Risk factors for poor health and performance in European broiler production systems

Background Conventional broilers are currently one of the most efficient protein converters. Although decades of progress in genetic selection and feed formulation have lead to high standards of efficient broiler production, still a lot of variability is found between farms and between successive flocks. The aim of this study was to investigate risk- and/or protective factors for poor health and performance in conventional broiler-farms in Europe by developing eight multivariable linear mixed models. Three different models were used to investigate mortality (overall, first week, after first week), three models for performance variables (growth, feed conversion, European production index) and two models were related to slaughterhouse data (i.e. dead on arrival and condemnation rate). Results Several factors related to management and housing were significantly associated with health and performance of broilers. The following factors were associated with increased mortality: floor quality, neonatal septicemia, ventilation type and other professional activities of the farmer. The factors associated with performance were chick sex, coccidiosis infections, necrotic enteritis, dysbacteriosis, light intensity adaptations, ventilation type, comparing daily flock results with previous flock results by farmer, daily check of feed and water system and type of feed. For dead on arrival three risk factors were identified i.e. daily growth, type of light adaptation and type of drinkers system. For condemnation rate seven risk factors were found, i.e. type of drinking system, daily growth, feed withdrawal time, type of ventilation, house size, septicemia after seven days and type of feed. Conclusions These results imply that a multifactorial approach is required with adaptations involving both improvements in management, housing, health programs and an increasing level of professionalism of the farmer in order to improve broiler performance and health

Central nervous system syndrome associated with Marek’s disease in Hubbard broilers = Syndroom van het centrale zenuwstelsel geassocieerd met de ziekte van Marek bij hubbard-vleeskuikens

Marek’s disease (MD) has a high economic impact in poultry production worldwide. MD consists of several pathologic syndromes of which the most commonly encountered are lymphoproliferative syndromes such as acute MD. Sporadically, MD leads to central nervous system syndromes characterized by non-neoplastic brain pathology. In this case report, an onset of neurological signs on two different broiler farms, housing ‘slow-growing’ Hubbard JA 757 broilers, is described. On the first farm, clinical signs were observed from 42 days of age onwards and on the second farm, respectively from 42 (stable 1) and 30 days (stable 2) of age onwards. The neurological symptoms consisted of acute central nervous system signs, which started with flaccid neck paralysis. Histopathological examination revealed multifocal perivascular cuffing of CD3 positive mononuclear cells in the brain tissues. These findings pointed towards the development of transient paralysis. qPCR analysis confirmed the diagnosis. In broiler flocks, which only have a limited life span, vaccination is not common practice. In flocks of slow-growing breeds, outbreaks of MD might become more important again. Therefore, vaccination of slow-growing broilers against MD seems recommended

Incidence and associated risk factors of necrotic enteritis in Belgian layer pullet flocks

Necrotic enteritis (NE) caused byClostridium perfringensis commonly reported in broilers. Recently, increased NE prevalence in layer breeds was reported in the Indian subcontinent. NE is also frequently observed by veterinary practitioners in Europe, mainly during the pullet rearing phase. In this study, data from layer pullet flocks in Belgium over a 5-year period (2013-2017) were used to assess the incidence of NE and identify potential risk factors for NE in layer pullets. NE was observed in 26% of the layer pullet flocks receiving veterinary intervention. This accounts for an overall estimated NE incidence of 12.3% in Belgian layer pullet flocks. Occurrence of NE was significantly associated with coccidiosis, with flocks being diagnosed with coccidiosis being two-fold more likely to develop NE. Additionally, birds kept in aviary houses were less prone to NE than flocks reared in floor systems or enriched cages. At necropsy, necrotic lesions in the small intestine were comparable to NE in broilers. A single strain ofC. perfringenswas isolated from the necrotic lesions of three different birds from the same flock; however, no NetB could be detected

Bacterial chondronecrosis with osteomyelitis related Enterococcus cecorum isolates are genetically distinct from the commensal population and are more virulent in an embryo mortality model

AbstractBacterial chondronecrosis with osteomyelitis (BCO) is a common cause of broiler lameness. Bacteria that are found in BCO lesions are intestinal bacteria that are proposed to have translocated through the intestinal epithelium and have spread systemically. One of the specific bacterial species frequently isolated in BCO cases is Enterococcus cecorum. In the current study, caecal isolates were obtained from birds derived from healthy flocks (12 isolates from 6 flocks), while isolates derived from caeca, colon, pericardium, caudal thoracic vertebrae, coxo-femoral joint, knee joint and intertarsal joint (hock) were obtained from broilers derived from BCO outbreaks (111 isolates from 10 flocks). Pulsed field gel electrophoresis was performed to determine similarity. Clonal E. cecorum populations were isolated from different bones/joints and pericardium from animals within the same flock, with intestinal strains carrying the same pulsotype, pointing to the intestinal origin of the systemically present bacteria. Isolates from the intestinal tract of birds from healthy flocks clustered away from the BCO strains. Isolates from the gut, bones/joints and pericardium of affected animals contained a set of genes that were absent in isolates from the gut of healthy animals, such as genes encoding for enterococcal polysaccharide antigens (epa genes), cell wall structural components and nutrient transporters. Isolates derived from the affected birds induced a significant higher mortality in the embryo mortality model as compared to the isolates from the gut of healthy birds, pointing to an increased virulence.</jats:p

A case of clubbed down syndrome in broilers

This study presents a case of clubbed down syndrome in conventional broilers. During the first week of life, severe growth retardation was observed in approximately 25% of the flock. The growth-retarded chicks weighed only 45 g and showed a typical feather disorder which was most apparent on their abdomen and was defined in literature as typical for clubbed down syndrome. Necropsies, histology, biochemical analysis of blood and liver samples, serology and different PCR tests were performed in broilers to assess the aetiology of the clinical signs that were present in the affected broiler farm. Because of the suspicion of a possible link with the broiler-breeder farms, different investigations including serology, PCR and feed analysis were also performed on these farms. The results suggest that an accidentally excessive amount of calcium and iron in the feed of broiler-breeders, 3 weeks prior to first clinical signs in broilers, led to the development of clubbed down in the offspring, because of a relative Zn-deficiency in broiler-breeders and an absolute Zn-deficiency in the hatching eggs that were produced during this period. This appeared to be a reversible process as no clinical signs were observed in younger offspring of these broiler-breeders after they had consumed more of the new batch of feed. A potential involvement of Astrovirus could not be completely ruled out. This study demonstrates the importance of correct mineral concentrations in broiler-breeder feed and the impact it can have on the development of the offspring