in human and veterinary medicine. As SHV-2 - encoding K. pneumoniae were recently detected in the broiler production we were interested in investigating a possible transmission along the broiler production chain and furthermore, in evaluating their possible impact on human health. Therefore, 41 ESBL-producing K. pneumoniae originating from a parent flock, from the hatcherys' environment during the hatching of that parent flocks' chickens, and from an associated fattening flock were investigated on an Illumina Miseq. Whole genome sequences were analyzed concerning their MLST-type, cgMLST-type, genotypic and phenotypic resistance, plasmid profiles and virulence genes. Irrespective of the origin of isolation all investigated isolates were multi-drug resistant, harbored the same ESBL-gene blaSHV−2, shared the same sequence type (ST3128) and displayed 100% similarity in core genome multilocus sequence typing (cgMLST). In addition, in silico plasmid typing found several Inc/Rep types associated with ESBL-plasmids. Summarizing, identical clones of SHV-2—producing K. pneumoniae were detected in different stages of the industrial broiler production in one out of seven investigated broiler chains. This proves the possibility of pseudo-vertical transmission of multi-resistant human pathogens from parent flocks to hatcheries and fattening flocks. Furthermore, the importance of cross-contamination along the production chain was shown. Although the ESBL-producing K. pneumoniae clone detected here in the broiler production has not been associated with clinical settings so far, our findings present a potential public health threat.

Livestock production development in AP Vojvodina

The aim of this paper is to present the effects of breeding program implementation on the development of animal breeding in Vojvodina since 2010. Data from the Main breeding organization (controlled population) and data from the Statistical Office of the Republic of Serbia (total population) were used as a basis for this research. The main breeding organization is the Departmant ofAnimal Science, Faculty of Agriculture, University of Novi Sad that implemented the main breeding programs in cattle, pig, sheep, goat, horse and poultry production. The milk yield in a recorded population of Holstein Friesian and Simmental cows shows evident phenotypic increasing trend as opposed to a population that is not controlled. The results of the selection measures in Vojvodina show that pig breeding has an upward trend and that we have an increasing number of small and medium (family) farms. Interest in sheep and goat production is increasing primarily because of the high demand for products made from sheep meat and goat milk and meat. In the recent decades, Vojvodina has been faced with a decrease in the number of horses. At the same time, there is an increasing interest in sports horses and recreation. According to poultry production results of parental flocks, an increasing tendency was observed in the production of controlled flocks recently, while the number of breeding stock breeders was reduced.

Different Selection Strategies for the Improvement of the Growth Performance and Carcass Traits of Japanese Quails

ABSTRACT The present study evaluated different selection strategies to improve the growth performance and carcass traits of Japanese quails. To this end, 540 Japanese quails previously selected for high body weight at three ages (10, 12 and 14 weeks) from four close-bred flocks (Major, Kaleem, Saadat and Zahid) were subjected to three selection strategies: pedigree-based, mass selection or random-bred (controls). For pedigree-based selection, 108 birds (4 close-bred flocks × 3 age groups × 9 replicates × 1 bird each) with full pedigree and selected for high body weight were used, whereas in mass selection 324 birds (4 close-bred flocks × 3 age groups × 9 replicates × 3 birds each) with high body weight were selected to be the parents of next generation. Random-bred controls included 108 birds (4 close-bred flocks × 3 age groups × 9 replicates × 1bird each) which were not previously submitted to selection. The effects of selection strategies of Japanese quail parents from four close-bred flocks (CBF) at three ages on the performance growth and carcass traits of their progenies were measured. The parent flocks were selected at three ages (10, 12 and 14 weeks) and reared for 20 weeks, and their progenies were reared for four weeks. The progeny of pedigree-based selected parents presented better feed intake (g), body weight gain (g), feed conversion ratio, live and carcass weights (g), and carcass yield. The progeny of 10- and 14-week-old parents showed better growth performance and carcass traits, respectively. Moreover, there was no influence of CBF on growth and carcass traits. It was concluded that pedigree-based selection had pronounced effect on the growth performance and carcass traits of the progeny compared with mass selection and random breeding. It is suggested that parental ages of 10 and 14 weeks of age promote better progeny growth performance and carcass traits.

Dynamics of cefotaxime resistant Escherichia coli in broilers in the first week of life

Extended-spectrum beta-lactamase producing E. coli (ESBL-E) are wide spread among broilers, with the highest prevalence among individual birds at broiler production farms. Previous research describes low prevalences among individual birds at arrival at the farm (below 30%), and a rapid increase up to 100% within the first week. Our goal was to investigate whether this rapid increase was due to latent contamination of ESBL-E or to contamination at the broiler farm. Two broiler groups, one hatched at a conventional hatchery and the other individually hatched in an ESBL-free environment, were housed individually in an experimental ESBL-free environment. A third group was hatched at a conventional hatchery and kept at a conventional broiler farm. The birds were sampled daily during the first week after hatch and tested for the presence of ESBL-E. In addition ESBL-E presence in eggs that were not incubated was investigated. All birds and eggs came from one ESBL-E positive parent flock. ESBL/AmpC genes, plasmids and E. coli sequence types were determined for a selection of isolates. ESBL-E was never found in the two groups kept in the ESBL-free experimental environment or in the sampled eggs, whereas all broilers sampled at the conventional farm became positive for ESBL-E within three days. One dominant E. coli strain (ST88) carrying blaCTX-M-1 gene on an IncI1/pST3 plasmid was found in parent and broiler samples. We conclude that the rapid increase in ESBL-E prevalence in the first week of life is not caused by a latent contamination of the majority of birds at arrival, but that this increase must be caused by other factors.

Environmental adaptation and vertical dissemination of ESBL-/pAmpC-producing Escherichia coli in an integrated broiler production chain in the absence of an antibiotic treatment.

SummaryHigh prevalence numbers of extended‐spectrum beta‐lactamase‐ (ESBL‐)/plasmid‐mediated AmpC beta‐lactamase‐ (pAmpC‐) producing Escherichia coli in broiler chicken and their distribution along the broiler production chain is an ongoing problem in food production. We, therefore, investigated resistant isolates along the broiler production chain to determine whether there is a constantly occurring direct vertical transmission of the ESBL‐/pAmpC‐producing E. coli from the parent flocks to their offspring or not. We, furthermore, analysed the isolates concerning the occurrence of virulence factors and their ability to form biofilms to estimate their potential to effectively colonize broiler chickens and/or persist and survive in the environment of the broiler production facilities. Using whole genome sequencing, we could show that ESBL‐/pAmpC‐producing E. coli were likely transferred in a step‐wise process along the broiler production chain but not directly from the parent flock to the fattening flock with every single batch of offspring chickens. Additionally, resistant E. coli strains showing an extraintestinal pathogenic genotype as well as high numbers of virulence‐associated genes including the production of curli fibres and cellulose have high capabilities to persist and spread in the broiler production chain.

Dietary Hemicell® Improved Reproductive Performance of Broiler Breeders under Commercial Settings

The objective of this work is to study the effect of dietary Hemicell®, a fermentation product that contains high amount of β-mannanase, on performance and health parameters of broiler breeders grown under commercial settings. Twenty six thousand broiler breeders of Ross 308 strain with an average egg production of 35% and 2600 roosters aged 26.5 weeks were used in this study and were subdivided equally into six individual environmentally controlled houses with 4333 hens per house and 10% roosters. Birds in three houses were fed regular diet provided by the Ross Company while those in the remaining three other houses were fed rations containing 250 g of Hemicell® per ton of finished feed for a period of 8.6 months. Hemicell® in breeder diets reduced feed cost and numerically improved number of total and hatching eggs per hen housed. It also increased hatchability by 0.32% during the 8.6 months trial period. Although Hemicell® improved yolk colour, it had no effect on other egg quality parameters such as egg weight and shell thickness. Regarding health parameters, Hemicell® reduced the incidence of pododermatitis in hens and increased the serum titer for NDV towards the end of the trial. Along with the little saving in feed cost, Hemicell® resulted in a gain of around 1.20 US dollar per hen housed. These results indicate that Hemicell® inclusion in the diets of broiler breeders is beneficial to parent flock growers and makes their operations more profitable.

Staphylococcus agnetis, a potential pathogen in broiler breeders

In this study, four broiler parent flocks have been followed from the onset of the production period (week 20) until slaughter (week 60). Every week, approximately ten dead broiler breeders, randomly selected among birds dead on their own, were collected and subjected to a full post mortem analysis including bacteriological examination. In total 997 breeders were investigated and for the first time Staphylococcus agnetis was isolated in pure culture from cases of endocarditis and septicemia from 16 broiler breeders. In addition, the cloacal flora from newly hatched chickens originating from the same four flocks were characterized and S. agnetis was found in pure culture of several newly hatched chickens (n=12) and only in one case in combination with another species. Clonality of the isolates was examined by pulsed-field-gel-electrophoresis which showed indistinguishable patterns in isolates from both broiler breeders and broilers. Three isolates were whole genome sequenced to obtain knowledge on virulence genes. The isolates harbored a number of genes encoding different fibrinogen binding proteins and toxins which might be important for virulence. The present findings demonstrate that S. agnetis may be associated with mortality in broiler breeders. No disease was associated with the broilers which were found positive for S. agnetis in the cloaca.

Longitudinal study of transmission of Escherichia coli from broiler breeders to broilers

Escherichia coli is of major importance in industrial broiler production as the main cause of salpingitis and peritonitis in broiler breeders. Furthermore E. coli is the most common cause of first week mortality in broiler chickens. The aim of the present study was to investigate the transmission of E. coli, isolated from broiler breeders with salpingitis, to the progeny and the possibility of subsequent first week mortality. Four parent flocks were followed during the whole production period (20-60 weeks) by post mortem and bacteriological examination of randomly selected dead birds. Newly hatched chickens from each flock were swabbed in the cloaca on four occasions (parent age 30, 40, 50, 60 weeks) and E. coli was isolated. Causes of first week mortality were determined pathologically and bacteriologically. E. coli isolates from parents, newly hatched chickens and first week mortality were selected for Pulsed-Field-Gel-Electrophoresis (PFGE) and Multi-Locus-Sequence-Typing (MLST) to determine their clonal relationships. E. coli was the main cause of both salpingitis in parents and first week mortality in broilers, and E. coli dominated the bacterial flora of the cloaca of newly hatched chickens. PFGE of E. coli showed identical band patterns in isolates from the three different sources indicating a transmission of E. coli from parent birds to chickens. In conclusion, E. coli isolated from salpingitis in broiler parents were found to be transmitted to broilers in which some sequence types contributed to the first week mortality.

The first serological investigation of Chicken astrovirus infection in China

Chicken astrovirus (CAstV) is associated with ‘white chick’ syndrome, which increases embryo mortality and reduces hatchability in chickens. In the present study, 1760 sera were collected from 21 provinces in China to detect antibodies directed against CAstV with an ELISA. The sera were from different varieties of chicken in 85 flocks and all the flocks produced positive reactions. The overall seroprevalence in the birds tested was 60.68%. The prevalence increased from 34.17% to 74.44% with the increase of age. The positivity rates in layer flocks, layer parent flocks, broiler flocks, broiler parent flocks, and domestic chicken flocks were 70.17%, 89.00%, 31.67%, 59.05%, and 45.79%, respectively. These data indicate that CAstV infections are very common in China. This is the first report of the seroprevalence of CAstV infections in China.